Regulatory Guide 1.59: Difference between revisions

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{{Adams
{{Adams
| number = ML13350A359
| number = ML13038A102
| issue date = 08/31/1973
| issue date = 04/30/1976
| title = Design Basis Floods for Nuclear Power Plants
| title = Design Basis Floods for Nuclear Power Plants
| author name =  
| author name =  
| author affiliation = US Atomic Energy Commission (AEC)
| author affiliation = NRC/RES, NRC/OSD
| addressee name =  
| addressee name =  
| addressee affiliation =  
| addressee affiliation =  
Line 10: Line 10:
| license number =  
| license number =  
| contact person =  
| contact person =  
| document report number = RG-1.059
| document report number = RG-1.059, Rev. 1
| document type = Regulatory Guide
| document type = Regulatory Guide
| page count = 16
| page count = 80
}}
}}
{{#Wiki_filter:1973 August at.
{{#Wiki_filter:Revision 1 U.S. NUCLEAR REGULATORY COMMISSION                                                                                                                    April 1976 REGULATORY GUIDE
OFFICE OF STANDARDS DEVELOPMENT
                                                            DESIGN
                                                        NUCLEAR                                  PLANTS
                                      iA~
                                      5,,.
                    .1 USNRC REGULATORY GUIDES                                        Comments should be sent to the Secretary of the Commission. U S. Nuclear Regulatory Guides are issued to describe and make available to the public              Regulatory Commission. Washington. D C 2055o. Attention Docketing and methods acceptable to the NRC staff of implementing specific parts of the Commission's regulations, to delineate techniques used by the staff in evalu          The guides are issued in the following ten broad divisions"
ating specific problems or postulated accidents, or to provide guidance to appli cants. Regulatory Guides are not substitutes for regulations, and compliance          t  Power Reactors                      6. Products with them is not required Methods and solutions different from those set out in        2. Research and Test Reactors          7. Transportation the guides wdi be acceptable if they provide a basis for the findings requisite to    3  Fuels and Materials Facilities      8  Occupational Health the issuance or continuance u Ia permit or license by the Commission                  4  Environmental and Siting            9. Antitrust Review Comments and suggestions for improvenments in these guides are encouraged              5  Materials and Plant Protection      10  General at all times, and guides will lbe revised. as appropriate, to accommodate coa ments and to reflect new intormatn or eyperience However. comments on                  Copies of published guides may be obtained by written request indicating the this guide. if received within about Iwo months after its issuance, will be par        divisions desired to the U S Nuclear Regulatory Commission. Washington. D.C
  -culariyuseful in evaluating the need for an early revision                          20655. Attention: Director. Office of Standards Development r'11 cx)--,7'-0" C."
                                                                                              66F(I
                                                                                    I


August 1973 U.S. ATOMIC ENERGY COMMISSION
TABLE OF CONTENTS
                                      REGULATORY
                                                                                                                            Page A . IN TRO DUCTIO N            . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .                        .59-5
                                      DIRE"W"TORATE OF REGULATORY STANDARDS
 
                                                                                                                                  GUIDE
==B. DISCUSSION==
                                                                      REGULATORY GUIDE 1.59 DESIGN BASIS FLOODS FOR NUCLEAR POWER PLANTS
..........................                              .........................                                595
 
==C. REGULATORY POSITION==
.......................                      .................................                      59-7
 
==D. IMPLEMENTATION==
.........................                  ....................................                      .59-8 APPENDIX A - Probable Maximum and Seismically Induced Floods on Streams .....                            .............    .59-9 APPENDIX B - Alternative Methods of Estimating Probable Maximum Floods .......                                .............    .59-23 *
APPENDIX C - Simplified Methods of Estimating Probable Maximum Surges .......                            ..............      .59-53
'LTines indicate substantive changes from previous issue.
 
1.59-3


==A. INTRODUCTION==
==A. INTRODUCTION==
TlThis guide describes a1n acceplahl'                    ntl lhod (it determinirng fOr siles aloi*g strealis tit riveis ilie design General Design Criterion 2. "-Design Bases for                                basis floods that nuclear power plants maust lie designed Protection Against Natural Phenomentia." of Appendix A                              to withstand without loss of saltety-related functions. It to 10 CFR Part 50. **General Design Criteria for Nuclear                            further discusses tlie phenomlena producing colmpar*able Power Plants." requires. in part. that structures. systems.                        design basis floods for coastal. estuary; and Gieat Lakes and components important to safety be designed to                                  sites. It does not discuss the design requirements for withstand the effects of natural phenomena such as                                  flood protection. The Advisory Committee on Reactor floods, tsunami. and seiches without loss of capability to                        Safeguards has been consulted concerning this guide and perform their safety functions. Criterion 2 also requires                          has concurred in the regulatory position.


that the design bases for these structures, systems. and components reflect: (I) appropriate consideration of the most severe of tihe natural phenomena that have been                                                            
==B. DISCUSSION==
General Design Criterion 2, "Design Bases for Pro-                Nuclear power plants should be designed to prevent tection Against Natural Phenomena," of Appendix A to            the loss of capability for cold shutdown and mainten-
  10 CFR Part 50, "General Design Criteria for Nuclear            ance thereof resulting from the most severe flood Power Plants," requires, in part, that structures, systems,    conditions that can reasonably be predicted to occur at a and components important to safety be designed to              site as a result of severe hydrometeorological conditions, withstand the effects of natural phenomena such as              seismic activity, or both.
 
floods, tsunami, and seiches without loss of capability to The Corps of Engineers for many years has studied perform their safety functions. Criterion 2 also requires that design bases for these structures, systems, and            conditions and circumstances relating to floods and components reflect (1) appropriate consideration of the        flood control. As a result of these studies, it has developed a definition for a Probable Maximum Flood most severe of the natural phenomena that have been (PMF)' and attendant analytical techniques for esti- historically reported for the site and surrounding region, mating, with an acceptable degree of conservatism, flood with sufficient margin for the limited accuracy and levels on streams resulting from hydrometeorological quantity of the historical data and the period of time in conditions. For estimating seismically induced flood which the data have been accumulated, (2) appropriate levels, an acceptable degree of conservatism for evalua- combinations of the effects of normal and accident ting the effects of the initiating event is provided by conditions with the effects of the natural phenomena, Appendix A to 10 CFR Part 100.
 
and (3) the importance of the safety functions to be performed.                                                          The conditions resulting from the worst site-related flood probable at the nuclear power plant (e.g., PMF,
      Paragraph 100.10(c) of 10 CFR Part 100, "Reactor            seismically induced flood, seiche, surge, severe local Site Criteria," requires that physical characteristics of      precipitation) with attendant wind-generated wave activ- the site, including seismology, meteorology, geology,          ity constitute the design basis flood conditions that and hydrology, be taken into account in determining the        safety-related structures, systems, and components iden- acceptability of a site for a nuclear power reactor.            tified in Regulatory Guide 1.292 should be designed to withstand and retain capability for cold shutdown and Section IV(c) of Appendix A, "Seismic and Geologic          maintenance thereof.
 
'* Siting Criteria for Nuclear Power Plants," to 10 CFR
  Part 100 suggests investigations for a detailed study of            For sites along streams, the PMF generally provides seismically induced floods and water waves. The ap-            the design basis flood. For sites along lakes or seashores, pendix also suggests [Section IV(c)(iii)] that the deter-      a flood condition of comparable severity could be mination of design bases for seismically induced floods          'Corps of Engineers' Probable Maximum Flood definition ap- and water waves be based on the results of the required            pears in many publications of that agency such as Engineering geologic and seismic investigations and that these design          Circular EC 1110-2-27, Change 1, "Engineering and Design- bases be taken into account in the design of the nuclear          Policies and Procedures Pertaining to Determination of Spill- power plant.                                                      way Capacities and Freeboard Allowances for Dams," dated 19 Feb. 1968. The Probable Maximum Flood is also directly analogous to the Corps of Engineers' "Spillway Design Flood"
                                                                    as used for dams whose failures would result in a significant This guide discusses the design basis floods that              loss of life and property.
 
nuclear power plants should be. designed to withstand          2Regulatory Guide 1.29, "Seismic Design Classification,"
    without loss of capability for cold shutdown and                  identifies structures, systems, and components of light-water- maintenance thereof. The design requirements for flood            cooled nuclear power plants that should be designed to protection are the subject of Regulatory Guide 1.102              withstand the effects of the Safe Shutdown Earthquake and
    "Flood Protection for Nuclear Power Plants."                      remain functional. These structures, systems, and components are those necessary to ensure (1) the integrity of the reactor coolant pressure boundary, (2) the capability to shut down the reactor and maintain it in a safe shutdown condition, or (3) the Appendix A outlines the nature and scope of detailed          capability to prevent or mitigate the consequences of accidents hydrologic engineering activities involved in determining        which could result in potential offsite exposures comparable to estimates for the probable maximum flood and for                  the guideline exposures of 10 CFR Part 100. These same seismically induced floods resulting from dam failures            structures, systems, and components should also be designed to withstand conditions resulting from the design basis flood and and describes the situations for which less extensive            retain capability for cold shutdown and maintenance thereof of analyses are acceptable. Two new appendices have been            other types of nuclear power plants. It is expected that added to this revision of the guide. Appendix B gives            safety-related structures, systems, and components of other timesaving alternative methods of estimating the prob-            types of nuclear power plants will be identified in future regulatory guides. In the interim, Regulatory Guide 1.29 should able maximum flood along streams and Appendix C                  'be used as guidance when identifying safety-related structures, gives a simplified method of estimating probable maxi-            systems, and components of other types of nuclear power mum surges on the Atlantic and Gulf coasts.                      plants.
 
1.59-5
 
produced by the most severe combination of hydro-                      waves that may be caused by multiple dam failures in a meteorological parameters reasonably possible, such as3                region where dams may be located close enough together may be produced by a Probable Maximum Hurricane,                      that a single seismic event can cause multiple failures.
 
or by a Probable Maximum Seiche. On estuaries, a Probable Maximum River Flood, a Probable Maximum                            Each of the severe flood types discussed above should Surge, a Probable Maximum Seiche, or a reasonable                      represent the upper limit of all potential phenomeno- combination of less severe phenomenologically caused                  logically caused flood combinations considered reason- flooding events should be considered in arriving at design            ably possible. Analytical techniques are available and basis flood conditions comparable in frequency of                      should generally be used for prediction at individual occurrence with a PMF on streams.                                      sites. Those techniques applicable to PMF and seismi- cally induced flood estimates on streams are presented in In addition to floods produced by severe hydro-                    Appendices A and B to this guide. Similar appendices for meteorological conditions, the most severe seismically                coastal, estuary, and Great Lakes sites, reflecting com- induced floods reasonably possible should be considered                parable levels of risk, will be issued as they become for each site. Along streams and estuaries, seismically                available. Appendix C contains an acceptable method of induced floods may be produced by dam failures or                      estimating hurricane-induced surge levels on the open landslides. Along lakeshores, coastlines, and estuaries,              coasts of the Gulf of Mexico and the Atlantic Ocean.
 
seismically induced or tsunami-type flooding shoUld be considered. Consideration of seismically induced floods                    Analyses of only the most severe flood conditions should include the same range of seismic events as is                  may not indicate potential threats to safety-related postulated for the design of the nuclear plant. For                    systems that might result from combinations of flood instance, the analysis of floods caused by dam failures,              conditions thought to be less severe. Therefore, reason- landslides, or tsunami requires consideration of seismic              able combinations of less-severe flood conditions should events of the severity of the Safe Shutdown Earthquake                also be considered to the extent needed for a consistent occurring at the location that would produce the worst                level of conservatism. Such combinations should be such flood at the nuclear power plant site. In the case of            evaluated in cases where the probability of their existing seismically induced floods along rivers, lakes, and es-                at the same time and having significant consequences is tuaries which may be produced by events less severe                    at least comparable to. that associated with the most than a Safe Shutdown Earthquake, consideration should                  severe hydrometeorological or seismically induced flood.
 
be given to the coincident occurrence of floods due to                For example, a failure of relatively high levees adjacent          (
severe hydrometeorological conditions, but only where                  to a plant could occur during floods less severe than the the effects on the plant are worse than and the                        worst site-related flood, but would produce conditions probability of such combined events may be greater than                more severe than would result during a greater flood an individual occurrence of the most severe event of                  (where a levee failure elsewhere would produce less either type. For example, a seismically induced flood                  severe conditions at the plant site).
produced by an Operating Basis Earthquake (as defined in Appendix A to 10 CFR Part 100) coincident with a                        Wind-generated wave activity may produce severe runoff-type flood of Standard Project Flood4 severity                  flood-induced static and dynamic conditions either may be considered to have approximately the same                      independent of or coincident with severe hydrometeoro- severity as the seismically induced flood from an                      logical or seismic flood-producing mechanisms. For earthquake of Safe Shutdown severity coincident with                  example, along a lake, reservoir, river, or seashore, about a 25-year flood. For the specific case of seismi-                reasonably severe wave action should be considered cally induced floods due to dam failures, an evaluation              coincident with the probable maximum water level should be made of flood waves that may be caused by                    conditions.5 The coincidence of wave activity with domino-type dam failures triggered by a seismically                    probable maximum water level conditions should take induced failure of a critically located dam and of flood              into account the fact that sufficient time can elapse between the occurrence of the assumed meteorological mechanism and the maximum water level to allow See References 2 and 4, Appendix C.
 
4 The Standard Project Flood (SPF) is the flood resulting from        'Probable Maximum Water Level is defined by the Corps of the most severe flood-producing rainfall depth-area-duration          Engineers as "the maximum still water level (i.e., exclusive of relationship and isohyetal pattern of any storm that is                local coincident wave runup) which can be produced by the considered reasonably characteristic of the region in which the        most severe combination of hydrometeorological and/or watershed is located. If snowmelt may be substantial, appropri-        seismic parameters reasonably possible for a particular location.
 
ate amounts are included with the Standard Project Storm              Such phenomena are hurricanes, moving squall lines, other rainfall. Where floods are predominantly caused by snowmelt,          cyclonic meteorological events, tsunami, etc., which, when the SPF is based on critical combinations of snow, temperature,        combined with the physical response of a body of water and and water losses. See "Standard Project Flood Determina-              severe ambient hydrological conditions, would produce a still tions," EM 1110-2-1411, Corps of Engineers, Departrlhent of            water level that has virtually no risk of being exceeded." (See the Army (revised March 1965).                                        Appendix A to this guide.)
                                                                  1.59-6
 
subsequent meteorological activity to produce sub-                  establishing the design basis flood. A simplified analyti- stantial wind-generated waves coincident with the high              cal technique for evaluating the hydrologic effects of water level. In addition, the most severe wave activity at          seismically induced dam failures discussed herein is the site that can be generated by distant hydrometeoro-            presented in Appendix A of this guide. Techniques for logical activity should be considered. For instance,                evaluating the effects of tsunami will also be presented coastal locations may be subjected to severe wave action            in a future appendix.
 
caused by a distant storm that, although not as severe as a local storm (e.g., a Probable Maximum Hurricane),                        d. Where upstream dams or other features which may produce more severe wave action because of a very              provide flood protection are present, in addition to the long wave-generating fetch. The most severe wave                    analyses of the most severe floods that may be induced activity at the site that may be generated by conditions            by either hydrometeorological or seismic mechanisms, at a distance from the site should be considered in such            reasonable combinations of less-severe flood conditions cases. In addition, assurance should be provided that              and seismic events should also be considered to the safety systems necessary for cold shutdown and main-                extent needed for a consistent level of conservatism. The tenance thereof are designed to withstand the static and            effect of such combinations on the flood conditions at dynamic effects resulting from frequent flood levels (i.e.,        the plant site should be evaluated in cases where the the maximum operating level in reservoirs and the                  probability of such combinations occurring at the same
10-year flood level in streams) coincident with the waves          time and having significant consequences is at least that would be produced by the Probable Maximum                      comparable to the probability associated with the most Gradient Wind 6 for the site (based on a study of                    severe hydrometeorological or seismically induced flood.
 
historical regional meteorology).                                    On relatively large streams, examples of acceptable combinations of runoff floods and seismic events that
 
==C. REGULATORY POSITION==
could affect the flood conditions at the plant include the Safe Shutdown Earthquake with the 25-year flood and
    1. The conditions resulting from the worst site-re-            the Operating Basis Earthquake with the Standard lated flood probable at a nuclear power plant (e.g., PMF,            Project Flood. Less severe flood conditions, associated seismically induced flood, hurricane,. seiche, surge, heavy          with the above seismic events, may be acceptable for local precipitation.) with attendant wind-generated wave            small streams which exhibit relatively short periods of activity constitute the design basis flood conditions that          flooding. The above combinations of independent events safety-related structures, systems, and components iden-            are specified here only with respect to the determination            fI
tified in Regulatory Guide 1.29 (see footnote 2) must be            of the design basis flood level.
 
designed to withstand and retain capability for cold shutdown and maintenance thereof.                                            e. The effects of coincident wind-generated wave activity to the water levels associated with the worst a. On streams the PMF, as defined by the Corps of            site-related flood possible (as determined from para- Engineers and based on the analytical techniques sum-              graphs a, b, c, or d above) should be added to generally marized in Appendices A and B of this guide, provides                define the upper limit of flood . potential. An an acceptable level of conservatism for estimating flood            acceptable analytical basis for wind-generated wave levels caused by severe hydrometeorological conditions.              activity coincident with probable maximum water levels is the assumption of a 40-mph overland wind from the b. Along lakeshores, coastlines, and estuaries.              most critical wind-wave-producing direction. However, if estimates of flood levels resulting from severe surges,            historical windstorm data substantiate that the 40-mph seiches, and wave action caused by hydrometeorological              event, including wind direction and speed, is more activity should be based on criteria comparable in                  extreme than has occurred regionally, historical data conservatism to those used for Probable -Maximum                    may be used. If the mechanism producing the maximum Floods. Criteria and analytical techniques providing this          water level, such as a hurricane, would itself produce level of conservatism for the analysis of these events will        higher waves, these higher waves should be used as the be summarized in subsequent appendices to this guide.              design basis.
 
Appendix C of this guide presents an acceptable method for estimating the stillwater level of the Probable                    2. As an alternative to designing hardened protec- Maximum Surge from hurricanes at open-coast sites on                tion 7 for all safety-related structures, systems, and the Atlantic Ocean and Gulf of Mexico.                              components as specified in Regulatory Position 1 above, c. Flood conditions that could be caused by dam              "Hardened protection means structural provisions incorporated in the plant design that will protect safety-related structures, failures from earthquakes should also be considered in                systems, and components from the static and dynamic effects of floods. In addition, each component of the protection must
6                                                                    be passive and in place, as it is to be used for flood protection, Probable Maximum Gradient Wind is defined as a gradient wind        during normal plant operation. Examples of the types of flood of a designated duration, which there is virtually no risk of      protection to be provided for nuclear power plants are exceeding.                                                          contained in Regulatory Guide 1.102.
 
1.59-7
 
it is permissible not to provide hardened protection for                effects of the increased flood. The following should be some of these features if:                                              reported: 9 a. The type of investigation undertaken to a. Sufficient warning time is shown to be available            identify changed or changing conditions in the site to shut the plant down and implement adequate                          environs.
 
emergency procedures;
                                                                                  b. The changed or changing conditions noted during the investigation.
 
b. All safety-related structures, systems, and com-                    c. The hydrologic engineering bases for estimating ponents identified in Regulatory Guide 1..29 (see foot- the effects of the changed conditions on the design basis note 2) are designed to withstand the flood conditions
                                                  8                      flood.
 
I resulting from a Standard Project event with attendant wind-generated      wave  activity  that  may  be produced by d. Safety-related structures, systems, or com- the worst winds of record and remain functional;
                                                                          ponents (identified in paragraph 2.b above) affected by the changed conditions in the design basis flood should be identified along with modifications to the plant c. In addition to the analyses in paragraph 2.b                facility necessary to afford protection during the in- above, reasonable combinations of less-severe flood                    creased flood conditions. If emergency operating pro- conditions are also considered to the extent needed for a              cedures must be used to mitigate the effects of these consistent level of conservatism; and                                  new flood conditions, the emergency procedures devel- oped or modifications to existing procedures should be provided.
 
d. In addition to paragraph 2.b above, at least those structures, systems, and components necessary for                    4. Proper utilization of the data and procedures in cold shutdown and maintenance thereof are designed                      Appendices B and C will result in PMF peak discharges with hardened protective features to remain functional                  and PMS peak stillwater levels which will in many cases while withstanding the entire range of flood conditions                be approved by the NRC staff with no further verifica- up to and including the worst site-related flood probable              tion. The staff will continue to accept for review (e.g., PMF, seismically induced flood, hurricane, surge.                detailed PMF and PMS analyses that result in less conservative estimates than those obtained by use of
                                                                                                                                            ( _4 seiche, heavy local precipitation) with coincident wind- generated wave action as discussed in Regulatory Posi-                Appendices B and C. In addition, previously reviewed tion I above.                                                          and approved detailed PMF and PMS analyses will continue to be acceptable even though the data and procedures in Appendices B and C result in more
      3. During the economic life of a nuclear power plant,              conservative estimates.
 
unanticipated changes to the site environs which may
 
==D. IMPLEMENTATION==
affect the flood-producing characteristics of the environs are possible. Examples include construction of a dam                      The purpose of this section is to provide information upstream or downstream of the plant, or comparably,                    to license applicants and licensees regardirng the NRC
  construction of a highway or railroad bridge and                      staff's plans for using this regulatory guide.
 
embankment that obstructs the flood flow of a river, and construction of a harbor or deepening of an existing                  This guide reflects current NRC practice. Therefore, harbor near a coastal or lake site plant.                              except in those cases in which the applicant or licensee proposes an acceptable alternative method for comply- ing with specified portions of the Commission's regula- Significant changes in the runoff or other flood-                  tions, the method described herein is being and will producing characteristics of the site environs, as they                continue to be used in the evaluation of submittals for affect the design basis flood, should be identified and                construction permit applications until this guide is used as the basis to develop or modify emergency                      revised as a result of suggestiQns from the public or operating procedures, if necessary, to mitigate the                    additional staff review.
 
8 For sites along streams, this event is characterized by the Corps    9 of Engineers' definition of a Standard Project Flood. (Also, see      Reporting should be by special report to the appropriate NRC
    footnote 4.) Such floods have been found to produce flow rates        Regional Office and to the Director of the Office of Inspection generally 40 to 60 percent of the PMF. For sites along                and Enforcement. Requirement for such reports should be seashores, this event may be characterized by the Corps of            included in theTechnical Specifications (Appendix A) unless it Engineers' definition of a Standard Project Hurricane. For            can be demonstrated that such reports will not be necessary other sites, a comparable level of risk should be assumed.            during the life of the plant.
 
1.59-8
 
APPENDIX A
                            PROBABLE MAXIMUM AND SEISMICALLY INDUCED
                                                    FLOODS ON STREAMS
                                                        TABLE OF CONTENTS
                                                                                                                                  Page A. 1  Introduction .........            ......................                                                                    1.59-11 A. 2  Probable Maximum Flood        ................                                                                              1.59-11 A. 3  Hydrologic Characteristics    . . . . . . . . . . . . . . . .                                                                1.59-12 A. 4  Flood Hydrograph Analyses          ...............                                                                          1.59-13 A. 5  Precipitation Losses and Base Flow            ............                                                                  1.59-13 A. 6  Runoff M odel      . . . . . . . . . . . . .. . .. . . . .                                                                  1.59-14 A. 7  Probable Maximum Precipitation Estimates .........                                                                          1.59-15 A. 8  Channel and Reservoir Routing ..............                                                                                1.59-17 A. 9  Probable Maximum Flood Hydrograph Estimates ..........                                                                      1.59-17 A.1O  Seismically Induced Floods .....              .................                          . . . . . . . . . . . . . . . . 1.59-18 A.] I Water Level Determinations        .....              . ....            ....            . . . . . . . . . . . . . . . . . 1.59-18 A.12  Coincident Wind-Wave Activity ..............                                              . . . . . . . . . . . . . . . . 1.59-19 REFERENCES ...................                          .....................................                              ...1.59-20
                                                                        1.59-9
 
(I
                  A.1 INTRODUCTION                                  Three exceptions to use of the above-described analyses are considered acceptable as follows:
      This appendix has been prepared to provide guidance for flood analyses required in support of applications for          a. No flood analysis is required for nuclear facility licenses for nuclear facilities to be located on streams.      sites where it is obvious that a PMF or seismically Because of the depth and diversity of presently available      induced flood has no bearing. Examples of such sites are techniques, this appendix summarizes acceptable                coastal locations (where it is obvious that surges, wave methods for estimating Probable Maximum Precipitation          action, or tsunami would produce controlling water (PMP), for developing rainfall-runoff models, for analyz-      levels and flood conditions) and hilltop or "dry" sites.
 
ing seismically induced dam failures, and for estimating the resulting water levels.                                        b. Where PMF or seismically induced flood estimates of a quality comparable to that indicated herein exist for The Probable Maximum Flood (PMF) may be                    locations near the site of the nuclear facility, the estimates may be extrapolated directly to the site if such thought of as one generated by precipitation and a extrapolations do not introduce potential errors of more seismically induced flood as one caused by dam failure.
 
than about a foot in design basis water level estimates.
 
For many sites, however, these two types do not (See Appendix B.)
  constitute the worst potential flood danger to the safety of the nuclear facilities. Subsequent appendices will present acceptable methods of analyzing other flood                c. It is recognized that an in-depth PMF estimate types, such as tsunami, seiches, and surges (in addition      may not be warranted because of the inherent capability to the surge method in Appendix C).                            of the design of some nuclear facilities to function safely with little or no special provisions or because the time and costs of making such an estimate are not com- The PMF on streams is compared with the upper limit        mensurate with the cost of providing protection. In such of flood potential that may be caused by other                  cases, other means of estimating design basis floods are phenomena to develop a basis for the design of acceptable if it can be demonstrated that the technique safety-related structures and systems. This appendix            utilized or the estimate itself is conservative. Similarly, outlines the nature and scope of detail.ed hydrologic          conservative estimates of seismically induced flood engineering activities involved in determining estimates        potential may provide adequate demonstration of for the PMF and for seismically induced floods resulting      nuclear facility safety.
 
-- rom dam failures and describes the situations fdr which less extensive analyses are acceptable.                                  A.2 PROBABLE MAXIMUM FLOOD
      Estimation of the PMF requires the determination of            Probable Maximum Flood studies should be com- the hydrologic response (losses, base flow, routing, and        patible with the specific definitions and criteria sum- runoff model) of watersheds to intense rainfall, verifica-    marized as follows:
  tion based on historical storm and runoff data (flood hydrograph analysis), the most severe precipitation                a. The Corps of Engineers defines the PMF as "the reasonably possible (PMP), minimum losses, maximum            hypothetical flood characteristics (peak discharge, base flow, channel and reservoir routing, the adequacy        volume, and hydrograph shape) that are considered to be of existing and proposed river control structures to          the most severe reasonably possible at a particular safely pass a PMF, water level determinations, and the        location, based on relatively comprehensive hydro- superposition of potential wind-generated wave activity.      meteorological analysis of critical runoff-producing pre- Seismically induced floods, such as may be produced by        cipitation (and snowmelt, if pertinent) and hydrologic dam failures or landslides, may be analytically evaluated      factors favorable for maximum flood runoff." Detailed using many PMF estimating components (e.g., routing            PMF determinations are usually prepared by estimating techniques, water level determinations) after conserva-        the areal distribution of PMP (defined below) over the tive assumptions of flood wave initiation (such as dam        subject drainage basin in critical periods of time and failures) have been made. Each potential flood com-            computing the residual runoff hydrograph likely to ponent requires an in-depth analysis. The basic data and      result with critical coincident conditions of ground results should be evaluated to ensure that the PMF            wetness and related factors. PMF estimates are usually estimate is conservative. In addition, the flood potential    based on the observed and deduced characteristics of from seismically induced causes should be compared            historical flood-producing stormsý Associated hydrologic with the PMF to ensure selection of the appropriate           factors are modified on the basis of hydrometeorological design basis flood. The seismically induced flood poten-      analyses to represent the most severe runoff conditions tial may be evaluated by simplified methods when              considered to be "reasonably possible" in the particular conservatively determined results provide acceptable          drainage basin under study. The PMF should be deter- iesign bases.                                                  mined for adjacent large streams. In addition, a local
                                                          1.59-11
 
PMF should be estimated for each local drainage course          records to "pre-project(s)"    and "with project(s)" con- that can influence safety-related facilities, including        ditions as follows:
drainage from the roofs of buildings, to assure that local intense precipitation cannot constitute a threat to the                (1) The term "pre-project(s) conditions" refers to safety of the nuclear facility.                                all characteristics of watershed features and develop- ments that affect runoff characteristics. Existing con- b. Probable Maximum Precipitation is defined by the        ditions are assumed to exist in the future if projects are Corps of Engineers and the National Oceanic and                to be operated in a similar manner during the life of the Atmospheric Administration (NOAA) as "the theoreti-            proposed nuclear facility and watershed runoff char- cally greatest depth of precipitation for a given duration    acteristics are not expected to change due to develop- that is meteorologically possible over the applicable          ment.
 
drainage area that would produce flood flows of which there is virtually no risk of being exceeded. These                    (2) The term "with project(s)" refers to the estimates usually involve detailed analyses of historical      future effects of projects being analyzed, assuming they flood-producing storms in the general region of the            will exist in the future and operate as specified. If drainage 'basin under study, and certain modifications        existing projects were not operational during historical and extrapolations of historical data and reflect more          floods and may be expected to be effective during the severe rainfall-runoff relations than actually recorded,      lifetime of the nuclear facility, their effects on historical insofar as these are deemed reasonably possible of            floods should be determined as part of the analyses occurrence on the basis of hydrometeorological reason-        outlined in Sections A.5, A.6, and A.8.
 
ing." The PMP should represent the depth, time, and spade distribution of precipitation that approaches the            c. Surface and subsurface characteristics that affect upper limit of what the atmosphere and regional                runoff and streamflow to a major degree (e.g., large topography can produce. The critical PMP meteorologi-          swamp areas, noncontributing drainage areas, ground- cal conditions are based on an analysis of air-mass            water flow, and other watershed features of an unusual properties (e.g., effective precipitable water, depth of      nature which cause unusual characteristics of stream- inflow layer, temperatures, winds), synoptic situations        flow).
prevailing during recorded storms in the region, topo- graphical features, season of occurrence, and location of d. Topographic features of the watershed and histor- the geographic areas involved. The values thus derived ical flood profiles or high water marks, particularly in are designated as the PMP, since they are determined the vicinity of the nuclear facility. For some sites one or within the limitations of current meteorological theory more gaging stations may be required at or very near the and available data and are based on the most effective combination of critical controlling factors.
 
facility site as soon as a site is selected to establish    (.
                                                                hydrologic parameters. (A regulatory guide is being prepared to provide guidance on hydrologic data collec- A.3 HYDROLOGIC CHARACTERISTICS                          tion.)
    Hydrologic characteristics of the watershed and e. Stream channel distances between river control stream channels relative to the facility site should be structures, major tributaries, and the facility site.
 
determined from the following:
    a. A topographic map of the drainage basin showing            f. Data on major storms and resulting floods-of- watershed boundaries. for the entire basin and principal      record in the drainage basin. Primary attention should be tributaries and other subbasins that are pertinent. The        given to those events having a major bearing on map should include the location of principal stream            hydrologic computations. It is usually necessary to gaging stations and other hydrologically related record        analyze a few major floods-of-record in order to develop collection stations (e.g., streamflow, precipitation) and      unit hydrograph relations, infiltration indices, base flow the locations of existing and proposed reservoirs.            relationships, information on flood routing relationships, and flood profiles. Except in unusual cases, climatol- b. The drainage areas in each of the pertinent            ogical data available from the Department of Commerce, watersheds or subbasins above gaging stations, reservoirs,    the U.S. Army Corps of Engineers, National Oceanic and any river control structures, and any unusual terrain          Atmospheric Administration, and other public sources features that could affect flood runoff. All .major            are adequate to meet the data requirements for storm reservoirs and channel improvements that will have a          precipitation histories. The data should include:
major influence on streamflow should be considered. In addition, the age of existing structures and. information              (1) Hydrographs of major historical floods for concerning proposed projects affecting runoff character-      pertinent locations in the basin from the U.S. Geological istics or streamflow are needed to adjust streamflow          Survey or other sources, where available.
 
1.59-12
 
(2) Storm precipitation records, depth-area-                A.5 PRECIPITATION LOSSES AND BASE FLOW
    duration data, and any available isohyetal maps for the most severe local historical storms or floods that will be          Determination of the absorption capability of the used to estimate basin hydrological characteristics.            basin should consider antecedent and initial conditions and infiltration during each storm investigated. Antece- A.4 FLOOD HYDROGRAPH ANALYSES                            dent precipitation conditions affect precipitation losses and base flow. The assumed values should be verified by studies in the region or by detailed storm-runoff studies.
 
Flood hydrograph analyses and related computations The fundamental hydrologic factors would be derived by should be used to derive and verify the fundamental analyzing observed hydrographs of streamflow and hydrologic factors of precipitation losses (see Section related storms. A thorough study is essential to deter- A.5) and the runoff model (see Section A.6). The                mine basin characteristics and meteorological influences analyses of observed flood hydrographs' of streamflow affecting runoff from a specific basin. Additional discus- and related storm precipitation (Ref. 1) use basic data sion and procedures for analyses are contained in various and information referred to in Section A.3 above. The publications such as Reference 2. The following discus- sizes and topographic features of the subbasin drainage          sion briefly describes the considerations for determining areas upstream of the location of interest should be used the minimum losses applicable to the PMF.
 
to estimate runoff response for each individual hydro- logically similar subbasin utilized in the total basin runoff model. Subbasin runoff response characteristics              a. Experience indicates that the capacity of a given are estimated from historical storm precipitation and            soil and its cover to absorb rainfall applied continuously streamflow records where such are available, and by              at high rate may rapidly decrease until a fairly definite synthetic means where no streamflow records are avail-          minimum rate of infiltration is reached, usually within a able. Reference 2 and the following provide guidance for        period of a few hours. Infiltration loss may include the analysis of flood hydrographs.                              initial conditions or may require separate determinations of initial losses. The order of decrease in infiltration a. The intensity, depth, and areal distribution of          capacity and the minimum rate attained are primarily precipitation causing runoff for each historical storm          dependent upon the type of ground cover, the size of (and rate of snowmelt, where this is significant) should        soil pores within the zone of aeration, and the condi- be analyzed. Time distributions of storm precipitation          tions affecting the rate of removal of capillary water
- k are generally based on recording rainfall gages. Total          from the zone of aeration. Infiltration theory, with precipitation measurements (including data from non-            certain approximations, offers a practical means of recording gages) are usually distributed, in time, using        estimating the volume of surface runoff from intense precipitation recorders. Areal distributions of precipita-      rainfall. However, in applying the theory to natural tion, for each time increment, are generally based on a          drainage basins, several factors must be considered.
 
weighting procedure. The incremental precipitation over a particular drainage area is the sum of the precipitation
                                                                            (1) The infiltration capacity of a given soil at the for each precipitation gage weighted by the percentage beginning of a storm is related to antecedent field of the drainage area considered to be represented by the        moisture and the physical condition of the soil. There- rain gage.                                                      fore, the infiltration capacity for the same soil may vary appreciably from storm to storm.
 
b. Base flow is the time-distribution of the difference between gross runoff and net direct runoff.                            (2) The infiltration capacity of a soil is normally highest at the beginning of rainfall. Rainfall frequently c. Initial and infiltration losses are the time distrib-    begins at relatively moderate rates, and a substantial uted differences between precipitation and net direct            period of time may elapse before the rainfall intensity runoff.                                                          exceeds the prevailing infiltration capacity. It is gen- erally accepted that, a fairly substantial quantity of d. The combined effect of drainage area, channel            infiltration is required to satisfy initial soil moisture characteristics, and reservoirs on the runoff character-        deficiencies before runoff will occur, the amount of istics, herein referred to as the "runoff model," should        initial loss depending upon antecedent conditions.
 
be established. (Channel and reservoir effects are dis- cussed separately in Section A.8.)                                      (3) Rainfall does not normally cover the entire drainage basin during all periods of precipitation with Streamflow hydrographs (of major floods) are available in      intensities exceeding infiltration capacities. Further- publications by the U.S. Geologic Survey, National Weather      more, soils and infiltration capacities vary throughout a Service, State agencies, and other public sources.            drainage basin. Therefore rational application of any
                                                              1.59-13
 
loss-rate technique must consider the varying nature of            Basin runoff models for a PMF determination should rainfall intensities over the basin in order to determine      provide a conservative estimate of the runoff that could the area covered by runoff-producing rainfall.                  be expected during the life of the nuclear facility. The basic analyses used in deriving the runoff model are not b. Initial loss is defined as the maximum amount of        rigorous but may be conservatively undertaken by precipitation that can occur without producing runoff.          considering the rate of runoff from unit rainfall (and Values of initial loss may range from a minimum of a            snowmelt, if pertinent) of some unit duration and few tenths of an inch during relatively wet seasons to          specific time-areal distribution (called a unit hydro- several inches during dry summer and fall months. Initial      graph). The applicability of a unit hydrograph or other losses prevalent during major floods usually range from        technique for use in computing the runoff from the about 0.2 to 0.5 inch and are relatively small in              Probable Maximum Precipitation over a basin may be comparison with the flood runoff volume. Conse-                partially verified by reproducing observed major flood quently, in estimating loss rates from data for major          hydrographs. An estimated unit hydrograph is first floods, allowances for initial losses may be approximated      applied to estimated historical rainfall-excess values to without introducing important errors into the results.          obtain a hypothetical runoff hydrograph for comparison with the observed runoff hydrograph exclusive of base c. Base flow is defined herein as that portion of a        flow (i.e., net runoff). The loss rate, the unit hydro- flood hydrograph which represents runoff from antece-          graph, or both, are subsequently adjusted to provide dent storms and bank flow. Bank flow is storm                  accurate verification.
 
precipitation which infiltrates the ground surface and flows, possibly as groundwater, into stream channels.              A study of the runoff response of a large number of Many techniques exist for estimating base flow. It is          basins for several historical floods in which a variety of generally assumed that base flow which could exist              valley storage characteristics, basin configurations, topo- during a PMF is high, the rationale being that a storm        graphical features, and meteorological conditions are producing relatively high runoff could meteorologically        represented provides the basis for estimating the relative occur over most watersheds about a week earlier than          effects of predominating influences for use in PMF
that capable of producing a PMF. An acceptable method          analyses. In detailed hydrological studies, each of the is to assume that a flood about half as severe as a PMF        following procedures may be used to advantage:
occurred 3 to 5 days earlier for frontal-type storms and about 24 hours for thunderstorms. The recession of this            a. Analysis  of  rainfall-runoff records  for  major t- flood is the base flow for the PMF.                            storms;
                  A.6 RUNOFF MODEL                                b. Computation of synthetic runoff response models by (1) direct analogy with basins of similar character- The hydrologic response characteristics of the water-      istics and/or (2) indirect analogy with a large number of shed to precipitation (i.e., runoff model) should be          other basins through the application of empirical rela- determined and verified from historical flood records.        tionships. In basins for which historical streamflow The model should include consideration of nonlinear            and/or storm data are unavailable, synthetic techniques runoff response due to high rainfall intensities or            are the only known means for estimating hydrologic unexplainable factors. In conjunction with data and            response characteristics. However, care must be taken to analyses discussed above, a runoff model should be            assure that a synthetic model conservatively reflects the developed, where data are available, by analytically          runoff response expected from precipitation as severe as
"reconstituting" historical floods to substantiate its use    the PMP.
 
for estimating a PMF. The rainfall-runoff-time-areal distribution of historical floods should be used to verify        Detailed flood hydrograph analysis techniques and that the reconstituted hydrographs correspond reason-          studies for specific basins are available from many ably well with flood hydrographs actually recorded at          agencies. Published studies such as those by the Corps of selected gaging stations (Ref. 2). In most cases, reconsti-    Engineers, Bureau of Reclamation, and Soil Conserva- tution studies should be made with respect to two or          tion Service may be utilized directly where it can be more floods and possibly at two or more key locations,        demonstrated that they are of a level of quality and particularly where possible errors in the determinations      conservatism comparable with that indicated herein. In could have a serious impact on decisions required in the      particular, the Corps of Engineers has developed analysis use of the runoff model for the PMF. In some cases the        techniques (Refs. 2, 3) and has accomplished a large lack of stream gage records, the lack of sufficient time      number of studies in connection with their water and areal precipitation definition, or unexplained causes      resources development activities.
 
may prevent development of reliable predictive runoff models. In such cases a conservative PMF estimate                  Computerized runoff models (Ref. 3) offer an ex- should be ensured by other means such as conservatively        tremely efficient tool for estimating PMF runoff rates developed synthetic unit hydrographs.                          and for evaluating the sensitivity of PMF estimates to
                                                          1.59-14
 
possible variations in parameters. Such techniques have        mated by maximizing observed intense storm parameters been used successfully in making detailed flood esti-          and transposing them to basins of interest. The param- mates.                                                        eters include storm duration, intensity, and the depth- area relation. The maximum storm should represent the Snowmelt may be a substantial runoff component for        most critical rainfall depth-area-duration relation fo- *he both historical floods and the PMF. In cases where it is      particular drainage area during various seasons oi -he necessary to provide for snowmelt in the runoff model,        year (Refs. 7-10). In practice, the storm parameters additional hydrometeorological parameters must be in-          considered are (1) the representative storm dewpoint corporated. The primary parameters are the depth of            adjusted to inflow moisture producing the maximum assumed existing snowpack, the areal distribution of          dewpoint (precipitable water), (2) seasonal variations in assumed existing snowpack, the snowpack temperature            parameters, (3) the temperature contrast, (4) the geo- and moisture content, the type of soil or rock surface        graphical relocation, and (5) the depth-area relation.
 
underlying the snowpack and the type and amount of            Examples of these analyses are explained and utilized in forest cover of the snowpack and variation thereof, and        a number of published reports (Refs. 7-10).
the time and elevation distribution of air temperatures and heat input during the storm and subsequent runoff                This procedure, supported with an appropriate period. Techniques that have been developed to reconsti-      analysis, is usually satisfactory where a sufficient num- tute historical snowmelt floods may be used in both            ber of historical intense storms have been maximized historical flood hydrograph analysis and PMF determina-        and transposed to the basin and where at least one of tions (Ref. 4).                                                them contains a convergent wind "mechanism" very near the maximum that nature can be expected to A.7 PROBABLE MAXIMUM
              PRECIPITATION ESTIMATES                          produce in the region (which is generally the case in the United States east of the Rocky Mountains). A general principle for PMP estimates is: The number and severity Probable Maximum Precipitation (PMP) estimates are of maximization steps must balance the adequacy of the the time and areal precipitation distributions compatible      storm sample; additional maximization steps are re- with the definition of Section A.2 and are based on            quired in regions of more limited storm samples.
 
detailed comprehensive meteorological analyses of severe storms of record. The analysis uses precipitation data and synoptic situations of major storms of record to              b. PMP determinations in regions of orographic determine characteristic combinations of meteorological        influences generally are for the high mountain regions.
 
conditions in a region surrounding the basin under            Additional maximization steps from paragraph A.7.a study. Estimates are made of the increase in rainfall          above are required in the use of the orographic model quantities that would have resulted if conditions during      (Refs. 5, 6). The orographic model is used where severe the actual storm had been as critical as those considered      precipitation is expected to be caused largely by the probable of occurrence in the region. Consideration is        lifting imparted to the air by mountains. This orographic given to the modifications in meteorological conditions        influence gives a basis for a wind model with maximized that would have been required for each of the record          inflow. Laminar flow of air is assumed over any storms to have occurred over the drainage basin under          particular mountain cross section. The "life" of the air, study, considering topographical features and location of      the levels at which raindrops and snowflakes are formed, the region involved.                                            and their drift with the air before they strike the ground may then be calculated.


==B. DISCUSSION==
The physical limitations in meteorological mecha- nisms for the maximum depth, time, and space distribu-                Models are verified by reproducing the precipita- tion of precipitation over a basin are (1) humidity          tion in observed storms and are then used for estimating (precipitable water) in the airflow over the watershed,      PMP by introducing maximum values of moisture and
historically reported for the site and surrounding region.
(2) the rate at which wind may carry the humid air into      wind as inflow at the foot of the mountains. Maximum the basin, and (3) the fraction of the inflowing atmos-      moisture is evaluated just as in nonorographic regions. In pheric water vapor that can be precipitated. Each of          mountainous regions where storms cannot readily be these limitations is treated differently to estimate the      transposed (paragraph A.7.a above) because of their PMP over a basin. The estimate is modified further for        intimate relation to the immediate underlying topo- regions where topography causes marked orographic            graphy, historical stor~ns are resolved into their convec- control on precipitation (designated as the orographic        tive and orographic components and maximized. Maxi- model as opposed to the general model which embodies          mum mroisture, maximum winds, and maximum values little topographic effect). Further details on the models    of the orographic component and convective component and acceptable procedures are contained in References 5      (convective as in nonorographic areas) of precipitation and6.                                                        are considered to occur simultaneously. Some of the published reports that illustrate the combination of a. The PMP in regions of limited topographicinflu-        orographic and convective components, including ence (mostly convergence precipitation) may be esti-          seasonal variation, are References 11-13.
 
1.59-15
 
In some watersheds, major floods are often the result          The position of the PMP, identified by "isohyetal of melting snowpack or of snowmelt combined with                patterns" (lines of equal rainfall depth), may have a very rain. Accordingly, the PMP (rainfall) and maximum              great effect on the regimen of runoff from a given associated runoff-producing snowpacks are both esti-            volume of rainfall excess, particularly in large drainage mated on a seasonal and elevation basis. The probable            basins in which a wide range of basin hydrologic runoff maximum seasonal snowpack water equivalent should be            characteristics exist. Several trials may be necessary to determined by study of accumulations on local water-            determine the critical position of the hypothetical PMP
sheds from historical records of the region.                    storm pattern (Refs. 8, 17) or the selected record storm pattern (Refs. .9, 16) to determine the critical isohyetal Several methods of estimating the upper limit of            pattern that produces the maximum rate of runoff at the ultimate snowpack and melting are summarized in                  designated site. This may be accomplished by super- References 4 and 5. The methods have been applied in            imposing the total-storm PMP isohyetal contour map on the Columbia River basin, the Yukon basin in Alaska,            an outline of the drainage basin (above the site) in such a the upper Missouri River basin, and the upper Mississippi      manner as to place the largest rainfall quantities in a in Minnesota and are described in a number of reports          position that would result in the maximum flood runoff by the Corps of Engineers. In many intermediate-                (see Section A.8 on Probable Maximum Flood runoff).
latitude basins, the greatest flood will likely result from    The isohyetal pattern should be consistent with the a combination of critical snowpack (water equivalent)          assumptions regarding the meteorological causes of the and PMP. The seasonal variation in both optimum snow            storm.
 
depth (i.e., the greatest water equivalent in the snow- pack) and the associated PMP combination should be                  A considerable range in assumptions regarding rainfall meteorologically compatible. Temperature and winds              patterns (Ref. II) and intensity variations can be made associated with PMP are two important snowmelt factors          in developing PMP storm criteria for relatively small amenable to generalization for snowmelt computations            basins without being inconsistent with meteorological (Ref. 14). The meteorological (e.g., wind, temperature,        causes. For drainage basins less than a few thousand dewpoints) sequences prior to, during, and after the            square miles in area (particularly if only one unit postulated PMP-producing storm should be compatible            hydrograph is available), the rainfall may be expressed as  (
with the sequential occurrence of the PMP. The user            average depth over the drainage area. However, in should place the PMP over the basin and adjust the              determining the PMP pattern for large drainage basins sequence of other parameters to give the most critical          (with varying basin hydrologic characteristics, including runoff for the season considered.                              reservoir effects), runoff estimates are required for different storm pattern locations and orientations to The meteorological parameters for snowmelt compu-          obtain the final PMF. Where historical rainfall patterns tations associated with PMP are discussed in more detail        are not used for PMP, two other methods are generally in References 11, 12, and 14.                                  employed.
 
Other items that need to be considered in deter- mining basin melt are optimum depth, areal extent and              a. The average depth over the entire basin is based on type of snowpack, and other snowmelt factors (see              the maximized areal distribution of the PMP.
 
Section A.8), all of which must be compatible with the most critical arrangement of the PMP and associated                b. A hypothetical isohyetal pattern is assumed.
 
meteorological parameters.                                      Studies of areal rainfall distribution from intense storms indicate that elliptical patterns may be assumed as Critical probable maximum storm estimates for very          representative of such events. Examples are the typical large drainage areas are determined as above but may            patterns presented in References 8, 14, 17, and 18.
 
differ somewhat in flood-producing storm rainfall from those encountered in preparing similar estimates for              To compute a flood hydrograph from the probable small basins. As a general rule, the critical PMP in a small    maximum storm, it is necessary to specify the time basin results primarily from extremely intense small-area      sequence of precipitation in a feasible and critical storms, whereas in large basins the PMP usually results        meteorological time sequence. Two meteorological from a series of less intense, large-area storms. In large      factors must be considered in devising the time se- river basins (about 100,000 square miles or larger) such        quences: (1) the time sequence in observed storms and.
 
as the Ohio and Mississippi River basins, it may be            (2) the manner of deriving the PMP estimates. The first necessary to develop hypothetical PMP storm sequences          imposes few limitations; the hyetographs (rainfall time (one storm period followed by another) and storm                sequences) for observed storms are quite varied. There is tracks with an appropriate time interval between storms.        some tendency for the two or three time increments The type of meteorological analyses required and typical        with. the highest rainfall in a storm to bunch together, as examples thereof are contained in References 9, 15, and        some time is required for the influence of a severe
16.                                                            precipitation-producing weather situation to pass a given
                                                          1.59-16
 
region. The second consideration uses meteorological            Care should be taken to ensure that the characteristics parameters developed from PMP estimates.                        determined represent historical conditions (which may be verified by reconstituting historical floods) and also An example of 6-hour increments for obtaining a            conservatively represent conditions to be expected dur- critical 24-hour PMP sequence would be that the most            ing a PMF.
 
severe 6-hour increments should be adjacent to each other in time (Ref. 17). In this arrangement the second              Channel and reservoir routing methods of many types highest increment should precede the highest, the third        have been developed to model the progressive down- highest should be immediately after this 12-hour se-            stream translation of flood waves. The same theoretical quence, and the fourth highest should be before the            relationships hold for both channel and reservoir rout-
18-hour sequence. This procedure may also be used in            ing. However, in the case of flood wave translation the distribution of the lesser, second (24-48 hours) and        through reservoirs, simplified procedures have been third (48-72 hours), 24-hour periods. These arrange-            developed that are generally not used for channel ments are permissible because separate bursts of precipi-      routing because of the inability of such simplified tation could have 'occurred within each 24-hour period          methods to model frictional effects. The simplified (Ref. 7). The three 24-hour precipitation periods are          channel routing procedures that have been developed interchangeable. Other arrangements that fulfill the            have been found useful in modeling historical floods, but sequential requirements would be equally reasonable.            care should be exercised in using such models for severe The hyetograph selected should be the most severe                hypothetical floods such as the PMF. The coefficients reasonably possible that would produce critical runoff at        developed from analysis of historical floods may not the project location based on the general appraisal of the      conservatively reflect flood wave translation for more hydrometeorologic conditions in the project basin.              severe events.
 
Examples of PMP time sequences fulfilling the sequential requirements are illustrated in References 11, 12, and                Most of the older procedures were basically attempts
17. For small areas maximized local records should be          to model unsteady-flow phenomena using simplifying considered to ensure that the selected PMP time                  approximations. The digital computer has allowed sequence is as severe as has occurred.                          development of analysis techniques that permit direct solution of basic unsteady flow equations utilizing The Corps of Engineers and the Hydrometeorological          numerical analysis techniques (Ref. 19). Most of the Branch of NOAA (under a cooperative -arrangement                older techniques have also been adapted for computer since 1939) have made comprehensive meteorological              use (Ref. 3).
studies of extreme flood-producing storms (Ref. 1) and have developed a number of estimates of PMP. The PMP                  For all routing techniques, care should be exercised estimates are presented in various unpublished memo-            to ensure that parameters selected for model verification randa and published reports. The series of published            are based on several historical floods (whenever possible)
reports is listed on the fly sheet of referenced Hydro-          and that their application to the PMF will result in meteorological Reports such as Reference 18. The                conservative estimates of flow rates, water levels, veloci- unpublished memoranda reports may be obtained from              ties, and impact forces. Theoretical discussions of the the Corps of Engineers or Hydrometeorological Branch,            many methods available for such analyses are contained NOAA. These reports and memoranda present general                in References2 and 19-22.
 
techniques and several contain generalized estimates of PMP for different river basins. The generalized studies (Refs. 7-13, 18, 29) are based on coordinated studies of                    A.9 PROBABLE MAXIMUM FLOOD
all available data, supplemented by thorough meteoro-                          HYDROGRAPH ESTIMATES
logical analyses and usually assure reliable and consistent estimates for various locations in the region for which              Probable Maximum Flood (PMF) net runoff hydro- they have been developed. In some cases, however,                graph estimates are made by sequentially applying additional detailed analyses are needed for specific river      critically located and distributed PMP estimates using basins (Refs. 7, 8) to take into account unusually large        the runoff model, conservatively low estimates of areas, storm series, topography, or orientation of drain-      precipitation losses, and conservatively high estimates of age basins not fully reflected in the generalized esti-        base flow and antecedent reservoir levels.
 
mates. In many river basins, available studies may be utilized to obtain the PMP without the in-depth analysis            In PMF determinations it is generally assumed that discussed herein.                                              short-term reservoir flood control storage would be depleted by antecedent floods. An exception would be when it can be demonstrated that a reasonably severe A.8 CHANNEL AND RESERVOIR ROUTING                          flood (e.g., about one-half of a PMF) less than a week (usually a minrimm of 3 to 5 days; 24 hours if the PMP
    Channel and reservoir routing of floods is generally an      is a thunderstorm) prior to a PMF can be evacuated from integral part of the runoff model for subdivided basins.          the reservoir before the arrival of a PMF. However, it is
                                                          1.59-17
 
unusual to use an antecedent storage level of less than          flood are assumed coincident with the Safe Shutdown one-half the available flood control storage.                    Earthquake. (An acceptable method of determining the
                                                                25-year flood is contained in Reference 30.) Also, The application of PMP in basins whose hydrologic          consideration should be given to the occurrence of a features vary from location to location requires the            Standard Project Flood with full flood control reservoirs determination that the estimated PMF hydrograph repre-          coincident with the Operating Basis Earthquake to sent the most critical centering of the PMP storm with          maintain a consistent level of analysis with other respect to the site. Care must be taken in basins with          combinations of such events. As with failures due to substantial headwater flood control storage to ensure            inadequate flood- control capacity, domino and essen- that a more highly concentrated PMP over a smaller area          tially simultaneous multiple failures may also require downstream of the reservoirs would not produce a                consideration. If the arbitrarily assumed total instan- greater PMF than a total basin storm that is partially          taneous failure of the most critically located (from a controlled. In such cases more than one PMP runoff              hydrologic standpoint) structures indicates flood risks at analysis would be required. Usually, only a few trials of        the nuclear facility site more severe than a PMF, a a total basin PMP are required to determine the most            progressively more detailed analysis of the seismic critical centering.                                            capability of the dam is warranted. In lieu of detailed geologic and seismic investigations at the site of the river Antecedent snowpack is included when it ýs deter-          control structure, the flood potential at the nuclear mined that snowmelt significantly contributes to the            facility may be evaluated assuming the most probable PMF (see Section A.7).                                          mechanistic-type failure of the questioned structures. If the flood effects of this assumed failure cannot be safely Runoff hydrographs should be prepared at key                accommodated at the nuclear facility site in an accept- hydrologic locations (e.g., streamgages and dams) as well        able manner, the seismic potential at the site of each as at the site of nuclear facilities. For all reservoirs        questioned structure is then evaluated in detail. The involved, inflow, outflow, and pool elevation hydro-            structural capability is evaluated in the same depth as for graphs should be prepared.                                      the nuclear facility. If the capability is not sufficient to ensure survival of the structure, its failure is assumed, Many existing and proposed dams and other river              and the resulting seismically induced flood is routed to control structures may not be capable of safely passing          the site of the nuclear power plant. This last detailed floods as severe as a PMF. The capability of river control      analysis is not generally required since intermediate structures to safely pass a PMF and local coincident            investigations usually provide sufficient conservative wind-generated wave activity must be determined as part          information to allow determination of an adequate of the PMF analysis. Where it is possible that such              design basis flood.
 
structures may not safely survive floods as severe as a PMF, the worst such condition with respect to down-                    A.11 WATER LEVEL DETERMINATIONS
stream nuclear facilities is assumed (but should be substantiated by analysis of upstream PMF potential) to              The preceding discussion has been concerned pri- be their failure during a PMF, and the PMF determina-            marily with determinations of flow rates. The flow rate tion should include the resultant effects. This analysis        or discharge must be converted to water surface eleva- also requires that the consequences of upstream dam              tion for use in design. This may involve determination of failures on downstream dams (domino effects) be                  elevation-discharge relations for natural stream valleys or considered.                                                      reservoir conditions. The, reservoir elevation estimates involve the spillway discharge capacity and peak reser- A.10 SEISMICALLY INDUCED FLOODS                        voir level likely to be attained during the PMF as governed by the inflow hydrograph, the reservoir level at Seismically induced floods on streams and rivers may        the beginning of the PMF, and the reservoir regulation be caused by landslides or dam failures. Where river            plan with respect to total releases while the reservoir is control structures are widely spaced, their arbitrarily          rising to peak stage. Most river water level determina:
assumed individual, total, instantaneous failure and            tions involve the assumption of steady, or nonvarying, conservative flood wave routing may be sufficient to            flow for which standard methods are used to estimate show that no threat exists to nuclear facilities. However,      flood levels.
 
where the relative size, location, or proximity of dams to potential seismic generators indicates a threat to nuclear          Where little floodplain geometry definition exists, a facilities, the capability of such structures (either singly    technique called "slope-area" may be employed wherein or in combination) to resist severe earthquakes (critically      the assumptions are made that (1) the water surface is located) should be considered. In river basins where the        parallel to the average -bed slope, (2) any available flood runoff season may constitute a significant portion        floodplain geometry information is typical of the river of the year (such as the Mississippi, Columbia, or Ohio          reach under study, and (3) no upstream or downstream River basins), full flood control reservoirs with a 25-year      hydraulic controls affect the river reach fronting the site
                                                          1.59-48
 
ander study. Where such computations can be shown to                The 'selection of windspeeds and critical wind indicate conservatively high flood levels, they may be          directions assumed coincident with maximum PMF or used. However, the usual method of estimating water              seismically induced water levels should provide assurance surface profiles for flood conditions that may be                of virtually no risk to safety-related equipment. The characterized as involving essentially steady flow is            Corps of Engineers suggests (Refs. 26, 27) that average called the "standard-step method." This method utilizes          maximum windspeeds of approximately 40 to 60 mph the integrated differential equation of steady fluid            have occurred in major windstorms in most regions of motion commonly referred to as the Bernoulli equation            the United States. For application to the safety analysis (Refs. 22-25). Water levels in the direction of flow            of nuclear facilities, the worst regional winds of record computation are determined by the trial and error                should be assumed coincident with the PMF. However, balance of upstream and downstream energy. Frictional            the postulated winds should be meteorologically com- and other types of head losses are usually estimated in        patible with the conditions that induced the PMF (or detail using characteristic loss equations whose coeffi-        with the flood conditions assumed coincident with cients have been estimated from computational reconsti-        seismically induced dam failures). The cqnditions in- tution of historical floods and from detailed floodplain        clude the season of the year, the time required for the geometry information. Where no data exist to reconsti-          PMP storm to move out of the area and be replaced by tute water levels from historical floods, conservative          meteorological conditions that could produce the postu- values of the various loss coefficients should be used.        lated winds, and the restrictions on windspeed and Application of the standard-step method has been                direction produced by topography. As an alternative to a developed into very sophisticated computerized models          detailed study of historical regional winds, a sustained such as the one described in Reference 23. Theoretical          40-mph overland windspeed from any critical direction discussions of the techniques involved are presented in        is an acceptable postulation.
 
References 22, 24, and 25.
 
Unsteady-flow models may also be used to estimate              Wind-generated setup (or windtide) and wave action water levels since steady flow may be considered a class        (runup and impact forces) may be estimated using the of unsteady flow. Computerized unsteady-flow models            techniques described in References 26 and 28. The require generally the same floodplain geometry defini-          method for estimating wave action is based on statistical tion as steady-flow models, and their use may allow            analyses of a wave spectrum. For nuclear facilities, more accurate water surface level estimates for cases          protection against the one-percent wave, defined in where steady-flow approximations are made. One such            Reference 28 as the average of the upper one percent of unsteady-flow computer model is discussed in Reference          the waves in the anticipated wave spectrum, should be
  19.                                                            assumed. Where depths of water in front of safety- related structures are sufficient (usually about seven- All reasonably accurate water level estimation models      tenths of the wave height), the wave-induced forces will require detailed floodplain definition, especially of areas    be equal to the hydrostatic forces estimated from the that can materially affect water levels. The models            maximum runup level. Where the waves can be should be calibrated by mathematical reconstitution of          "tripped" and caused to break, both before reaching and historical floods (or the selection of calibration coeffici-    on safety-related structures, dynamic forces may be ents based on the conservative transfer of information          estimated from Reference 28. Where waves may induce derived from similar studies. of other river reaches).          surging in intake structures, the pressures on walls and Particular care should be exercised to ensure that              the underside of exposed floors should be considered, controlling flood level estimates are always conserva-          particularly where such structures are not vented and air tively high.                                                  compression can greatly increase dynamic forces.
 
A.12 COINCIDENT WIND-WAVE ACTIVITY
                                                                    In addition, assurance should be provided that safety The superposition of wind-wave activity on PMF or          systems are designed to withstand the static and seismically induced water level determinations is re-          dynamic effects resulting from frequent (10-year) flood quired to ensure that, in the event either condition did      levels coincident with the waves that would be produced occur, ambient meteorological activity would not cause        by the Probable Maximum Gradient Wind for the site a loss of any safety-related functions due to wave action.    (based on a study of historical regional meteorology).
                                                          1.59-19
 
APPENDIX A
                                                  REFERENCES
1. Precipitation station data and unpublished records            Square Miles and Durations from 6 to 72 Hours,"
  of Federal, State, municipal, and other agencies may          draft report, National Weather Service, ESSA (now be obtained from the National Weather Service                U.S. Weather Service, NOAA), 1972.
 
(formerly called the U.S. Weather Bureau). In addition, studies of some large storms are available      8. "Probable Maximum Precipitation, Susquehanna in the "Storm Rainfall in the United States,                  River Drainage Above Harrisburg, Pa.," Hydro- Depth-Area-Duration Data," summaries published              meteorological Report No. 40, U.S. Weather Bureau by Corps of Engineers, U.S. Army. A list of                  (now U.S. Weather Service, NOAA), 1965.


with sufficient margin for the limited accuracy and                                      Nuclear poower plants must be designed itf prevent quantity of the historical data and the period of time ill                          the loss of safety-relat ed functions resulltig front the which the data have been accumulated. (2) appropriate                              most severe flood conditions thai                    call reasonably be combinations of the effects of normal and accident                                  predicted to occur at a site as a result of sevele conditions with the effects of the natural plhenonlena.                             hydrometenrological conditions, seismic activity. or and (3) the importance of the safety functions to be                                both.
references is contained in Section 2.4 of
  "Regulatory-Standard Review Plan," U.S. Nuclear          9. "Meteorology of Flood Producing Storms in the Regulatory Commission, October 1974.                          Ohio River Basin," Hydrometeorological Report No. 38, U.S. Weather Bureau (now NOAA), 1961.


performed.
2. Corps of Engineers publications, such as EM
    1110-2-1405, August 31, 1959, "Engineering and          10. "Probable Maximum      and TVA Precipitation Over Design-Flood Hydrograph Analyses and Computa-                the Tennessee River    Basin Above Chattanooga,"
  tions," provide excellent criteria for the necessary          Hydrometeorological  Report No. 43, U.S. Weather flood hydrograph analyses. (Copies are for sale by            Bureau (now NOAA),    1965.


The Corps of Engineers for many years has studied Paragraph 100.10 (c) of 10 CFR Part 100,"Reactor conditions arid circumstances relating to floods and Site Criteria," requires that physical characteristics of flood control. As a result of these studies, it has the site, including seismology. meteorology, geology.
Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.) Isohyetal      11. "Interim Report-Probable Maximum Precipitation patterns and related precipitation data. are in the          in California," Hydrometeorological Report No. 36, files of the Chief of Engineers, Corps of Engineers.


developed a definition for a probable niaxinmui 'lood and hydrology, be taken into account in determining the (PM F)'        and attendant analytical techniques for acceptability of a site for a nuclear power reactor.                               estimating with an acceptable degree oft conservattsm flood levels on streatis or rivers resulting fromi Appendix A. "Seismic arid Geologic Siting Criteria                            hydromLeteorological conditions. For estimating for Nuclear Power Plants." was published in the Federal                            seismtiically induced flood levels. an acceptable degree of Register on November 25, 1971 (36 FR 22601) as a proposed amendment to 10 CFR Part 100. The proposed appendix would specify investigations required                                  'Corps ot tEngincecr Pribahltc Ma',intsni ItIodt definlililn for a detailed study of seismically induced floods and                            appears in many publication, of thait :g00ncy sch1is IEngineering water waves. Proposed Appendix A to 10 CFR Part 100                                Circular EC-I 110-2-27, Change I. 'T"ngincering :snd would also require that (lie determination of design                              Design -Policies and Procedures Perlaining 10 t)eerminaition of Spillway Capalities and Frecboard Allowances fir t)jn<,. dated bases for seismically induced floods and water waves be                            19 Feb. 1968. Ttie probahble niamimuni fhlood is atso direclly based on the results of the required geologic and seismic                          analogous to ftte Corps (if 1'ngineers "Spillway Design Itlod" as investigations and that these design bases be taken into                            used for darns whose failures would result in a significant toss of account in the design of tile nuclear power plant.                                  lire and property.
3. A publicly available model is "Flood Hydrograph U.S. Weather Bureau (now NOAA), 1961; revised
                                                                196


USAEC REGULATORY GUIDES                                    Copies of published guides may be obtained by request indicating the divietoat desired to the US. Atomic Energy Commrstiori, Washington. D.C. 20545, Regulatory Guides e        issued to describe and make available to the public    Attention: Director of Regulatory Standards. Comments and stuggetions fot methods aeceptsble to the AEC Regulatory staff of implementing specific parts of    Irtroovements In these guides are encouraged and should be sent to the Secrets'y the Commission's      regulations. to delineate techniques used by the stafl in    of the Commission, U.S. Atomic Energy Commission. Washington, D.C. 20545.
===9.     I===
  Package, HEC-l Generalized Computer Program,"            12. "Probable      Maximum Precipitation, Northwest available from the Corps of Engineers Hydrologic              States," Hydrometeorological Report No. 43, U.S.


evaluating    ecilfic problems or posttulatd accidents, or to provide guidane to    Attention: Chief, Public ProctedingtStlff.
Engineering Center, Davis, California, October              Weather Bureau (now NOAA), 1966.


eaplicants. RegAnftory Guides are not substitutes for regulationt and compliance with thern is not required. Methods and solutions different from those set out in   The guides are issued In the following ten broad divisions:
1970.                                                                                         1
    the guides will be acceptable if they provide a basis for the findings requisite to
                                                            13. "Probable Maximum Precipitation in the Hawaiian
                                                                                          2. Research and Test Reactors              6. Tranportation the itauence or continuance of a permit or license by the Commitsion.
4. One technique for the analysis of snowmelt is                Islands," Hydrometeorological Report No. 39, U.S.


3. Fuels ard Materials racilitien         
contained in Corps of Engineers EM 1100-2-406,              Weather Bureau (now NOAA), 1963.


===8. Occupational Health===
"Engineering and Design-Runoff From Snowmelt,"
                                                                                          4. Environmentall and Siting              9. Antitrust Review Published guides will be revised periodically, as appropriate, to accommodate                                                  10. General comments end to reflect new information or experlence.                               5. Materialt and Plant Protection
  January 5, 1960. Included in this reference is also      14. "Meteorological Conditions for the Probable Maxi- an explanation of the derivation of probable maxi-          mum Flood on the Yukon River Above Rampart, mum and standard project snowmelt floods.                   Alaska," Hydrometeorological Report No. 42, U.S.


conservatism for evaluating the effects of lte initiating                for the design of the nuclear plant. For instance, the event is provided by the proposed Appendix A to 10                        analysis of floods caused by darn failures, landslides, or CFR Part 100.                                                            tsunami requires consideration of seismic events of the severity of the Safe Shutdown Earthquake occurring at The *onditions resulting I'rom the worst site-related            the location that would produce the worst such flood at flood precHble at the nuclear power plant (e.g.. PMF,                    the nuclear power plant site. In the case of seismically seismically induced flood, seiche. surge. severe local                    induced floods along rivers, lakes, and estuaries which precipitation) with attendant wind-generatcd wave                        may be produced by events less severe than a Safe activily constitute the design basis flood conditions that                Shutdown Earthquake, consideration should be given to safety-related structures. systems. and components                        the coincident occurrence of floods due to severe identified in Regulatory Guide 1.292 must he designed                    hydrometeorological conditions, but only where the ito withstand and remain functional.                                      effects on the plant are worse, and the probability of such combined events may be greater, than the effects For sites along streams or rivers, a hypothetical                on the plant of an individual occurrence of the most probable maximumiflood of the severity defined by the                    severe event of either type. For example. a seismically Corps of Engineers generally provides the design basis                    induced flood produced by an earthquake of flood. Ior sites alone lakes or seashores, a flood                      approximately one-hal f the Safe Shutdown severity Condition of cotinparahle severity could be produced by                  coincident with a runoff-type flood produced by tihe the most severe combination of hydrometeorological                      worst regional storm of record may be considered to parameters reasonably possible, such as may be                            have approximately the same severity as an earthquake protduced by a probable maxinmum hurricane" . or by a                    of Safe Shutdown severity coincident with about a probable matximum seiche. On estuaries. a probable                        25-year flood. For the specific case of seismically inaxinitun rivet  c lood. a probable maximum surge. a                    induced floods due it) dam failures, an evaluat ion should probable tuaximnuni seiche. or a reasonable combination                  be made of flood wave! which may be caused by of less severe phenomenologically caused flooding events                  domino-type darn failures triggered by a seismically should all he considered in arriving at design basis flood                induced failure of a critically located dam and of flood conditions comparable in frequency of occurrence with                    waves which may be caused by multiple darn failur':s in a a probable ;naximum flood on streams and rivers.                          region where dams may be located close enough together that a single seismic event can cause multiple failutes.
Weather Bureau (now NOAA), 1966.


Ini addition to floods produced by severe Ihy drometeorological conditions. Ihe most severe seismically induced floods reasonably possible should be                        Each of the severe flood types discussed above considered for each site. Along streams. rivers, and                      should represent the upper limit of all estuaries, seisinically induced floods may be produced                    phenomenologically caused flood potential combi- by dam failures or landslides. Along lakeshores,                         nations considered reasonably possible, and analytical coastlines, and estuaries. seismically induced or                        techniques are available and should generally be used for tst,namit-ype flooding should be considered.                              their prediction for individual sites. Those techniques Consideration of seismically induced floods should                        applicable to PMF and seismically induced flood include the same range of seismic events as is postulated                estimates on streams and rivers are presented in Appendix A to this guide. Similar apperdices for coastal, estuary. and Great Lakes sites, reflecting comparable
5. "Technical Note No. 98-Estimation of Maximum'
        2Regulatory Guide 1L29 (Safety Guide 29), "Seismic Design        levels of risk. will be issued as they become available.
  Floods," WMO-No. 233.TP.126, World Meteorologi-          15. "Meteorology of Flood-Producing Storms in the cal Organization, United Nations, 1969, and                 Mississippi River Basin," Hydrometeorological
  "Manual for Depth-Area-Duration Analysis of                 Report No. 34, U.S. Weather Bureau (now NOAA),
  Storm Precipitation," WMO-No. 237.TP. 129, World              1965.


Classification," identifies waler.cooled nuclear power plant structures. system,. and components that should be designed to withstand the effects of the Safe Shutdown Earthquake and                      Analyses of only the most severe flood conditions remain funetionalt These structures. systems. and components              may not indicate potential threats to safety-related are those necessary to assure (I) the integrity of the reactor coolant pressure boundary, (2) the capability to shut down the            systems that might result from combinations of flood reactor and maintain it in a ,.afe shutdown condition, or (3) the          conditions thought to be less severe. Therefore.
Meteorological Organization, United Nations, 1969.


capability to prevent or mitigate the consequences of accidents            reasonable combinations of less-severe flood conditions which could result in potential offsite exposures comparable to            should also be considered to the extent needed for a the guideline exposures, of I1t CFR Part tI0O. These same structure%, systems, and components should also be designed to            consistent level of conservatism. Such combinations withstand conditions resulting from the design basis flood and            should be evaluated in cases where the probability of remain functional.                                                         their existing at the same time and having significant If is expected that safety-related structures, systemns. and      consequences is at least comparable to that associated components of other types of nuclear power plants will be identified in future Regulatory guides. In the interim. Regulatory        with the most severe hydrometeorological or seismically Guide 1.29 should be used as guidance when identifying                    induced flood. For example, a failure of relatively high rafety-related structures, systems, and components of other            levees adjacent to a plant could occur during floods less types of nuclear power plants.                                             severe than the worst site-related flood, but would
16. "Meteorology of Hypothetical Flood Sequences in
      'See Corps of Engineers Coastal Engineering Research                produce conditions more severe than would result during Center "Technical Report No. 4, Shore Protection, Planning and            a greater flood (where a levee failure elsewhere would Design." third edition. 1966.                                              produce less severe conditions a[ the plant site).
6. "Meteorological Estimation of Extreme Precipita-             the Mississippi River Basin," Hydrometeorological tion for Spillway Design Floods," Tech. Memo                Report No. 35, U.S. Weather Bureau (now NOAA),
                                                                    1.59-2
  WBTM HYDRO-5, U.S. Weather Bureau (now                      1959.


Wind-generated wave activity may produce severe                        b. Along lakeshores. coastlines, and estuaries.
NOAA) Office of Hydrology, 1967.


flood-induced static and dynamic conditions either                    eslimales of flood levels resulting frorn severe surges.
17. "Engineering and Design-Standard Project Flood
7. "Seasonal Variation of the Probable Maximum                  Determinations,"        Corps of Engineers EM
  Precipitation East of the 105th Meridian for Areas          1110-2-1411, March 1965, originally published as from 10 to 1,000 Square Miles and Durations of 6,            Civil Engineer Bulletin No. 52-8, 26 March 1952.


independent of or coincident with severe                              seiches. and wave action caused by hydronteteorological hydromelcorological or scisnmic flood-producing                      activity should he based on criteria cOluparahle in mechanisms. For example, along a lake. reservoir. river,             conservatism to those used for probable maximum or seashore, reasonably severe wave action should he                  Ihoods. Criteria and analytical techniques providing this considered coincident with the probable maximum                      level of conservatism for the analysis of these events will water level conditions. 4 The coincidence of wave                    he summai'zed in subsequent appendices to ilbis guide.
12, 24, and 48 hours." Hydrometeorological Report No. 33, U.S. Weather Bureau (now U.S. Weather            18. "Probable Maximum Precipitation Over South Service, NOAA), 1956; and "All-Season Probable              Platte River, Colorado, and Minnesota River, Minne- Maximum Precipitation-United States East of the             sota," Hydrometeorological Report No. 44, U.S.


activily with probable maximum water level conditions                      c. Flood Aronditions Ihat could be caused by should take into account the fact that sufficient time               earthquakes of the severity used in thie design of the can elapse between the occurrence of the assumed                      nuclear facility should also be considered in establishing meteorological mechanism and the maximum water level                  the design hasis flood. A simplified analytical technique to allow subsequent meteorological activity to produce                for evaluating the hydrologic effects of seismically substantial wind-generated waves coincident with the                  induced dam failures disctrssed herein is presented in high water level produced by the initial event. In                    Appendix A of this guide. Techniques for evaluating the addition, the most severe wave activity at the site that              effects of tsunami will be presented in future can be generated by distant hydrometeorological activity              appendices.
105th Meridian, for Areas from 1,000 to 20,000               Weather Bureau (now NOAA), 1969.


should be considered. For instance, coastal locations                      d. In addition to the analyses of the most severe may be subjected to severe wave action caused by a                    floods I hat            may be induced by either distant storm that, although not as severe as a local                hydrometeorological or seismic mechanisms. reasonable storm (e.g., a probable maximum hurricane), may                      combinations of less-severe flood conditions should also produce more severe wave action because of a very long                be considered to the extent needed for a consistent level wave-generating fetch. The most severe wave activity at              of conservatism, Such combinations should be evaluated tile site that may be generated by conditions at a                    in cases where the probability of their existing at the distance from the site should be considered in such                  same time and having significant consequenceL is at least cases. In addition, assurance should be provided that                comparable to that associated with the most severe safety systems necessary for cold shutdown and                        hydrometeorological or seismically induced flood.
1.59-20


maintenance thereof are designed to withstand the static                  e.     To the water levels associated with the worst and dynamic effects resulting from frequent flood levels              site-related flood possible (as determined from coincident with the waves that would be produced by                   paragraphs a.. b.. c.. or d. above) should be added the the maximum gradient wind for the site (based on a                    effects of coincident wind-generated wave activity to study of historical regional meteorology).                            generally define the upper limit of flood potential. An acceptable analytical basis for wind-generated wave
19. "Unsteady Flow Simulation in Rivers and Reser-             26. "Coxlnutation of Freeboard Allowances for Waves voirs," by J.M. Garrison, J.P. Granju, and J.T. Price,        in Reservoirs," Engineer Technical Letter ETL
    pp. 1559-1576, Vol. 95, No. HY5, (September                    1110-2-9, U.S. Army Corps of Engineers, August 1,
    1969), Journal of the Hydraulics Division, ASCE,                1966.


==C. REGULATORY POSITION==
(paper 6771).
activity coincident with probable maximum water levels is the assumption of a 40-mph overland wind from the I. The conditions resulting from the worst site-related              most critical wind-wave-producing direction, unless flood probable at a nuclear power plant (e.g., PNIF.                 historical windstorm data can be used to substantiate seismically induced flood, hurricane. seiche, surge. heavy            that such an event (i.e., wind direction and/or speed) is local precipitation) with attendant wind-generated wave              more extreme than has occurred regionally. However. if activity constitute the design basis flood conditions that            the mechanism producing the maximum water level.
20. "Handbook of Applied Hydrology," edited by Ven            27. "Policies and Procedures Pertaining to Deter- Te Chow, McGraw-Hill, 1964, Chapter 25.                        mination of Spillway Capacities and Freeboard Allowances for Dams," Engineer Circular EC
21. "Routing of Floods Through River Channels," EM                  1110-2-27, U.S. Army Corps of Engineers, August
    1110-2-1408, U.S. Army Corps of Engineers, March              1, 1966.
 
1, 1960.
 
22. "Engineering Hydraulics," edited by Hunter Rouse,         28. "Shore Protection Manual," U.S. Army Coastal John Wiley & Sons, Inc., 1950.                                 Engineering Research Center. 1973.


safety-related structures. systems, and compor.Ents                  such as a hurricane, would itself produce higher waves, identified in Regulatory Guide 1.292 must be designed                then these higher waves should be used as the design to withstand and remain functional.                                   basis.
23. "Water Surface Profiles, HEC-2 Generalized Com- puter Program," available from the Corps of Engi-        29. "Probable Maximum and TVA Precipitation for neers Hydrologic Engineering Center, Davis, Calif.           Tennessee River Basins up to 3,000 Square Miles in Area and Durations to 72 Hours," Hydrometeoro- logical Report No. 45, U.S. Weather Bureau (now
24. "Open Channel Hydraulics"        by Ven Te Chow,              NOAA), 1969.


a. On streams and rivers, the Corps of Engineers definition of a probable maximum flood (PMF) with                    2.    As    an    alternative  to    designing  "hardened"
McGraw-Hill, 1959.
attendant analytical techniques (summarized in                        protection- for all safety-related structures. systems. and Appendix A of this guide) provides an acceptable level                components as specified in regulatory position I . above, of conservatism for estimating flood levels caused by                it is permissible to not provide hardened protection for severe hydrometeorological conditions.                                some of these features if:
                                                                            a.    Sufficient warning time is shown to be available to shut      the plant down and implement adequate
    4Probable Maximum Water Level Is deflined by the Corps of        emergency procedures"
Engineers as "the maximum still water level (i.e.. exclusive of            b. All safety-related structures. systems. and local coincident wave runup) which can be produced by the            components identified in Regulatory Guide 1.29) are most severe combination or hydrometeorological and/or seismic parameters reasonably possible for a particular location. Such phenomena are hurricanes, moving squall lines, other cyclonic                I tardened portection means structural provisions meteorological events. tsunami, etc., which, when combined            incorporated in the plant design that will protect %afcty-related with the physical response of a body of water and severe              structures, systems, and components from the static and ambient hydrological conditions, would produce a still water          dynamic effects of floods. Examples of the types of flood level that has virtually no risk of being exceeded." (Sec            protection to be provided for nuclear power plants will le the Appendix A to this guide)                                            subject of a separate regulatory guide.


1.59-3
25. "Backwater    Curves in River Channels," EM              30. "Floods in the United States, Magnitude and Fre-
    1110-2-1409, U.S. Army Corps of Engineers,                    quency, (Basin)," series of Water-Supply Papers.


designed to withstand the flood conditions resulting                      less-severe flood conditions are also considered to the    i from a severe slorm such as tie worst regional storm of                    extent needed for the consistent level of conservatism:
December 7, 1959.                                             U.S. Geological Survey, various dates.
record"' with attendant wind-generated wave activity                      and Ihl1 mw. lie produced by the worst winds of record and reiain functional:
                                                                                d. In addition it) paragraph 2.b. above, at least c.    In addition to the analyses required by                        those structutres, systems, and components necessary for paragraph 2.b. above, reasonable combinations of                          coldl shutdown and maintenance thereof are designed with "hardened" protective fealtures to withstand tlie For sites along streams and rivers thik event is characterized      entire range of flo0d conditions up to and including the by the Corps of. Engineer! definition of a Standard Projcct                worst site-related flood probable (e.g., PM F. seismically Flood. Such floods have been found to produce tlow rates                  induced flood. hutricane, surge, seiclhe, heavy local generally 40 wofill percenrtl tihte P.SIF. For sites along seahorc, this event    m)*" le ch;taracterized b% the Corp,    oit" :ineinctrs    iercipitalion) with coincident wind-generated wave defiNition of j Standard Projecl Ilurricane. For other        'ijC  a    act ion as discussed in regulatory positiotn I. above and comparable level olf risk should le assumed.                              remain funictiolnal.


1.59-4
1.59-21


* a
ft -i-i APPENDIX B
0                                                                      APPENDIX A
                                                  ALTERNATIVE METHODS OF
                                ESTIMATING PROBABLE MAXIMUM FLOODS
                                                           TABLE OF CONTENTS
                                                           TABLE OF CONTENTS
                      A.I Introduction ..........................                         ......................                        .5(1.5 A.2 Probable Maxinmum Flood (PMF) .......... .......................................................... I .q A.3 Hydrologic Characieristics ................                      . . . . .. . . . . . . . . . . . . . . . . .5' .6 A.4 Hlood Hydrograph Analyses ..............                           I..,. I...................                1.59*.7 A.5 Precipitation Losses and Base Flow .........                     ......................                     1.59-7 A.6 Runoff Model .........................                            ......................                        59 -8 A.? Probable Maximum Precipitation Estimates .. .. . . .. . . . . . .. . .. . . . . ... 1.5- AS8 Channel and Reservoir Routing ............                        ... .....................                 1.59-1 I
                                                                                                                            Page B.1 INTRODUCTION          ...............                                                                                   1.59-25 B.2 SCOPE ........           ....................                                                                         1.59-25 B.3 PROBABLE MAXIMUM FLOOD PEAK DISCHARGE .........                                           .....................       1.59-25 B.3.1 Use of PMF Discharge Determinations                        ....         . . . . . . . . . . . . . . . . . . . . 1.5 9 -2 5 B.3.2 Enveloping isolines of PMF Peak Discharge . . . . . . . . . . . . . . . . . . . . . . . 1.5 9 -2 5 B.3.2.1 Preparation of Maps                ...         ..     .. . . . . . . . . . . . . . . . . . . . . . 1.59 -2 5 B.3.2.2 Use of Maps            . . . . . . . . . . . . ......                   . . . . . . . . . . . I.     . 1.59-26 B.3.3 Probable Maximum Water Level                    .......                . . . . . . . . . . . . . . . . . . . . 1.5 9 -2 6 B.3.4 Wind-Wave Effects          . . ..       . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 9 -26 B.4 LIMITATIONS        . . . . . . . . . ..                   . . . . . .                                                 1.59-26 REFERENCES            . . . . . . . . . . . . . . . . . . . . . . . .                                             *. . . 1.59-27 FIG UR ES          . . . . . . . . . . . . . . . . . . . .. . . . . .                                                     1.59-28 TABLE                                                                                                                      1.59-36 FIGURES
                    A.9 PNI F llydrograph Estimates ...............                       ....................                     1.5 i. 1 2 A.10 Seismically Induced Floods ..............                         .....................                     1.59 -12 A.1 I Water Level Detei minations .............                        ....................                     1.59-)13 A.1 2 Coincident Wind-Wave Activity .................................                                            1.59-13 References .......................................                                         ........      1.59-15 PROBAELE MAXIMUM AND SEISMICALLY INDUCED FLOODS
Figure B.I -  Water Resources Regions.               ................                                                       1.59-28 B.2 -  Probable Maximum Flood (Enveloping Isolines) - 100 Sq. Mi. .                                                 1.59-29 B.3 -  Probable. Maximum Flood (Enveloping Isolines) - 500 Sq. Mi..                                                 1.59-30
                                                    ON STREAMS AND RIVERS
        B.4 - Probable Maximum Flood (Enveloping Isolines) - 1,000 Sq. Mi.                                                 1.59-31 B.5 - Probable Maximum Flood (Enveloping Isolines) - 5,000 Sq. Mi.                                                 1.59-32 B.6 - Probable Maximum Flood (Enveloping Isolines) - 10,000 Sq. Mi.                                                 1.59-33 B.7 - Probable Maximum Flood (Enveloping Isolines) - 20,000 Sq. Mi.                                                 1 .59-34 B.8 - Example of Use of Enveloping Isolines ....                       ...........                                 1.59-35 TABLE
                    A.1 INTRODUCTION                                              historical storm and runoff data (fhood hydrograph analysis). the most severe precipitation reasonably This appendix has been prepared to provide                                possible (probable maximurn precipitation-.lPI
Table B. I - Probable Maximum Flood Data                                                                                    1.59-36
    guidance for flood analyses required in support of                             riinimum losses. tnaximum base flow. channel and applications for licenses for nuclear power plants to be                       reservoir routing, the adequacy of existing and propetsed located on streams and rivers. Because of the depth and                         river control structures to safely pass a PMF. water level diversity of presently available techniques. this appendix                    determinations, and the superposition of potential summarizes acceptable methods for estimating probable                          wind-generated wave activity. Seismically induced Ihoods maximum precipitation, for developing rainfall-runoff                          such as may be produced by dam failures or landslides.
                                                                        1.59-23
 
r B.1 INTRODUCTION *                                          B.3 PROBABLE MAXIMUM FLOOD
                                                                                        PEAK DISCHARGE
    This appendix presents timesaving alternative methods of estimating the probable maximum flood                        The data presented in this section are as follows:
(PMF) peak discharge for nuclear facilities on nontidal streams in the contiguous United States. Use of the                      1. A tabulation of PMF peak discharge determina- methods herein will reduce both the time necessary for              tions at specific locations throughout the contiguous applicants to prepare license applications and the NRC              United States. These data are subdivided into water staff's review effort.                                               resources regions, delineated on Figure B.1, and are tabulated in Table B.1.
 
The procedures are based on PMF values determined by the U.S. Army Corps of Engineers, by applicants for                  2. A set of six maps, Figures B.2 through B.7, licenses that have been reviewed and accepted by the                covering index drainage areas of 100, 500, 1,000, 5,000,
NRC staff, and by the staff and its consultants. The                10,000, and 20.000 square miles, containing isolines of information in this appendix was developed from a                  equal PMF peak discharge for drainage areas of those study made by Nunn, Snyder, and Associates, through a                sizes east of the 103rd meridian.
 
contract with NRC (Ref. 1).
                                                                    B.3.1 Use of PMF Discharge Determinations PMF peak discharge determinations for the entire contiguous United States are presented in Table B.1.                   The PMF peak discharge determinations listed in Under some conditions, these may be used directly to                Table B.1 are those computed by the Corps of Engi- evaluate the PMF at specific sites. In addition, maps                neers, by the NRC staff and their consultants, or showing enveloping isolines of PMF discharge for several            computed by applicants and accepted by the staff.
 
index drainage areas are presented in Figures B.2 through B.7 for the contiguous United States east of the                For a nuclear facility located near or adjacent to one
103rd meridian, including instructions for and an                  of the streams listed in the table and reasonably close to example of their use (see Figure B.8). Because of the              the location of the PMF determination, that PMF may enveloping procedures used in preparing the maps,                  be transposed, with proper adjustment, or routed to the results from their use are highly conservative.                     nuclear facility site. Methods of transposition, adjust- ment, and routing are given in standard hydrology texts Limitations on the use of these generalized methods            and are not repeated here. Limits for acceptable trans- of estimating PMFs are identified in Section B.4. These            positions are contained in Appendix A, Section A.I .b.
 
limitations should be considered in detail in assessing the applicability of the methods at specific sites.                     B.3.2 Enveloping lsolines of PMF Peak Discharge Applicants for licenses for nuclear facilities at sites on      B.3.2.1 Preparation of Maps nontidal streams in the contiguous United States have the option of using these methods in lieu of the more                  For each of the water resources regions, each PMF
precise but laborious methods of Appendix A. The                    determination in Table B.1 was plotted on logarithmic results of application of the methods in this appendix              paper (cubic feet per second per square mile versus will in many cases be accepted by the NRC staff with no            drainage area). It was found that there were insufficient further verification.                                              data and too much scatter west of about the 103rd meridian, caused by variations in precipitation from B.2 SCOPE                                  orographic effects or by melting snowpack. Accordingly, the rest of the study was confined to the United States The data and procedures in this appendix apply only            east of the 103rd meridian. For sites west of the 103rd to nontidal streams in the contiguous United States.              meridian, the methods of the preceding section may be Two procedures are included for nontidal streams east of            used.
 
the 103rd meridian.
 
Envelope curves were drawn for each region east of Future studies are planned to determine the applica-            the 103rd meridian. It was found that the envelope bility of similar generalized methods and to develop such          curves generally paralleled the Creager curve (Ref. 2),
methods, if feasible, for other areas. These studies, to be         defined as included in similar appendices, are anticipated for the main steins of large rivers and the United States west of                                               0 4 8 )-l the 103rd meridian, including Hawaii and Alaska.                                  Q = 46.0 CA(0.894A-O'
                                                              1.59-25
 
where                                                              4. Plot the six PMF peak discharges so obtained on logarithmic paper against drainage area, as shown on Q is the discharge in cubic feet per second (cfs)          Figure B.8.


models, for analyzing seismically induced dam failures.                        may be analytically evaluated using many PMF
C is a constant, taken as 100 for this study A is the drainage area in square miles.                        5. Draw a smooth curve through the points. Reason- able extrapolations above and below the defined curve Each PMF discharge determination of 50 square miles        may be made.
    and for estimating the resulting water levels.                                  estimating components (e.g.. routing techniques. water level determinations) after conservative assumptions of The probable maximum flood may be thought of as                          flood wave initiation (such as dam failures) have been one generated by precipitation, and a seismically                              made. Each potential flood component requires an induced flood as one caused by dam failure. For.many                            in-depth analysis. and the basic data and results should sites, however, these two types do not constitute the                          be evaluated to assure that the PMF estimate is worst potential flood danger to the safety of the nuclear                      conservative. In addition. the flood potential from power plant. Analyses of other flood types (e.g.,                              seismically induced causes must be compared with the tsunami, seiches, surges) will be discussed in subsequent                      PMF to provideappropriate flood design bases. but the appendices.                                                                    seismically induced flood potential may be evaluated by simplified methods when conservatively determined The probable maximum flood (PMF) on streams                                results provide acceptable design bases.


and rivers is compared with the upper limit of flood potential that may be caused by other phenomena to                                   Three exceptions to use of the above-descrihed develop a basis for the design of safety-related structures                    analyses are considered acceptable as follows:
or more was adjusted to one or more of the six selected            6. Read the PMF peak discharge at the site from the index drainage areas in accordance with the slope of the        curve at the appropriate drainage area.
    and systems required to initiate and maintain safe                                  a. No flood analysis is required for nuclear power shu.tdown of a nuclear pow'er plant. This appendix.                            plant sites where it is obvious that a PMF or sismically outlines the nature and scope of detailed hydrologic                          induced flooding has no bearing. Examples of such sites engineering activities involved in determining estimates                      are coastal locations (where it is obvious that surges.


for the PMF and for seismically induced floods resulting                      wave action, or tsunami would produce controlling from dam failures, and describes the situations for which                      water levels and flood conditions) and hilltop or "dry"
Creager *curve. Such adjustments were made as follows:
    less extensive analyses are acceptable.                                       sites.
                                                                B.3.3 Probable Maximum Water Level PMF Within Drainage                    Adjusted to Index            When the PMF peak discharge has been obtained as Area Range, sq. mi.                Drainage Area, sq. mi.   outlined in the foregoing sections, the PMF stillwater level should be determine


b. Where PNIF or seismically induced flood Estimation of a probable maximum flood (PMF)                             estimates of a quality comparable to that indicated requires the determination of the hydrologic response                          herein exist for locations near the site of the nuclear (losses, base flow, routing, and runoff model) of                              power planw, they may be extrapolated directly to the watersheds to intense rainfall, verification based on                          site, if such extrapolations do not introduce potential
====d. The methods given in====
                                                                              1.59-5
          50 to 500                             100            Appendix A, Section A.11, are acceptable for this
        100  to 1,000                          500            purpose.


errors of more than about a foot in PMF water level                insofar as these are deemed reasonably possible of estimates.                                                         occurrence on the basis of hydrometeorological c. It is recognized that an in-depth PNF estimate            reasoning." The PMP should represent the depth, time, may not le warranted because of the inherent capability            and space distribution of precipitation that approaches of lihe design of some nuclear power plants to function            tile upper limit of what the atmosphere and regional sofely with little or no special provisions or because the         topography cani Iroduc
500  to 5,000                        1,000
      1,000  to 10,000                        5,000
                                                                B.3.4 Wind-Wave Effects
      5,000  to 50,000                      10,000
      10,000  or greater                      20,000                Wind-wave effects should be superimposed on the PMF stillwater level. Criteria and acceptable methods are The PMF values so adjusted were plotted on maps of        given in Appendix A, Section A.12.


====e. The critical PMP====
the United States east of the 103rd meridian, one map for each of the six index drainage areas. It was found                              B.4 LIMITATIONS
time and costs of making such an estinate ate not                  meteorological conditions are based on an analysis of coninmensurate with the cost of providing protection. In          air-mass properties (e.g., effective precipitable water, such cases, other nieans of estimating design basis flnois        depth of inflow layer, temperatures, winds), synoptic are acceptable if it can he demonstrated that the                  situations prevailing during recorded storms in tile technique utiliied or the estimate itself' is conservative.       region, topographical features, season of occurrence, and Similarly. conservative estimates of seisinically induced         location oh the respective areas involved. The values thus flood potenti:al may provide adequate denmonstration of            derived are designated as the PMP, since they are nuclear power plant safety.                                        deterinited witthin Ilie limitations of current meteorological theory and available data and are based A.2. PROBABLE MAXIMUM FLOOD (PMF)                           on the most effective combinalion of critical factors con Iollinrg.
that there were areas on each map with insufficient points to define isolines. To fill in such gaps, conserva-          1. The NRC staff will continue to accept for review tive computations of approximate PMF peak discharge            detailed PMF analyses that result in less conservative were made for each two-degree latitude-longitude inter-        estimates. In addition, previously reviewed and appruved section on each map. This was done by using enveloped         detailed PMF analyses at specific sites will continue to relations between drainage area and PMF peak discharge        be acceptable even though the data and procedures in            I
(in cfs per inch of runoff), and applying appropriate          this appendix result in more conservative estimates.


Probable maxir'inn Ilood sttid:,-         should be coiripatible with the specific definitions and criteria                    A.3 HYDROLOGIC CHARACTERISTICS
probable maximum precipitation (PMP) at each two- degree latitude-longitude intersection. PMP values, ob-           2. The PMF estimates obtained as outlined in Sec- tained from References 3 and 4, were assumed to be for        tions B.3.1 and 13.3.2 are peak discharges that should be a 48-hour storm to which losses of 0.05 inch per hour          converted to water level to which appropriate wind-wave were applied. These approximate PMF values were also           effects should be added.
summnnarized as follows:
      a. The Corp; of Engineers defines the PMF as "the                  Hydrologic characteristics of the watershed and hyp.,thetical I1(x)d characteristics (peak discharge.              sireani channels relative to the plant site should be Volmnc. arid hydroge? ih shape) that are considered to he          duierniniied fromt the Iollowing:
the most      severe reasonrabl\  possible at a particular              a. A topographic map of the drainage basin location. haised on relatIively comprehensive                      showing watershed boundaries for the entire basin and hvdr ometeoro logic:' I analysis o f critical                      principal tributaries and other subbasins that are rt niill-producing precip tation (and snowmell. if                pertinent. The mnap should include ;          location of pertinent) and hydroltgic factors favorable for                    principal stream gaging stations and other hydrologically ima*inuirm fltiod ruinoff." Detailed PM F determinations           related record collection stations (e.g., streamflow, are usuially prepared by estimating the areal distribution        precipitation) and the locations of existing and proposed of *'prohbahe maximurn" precipitation (PNIP) over flie            reseroirs.


subject drainage basin in critical periods of time. and                 b. The drainage areas in each of the pertinent computing the residual runoff hydrograph likely to                watersheds or subbasins above gaging stations, reservoirs, result with critical coincident conditions of ground              any river control structures, and any unusual terrain wetness and related factors. PMF estimates are usually             features that could affect flood runoff. All major based un the observed and deduced characteristics of              reservoirs and channel improvements that will have a hi St ori:al flood-producing storms anid associated                major influence on streamfnow during flood periods hy dro log ic factors modified on the basis of                    should be considered. In addition, the age of existing hydronietecorological    analyses  to represent  the most        structures and information concerning proposed projects severe runoff conditions considered to be "reasonably              affecting runoff characteristics or streamflow is needed possible" in the particular drainage basin under study. In        to adjust streamflow records to "pre-project(s)" and addition to determining the PMF for adjacent large rivers          "with project(s)" conditions as follows:
plotted on the maps for each index drainage area and the enveloping isolines were drawn as shown on Figures B.2             3. If there are one or more reservoirs in the drainage through B.7.                                                   area upstream of the site, seismic and hydrologic dam failure' flood analyses should be made to determine B.3.2.2 Use of Maps                                            whether such a flood will produce the design basis water level. Criteria and acceptable methods are included in The maps may be used to determine PMF peak                Appendix A, Section A.10.
and strearims. a local PMF should be estimated for each                      (1) The term "pre-project(s) conditions" refers local drainae coUrSe that can influence safety-related            to all characteristics of watershed features and facilities, including lie roofs of safety-related buildings.       developments that affect runoff characteristics. Existing to assure that local intense precipitation cannot                  conditions are assumed to exist in the fiture if projects constitule a threat to tile safety of tlie nuclear power          are to be operated in a similar manner during the life of plant.                                                             the proposed nuclear power plant and watershed runoff b. Probable maxinium precipitation is defined by            characteristics are not expected to change due to tile Corps of Engineers and the National Oceanic and              development.


Atnmospheric Administrat ion (NOAA) as "thie t liheret ically                (2) The term "with project(s)" refers to the greatest depth of precipitation for a given duration that          future effects of projects being analyzed, assuming they is nieleorologically possible over the applicable drainage        will exist in the future and operate as specified. If area that would produce flood flows of which there is              existing projects were not operational during historical virtually no risk of being exceeded. These estimates              floods and may be expected to be effective during the usually involve detailed analyses of historical                    lifetime of the nuce.r, power plant. their effects on flood-producing storms in the general region of the               historical floods should be determined as part of the drainage basin under study. arid certain nmodificalions            analyses out lined in Sections A.5. A.6. and A.8.
discharge at a given site with a known drainage area as follows:                                                          4. Because of the enveloping procedures used, PMF
                                                                peak discharges estimated as outlined in Section B.3.2
    1. Locate    the   site on the 100-square-mile  map,    have a high degree of conservatism. If the PMF so Figure B.2.                                                    estimated casts doubt on the suitability of a site, or if protection from a flood of that magnitude would not be
    2. Read and record the 100-square-mile PMF peak            physically or economically feasible, consideration should discharge by straight-line interpolation between the           be given to performing a detailed PMF analysis, as isolines.                                                     outlined in Appendix A. It is likely that such an analysis will result in appreciably lower PMF.levels.


and extrapolations of historical data and reflect more                  c. Surface and subsurface characteristics that severe rainfall-runoff relations than actually recorded.           affecl runoff and streamiflow to a major degree, (e.g..
3. Repeat Steps 1 and 2 for 500, 1,000, 5,000,
                                                              1.59-6
  10.000, and 20,000 square miles from Figures B.3                In this context, "hydrologic dam failure" means a failure through B.7.                                                     caused by a flood from the drainage area upstream of the dam.


large swamp areas, noncontributing drainage areas,                  precipitation measurements are usua~ly distributed, in groundwater flow, and other watershed features of an                time, using precipitation recorders. Areal distributions of unusual nature to the extent needed to explain unusual              precipitation. for each time increment, are generally characteristics of streamflow).                                      based on a weighting procedure in which tihe incremental d. Topographic features of the watershed and                  precipitation over a particular drainage area is computed hi-!orical flood profiles or high water marks. particularly          as tile sum of tihe corresponding incremental in the vicinity of the nuclear power plant.                          precipitation for each precipitation gage where cacch e. Stream channel distances hetween river control              value is separately weighted by the percL1ntage of the structures, major tributaries, and the plant site.                  drainage area considered to be represented by the rain f. Data on major storms and resulting floods of                gage.
1.59-26


record in the drainage basin. Primary at tcntion should be                b. The determination of base flow as the time given to those events having a major bearing on                      distribution( of the difference between gross runoff arnd hydrologic computations. It is usually necessary to                  net runoff.
APPENDIX B
                                                  REFERENCES
1. Nunn, Snyder, and Associates, "Probable Maximum              Maximum Precipitation East of the 105th Meridian,"
  Flood and Hurricane Surge Estimates," unpublished            Hydrometeorological Report No. 33, 1956.


analyze a few major floods of record in order to develop                  c. Computation of distributed (in time)
report to NRC, June 13, 1975 (available in the public document room).
such things as unit hydrograph relations, infiltration              differences between precipitation and net direct runoff.
2. W.P. Creager, J.D. Justin, and J. Hinds, "Engineering      4. U.S. Department of Commerce, N.OAA, "All-Season For Dams," J. Wiley and Sons, Inc., New York, 1945.          Probable Maximum Precipitation-United States East of the 105th Meridian, for Areas from 1,000 to
3. U.S. Weather Bureau (now U.S. Weather Service,                20,000 Square Miles and Durations From 6 to 72 NOAA), "Seasonal Variation of the Probable                    Hours," draft report, July 1972.


indices, base flow relationships, information on flood              the difference being considered herein as initial and routing relationships, and flood profiles. lxcept in                inflitrafion losses.
1.59-27


unusual cases, climatological data available from the                      d. The determination of the combined effect of Department of Commerce. The U.S. Army Corps of                      drainage area. channel characteristics, and reservoirs on Engineers. National Oceanic and Atmospheric                          the runoff regimen, herein referred to as the "'runoff Administration and other public sources are adequate to              model." (Channel and reservoir effects are discussed meet the data requirements for storm precipitation                  separately in Section A.8.)
450'
histories. The data should include:
          410
           (I) Hydrographs of major historical floods for                A.5 PRECIPITATION LOSSES AND BASE FLOW
'l0            CALIFORNIA-
pertinent locations in the basin, where available, from the U.S. Geological Survey or other sources.                               Determination of the absorption capability of the
    t'.)00SOUTH        PACIFIC
          (2) St o rmi precipitation              records,          basin should consider antecedent and initial conditions depth-area-duration data, and any available isohyetal                and infiltration during each storm considered.
                                                                                                133'
                                        ROGRANDEmis
           290                                            TEXAS-GULF                          I 290
                                                                                                1250
                    1170      1130 1090    1050      1010        970    930      890 850 810
                                                FIGURE B.1 WATER RESOURCES REGIONS
                                                                      F


maps for the most severe local historical storms or floods          Antecedent precipitation conditions affect precipitation that will be used to estimate basin hydrological                    losses and base flow. These assumptions should be characteristics.                                                    verified by studies in the region or by detailed storm-runoff studies. Tile fundamental hydrologic A.4 FLOOD HYDROGRAPH ANALYSES                                factors should be derived by analyzing observed hydrographs of streamflow and related stormis. A
t    ISOLINE REPRESENTING PEAK FLOW OF
      Flood hydrograph analyses and related                          thorough study is essential to determine basin computations should be used to derive and verify the                characteristics and meteorological influences affecting fundamental hydrologic factors of precipitation losses              runoff from a specific basin. Additional discussion and (see Section A.5) and the runoff model (see Section                  procedures for analyses are contained in various A.6). The analyses of observed flood hydrographs' of                publications such as Reference 2. The following streamflow and related storm precipitation (Ref. I) use              discussion briefly describes the considerations to be basic data and information referred to in Section A.3                taken into account in determining the minimum losses above. The sizes and topographic freatures of the                    applicable to the PMF:
      PMF IN 1,000 CFS.
subbasin drainage areas upstream of the location of                        a. Experience indicates the capacity of a given soil interest should be used to estimate runoff response for              and its cover to absorb rainfall applied continuously at each individual hydrologically similar subbasin utilized            an excessive rate may rapidly decrease until a fairly in the total basin runoff model. Subbasin runof'                    definite minimum rate of infiltration is rcached. usually response characteristics are estimated from historical              within a period of a few hours. Infiltration relationships storm precipitation and streamflow records where suchi              are defined as direct precipitation losses such that the are available, and by synthetic means where no                      accumulated difference between incremental streamflow records are available. The analysis of flood              precipitation and incremental infiltration equals the hydrographs (Ref. 2) should include the following:                  volume of net direct runoff. The infiltration loss relationships may include initial conditions directly, or a. Estimates of the intensity, depth, and areal may require separate determinations of initial losses. The distribution of precipitation causing the runoff for each            order of decrease in infiltration capacity and the historical storm (and rate of snowmelt. where this is                minimum rate attained are primarily dependent upon significant). Time distributions of storm precipitation              the vegetative or other cover, the size of soil pores are generally based on recording rainfall gages. Total within the zone of aeration, and the conditions alfecting the rate of removal f"capillary water from the zone of
    'Strcamflow hydrographs (of major floods) are available in      aeration. The infiltration theory, with certain publications by the US. Geological Survey. National Weather Service, State agencies, and other public Sources.                    approximations, offers a practical means of estimating
                                                                1.59.7


the volume of surface runoll fronm intense rainlfall.                                  A.6 RUNOFF MODEL
NOTE: PMF ISOLINES ON THIS CHART REPRESENT ENVELOPED
   However. in applying tile method to natural drainage basins, tile following factors must be considered:                         The hydrologic response characteristics of the (I) Since the infiltration capacity of a given          watershed to precipitation (such as unit hydrographs)
  VALUES OF PEAK RUNOFF FROM 100-SQUARE MILE DRAINAGE          160
   soil at the beginning of a storm is related to antecedent          should be determined and verified from historical floods field moisture and the physical condition ofthe soil. the          or by conservative synthetic procedures. The model infiltration capacity for the same soil may vary                   should include consideration of nonlinear runoff appreciably from storm to storm.                                    response due to high rainfall intensities or unexplainable
   AREA UNDER NATURAL RIVER CONDITIONS. ACCORDINGLY,
            (.2) The infiltration capacity of' a soil is            factors. In conjunction with data and analyses discussed normally highest at the beginning of rainfall, and since            above, a runoff model should be developed, where data rainfall frequently begins at relatively moderate rates, a          are available, by analytically "reconstituting" historical substantial period of time may elapse before the rainfall            floods to substantiate its use for estimating a PMF. The intensity exceeds the prevailing infiltralion capacily. It is        raiitfall-runofftlime-areal distribution of historical floods gnerally accepted that a fairly definite quantity of                should be used to verify that tile "reconstituted"
I PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU-
waler loss is required to satisfv initial soil moislture            hydrographs correspond reasonably well with flood deficiencies before nnoff will occur, the amount of                  hydrographs actually recorded at selected gaging stations initial loss depending upon antecedent conditions.                    kRef. 2). In most cases. reconstil ut ion studies should he
  TIONS TO PEAK FLOW THAT WOULD RESULT FROM                         140
            (3) Rainfall does not normally cover the entire          made with respect to two or more floods and possibly at drainage basin during all periods of* precipitation with            two or more key locations, particularly where possible intensities exceeding infillration capacities. Futhermore.          errors in the determinations could have a serious impact soils and infiltration capacities vary throughout a                  on decisions required in the use of* the runoff model for drainage basin. Therefore, a rational application of any            the PMF. In some cases, the lack of sufficient time and loss.rate technique must consider varying rainfall                  areal precipitation definition, or unexplained causes.
   UPSTREAM DAM FAILURES OR OTHER UNNATURAL EVENTS.                    1
    1190    1170  1150  113'  111&deg;  1090  1070  1050 1030 101'   990
                              FIGURE B.2 PROBABLE MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 100 SOUARE MILES


intensities in various portions of the basin in order to            have not allowed development of' reliable predictive de te rmine        tile area covered by effective                    runoff models, and a conservative PMF model should be runolf-producing rainfall.                                           assured by other means such as conservatively developed b. Initial loss is defined as thie maximnum amount            synthetic unit hydrographs. Basin runoff' models for a of precipitation that can occur without producing                    PMF determination should provide a conservative runoff. Initial loss values may range from a minimum                estimate of the runoff that could be expected during the value of a few tenths of an inch during relatively wet                life of the nuclear power plant. The basic analyses used seasons to several inches during dry summer and fall                in deriving thie runoff model are not rigorous, but may months. Tile initial loss conditions conducive to major              be conservatively undertaken by considering the rate of floods usually range from about 0.2 to 0.5 inch and are              runoff from a unit rainfall (and snowmelt. if pertincnt)
470
relatively small in comparison with the flood runoff                of some unit duration and specific time-ae.ral volume. Consequently. in estimating loss rates from data              distribution (called a unit hydrograph). The applicability for major floods, allowances for initial losses may be              of a unit hydrograph. or other technique, for use in estimated approximately without introducing important                computing the runoff from an e..'uiiated probable errors in the results.                                                maximum rainfall over a basin may be partially verified c.  Base flow is defined herein as that portion of a        by reproducing observed major flood hydrographs. An flood hydrograph which represents antecedent runoff                  estimated unit hydrograph is first applied to estimated condition and that portion of the storm precipitation                historical rainfall-excess values to obtain a hypothetical which infiltrates the ground surface and moves either                runoff hydrograph for comparison with the observed laterally toward stream channels, or which percolates                runoff hydrograph (exclusive of base flow-net ninoff),
                                                                                                                450
into the ground, becomes groundwater, and is discharged              and the loss rate, the unit hydrograph. or both. are into stream channels (sometimes referred to as bank                  subsequently adjusted to provide accurate verification. A
                                                                                                                430
flow). The storm precipitation, reduced by surface                  study of the runoff response of a large number of basins losses, is then resolved into the two runoff components:            for several historical floods in which a variety of valley direct runoff and base flow. Many techniques exist for              storage characteristics, basin configurations, estimating thie base flow component. It is generally                topographical features, and meteorological conditions assumed that base flow conditions which could exist                  are represented provides the basis for estimating the during a PMF are conservatively high. the rationale being            relative effects of predominating influenm-i for use in that a storm producing relatively high runoff could                  PMF analyses. In detailed hydrological studies, each of meteorologically occur over most watersheds about a                  the following procedures may be used to advantage:
                                                                                                                410
week earlier than that capable of producing a PMF. One                      a. Analysis of rainfall-runoff records for major assumption sometimes made for relatively large basins is            storms;
                                                                                                                390
that a flood about half as severe as a PMF can occur                        b. Computation of synthetic runoff response three to five days earlier. Another method for evaluating            models by (I) direct analogy with basins of similar base flow relates historical floods to their corresponding          characteristics and/or (2) indirect analogy with a large base flow. The base flow analyies of historical floods.              number of other basins through the application of there"fore,       may he readily utilized in PMF                    empirical relationships. In basins for which historical determinations.                                                      streamflow and/or storm data are unavailable, synthetic i .59.9
                                                                                                                370
                                                                                                                350
'.
                                                                                                                330
                                                                                                                310
                                                                                                                290
      ,-ISOLINE REPRESENTING PEAK FLOW OF
        PMF IN 1,000 CFS.


4 techniques are the only known means for estimating                estimates are made of tile amount of increase in rainfall hydrologic response characteristics. However, care must            quantities that would have resulted if condilions during be taken ito assure that a synthetic model conse.rvatively        the actual storm had been as critical as those considered reflects tile runoff response expected froin precipitation        probable of occurrence in tile region. Consideralion is as severe as thie estimated PMP.                                  given to the modifications in meteorological conditions that would have been required IOr each of" the record Detailed flood hydrograph analysis techniques and            storms to have occurred over the drainage haisin under studies fkor specific basins are available from many              study. considering topographical features and locations agencies. Published studies such as those by tile Corps of        of the respective areas involved.
270
  NOTE: PMF ISOLINES ON THIS CHART REPRESENT ENVELOPED
  VALUES OF PEAK RUNOFF FROM 500-SQUARE MILE DRAINAGE
  AREA UNDER NATURAL RIVER CONDITIONS. ACCORDINGLY,
  PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU-                                                        250
  TIONS TO PEAK FLOW THAT WOULD RESULT FROM UPSTREAM
  DAM FAILURES OR OTHER UNNATURAL EVENTS.


Engineers, Bureau of Reclamation. and Soil Conservation Service may be utilized directly where it can be demonstrated that they are of a level of' quality                The physical linimiations in meteorological comparable with that indicated herein. In particular, the          mechanisms *orthe maximum depth. time. and space Corps of Engineers have developed analysis techniques              distribution of precipitation over a basin are I )
I     I      1    I    I      I      T    -
  (Rfs. 2, 3) and have accomplished a large number of                humidity (precipitable water) in tile air flow over the studies in connection with their water resources                  watershed. (2) the rate at which wind may carty lhie development activities.                                          humid air into tile basin. :ind (3) tile fraction of tile inflowing atmospheric water vapor that can be Computerized runoff models (Ref. 3) offer an                precipitated. Each of these limitations is handled extremely efficient tool for estimating PMF runoff rates          differently to estimate tile probable miaximum and for evaluating tihe sensitivity of PMF estimates to            precipitation over a basin, and is modified further for possible variations in parameters. Such techniques have          regions where topography causes marked orographic been used successfully in making detailed flood                    control (designated as the orographic model) as opposed estimates.                                                        to the general model (with little topographic effect}) 0
                              FIGURE B.3 PROBABLE MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 500 SQUARE MILES
                                                                    precipitation. Further details on the models and Snowmelt may be a substantial runoff component              acceptable procedures ate contained in References 5 for both historical floods and the PMF. In cases where it        and 6.


is necessary to provide for snowmelt in the runoff                    a. The PNIP in regions of limited t opographic
470
. model, additional hydrometeorological parameters must be incorporated. The primary parameters are the depth of assumed existing snowpack. the areal distribution of influence (mostly convergence precipitation) may he estimated by maximizing observed intense storm patterns in thie site region for various durations.
470
450                                                                                                                14                              45'
430                                                                                                                  200                      250  43'
                                    4300
410                                                                                                1                      2                        410
                  3 9 0
                                                                                                                            0            4 04    3 9.0
                                                                                                                                                      0
370                                                                                                                                                370
                                                                                                  4.5                                  350
330                                                                                                                                                330
31040                                                                                                                            5                310
290                                                                                                                                                290.


intensities, and depth-area relations and transposing assumed existing snowpack ( and in basins with distinct changes in elevation, the areal distribution of snowpack         them to basins of interest. The increase in rainfall with respect to elevation), the snowpack temperature              quantities that might have resulte! from maximizing and density distributions, the moisture content of the            meteorological conditions during the rtcord storm and snowpack. the type of soil or rock surface and cover of           tile adjustments necessary to transpose the respective the snowpack, the type of soil or rock surface and cover          storms to the basin under study should be taken into in different portions of the basin, and the time and              account. The maximum storm should represent tli.. most elevation distribution of air temperatures and heat input         critical rainfall depth-area-duration relation for the during the storm and subsequent runoff period.                   particular drainage area during various seasons o" ithe Techniques that have been developed to reconstitute                year (Refs. 7. 8. 9, 10). In practice. the parameters historical snowmelt floods may be used in both                    considered are (I) the representative storm dewpoint historical flood hydrograph analysis and PMF (Ref. 4)              adjusted to inflow moisture producing the maximum determinations.                                                    dewpoint (precipitable water), (2) seasonal variations in parameters. (3) the temperature contrast. (4) thie A.7 PROBABLE MAXIMUM                             geographical relocation, and (5) thie depth-area PRECIPITATION ESTIMATES                            distribution. Examples of these analyses are explained and utilized in a number of published reports (Refs. 7.8.
270          PMF IN 1 000 CFS.                                  503020270
        NOTE: PMF ISOLINES ON THIS CHART REPRESENT ENVELOPED
        VALUES OF PEAK RUNOFF FROM 1,000-SQUARE MILE DRAINAGE                500        350
         AREA UNDER NATURAL RIVER CONDITIONS. ACCORDINGLY,          ___I
25      PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU-                                                                                    250
                        I *,;^,*                        ....
         TIONS TO PEAK FLOW THAT WOULD RESULT FROM UPSTREAM45              I      045ol1      I
        DAM FAILURES OR OTHER UNNATURAL EVENTS.0
    1210    1190  1170  1150  113"  111'  1090  1070    105"  103"   101l          97'  95" 93" 91" 89" 87'    850    83'  81, FIGURE B.4   PROBABLE MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 1.000 SQUARE MILES


Probable maximum precipitation (PMP) estimates               9. 10).
470
   are the time and areal precipitation distributions                          This procedure, supported with an appropriate compatible with the definition of Section A.2 and are              analysis. is usually satisfactory where a sufficient based on detailed comprehensive meteorological analyses            number of historical intense storms have been of severe storms of record. The analysis uses                      maximized and transported to the basin and where at precipitation data and synoptic situations of major                least one of them contains a convergent wind
450
                                                                    "mechanism" very near the maximum that nature can be storms of record in a region surrounding the basin under study in order to determine characteristic combinations            expected to produce in the region (which is generally the
410
. of meteorological conditions that result in various rainfall patterns and depth-area-duration relations. On the basis of an analysis of airmass properties and case in the United States east of the Rocky Mountains).
390
                                                                    A general principle for PMP estimates is: The numher and seperily of JnaximiyathiV steps must balance ihe synoptic situations prevailing during the record storms,          adequacy of the storm sample, additional inaximizatioun
350
                                                              1.59-9
                                                                          700                        6000,.
330                        29&deg;I800
                          2900
3106
               27~  IN 1,000 CFS.000
                            _1PMF
25&deg;    PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU9 TIONS TO PEAK FLOW. THAT WOULD RESULT FROM UPSTREAM DAM
      FAILURE OR OTHERUNARLEVTS
    121&deg;   1190  1170  1150    T13&deg;  1110 1090  1070  1Q05 1030 j01&deg;  gg0  970  950  930  910  890    870  850
                                                                                                                        830
                                      FIGURE B.5  PROBABLE MAXIMUM  FLOOD (ENVELOPING PMF ISOLINES) FOR 5,000 SQUAR
                                                                                                                      E MILES


* .. .
470
steps are required in regions of more limiteid storm               amenable to generalization for snowinell computations sanmples.                                                          (Ref. 14). The meteorological (e.g., wind, temperature, b.  PMI1 determinations in regions of orograplhit            dewpoints) sequences prior to, during, and after the influences generally are for hlie high mountain regions            postulated PMP-producing storm should be compatible that lie in the path of Ithe prevailing moist wind.                with the sequential occurrence of the PMIP, The user Additional maximization steps front paragraph A.77.a.              should place the PNIP over the basin and adjust the above are required in the use of the orographic model              sequence of olher parameters to give the most critical (Refs. 5, 6). The orographic moxlel is developed for the            runof flor t(ie season considered.
                                                                                                                                450
                                                                                                                                430
                                                                                                                                410
                                                                                                                                390
                                                                                                                                370
.J1                                                                                                                              350
                                                                                                                                330
                                                                                                                                310
                                                                                                                                290
              ISOLINE REPRESENTING PEAK FLOW OF
               PMF IN 1,000 CFS.


orographic component of precipitation where severe precipitation is expected it) be caused largely by tire                  The meteorological parameters for snowniel lifting imparted to fie ait by' mounwains. This orographic          comIpu tations associated with PNIP are discussed in more influence gives a basis for a wind model with maximized            detail in References II 12, and 14.
"..#    ,.                        I                                                                                  270
        NOTE: PMF ISOLINES ON THIS CHART REPRESENT ENVELOPED
      / VALUES OF PEAK RUNOFF FROM 10,000-SOUARE MILE DRAINAGE
        AREA UNDER NATURAL RIVER CONDITIONS. ACCORDINGLY,
        PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU.                                                                  250
        TIONS TO PEAK FLOW THAT WOULD RESULT FROM UPSTREAM DAM
        FAILURES OR OTHER UNNATURAL EVENTS.


inflow. Assuming laminar        %low of air over any particular mountain cross section. one can calctlate Ihe liife" of                  Other items that need to be considered in the air. the levels at which raindrops and snowflakes are          determining basin melh are optimntum depth. areal extent.
1210    1190    1170 1150  1130    1110 1090  1070 1050  1030 1010 990  970  950 930    910  890  870  850  830  810
                                      FIGURE B.6  PROBABLE MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 10,000 SQUARE MILES


formed. and their drift with the air before they strike            and type of snowpack. and other snowmuell factors (see lhe ground. Such mnodels are verified by reproducing the            Section A.8). all of which must he compatible with the precipitation'in observed storms and are then used for              most critical arrangement of the PMP and associated estimating PIMP by introducing maximum values of                    nueiiorological paramneters.
~100
350
                        4&#xfd;                                          100                                                400 1600 1800
330&deg;50
311
                                      2900
      TIN T      ISOLINE REPRESENTING PEAK FLOW OF                  DAM            1200
                                                      C O DN L          1300                                        16
250    AR AU D RN T R LRV R O DTO S
                  PMDF IN 1,000 C FSO
                                                                                                                                                                2?
      NOTE: PMF    ISOLINES ON THIS CHART    REPRESENTMILE
                                        20,000-SQUARE    ENVELOPED
                                                              DRAINAGE .     1400MI              1100
      VALUES OF PEAK RUNOFF FROM
                                                                        .   . 1310
250    AREA UNDER NATURAL RIVER CONDITIONS. ACCORDINGLY.


mtoisture and wind as inllow at thie foot of thie mountains. Maximum moisture is evaluated just as in                       Critical piobable maxiniuni storm estimates for very nonorogiaphic regions. In mnotntainous regions, where                large drainage areas are determined as above, but may storms cannot readily be transposed (paragraph A.7.a.               differ somewhat in flood-producing storm rainfall from above) because of !heir intimate relation to the                    those encountered in preparing similar estimates for immnediate tuderlying topography. historical stornits are          small basins. As a general rule. the critical PMP in a small resolved into their convective and orographic                        basin results primarily from extremely intense small-area compnecnts and maximnized as follows: (I) mraximuim                storms; whereas in large basins the PMP usually results moisture is assunied. (2) maxinmum winds are assumed.                from a series of less intense, large-area storms. In very and finally (3) maximum values of tIle orographic                    large river basins (about 100,000 square miles or larger)
1 3      0 0              0    0
consponent and convective component (convective as in                si.:h as the Ohio and Mississippi River basins, it may be nonorographic areas'l of precipitation are considered to            necessary to develop hypothetical PMP storm sequences occur simultanretously. Some of the published reports              (one storm period followed by another) and storm that ill ustr:ute the combination of orographic and                  tracks with an appropriate limte interval between storms.
                                                                                                        0g 9    9 0    8 0  8 0  8 0  3      9        7
  1270PMF110 VALUES 17OBTAINED    NOT INCLUDE
                            15 DO 13    11 0      9    0 0CONTRIBU-
                                                1POSSIBLE    . 00                       g 0 9               300
                                                                                                                                                                25 T'IONS TO PEAK FLOW THAT WOULD RESULT FROM UPSTREAM DAM                      10
      DAM FAILURES OR OTHER UNNATURAL EVENTS.                 .
  121&deg;    119&deg;  1170    1150  113&deg;     Ili,   109&deg;  107'  "1050  103&deg;    101'    99&deg;  97o    95'    93&deg;  91&deg;    89'  B7'  85&deg; 83o 810 79&deg;      77'
                                                                                                                                                            75' 73'
                                    FIGURE B.7      PROBABL E MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 20,000 SQUARE MILES


convective components. including seasonal variation, are            The type of meteorological analyses required and typical References II. 12, and 13.                                         examples thereof are contained in References 9, 15, and
I
                                                                    16.
            r*V
                              I      I I  I  III
                                                          I                          I  I        SI  I I    lfl &#xfd; I  I I  I  I I I
  LLf                                                                                            I I I      T    I I I  I I I I
                        -EXAMPLE:                                                                                        .1 Li L
                          -FOR DRAINAGE AREA OF
                        -2,300 SQ. MI. AT LAT. 95",
                          LONG. 430, DETERMINE PMF -1-4.                                      -SOLUTION:
                          PEAK
                              I
                                DISCHARGE.


In somne large watersheds. major floods ate often the result of melting snowpack or of snownilt combined with rain. Acco:dingly.        the probable maxinmum                    The position of probable maximum rainfall centers.
II I    I III!        I  I
                                                                  I I I  I I
                                                                                  -                FOR DRAINAGE AREA OF
                                                                                                -2,300 SQ. MI., PMF PEAK =
      Lci il-HI                        -
                                                                                                    400,000 CFS.


precipitation (rainfall) and maximunt associated identified by "isolyetal patterns" (lines of constant runoff-producing snowpacks are both estimated on a rainfall depth), may have a very great effect on the seasonal and elevation basis. The probable maximum                   regimen of runoff from a given volume of rainfall excess.
;  [ i I
                                                                            POINTS FROM
  0                                                                        FIGURES B.2-B. J
  0
'C            11flai IL
                                                                                          ~flh1IEl3~
              .  _W=I
      0                i    i  I I I I I1'r          Z  i  i I
  0
  Cc
                  1 01                                .
                    .10
                                                  100                   1000                      10,000                      100,000
                                                        DRAINAGE AREA, SQUARE MILES
                                    FIGURE B.8 EXAMPLE OF USE OF ENVELOPING ISOLINES


seasonal snowpack water equivalent should be                        particularly in large drainage basins in which a wide determined by study of accumulations on local range of basin hydrologic runoff characteristics exist.
TABLE B.1 PROBABLE MAXIMUM FLOOD DATA ( )
                                                                            Drainage  Basin Average PMF Peak Project      State    River Basin            Stream              Area      (in inches)  Discharge (sq.mi.)  Prec. Runoff    (cfs)
                              North.Atlantic Region (Northeast Atlantic Sub-region)
    Ball Mountain    Vt,      Connecticut      West River                      172  20.6    18.1      190,000
    Barre Falls      Mass.    Connecticut        Ware River                      55  20.1    18.9      61,000
    Beaver Brook      N. H.    Connecticut      Beaver Brook                      6.0 21.3    19.7      10,400
    Birch Hill        Mass.    Connecticut      Millers River                  175  18.3    17.1      88.500
    Black Rock        Conn.    Housatonic        Branch Brook                    20  22.2    20.6      35,000
    Blackwater        N. H.    Merrimack        Blackwater River                128  18.3    16.4      95,000
    Buffumville      Mass.    Thames            Little River                    26  26.6    25.3      36,500
    Colebrook        Conn.    Connecticut      Farmington River                118  22.7    21.1      165,000
    Conant Brook      Mass.    Connecticut        Conant Brook                    7.8 24.4    23.2      11,900
    East Barre        Vt.      Winooski          Jail Branch                      39  21.5    18.6      52,500
    East Branch      Conn.    Housatonic        Naugatuck River                  9.2 24.0    22.8      15,500
    East Brimfield    Mass.    Thames            Quinebaug River                  68  24.2    22.9      73,900
W*
0\
CYN Edward McDowell  N. H.    Merrimack        Nubanusit River                  44  19.5    18.3      43,000
    Everett          N. H.    Merrimack        Piscataquog River                64  20.7    18.2      68,000
    Franklin Falls    N.H.    Merrimack        Pemigewasset River          1,000    15.8    13.3      300,000
    Hall Meadow      Conn.    Connecticut      Hall Meadow Brook                17  24.o    22.8      26,600
    Hancock          Corn.    Housatonic        Hancock Brook                  12  24.0    22.8      20,700
    Hodges Village    Mass.    Thames            French River                    31  26.2    22.3      35,600
    Hop Brook        Conn.    Housatonic        Hop Brook                      16  25.0    23.8      26,400
    Hopkinton        N. H.    Merrimack          Contoocook River              426  17.4    14.7      135,000
    Knightville      Mass.    Connecticut        Westfield River                162  18.8    17. 6    160,000
    Littleville      Mass.    Connecticut        Westfield River                52  25.1    22.4      98,000
    Mad River        Conn.    Connecticut      Mad River                        18  24.0    22.8      30,000
    Mansfield Hollow  Conn.    Thames            Natchaug River                  159  19.8    18.5      125,000
    Nookagee          Mass.    Merrimack        Phillips Brook                  11  21.8    20.2      17,750
    Northfield        Conn.    Housatonic        Northfield Brook                  5.7 24.4    23.2        9,000
    North Hartland    Vt.      Connecticut      Ottauquechee River              220  19.3    17,2      199,000
    North Springfield Vt.      Connecticut      Black River                    158  20.0    18.3      157,000
    Otter Brook      N. H.    Connecticut      Otter Brook                      47  19.1    17.9      45,000
    Phillips          Mass.    Merrimack        Phillips Brook                    5.0 24.2    23.0        7,700
    Sucker Brook      Conn.    Connecticut      Sucker Brook                      3.4 22.4    21.4        6,500
    Surry Mountain    N. H.    Connecticut      Ashuelot River                  100  22.2    19.6      63,000
    Thomaston        Conn.    Housatonic        Naugatuck River                  97  24.5    22.4      158,000


watersheds from historical records of the region.
TABLE B.1 (Page  2 of 17)
                                                                              Drainage    Basin Average  PMF Peak Project          State    River Basin                Stream            Area        (in inches)  Discharge Prec.., Runoff  (cfs)
                                                                              (sa  mi                      L    .
Townshend              Vt.      Connecticut          West River                    278    21.3    17.2      228,000
Trumbull              Conn.    Pequonnook          Pequonnook River                14    23.0    21.8        26,700
Tully                  Mass.    Connecticut          Tully River                      50  20.0    16.6      47,000
Union Village          Vt.      Connecticut          Ompompanoosuc River            126    1760    15.8      110,000
Vermont-Yankee        Vt.      Connecticut          Connecticut River            6,266                      48O,O00
Waterbury              Vt.      Winooski            Waterbury River                109    18.9    16.0      128,000
West Hill              Mass.    Blackstone          West River                      28    28.0    25.6        26,000
West Thompson          Conn.    Thames              Quinebaug River                74    2064    17.5      85,000
Westville              Mass.    Thames              Quinebaug River                32    25,4    22.8        38,400
                                Merrimack            Whitman River                  18    21.4    19.8        25,000
Whitemanville          Mass.


Several trials may be necessary to determine the critical position of the hypothetical PMP storm pattern (Refs. 8.
Wrightsville          Vt.      Winooski            North Branch                    68    2092    17.3      74,000
                                      North Atlantic Region (Mid-Atlantic Sub-region)
Almond                N. Y.    Susquehanna          Canacadea Creek                  56  22.0    18.8        59,000
Alvin R. Bush          Pa.      Susquehanna          Kettle Creek                  226    24.0    21.1      154,000
Aquashicola            Pa.      Delaware            Aquashicola Creek              66    28.0    24.2      42,500
Arkport                N. Y.    Susquehanna          Canister River                  31    22.5    17.7      33,400
Aylesworth            Pa.      Susquehanna          Aylesworth Creek                  6.2 23.8    22.0      13,700
Baird                  W. Va.  Potomac              Buffalo Creek                  10    34.0    30.2      14,600
Beltzville            Pa.      Delaware            Pohopoco Creek                  97    27.1    25.6      68,000
Bloomington            Md.      Potomac              North Branch                  263    22.2    17.6      196,000
Blue Marsh            Pa.      Delaware            Tulpehockan Creek              175    24.0    21.3      110,600
Burketown              Va.      Potomac              North River                    375    24.3    21.2      272,200
Cabins                W. Va.  Potomac              South Branch                  314    20.8    16.8      195,900
Chambersburg          Md.      Potomac              Conococheague River            141    28.9    26.0      81,400
Christiana            Del.    Delaware            Christiana River                41    32.1    28.3      39,200
Cootes Store          Va.      Potomac              North Fork River              215    22.5    19.1      140,200
Cowanesque            Pa.      Susquehanna          Cowanesque River              298    21.9    18.5      285,000
Curwensville          Pa.      Susquehanna          Susquehanna River              36,;  22.0    18.9      205,000
Dawsonville            Md.      Pot ciMac            Seneca Creek                          206.I    2?.1      i61,900
Douglas Point          Md.      Potomac              Potomac River                        13.4    10.2    1,490,000
East Sidney            N. Y.    Susquehanna          Oulelot River                  102    24.0    22.1      99, 900
Edes Fort              W. Va.  Potomac              Cacapon River                  679    21.2    17.3      410,800
Fairview              Md.      Potomac              Conococleaque Creek            494    22..9    18.8      150,100
Foster Joseph Say( ers Pa.      Susquehanna          Bald Eagle Creek              339    21,8    19.0      251,000
Francis E. Walter      Pa.      Delaware            Lehigh River                  288    2264    19.8     170,000
                                                                  .4


17) or the selected record storm pattern (Refs. 9, 16) to Several methods of estimating the upper limit of               determine the critical isohyetal pattern that produces ultimnate snowpack and rueling are summarized in                     the inaxiumtm rate of runoff at thie designated site. This References 4 and 5. The methods have been applied in                may be accomplished by superimposing an outline of the Columbia River basin, the Yukon basin in Alaska.                 the drainage basin (above the site) on the total-storm the tipper Missouri River basin, and the upper Mississippi           PMP isohyetal contour map in such a manner as to place in Minnesota and are described in a number of reports of            the largest rainfall quantities in a position that would the Corps of Engineers. In many internmediate-latitude              result in the maximum flood runoff (see Section A.8 on basins, the greatest flood will likely result from a                 probable maximuni flood runoff). Thi isohyetal pattern combination of critical snowpack (water equivalent) and              should be reasonably consistent with the assumptions PMP. Thie seasonal variation in both optimum snow                    regarding the meteorological causes of the storm. A        -
TABLE B.1 ( )
depth (i.e., the greatest water equivalent inl the                  considerable range in assumptions regarding rainfall snowpack) and the associated PMP combination should                  patterns (Ref. 11) and intensity variations can be made be meteorologically compatible. Temperature and winds                in developing PMP storm criteria for relatively small associated with PMP are two important snowmelt factors               basins, without being inconsistent with meteorological
                                                                    Drainage  Basin Average P1* Peak Project        State    River Basin            Stream          Area      (in inches)  Discharge (sn.mi.)   Prec.  Runoff    (cfsR
                                                              1.59-10
Franklin            W. Va.  Potomac          South Branch              182  24.2    20.6      174,000
Frederick          Md.      Potomac          Monocacy River            817  23.2    20.9       363,400
Front Royal        Va.      Potomac          S.Fk.Shenandoah River  1,638    18.0    14.3      419,000
Fulton (Harrisburg) Pa.      Susquehanna      Susquehanna River      24,100    12.7    8.2    1,750,000
Gathright          Va.      James            Jackson River              344  24.4    21.3      246,0OO
Gen. Edgar Jadwin  Pa.      Delaware          Dyberry Creek               65  24.8    24.0      119,700
Great Cacapon      W. Va.  Potomac          Cacapon River              677  21*2    17.3      373,400
Harriston          Va.      Potomac          South River                222  29.6    26.5      153,700
Hawk Mountain      Pa.      Delaware          E.Br. Delaware River      812    16.5    12.7      202,000
Headsville          W. Va.  Potomac          Patterson Creek            219  23.4    19.0      176,000
John H. Kerr        Va.      Roanoke          Roanoke River          7,800    16.8    12,9    1,000,000
                    W. Va.                     South Branch            1,577    18.9    14.9      430,000
Karo                        Potomac Keyser              W. Va.  Potomac          North Branch              495    21.5    16.3      279,200
Kitzmiller          Md.      Potomac          North Branch              225  22,3    17,1      120,200
Leesburg            Va.      Potomac          Goose Creek                338  26.5    24.2      340,900
Lewistown          Md.      Potomac          Fishing Creek                7.1 34.8    32.7        12,200
Licking Creek      W. Va.  Potomac          Licking Creek              158  29.0    26.1      125,800
Little Cacapon      W. Va.  Potomac          Little Cacapon River      101  29.7    27o4      122,700
Maiden Creek        Pa.      Delaware          Maiden Creek              161  27.3    23.5       118,000
Martinsburg        W. Va.  Potomac          Opequon Creek              272  27.2    24.1      174,600
Mikville            W, Va.  Potomac          Shenandoah River        3,040    16.2    11.7        592,000
Moorefield          W. Va.  Potomac          South Branch            1,173    18.0    14.0      389,700
Moorefield          W. Va.  Potomac          So. Fk. South Branch      283  21,1    17.1      173,800
Newark              Del.    Delaware          White Clay River           66  29.8    26.0      103,000
North Anna          Va.     Pamunkey(York)   North Anna River           343  25.0    21.3      220,000
North Mountain      W. Va.  Potomac           Back Creek                231  27.9    24.8      256,000
Peach Bottom        Pa.     Susquehanna      Susquehanna River      27,000    12.7    8.2    1,750,000
Perryman            Md.      Chesapeake Bay    Bush River                 118                        87,400
Petersburg          W. Va.  Potomac          South Branch              642  19,3    15.3      208,700
Philpott            Va.     Roanoke          Smith River                212  27.5    24.3      160,000
Prompton            Pa,      Delaware          Lackawaxen River            60  25.0    24.2        87,190
Raystown            Pa.      Susquehanna      Juniata River (Br.)       960  21-4    17.5      353,400
Royal Glen          Md.     Potomac          South Branch               640  19.3    15.3      208,700
Salem Church        Va.      Rappahannock      Rappahannock River      1,598    23.6    19.6      552,000
Savage River        Md.      Potomac          Savage River              105  26.3    22.2      107,400
Seneca              Md.      Potomac          Potomac River          11,400    13.5    10.3    1,393,000
Sharpsburg          Md.      Potomac          Antietem Creek            281  26.6    23.5      154,900


L
TABLE B.1 ( )
,1 0. causes. Drainage basins less than a tew thousand square                 The Corps             of Engineers arnd the miles in area (particularly if only one unit hydrograph is       Hydrometeorological        Branch of NOAA (under a available) may be expressed as average depth over tile           cooperative       arrane tientI since   19)39)) have  made drainage area. However. in deoerntining the BilP pattern          cor nprchlenrsive inet corological studies of extremno for large drainage basins (with varing basin hydrologic           flood-producing storms ( Ref. I ) and have developed a characteristics, including reservoir etfects). runoff             ntuimbe r     o(f   estimates   of   "probahle   maximunm estimates are required for different storm pattern                precipilation." The PMP estimates arc presented in locations and orientations to ohtain the final PMF.               various unpublished mnemoranda and published reports.
                                                                    Drainage  Basin Average  PMF Peak Project    State    River Basin              Stream          Area      (in inches)  Discharge (sq.mi.)  Prec. Runoff    (cfs)    -w Sherrill Drive    Md.    Potomac            Rock Creek                    62  30.6    28,3      111,900
Six Bridge        Md.    Potomac            Monocacy River              308  27.1     24.0       225,000
Springfield      W. Va. Potomac            South Branch              1,471  17.5    15,5      405,000
Staunton          Va.    Potomac            South Branch Shen.          325  25.0    21.3      226,000
Stillwater        Pa.    Susquehanna        Lacawanna River              37  27.3    24.1        39,600
Summit            N. J.  Delaware          Delaware River          11,100                    1,000,000
Surry            Va.    James              James River              9,517                    1,000,000
Tioga-Hammond    Pa.    Susquehanna        Tioga River                  402  23.5    19.2      318,000
Tocks Island      N. J.  Delaware          Delaware River            3,827  13.3    10.5      576,300
Tonoloway        Md.    Potomac            Tonoloway Creek              112  29.9    26.8      117,600
Town Creek        Md.    Potomac            Town Creek                  144  27.5    25.2      102,900
Trenton          N. J.  Delaware          Delaware River            6,780                      830,000
Trexler          Pa.    Delaware          Jordon Creek                  52 25.2    22.6        55,500
Tri-Towns        W. Va.  Potomac            North Branch                 478  21.6    16.4      268,000
Verplanck        N. Y,  Hudson             Hudson River            12,650    14.0      9.7    1,100,000
Washington, D. C. Md.    Potomac            Potomac River          11,560    13.4    10.2    1,280,000
Waynesboro       Va.    Potomac            South River                136  29.6    26 .5      116,000
West Branch       W. Va.  Potomac            Conococheague River          78  30.7    27.0        78,700
Whitney Point    N. Y.  Susquehanna        Otselie River              255  20.7    19.1      102,000
Winchester        Va.    Potomac           Opeqnon Creek              120  28.9    25.8       142,100
York Indian Rock Pa.    Susquehanna        Codorus Creek                94  22,1    17.7        74,300
                                          South Atlantic-Gulf Region Allatoona        Ga.    Alabama-Coosa      Etowah River            1,110   22.2    19.8      440,000
Alvin W. Vogtle  Ga.    Savannah          Savannah River          6,144    21.8    14.5    1,001,000
Bridgewater      N. C.  Santee            Catawba River              380                      187,000
Buford            Ga.    Apalachicola      Chattahoochee River      1,040    21.7    19.7      428,900
Carters           Ga.    Alabama-Coosa      Coosawattee River          376  26.6    22.3      203,100
Catawba          N. C.   Santee             Catawba River            3,020            16.6      674,000
Cherokee          N. C.  Congaree-Santee    Broad River              1, 550                      560,000
Claiborne        Ala.    Alabama-Coosa    Alabama River            21,520    14.9    12.3      682,500
Clark Hill        Ga.    Savannah          Savannah River          6,144    21.8    14.5    1,140,000
Coffeeville      Ala.    Tombigbee          Black Warrior River     18,600    13.6    11.2      743,400
Cowans Ford      N. C.   Santee            Catawba River            1,790                      636,000
Demopolis        Ala.   Tombigbee          Tombigbee River        15,300   16.7    14.3   1,068,000
Falls Lake        N. C.   Neuse              Neuse River                760  23.2    21.2      323,000


Where historical rainfall patterns are not used for PMP,         The series of' published reports is listed on the lyv sheet two other methods are generally employed as follows:              of referenced Hydronietcorological Reports such as a. Average depth over the entire basin is based onl         Reference I8. The published memoranda reports mtay he the maximized areal distribution of Ihe PMP.                     obtained from thie Corps of iEngineers or h. A hypothetical isohyclal pattern is assumed.             HyJrometeorological Branch. NOAA. These reports and Studies of areal rainfall distribution from intense storms        memoranda present pgneral techniques: included among indicate elliptical patterns may be assumed as                    the reports are several that contain "generalized"
TABLE B.1 ( )
       representative of such events. Examples are the typical           estimates of PM I' for different river basins. The patterns presented in References 8. 14. 17. and 18.               generalized studies (Refs. 7. 12) usually assure reliable and consistent estimates for various locatlions in the To compute a flood hydrograph from the probable             region for which they have been developed inasniuch as maximum storm, it is necessary to specify the time                they 'are based on coordinated studies of all available sequence of precipitalion in a feasible and critical             data. supplemented by thorough meteorological analyses. In sonic cases. however, additional detailed meteorological time sequence. Two meteorological analyses are needed for specific river basins (Refs. 7. 8)
                                                                    Drainage  Basin Average PMF Peak Project    State    River Basin            Stream          Area    (in inches)  Discharge (sq.mi.)  Prec. Runoff    (cfs)
       factors must be considered in devising the time to take into account unusually large areas. storm series, sequences: ( I) the time sequence in observed storms and topography, or orientation of drainage basins not fully
  Gainsville      Ala.    Tombigbee          Tombigbee River          7,142  19.6    16.8    702,400
       (2) the manner of deriving the PMP estimates. The first reflected in the generalized estimates. In many river imposes little limitations: the lhetographs (rainfall time basins available studies may be utilized to obtain the sequences) for observed storms are quite varied. There is        PMP without the in-depth analysis herein or in tihe some tendency for the two or three time increments               referenced reports.
  Hartwell         Ga.     Savannah          Savannah River          2,088  24.8    18.8    875,000
  Holt            Ala.    Warrior            Warrior River            4,232  22.1    19.2    650,000
  Howards Mill    N. C.  Cape Fear          Deep River                . 626 26.8    24.2    305,000
  Jim Woodruff    Fla.    Apalachicola       Apalachicola River      17,150  17,6    12.3  1,133,800
  John H. Bankhead Ala.    Tombigbee          Black Warrior River      3,900  22.3    19.4    670,300
  Jones Bluff      Ala.    Alabama            Alabama River           16,300  14.2    11.6    664,000
  Lazer Creek      Ca.    Apalachicola      Lazer Creek              i,41O  24.6    20.7    303,600
  Lookout Shoals  N. C,  Santee            Catawba River            1,450                    492,000
  Lower Auchumpkee Ga.     Apalachicola      Flint River              1,970  23.7   19.8    355,600
  McGuire          N. C,  Santee            Catawba River            1,770                    750,000
  Millers Ferry    Ala.    Alabama            Alabama River          20,700  14.7    12.1    844,000
  Mountain Island  N. C.  Santee             Catawba River            i, 860                  362,000
  New Hope        N. C.  Cape Fear          New Hope River          1,69o  22.0    19.4    511,000
  Oconee          S. C.  Savannah          Keowee River                439 26.5    23.5    450,000
0 Oconee          S. C.  Savannah          Little River                            26.6    245,000
  Okatibbee        Miss.  Pascagoula        9katibbee Creek             154 33.0    28.4      8?, 700
  Oxford          N. C.   Santee            Catawba River            1,31.0                  479,000
  Perkins          N. C.   Pee Dee            Yadkin River            2,4?3                    440,600
  Randleman        N, C.  Cape Fear          Deep River                  169 28.6    26.0    126,000
  Reddies          N. C.  Pee Dee            Reddies River                94 28.0    24.8     174,200
  Rhodhiss        N. C,  Santee            Catawba River            1,090                    379,000
  Shearon Harris  N. C.  Cape Fear          White Oak Creek              79                  163, 500
  Sprewell Bluff  Ca.    Apalachicola       Flint River              1,210  25.8    21.3    318,000
  Trotters Shoals  Ga.     Savannah          Savannah River          2,900  24.0    19.1    800,000
  Walter F. George Ga.    Apalachicola       Chattahoochee River      7,4460  16.6    15.2     843,000
  Warrior          Ala.    Tombigbee          Black Warrior River      5,828  19.5    16.6    554,000
  West Point      Ga.    Apalachicola      Chattahoochee River      3,44o  21.9    17.4    440,000
  W. Kerr Scott    N. C.  Pee Dee            Yadkin River                348 25.6    21.5    318,000
                                              Great Lakes Region Bedford          Ohio    Cuyahoga          Tinkers Creek                91 28.6    25.9      79,000
  Bristol          N. Y.  Oswego            Mud Creek                    29 29.9    28.1      64,900
                  N. Y.                                                              16. 1    63,400
  Fall Creek              Oswego            Fall Creek                  123 17.1 Ithaca          N. Y.   Oswego            Six Mile Creek               43 26.9    25.1      77,900
  Jamesville      N. Y.   Oswego            Butternut Creek              37 26.0    24.1      35,200
  Linden          N. Y.  Niagara            Little Tonawanda Creek        22 30.8    29.0      64,400


with thie highest rainfall in a storm to bunch together. as
TABLE B.1 ( )
   0  sonie time is rcouired for the influence of a severe precipitation-producing weather situation to pass a given region. The second consideration uses meteorological parameters developed from PMP estimates.
                                                                  Drainage  Basin Average PMF Peak Pr,,ject    State    River Basin            Stream          Area   _Lin inches)  Discharge (sq.mi.)  Prec.  Runoff  (cfs)
Mount Morris      N. Y.    Genesee River    Genesee River            1,077  17.0   14.6    385,000
Onondago          N. Y.    Lake Ontario    Onondago Creek              68  24.2    23.3      61,800
Oran              N. Y.    Oswego          Limestone Creek              47  25.1    23.4      80,790
Portageville      N. Y.    Genesee          Genesee River              983  17.8    15.8    359,000
Quanicassee      Mich.    Saginaw Bay      Saginaw River            6,260                    440,000
Quanicassee      Mich.    Saginaw Bay      Tittabawassee River      2,400                    270,000
Quanicassee      Mich.    Saginaw Bay      Quanicassee River            70                    46,000
Standard Corners  N. Y.    Genesee          Genesee River              265  22.3    20.3    189,900
                                              Ohio Region Alum Creek        Ohio    Ohio            Alum Creek                123   24.6    21.8    110,000
Barkley          Ky.      Ohio            Cumberland River        8,700  22.6    21.5  1,000,000
Barren            Ky.      Ohio            Barren River              940  17.6    16.9    531,000
Beaver Valley    Pa.      Ohio            Ohio River              23,000                  1,500,000
Beech Fork        W. Va.  Ohio            Twelve Pole Creek            78  26.4    23.5      84,000
Big Blue          Ind.    Ohio            Big Blue River              269  23.5    21.2    161,000
Big Darby        Ohio    Ohio            Big Darby Creek            441  24.1    21.3    294,000
Big Pine          Ind.    Ohio            Big Pine Creek            326  22.4    20.4    174,000
Big Walnut        Ind.    Ohio            Big Walnut Creek          19?  24.0    22.0    144,000
Birch            W. Va.  Ohio            Birch River                142  28.4    25.2    102,000
Bluestone        W. Va.  Ohio            New River                4,565          13.8    410,000
Booneville        Ky.      Ohio            So. Fk. Kentucky River    665  23.2    21.0    425,000
Brookville        Ind.    Ohio            Whitewater River          379  24.2    22.1    272,000
Buckhorn          Ky.      Ohio            M. Fk.Kentucky River      408  23.8    21.5    239,000
Burnsville        W. Va.  Ohio            Little Kanawha River        165  24.8    22.3    138,800
Caesar Creek      Ohio    Ohio            Caesar Creek              237  24.1    21.9    230,200
Cagles Mill      Ind.    Ohio            Mill Creek                  295  24.6    22.7    159,000
Carr Fork        Ky.      Ohio            No. Fk. Kentucky River      58  27.4    25.0    132,500
Cave Run          Ky.      Ohio            Licking River              826  22.8    20.6    510,000
Center Hill      Tenn.    Ohio            Caney Fork              2,174  22.3    21.8    696,000
Clarence J. Brown Ohio    Ohio            Buck Creek                  82  29.0    26.7    121,000
Claytor          Va.      Ohio            New River                2,382  22.3    18.0  1,109,000
Clifty Creek      Ind.    Ohio            Clifty Creek              145  24.9    23.0    112,900
Dale Hollow      Tenn.    Ohio            Obey River                935  23.8    2303    435,000
Deer Creek        Ohio    Ohio            Deer Creek                278  22.9    20,1    160,000
Delaware          Ohio    Ohio            Olentangy River            381  22.7    20.4    296,000
Dewey            Ky.      Ohio            Big Sandy River            207  25.0    22.6      75,500
                                                        1;


A.8 CHANNEL AND RESERVOIR ROUTING
TABLE B.1 ( )
                                                                              Channel and reservoir routing of floods is generally an integral part of the runoff model for subdivided basins, and care should be taken to assure not only that An example of 6-hour increments for obtaining a             the characteristics determined represent historical critical 24-hour PMP sequence would be that the most             conditions (which may be verified by reconstituting severe 6-hour increments should be adjacent to each              historical floods) but ;dso that they would conservatively other in time (Ref. 17). In this arrangement the second          represent conditions to be expected during a PMF.
                                                                          Drainage Basin Average PMF Peak Project        State    River Basin            Stream            Area    (in inches)  Discharge (sa.mi.) Prec.  Runoff  (cfs)
    Dillon            Ohio      Ohio            Licking River                748  19.8    16.3    246,000
    Dyes              Ohio      Ohio            Dyes Fork                      44  30.7    27.8      49,500
    Eagle Creek        Ky.      Ohio            Eagle Creek                  292  24.?    22.1    172,800
    E. Br. Clarion    Pa.      Ohio            E. Br. Clarion River          72  22.7    18.9      41,500
    East Fork          Ohio      Ohio            E. Fk. Little Miami River    342  23.8   21.2    313,200
    East Lynn          W. Va.    Ohio            Twelve Pole Creek            133  29.4    26.5      72,000
    Fishtrap          Ky.      Ohio            Levisa Fk. Sandy River        395  26.1    23.2    320,000
    Grayson            Ky.      Ohio            Little Sandy River            196  27.5    24.7      83,300
    Green River        Ky.      Ohio            Green River                  682  26.5    23.9    409,000
    Helm              Ill.      Ohio            Skillet Fk. Wabash River      2LO  24.8    22.6    152,800
    John W. Flannagan  Va.      Ohio            Pound River                  222  27.6   24.9    235,800
    J. Percy Priest    Tenn.    Ohio            Stones River                  892  25.9    18.8    430,000
    Kehoe             Ky.      Ohio            Tygarts Creek                127  26.0    23.4    105,900
    Kinzua            Pa.      Ohio            Allegheny River            2,180  16.4    12.8    115,000
    Lafayette          Ind.      Ohio            Wildcat Creek                791  20.6    18.5    182,000
'.0
    Laurel            Ky.      Ohio            Laurel River                  282  25.9    20.7    120,000
    Leading Creek      W. Va.    Ohio            Leading Creek                146  25.0    22.5    131,000
    Lincoln            Ill.      Ohio            Embarras River                915  21.2    19.0    502,000
    Logan              Ohio      Ohio            Clear Creek                    84  29.5    27.0      78,000
    Louisville        Ill.      Ohio            Little Wabash River          661  22.1    19.9    310,000
    Mansfield          Ind.      Ohio            Raccoon Creek                216  25.9    23.0    175,800
    Martins Fork      Ky.      Ohio            Cumberland River                56 27.9    22.7      61,800
    Meigs              Ohio      Ohio            Meigs Creek                    72  29.5    26.6      72,100
    Meigs              Ohio      Ohio            Meigs Creek                    27 32.2    29.3      45,500
    Mill Creek        Ohio      Ohio            Mill Creek                    181  24.0    2i.4      92,000
    Mississinewa      Ind.      Ohio            Mississinewa River            809  20.6    18.4    196,000
    Michael J. Kirwin  Ohio      Ohio            Mahoning River                80  26.0    20.1      51,800
    Monroe            Ind.      Ohio            Salt Creek                    441  25.9    25.4    366,000
                      Pa.      Ohio            Muddy Creek                    61  22.8    19.6      59,300
    Muddy Creek Nolin             Ky.      Ohio            Nolin River                  703  14.2    13.2    158,000
                      Ohio      Ohio            N. Br. Kokosing River          44  25.4    22.6      50,000
    N. Br. Kokosing Va.      Ohio            N. Fk. Pound River            18  35.3    32.2      51,200
    N. Fk. Pound River Ohio      Ohio            Paint Creek                  573  21.8    18.8    305,000
    Paint Creek Ky.      Ohio            Paint Creek                    92  26.3    23.8      77,500
    Paintsville Panthers Creek    W. Va.    Ohio            Panther Creek                  24 36.7    3309      59,800
    Patoka            Ind.      Ohio            Patoka River                  168  25.6   23.5    292,000
    R. D. Bailey      W. Va.    Ohio            Guyandotte River              540  23.1    20.3    349,000
    Rough River        Ky.       Ohio            Rough River                  454  27.6    25.1    358,000
                                                                1


highest increment should bc adjacent to the highest. the third highest should be immediately before or after this                Channel and reservoir routing methods of many
TABLE B.1 ( )
       12-hour sequence. and the fourth highest should be                types have been developed to model the progressive before or after the 18-hour sequence. This procedure              downstream translation of flood waves. Tihe same may also be used in the distribution of the lesser second          theoretical relationships hold for both channel and
                                                                          Drainage  Basin Average  PMF Peak Project       State    River Basin              Stream          Area      (in inches)  Discharge Prec    Runoff  (cfs)
       (24-48 hours) and third (48-72 hours) 24-hour periods.             reservoir routing. However, in the case of flood wave These arrangements are permissible because separate                translation through reservoirs, simplified procedures bursts of precipitation could have occurred within each           have been developed that are generally not used for
    Rowlesburg        W. Va.    Ohio              Cheat River                  936  21.2    18.4      331,000
       24-hour period (Reference 7). The three 24-hour                   channel routing because of the inability of such precipitation periods are interchangeable. Other                 simplified methods to model frictional effects. The arrangements that fulfill the sequential requirements             simplified channel routing procedures that have been would be equally reasonable. The hyclograph. or                   developed have been found useful in modeling historical precipitation time sequence. selected should be the most           floods, but particular care must be exercised in using severe reasonably possible that would produce critical            such models for severe hypothetical floods such as the runoff at the project location based on tihe general               PMF because the coefficients developed from analysis of appraisal of the hydrometeorologic conditions in the               historical floods may not conservatively rellect flood project basin. Examples of PMP time sequences fulfilling          wave translation for more severe events.
    Salamonia        Ind.      Ohio              Salamonia River              553  2143    19.0      201,000
    Stonewall Jackson W. Va.    Ohio              West Fork River              10?            22.2       85, 500
    Summersville      W. Va.   Ohio              Gauley River                80,   23.8    21.1    412,000
    Sutton           W. Va.    Ohio              Elk River                    53?  20.4    20.4      222,400
    Taylorville       Ky.      Ohio              Salt River                  353  24.8    22.2    426, 000
    Tom Jenkins      Ohio      Ohio              Hocking River                33  26. 7    25.8      43,000
    Union City        Pa.      Ohio              French Creek                222  20.3    17.8      87, 500
    Utica            Ohio      Ohio              N. Fk. Licking River        112  24.7     22.1      73,700
    West Fork        W. Va.    Ohio              W. Fk. Little Kanawha        238  24.4    21.8    156,400
    West Fk. Mill Ck. Ohio      Ohio              Mill Creek                    30  31.9    30.0      81,600
    Whiteoak          Ohio      Ohio              Whiteoak Creek              214  24.5    21.6    134,000
    Wolf Creek        Ky.      Ohio              Cumberland River          5,789    20.6    20.0    996,000
    Woodcock          Pa.      Ohio              Woodcock Creek                46  23.5    20.9      37,700
    Yatesville        Ky.      Ohio              Blaine Creek                208  25.2    22.6    118,000
    Youghiogheny      Pa.      Ohio              Youghiogheny River          434            25.4    151,000
-J~. Zimmer, Wm. H.    Ohio      Ohio              Ohio River              70,800                    2,150,000
                                                Tennessee Region Bellefonte        Ala.      Ohio              Tennessee River          23,340                   1,160,000
    Browns Ferry      Tenn.     Ohio              Tennessee River          29,130                    1,200,000
    Sequoyah          Tenn.    Ohio              Tennessee River          20,650                    1,205,000
                                                Upper Mississippi Region Ames              Iowa      Upper Miss.      Skunk River                 314  21.3    18.4      87,200
    Bryon             Ill.      Upper Miss.      Rock River                8,000                      308,000
    Bear Creek        Mo.       Upper Miss.       Bear Creek                   28  29.0    26.2      38,000
    Blue Earth        Minn.    Upper Miss.      Minnesota River        11,250    14.2    10.9    283,000
    Blue Earth        Minn.    Upper Miss.      Blue Earth River          3,550    18.4    14.8    206,000
    Carlyle          Ill.      Upper Miss.       Kaskaskia River           2,680    19.2    15.8    246,000
    Clarence Cannon  Mo.      Upper Miss.      Salt River                2,318    21.8    15.7    476,200
    Clinton          Ill.      Upper Miss.      Salt Creek                  296                      99,500
    Coralville        Iowa      Upper Miss.      Iowa River                3,084    20.8    14.4    326,000
    Duane Arnold      Iowa      Upper Miss.      Cedar River               6,250                      316,000
    Farmdal e        Ill.      Upper Miss.      Farm Creek                    26  24.0    22.1      67,300
    Fondulac          Ill.      Upper Miss.      Fondulac Creek                5.4 21.4    19.9      21,200
    Friends Creek    Ill.      Upper Miss.      Friends Creek               133    27.8    21.6      83,160


the sequential requirements are illustrated in References I1, 12. and 17. For small areas. maximized local records               Most of tihe older procedures were basically should be considered to assure that the PMP time                  attempts to model unsteady-flow phenomena using sequence selected is severe.                                       simplifying approximations. The evolutiorn of computer
TABLE Bi1 ( )
                                                                  1.59-1 I
                                                                        17)
                                                              B.I 9 of (Page TABLE                Drainage Basin Ave-age  PMF Peak Project        State    River Basin              Stream                Area    (in inches)  Discharge (sq.mi.) Prec.. Runoff    (cfs)
Jefferson          Iowa      Upper  Miss.      Raccoon River                  1,532  21.7    19.0    267,300
LaFarge            Wisc.      Upper  Miss.      Kickapoo River                    266 22.8    18.9    128,000
Mankato            Minn.      Upper  Miss.      Minnesota River                14,900  13.9    10.6    329,000
Meramec Park      Mo.        Upper  Miss.      Meramec River                  1,497  22.9    17.5    552,000
Montevideo        Minn.      Upper  Miss.      Minnesota River                6,180  15.2    11.6    263,000
Monticello        Minn.      Upper  Miss.      Mississippi River              13,900                    365,000
New Ulm            Minn.      Upper  Miss.      Minnesota River                9,500  14.4    11.1    263,000
New Ulm            Minn.      Upper  Miss.      Cottonwood River                1,280  21.2    17.6    128,000
Oakley            Ill.      Upper  Miss.      Sangamon River                    808 23.5    17.2    178,000
Prairie Island    Minn.      Upper  Miss.      Mississinpi River              44,755                    910,000
Red Rock          Iowa      Upper  Miss.      Des Moines River              12,323  12,1      7.5    613,000
Rend              Ill.      Upper  Miss.      Big Muddy River                    488 27.5    21.5    308,200
Saylorville        Iowa      Upper  Miss.     Des Moines River               5,823  13.8    10.3    277,800
Shelbyville        Ill.      Upper  Miss.      Kaskaskia River                1,030  22.1    .19.1    142,000
                                              Lower Mississippi Regaon Arkabutla          Miss.      Lower Miss.        Coldwater River                1, 000 22.5    21.2    430, 000
Enid              Miss.      Lower Miss.        Yacona River                      560 25.4    24.7    204,900
Grenada            Miss.      Lower Miss.        Yalobusha River                1,320  24.0    23.1    390,800
Sardis            Miss.      Lower Miss.        Tallahatchia River              1, 545 32.5    26.0    290,400
Union              Mo.        Lower Miss.        Bourbeuse River                    771 25.0    19.9    264,000
Wappapello        Mo.        Lower Miss.        St. Francis River              1,310  13.0    11.7    344,000
                                              Souris-Red-Rainy    Region Burlington        N. D.      Souris            Souris River                    9,490  13.2      5.7    89,100
Fox Hole          N. D.      Souris            Des Lacs River                    939 19.9    12.4      52,700
Homme              N. D.      Red  of North      Park River                        229 15.2    12.3      35,000
Kindred            N. D.      Red  of  North    Sheyenne River                  3,020  13.4      8.6      68,700
Lake Ashtabula    N. D.     Red  of North      Sheyenne River                    983 12.4      9.5      86,500
Orwell            Minn.      hid  of  North    Otter Tail River                1,820  17.1     14.7      25,500
                                                Missouri Region Bear Creek        Colo.      Missouri          Bear Creek                        236 24.4      6.7    225,000
Big Bend          S. D.      Missouri          Missouri River                  5,840            9.0    725,000
Blue Springs      Mo.        Missouri          Blue Springs Creek                  33 26.5    23.8      42,4OO
Blue Stem          Nebr.      Missouri          Olive Br. Salt Creek                17 25.0    21.7      69,200
Bowman-Haley      N. D.      Missouri          Grand River                        446 15.5    12.7    113,000
Branched Oak      Nebr.      Missouri          Oak Creek                            89 20.1     16.8      93,600
                .~                                        ~      F        I


itnv olvedt.    in flvw. out hllow, and       pool   elevat ion
TABLE 8.1 ( )
                                                                                                                                              - I
                                                                          Drainage    Basin Average  PMF Peak Project        State   River basin            Stream            Area        (in inches)  Discharge (an    ml.)  Pre.~  RInnff  (eflf (s    mi    Prec    Runoff  (cfs)
use has allowed development ,,ofIanalysis techniques that permit direct solutiontit' basic 'Instead% flow equations                 hydrographs should be prepared.
    Braymer            Mo.      Missouri        Shoal Creek                    390    24.7    22.2      173,800
    Brookfield        Mo.      Missouri        West Yellow Creek              140    24.5    22.0        64, 500
    Bull Hook          Mont.    Missouri        Bull Hook Creek                  54            10.8        26,200
    Chatfield          Colo.    Missouri        South Platte River          3,018    13.2      2.0    584, 500
    Cherry Creek      Colo.     Missouri        Cherry Creek                  385    23.9      9.5      350,000
    Clinton            Kans.    Missouri       Wakarusa River                367   23.6    22.4      153,500
    Cold Brook        S. D.    Missouri        Cold Brook                      70              6.4        95,700
    Conestoga          Nebr.    Missouri        Holmes Creek                    15  25.2    21.9        52,000
    Cottonwood Springs S. D.    Missouri        Cheyenne River                  26  18.7    11.1        74,700
    Dry Fork          Mo.      Missouri        Fishing River                    3.2 26.1    22.5        19,460
    East Fork          Mo.      Missouri        Fishing River                  19    25.7    24.1        62,700
    Fort Scott        Kans.    Missouri        Marmaton River                279    23.8    22.7      198,000
    Fort Peck          Mont.    Missouri        Missouri River            57,725              3.2      360,000
    Port Randall      S. D.    Missouri        Missouri River            14,150                3.7    849,000
    Fort St. Vrain    Colo.    Missouri        South Platte River          4,700                        500,000
(J* Garrison          N. D.    Missouri        Missouri River          123,215                2.7  1,026,000
(I' Gavins Point      Nebr.    Missouri        Missouri River            16,000                3.3    642,000
    Grove              Kans.    Missouri        Soldier Creek                  259    23.8    22.?        79,800
    Harlan County      Nebr.    Missouri        Republican River            7, 142    7.6      2.8    485,000
    Harry S. Truman    Mo.      Missouri        Osage River                7,856              13.1  1,060,000
    Hillsdale          Kans.    Missouri        Big Bull Creek                144    25.4    24.3    190,500
    Holmes            Nebr.    Missouri        Antelope Creek                    5.4 27.1    23.8        41,600
    Kanopolis          Kans.    Missouri        Smoky Hill River            2,560      6.9      3.6    456,300
    Linneus            Mo.      Missouri        Locust River                  5446  23.7    21.2      242,300
    Long Branch        Mo.      Missouri        E. Fk. Little Chariton        109    24.5    21.9      66,500
    Longview          Mo.      Missouri        Blue River                      50    26.2    23.4      74,800
    Melvern            Kans.    Missouri        Marias des Cygnes River        349    23.1    22.1      182,000
    Mercer            Mo.      Missouri        Weldon River                  427    21.0    17.8      274,000
    Milford            Kans.    Missouri        Republican River            3,620      8.8      5.0    757,400
    Mill Lake          Mo.      Missouri        Mill Creek                        9.5 27.7    26.4      13,000
    Oahe              S. D.    Missouri        Missouri River            62,550                6.5    946,000
    Olive Creek        Nebr.    Missouri        Olive Br. Salt Creek              8.2 26.0    22.7        36,650
    Onag              Kans.    Missouri        Vermillion Creek              301    23.5    22.2    251,000
    Pattonsburg        Mo.      Missouri        Grand River                 2,232    18.8    16.3    40o0,100
    Pawnee            Nebr.    Missouri        Pawnee Br. Salt Creek          36    23.5    20.2        59,000
    Perry              Kans.    Missouri        Delaware River              1,117    21.5    18.4    387,400
    Pioneer            Colo.    Missouri        Republican River              918    15.0      8.3    390,000
    Pomme de Terre    Mo.      Missouri        Pomme de Terre River          611    23.9    21.6    362,000


mlilizinig ntimerical analysis teclinitques adaptable to the digital comptuter (Ref. I19). In addition. most of' the                          Many existing and proposed dams and oilier river older techniques have been adapted for computer use                        control structures may niot be capaible of safely passing (Ref. 3).                                                                   floods as severe as a PMF. Tile capability of river control structures to safely pass a PMF and local coincident In all rout ing techniques. care must be ,:xercised in             wind.generated wave activity must be determined as part assurinig hat1 ijmiramet ers selectLed Jor model verification             of' the PM F atnalysis. Where it is poissible that such are based on several hislorical floods (whenever possible)                 structures imaynitot safely survive Iloods as severe as a and that their applicationl Ith1 PMF will restilt in                      PM F. tile \vtwrst such conidition withi resipect to conserva.liVe est mates            1 l'h\     ata Cles. water levels.       downstream nuclear lpower plants is assuimied (hut should velocities, and ilIpacM        torceI . Theoretical discussions of1         be suhtsltanlialed hr analysis ohl lpsl eamn PNIF poi':litiall the many methods availahle for such analyses are                          to be their failuore during a PMF. and the PM F
TABLE B.1 ( )
contained in Refelences 2. 19).20.- I . mnd 22.                           detertminatiion should include the resuiltant effects. This analysis:also requires that tihe consequncces otflupsreamii dam failures on downtstreanm damis ( domtino effects) he A.9 PMF HYDROGRAPH ESTIMATES
                                                                      Drainage    Basin Average    PFY Peak Project      State      River Basin            Stre:an        Aren      ' ir. 4nchesq_  Discharge (sa.'ni.)  Prec.    Runcff  (cf s)
                                                                            considered.
Pomona          Kans.    Missouri            110 Mile Creek              322    26.2      25.2    186,000
Rathbun          Iowa      Missouri          Chariton River                      23.7      21.1    188,000
Smithville      Mo.      Missouri          Little Platte River          213    23.9      20.2    185,000
Stagecoach      Nebr.    Missouri          Hickman Br. Salt Creek          9.7 26.0      22.7      50,500
Stockton        Mo.      Missouri          Sac River                1,160    19.7      18.9    470,000
Thomas Hill      Mo.      Missouri          Little Chariton River        1a47  25.0      23.0      79,000
Tomahawk        Kans.    Missouri          Tomahawk Creek                24  26.4      24.8      26,800
Trenton          Mo.      Missouri          Thompson River            1,079    22.6      20.1    342,400
Tuttle Creek    Kans.    Missouri          Big Blue River            9,556    14.5        8.1    798,000
Twin Lakes      Nebr.    Missouri          S. Br. Middle Creek          11    25.9      22.6      56,000
Wagon Train      Nebr.    Missouri          Hickman Br. Salt Creek        16    25.2      21.9      53,500
Wilson          Kans.    Missouri          Saline River             1, q1?    20.2      10.8    252,000
Wolf-Coffee      Kans.    Missouri          Blue River                    45    26.1      24.5      58,000
Yankee Hill      Nebr.    Missouri          Cardwell Br. Salt Creek        8.4 26.0      22.?      58,400
                                          Arkansas-White-Red Region Arcadia          Okla.    Arkansas          Deep Fork River             105    28.5      24.9    1i44,000
Bayou Bodcau    La.       lied              Bayou Bodcau                 656    35.3      33.6    168,?00
Beaver          Ark.      White              White River              1,186    24.3      22.4     480,000
Bell Foley      Ark.      Arkansas          Strawberry River              78    26.4      23.5      57,000
Big Hifl        Kans.    Arkansas          Big Hill Creek                3?  25.4      23.6      47, 500
Big Pine         Tex.      Red                Big Pine Creek                      31.3      29.3      86,ooo Okla.    Arkansas          Birch Creek
                                                                            66    29.0      26.0      91,000
Birch Blakely Mountain Ark.      Red                Ouachita River            1,105    21.5      19.6    418,000
Blue Mountain    Ark.      Arkansas          Petit Jean River            500    21.8      18.2     258,000
Boswell          Okla.     Red                Boggy Creek              2,273    27.6      20.8    405,000
Broken Bow      Okla.    Red                Mountain Fork                754    32.5      29.4    569,000
Bull Shoals      Ark.      White              White River              6,036    15.2      1&#xfd;.0    765, 000
Candy            Okla.    Arkansas          Candy Creek                  43    29.-3      27 5      67, 500
Canton          Okla.     Arkansas          North Canadian River      7,600    12.4        4.1    371,000
Cedar Point      Kans.    Arkansas          Cedar Creek                  119    25.4      22.6    208,000
Clayton          Okla.    Red                Jackfort Creek              275    31.3      29.3    24O0,oo Clearwater      Mo.      White              Black River                  898    16.0      13.8    432,000
Conchas          N. Mex.  Arkansas          South Canadian River      7,409      4.8        3.0    582,000
Cooper          Tex.      Red                South Sulphur River          476    30.9       29.2    194,40o Copan            Okla.    Arkansas          Little Caney River          505    26.2      21.1    169,000
Council Grove    Kans.    Arkansas          Grand River                  246    25.5      22.7    250,000
County Line      Mo.      White              James River                  153    27.2      25.3    133,000


PM F net runolf hydrograph estimates are made bh sequentially applying critically located and distributed                            A.10 SEISMICALLY INDUCED FLOODS
TABLE B.1 ( )
PM P estinmt tes using the runoff timodel. conservatively low%, estimates of prcipitalioti losses, and conservatively                      S.isinically induced bloods on streams and rivers hilh estimates (1' base Ilow z'nd antecedent reservoir                      may be caused hr landslides or dain failures. Where river levels.                                                                     Coitrol structures are widely spaced, their arbitrarily as.suilied indiciduwil total.l instantaneous failure and lit PlMF determinationis it is cenerall v assumed that               resul tinig downsttreailmi flotodl wave atltenuation (routing)
                                                                        Drainage  Basin Average  PMF Peak Project    State    River Bas in            Stream          Area    (in  inches)  Discharge (sq.mi.)  Prec.  Runoff  _(cfs)  _
short-lerin reservoir flood control storage would be                        mliar be showII to coTIns6lcite lbi) threat to nuclear depleted by possible antecedent floods. An exception                        facilities. Where the relative size. location, and proximity would be whet it cat be demonstrated that tile                              of' dams !o ptentiial seismic generators indicate a threat occurrence oif a measonably seveie flood I say aboolu;                       to nuclear power plants. tite capability of suIch structures one-h:alf ofl a P1I\)     less than a week (usually a tinitnrtni           (cither singly or in combination) Ito resist severe oit' 3 to- 5 days prior :ii a lIFM c:nli        be evacialetl frotil        earthquakes (critically located) shimald he considered. Ili the reservoir helfre tile artival otf a PMVF. However, it is               river basins where the flood aunoff season may unusual to use all antecedent storage level less than                      constitute a significant portion of' the year (such as the one-halftile flood control storage available'                              Mississippi. Columbia. or Ohio River basins). f'ull flood control reservoirs willi ai 25-year flood is assunied Time applicatiomn (i P\MP in bhasins whose hydrologic                coincident with the Safe Shutdown        t..artliquake. Also.
    DeGray            Ark.   Red              Caddo River                  453  28.4    26.0    397,000
    Denison          Okla.  Red              Red River                33,783  12.9      6.5  1,830,000
    DeQueen          Ark.    Red              Rolling Fork                  169  35. 5    32. 5    254,000
    Dierks            Ark.    Red              Saline River                  113  36.2    33.2    202,000
    Douglas          Kans.  Arkansas          Little Walnut Creek          238  26.7    22.9    156,000
    El Dorado        Kans.  Arkansas          Walnut River                  234          22.8    196,000
    Elk City          Kans.  Arkansas          Elk River                    634  23.0    20.3    319,000
    Eufaula          Okla.  Arkansas          Canadian River            8,405  15.9    10.9    700,000
    Fall River        Kans.   Arkansas          Fall River                    556  27.1    23.0    442,000
    Ferrells Bridge  Tex.    Red               Cypress Creek                880  31.1    28.1    367,000
    Fort Gibson      Okla.  Arkansas          Grand River                9,477  15.2    12.6    865,000
    Fort Supply      Okla.  Arkansas          Wolf Creek                1,494  20. 5    15.7    547,000
    Gillham          Ark.    Red              Cossatot River                271  34.6    31.5    355,000
    Great Salt Plains Okla.   Arkansas          Salt Fk. Arkansas River    3,200  i6&#xfd;?      9.3    412,000
    Greers Ferry     Ark.    Red              Little Red River          1, !i46 17.9    17.5    630,000
    Heyburn           Okla.  Arkansas          Polecat Creek                123  26.3     24.2    151,000
                                                                          1,709  27.1    25.8    339,000
Lu  Hugo              Okla.  Red               Kiamichi River Hulah            Okla.   Arkansas          Caney River                  732  16. 5    13.5    239,000
--1 Arkansas          Arkansas River            18,130    7.4      2.0    630,000
    John Martin      Colo.


features vat        fron llcation to location requires the                  cotnsideration should he given to the occurrence of' a detenriiimatit, that thie estimated PM F hydrograph                        flood of approximately one-half the severity of a PM F
John Redmond      Kans.  Arkansas          Grand River                3,015  16.2      ;56    038,000
represents the most critical centering of the PIMP storm                    with frill flood control reservoirs coincident wi\h the with respect to the site. ('are must be taken in basins                    maximumi      earthquake determined on the basis of'
    Kaw              Okla.  Arkansas          Arkansas River            7,250  14.5      9.9    774,000
witlhi substantial headwater flood control storage to                      historic seismicity ito mainlain a consistent level of assure that         maoire highly concentrated PMP over a                 analysis I'or Other combinations of such events. As with smaller area dowistireant of' the reservoirs would not                      failures dime to inadequiate flood control capacity, produce a greater PNIF tIan a total basin storm that is                    domino and essentially simultaneous multiple f'ailures partially controlled. In siich cases more than oCe P['NIP                  may also require consideration. If the arbitrarily runoff analysis maylhe required. Usually. only a few                        assumed total failure of the most critically located (from trials oft a total basin l.NI' are required to determine the                a hydrolh.:,ic standpoint ) struct ures indicates flood risks at most critical centering.                                                   the nuclear power plant site more severe than a PMF, a progessively more detailed analysis of the seismic capability of the dam is warranted. Without benefit of The antecedent snowpack and its contribution to detailed geologic and seisunic investigations. the flood the PNIF are included when it is determined that potential at the nuclear power plant site is next generally snowrnell coilrihntions to thie flood Would produce a evaluated assuming the most probable mechanistic-type PNIF (see Section A.7). However. these typcs of failure of' the quest ioned struci tires. IfItile results of each hypothetical floods are generally the controlling events step of the above analysis cannot be safely only in the far west and northern United States.
    Keystone          Okla.  Arkansas         Arkansas River            22,351  12.9      6.7  1,035,000
    Lake Kemp        Tex.    Red              Wichita River              2,056  23.7    19.2    566,000
    Lukfata          Okla.  Red              Glover Greek                 291  34.6    31.5    349,0o0
    Marion            Kans.  Arkansas          Cottonwood River              200  24.8    2J..9    160,000
    Millwood          Ark.    Red              Little River              4,104            25.3    442,o00
    Narrows          Ark.   Red              Little Missouri River        23?  25.0    23.0    194,000
    Neodesha          Kans,  Arkansas          Verdigris River            1,100  18.7    16.6    287,000
    Nimrod            Ark.    Arkansas          Fourche La Fave River        68o  20.2    17.2    228,000
    Norfolk          Ark.   White            North Fork White River    1,765  15.7     12.8    372,000
    Oologah          Okla.   Arkansas          Verdigris River            4,339  17.8    13.9    451,000
    Optima                    Arkansas          North Canadian hiver      2,341  13.8      9.0    386,000
                      Okla.


acconmnodated at the nuclear power plant site in an acceptable manner, the seismic potential at tile site of Runoff hydrogruphs should be prepared at key hydrologic hlcations (e.g.. strcanigages and dams) as well                  each questioned structure is then evaluated in detail, the as at the site of mnclear facilities. For all reservoirs                   structural capability is evaluated in the same depth as for
Pat Mayse        Tex.    Red              Sanders Creek                175  31.8    29.4    150,000
                                                                    1.59. 12
    Pine Creek        Okla.   Red              Little River                  635  32.8    29.8    523,000
                      Okla.  Arkansas          Arkansas River            64,386  10.0      5.8  1,884,000
    Robert S. Kerr Sand              Okla.   Arkansas          Sand Creek                   137  31.3    28.3    154,000
    Shidler          Okla.  Arkansas          Salt Creek                    99  27.3    24.0    104,100
    Skiatook          Okla.  Arkansas          Hominy Creek                  354          23.8    147,800
    rable Rock        No.    White            White River                4,020  18.3    15.4    657,000


&deg; nuclear power plant sites, and the resulting seismically             floodplain georrit tv definition as steady-fiowv models.
TABLE B.1 ( )
                                                                      Drainage  Basin Average PMF Peak Project    State    River Basin          Stream            Area    (in inches)  Discharge (s .mi.)  Prec. Runoff    (cfs)
    Tenkiller Ferry Okla.    Arkansas        Illinois River              1,61o  20.4    17.6    406,ooo Texarkana      Tex.    Red            Sulphur River                3,400  26.6    20.1    451,000
    Toronto        Kans.    Arkansas        Verdigris River                730  23.9    21.1    400,000
    Towanda        Kans.    Arkansas        Whitewater River              422 24.3    20.5    198,000
    Trinidad        Colo.    Arkansas        Purgatorie River              671  10.0    4.5    296,000
    Tuskahoma      Okla.    Red             Kiamichi River                347  16.5    14.6    188,400
    Wallace Lake    La.      Red            Cypress Bayou                  260  38.4    35.6    197,000
    Waurika        Okla.    Red            Beaver Creek                    562 26.5    22.2    354,ooo Webbers Falls  Okla.    Arkansas        Arkansas River              48,127  10.7    6.1  1,518,000
    Wister          Okla.    Arkansas        Poteau River                  993  25.9    23.2    339,000
                                              Texas-Gulf Region Addicks        Tex.    San Jacinto    South Mayde Creek              129  2q.7    27.9      68,670
    Aquilla        Tex.    Brazos          Aquilla Creek                  294  31.2    28.6    283,800
    Aubrey          Tex.    Trinity        Elm Fork Trinity Hiver        692  28.5    26.0    445,300
L1A                                                                        178          28. 3    163,500
    Bardwell        Tex.    Trinity        Waxahachie Creek                    31.1
00  Barker          Tex.    San Jacinto    Buffalo Bayou                  150  29.4    29.9      55,900
    Belton          Tex.    Brazos          Leon River                  3,560  29.4    20.6    608,400
    Benbrook        Tex.    Trinity        Clear Fork Trinity River      429  28.2    21.1    290,100
    Big Sandy      Tex.    Sabine          Big Sandy Creek                196  36.2    32.2    125,200
    Blieders Creek  Tex.    Guadalupe      Blieders Creek                  15 431.8  34.6      70,300
    Brownwood      Tex.    Colorado        Pecan Bayou                  1,544  27.8    21.0    676,200
    Canyon Lake    Tex.    Guadalupe      Guadalupe River              1,432  24.5    16.9    687,000
    Carl L. Estes  Tex.    Sabine          Sabine River                1,146  34.5    30.4    277,000
    Coleman        Tex.    Colorado        Colorado River                287  30.9    24.1    267,800
    Comanche Peak  Tex.    Brazos          Squaw Creek                      64 39.1    34.1    149,000
    Ferguson        Tex.    Brazos          Navasota River              1,782  26.0    22.4    355,800
    Gonzales        Tex.    Guadalupe        San Marcos River            1,344  24.9    15.4    633,900
    Grapevine      Tex.    Trinity        Denton Creek                  695  26.5    21.5    319,400
    Hords Creek    Tex.    Colorado        Hords Creek                      4b 28.9    23.4      92,400
    Lake Fork      Tex.    Sabine          Lake Fork Creek                507 33.8    29.7    247,600
    Lakeview        Tex.    Trinity        Mountain Creek                232  31.b    28.8    335,0o0
                    Tex.    Brazos          San Gatriel Piv-r              eC9  28 .9  23?7    52i,'00
    Laneport Lavon          Tex.    Trinity        East Fork, Trinity River      770  26.2    23.4    430,300
    Lewisville      Tex.     Trinity        Elm Fork, Trinity River      i,66o  23.2    20.5    632,200
    Millican        Tex.    Brazos          Navasota River              2,120  25.5    22.4    393,400
    Navarro Mills  Tex.    Trinity        Richland Creek                320  33.6    30.5    280,500
    Navasota        Tex.    Brazos          Navasota River              1,341  27.2    24.2    327,400


induced flood is routed to the site of the nuclear power           and thelrefore hit li use may allowv more accurate water plant. This last detailed analysis is not generally required       surface level t"'caini;ws                          whiiere &#xfd;id'*'-t~i'w since intermediate investigalions usually provide                   approxinmatlions are inlle. ()n.e such iilwloidV-Iw sufficient conscrvalive inflormiation to allow                      coriputier 1t1odel is dicused ill Re*('tih. e 11).
TABLE B.1 ( )
    determinalion of an adequate design basis flood.
                                                                      Drainage  Basin Average  PMF Peak Project      State    River Basin            Stream           Area    (in inches)    Discharge (so.mi.)  Prec. Runoff      (cfs)
North Fork       Tex.    Brazos            N. Fk. San Gabriel River      246  31.7    26.6      265,800
Pecan Bayou      Tex.    Colorado          Pecan Bayou                    316  30.7    23.8      236,200
Proctor          Tex.    Brazos            Leon River                  1,265  27.*0  21.4      459,200
                                            Denton Creek                  604  28.9    ;>',. I    313,600
Roanoke          Tex.    Trinity Rockland          Tex.    Neches            Neches River                3,557  21.0              150, 00
                                                                                23.7 Sam Rayburn      Tex.    Neches            Angelina River              3,449          20.6      395,600
San Angelo        Tex.    Colorado          North Concho River          1,511  21.2    13.1      (14,-00
Somerville        Tex.    Brazos            Yogua Creek                1,006  22.0    13.6      415,700
                                                                                32.6    27.*4 South Fork        Tex.    Brazos            S. Fk. San Gabriel River      123                    145,300
                                            Lampasas River              1,318  27 *7              686,400
Stillhouse Hollow Tex.    Brazos                                                        22.5 Tennessee Colony  Tex.    Trinity          Trinity River            12,687            20.4      575,600
                                                                                2?. 7
                                                                                18.9 Town Bluff        Tex.    Necnes            Neches River                7, 573  25.7    15.7      326,000
Waco Lake        Tex.    Braazos          Bosque River                i, 670  25. 7  20.6      622,900
Whitney          Tex.    Brazos            Brazos River              17,656              7.7      700,000
                                            Rio Grande Region Abiquiu          N. Me    Rio  Grande      Rio Grande                  3,159            8.2      130,000
                                                                        3,917 Alamogordo        N.  M.  Rio  Grande      Pecos River                                  1.9      277,000
Cochita          N.  M.  Rio  Grande      Rio Grande                  4,065    4.6      1.9      320,000
Jemez Canyon      N.  M.  Rio  Grande      Jemez Canyon                1,034    9.2      3.7      220,000
Los Esteros      N.  M.  Rio  Grande      Peccs River                2,434  12.2      4.7      352,000
Two Rivers        N.  M.  Rio  Grande      Rio Hondo                  1,027                      282,400
                                          Lower Colorado RegLon Alamo            Ariz.    Colorado          Bill Williams River        4,770  12.0      3.5      580,000
McMicken          Ariz.    Colorado          Aqua Fria River                247            3,3      52,000
Whitlow Ranch    Ariz.    Colorado          Queen Creek                   143  11 .5    9.7      230,000
Painted Rock      Ariz.    Colorado          Gila River                50,600    7.7      2.8      620,000
                                            Great Basin Region Little Dell      Utah    Jordon (Great)   Dell Creek                      36  6.1      6.0      23,000
Mathews Canyon    Nev.    Great Basin      Mathews Canyon                  34  8.6      7.4      35,000
Pine Canyon      Nev.    Great Basin      Pine Canyon                    4&#xfd;5  8.2      6.6      38,000
                                      Columbia-North Pacific Region Applegate        Oreg.   Rogue            Applegate River                223          28.9        99,500
Blue River        Oreg.    Columbia          S. Fk. McKenzie River          88          22.7        39,500


All   ieas.omahly     i,'cnr:ile   wvacr   h'ct,    c*{irnwilii'u A.11 WATER LEVEL DETERMINATIONS                              nlrdels reqmuire       11;1,lpl:1    &lfiminitiori   l :11c.ts that cat1 inatetialklv affect w* ticl levels. I.ood wa%(               t .l;:iriom .
TABLE B.1 ( )
           All the preceding discussion has been concerned              and c:litihratlini       by lv       rnr:henirl~ical iecii.,-iwii             of primarily with determinations of flow rates. The Ilow              hislorical       l*d)ts (tit mte ,hcclioit             of- c.1iblat:ioi rate or discharge must be converted to water level                  cocttficiellts based (itl the cil 'itsa,;li'c liallnIerl of elevation for use in design. This may involve                        information derived torll SAilr 'lildies -I'oilier iv,.r determination of' elevation-discharge relations Ifor natural        reaches). Particular c:are should he cxercis-d it, asstiie stream valleys or reservoir conditions. The reservoir              that      corntrolling   tlfomd     lc.el   est iniates     tic   tilwvayvs elevation estimates involv,: the spillway discharge                conservatively high.
                                                                          Drainage  Basin Average  PMF Peak Project    State      River Basin            Stream              Area      (in inches)  Discharge (sa.mi.)  Prec.  Runoff  (cfs)
  Bonneville      Oreg.  Columbia          Columbia River              240,000            22,1  2,720,000
  Cascadia        Oreg.  Columbia          South Santiam River              179          42,2      115,000
  Chief Joseph    Wash.  Columbia          Columbia River              75,000            29.0  1,550,000
  Cottage Grove    Oreg.  Columbia          Coast Fk. Willamette River        104          29.7      45,000
   Cougar          Oreg.   Columbia          S. Fk. McKenzie River            208          34.2      98,000
  Detroit          Oreg.  Columbia          North Santiam River              438          36.0      203,000
  Dorena          Oreg.  Columbia          Row River                        2hc          34.6     131,600
  Dworshak        Ida.    Columbia          N. Fk. Clearwater River        2,440O          70.5      280,000
   Elk Creek        Oreg.  Rogue            Elk Creek                        132          32.6      63,500
   Fall Creek      Oreg.  Columbia          Willamette River                  184          33.8    100,000
   Fern Ridge      Oreg.  Columbia          Long Tom River                    252          20.3       4,8,600
  Foster          Oreg.  Columbia          South Santiam River              4c!4          40 .8    260,000
  Green Peter      Oreg.  Columbia          Middle Santiam River              277          41.1    160,0oo Gate Creek      Oreg.   Columbia          Gate Ck. McKenzie River            50          4*.3      37,000
  Hills Creek      Oreg.   (2olum bia        Middle Fk. Willamette River      38q          33.0    197,000
  Holley          Oreg.  Columbia          Gala.pooia River                  105           35.8       59,000
  Howard A. Hanson Wash.  Green            Green River                      22*          26. 8    164,000
  Ice Harbor       Wash.  Columbia          Snake River                109,000            13.a    954,000
C)
  JOhn Day        Oreg.  Columbia          Columbia River              226,000            21.1  2,650,000
                                                                                              3r:.5 Libby            Mont.  Columbia          Kootenai River                9,070                      282,000
  Little Goose    Wash.  Columbia          Snake River                3.03.900            14.6    850,000
  Lookout Point    Oreg.  Columbia          MiddJe Fk. Wilamette ?iver      9ga            -40.8    360,000
  Lost Fork        Oreg.  Rogue            Lost Fk. Howie River             6L            22.7    169,OOC
  Lower Granite    Wash.  Columbia          Snake River                10*,400            14.7    850,000
  Lower Monumental Wash.  Columbia          Snake River                1.08,500            14.0    850,000
  Lucky Peak       Ida,    Columbia          Boise River                    2,650            32. 5    123,000
  McNary          Oreg.  Columbia          Columbia River              21.4,000            23.0  2,610,000
  Mud Mountain    Wash.  Puyallup          White River                      '400          33.9    386,000
  Ririe            Ida.    Columbia          Willow Ck. Snake River          620              *,4      4?, 000
  The Dalles      Oreg.  Columbia          Columbia River             237,000            2i.1  2,660,000
  Wynoochee        Wash.  Chechalis        Wynoochee River                    4i          69.9      52, 500
  Zintel          Wash.  Columbia          Zintel Canyon Snake River          1Q            7.8      40, '500
                                              California Region Bear            Cal.   San Joaquin      Bear Creek                        72  I 3.b    13.6      30,400
  Big Dry Creek    Cal.    San Joaquin      Big Dry Creek                      91. 19.0     13.8      17,000
  Black Butte      Cal.    Sacramento        Stony Creek                      741   19.7    12,3     254,000
   Brea            Cal.    Santa Ana        Brea Creek                        23  10. LL    6.6      37,000
                                                                        K-


capacity and peak reservoir level likely to be attaiiied during the PMF as governed by the inflow hydrograph.                       A.12 COINCIDENT WIND-WAVE ACTIVITY
TABLE B.1 ( )
     the reservoir level at the beginning of the 'M[:. and the reservoir regulation plan with respect to total releases                   The superposition tlt \n'd-wave :activitv on I'MF tir while the reservoir is rising to peak stage. Most river             seismically induced wael!                level dcte rnin ltions is water level deterininations involve the assumption of               required to assure that. in 11le event Cilt hr coildit ito did steady, or nonvarying, flow for which standard methods             occur, ambient nieteorological activityv would Inot cause are used to estimate flood levels. Where little floodplain          a loss of safe ty-related tun t iotn due to wav, act ion.
                                                                          Drainage      Basin Average PMF Peak Project    State    River Basin            Stream              Area        (in inches)  Discharge (sq.mi.)      Prec.  Runoff  (cfs)
    Buchanan        Cal.    San Joaquin      Chowchilla River                  235      26.0    20.1    127,000
    Burns            Cal.    San Joaquin      Burns Creek                        74    17.4    10.6      26,800
    -Butler Valley  Cal.    Mad              Mad River                        352              35.2    137,000
    Carbon Canyon    Cal.    Santa Ana        Santa Ana River                    19    10.4    10.3      56,000
    Cherry Valley    Cal.    San Joaquin      Cherry Creek                      117      24.3    23.1      60,000
     Comanche        Cal.   San Joaquin      Mokelumne River                   618      25.0    19.9    261,000
    Coyote Valley    Cal.    Russian          East Fk. Russian River            105              22.9      57,000
    Dry Creek        Cal.    Russian          Dry Creek                          82    21.3    15.6      4-5,000
    Farmington      Cal.    San Joaquin      Little John Creek                212      11.3    10.9      56, 000
    Folsom          Cal.    Sacramento        American River                1,875      21.2    17.5    615,000
    Fullerton        Cal.    Santa Ana        Fullerton .Creek                      5.0  9.0    6.8      16,000
tJ*
    Hansen          Cal.    Los Angeles      Tujunga Wash                      147              9.8    130,000
    Hidden Lake      Cal.    San Joaquin      Fresno River                      234      29.9    18.4    114,000
    Isabella        Cal.    San Joaquin      Kern River                    2,073      27.1    6-5    235,000
    Knights Valley  Cal.    Russian          Franz-Maacama Creek                59    31.6    28.9      44,300
    Lakeport        Cal.    Sacramento        Scotts Creek                        52    30.9    24.0      36,100
    Lopez            Cal.   Los Angeles      Pacoima Creek                      34             20.8      32,000
    Mariposa        Cal.    San Joaquin      Mariposa Creek                    108      18.6    13.0      43,000
    Martis Creek    Cal.    Truckee          Martis Creek                        39    26.5    12.7      12,400
    Marysville      Cal.    Sacramento        Yuba River                    1,324      38.9    27.0    460,000
    Mojave River    Cal.    Mojave            Mojave River                      215      40.4    30.4    186,000
    New Bullards Bar Cal.    Sacramento        North Yuba River                  489      38.9    25.7    226,000
    New Exchequer    Cal.    San Joaquin      Merced River                  1,031      27.1    15.9    396,000
    New Hogan        Cal.    San Joaquin      Calaveras River                  362              18.3    132,000
    New Melones      Cal.    San Joaquin      Stanislaus River                  897      25.8    16.3    355,000
    Oroville        Cal.    Sacramento        Feather River                  2,600      23.3    22.8    720,000
    Owens            Cal.    San Joaquin      Owens Creek                        26    14.4    9.2      11,400
    Pine Flat        Cal.    San Joaquin      Kings River                    1,542      28.5    14.4    437,000
    Prado            Cal.    Santa Ana        Santa Ana River               2,233      26.3    13.0    700,000
    San Antonio      Cal.    Santa Ana        San Antonio Creek                  27            13.0      60,000
    Santa Fe        Cal.    San.Gabriel      San Gabriel River                236             35.5    194,000
    Sepulveda        Cal.    Los Angeles      Los Angeles River                152              15.0    220,000
                                                                      I --  - -  - -


geometry definition exists, a technique called
TABLE B.] ( )
   "slope-area" may be employed wherein the assumptions                        The selection of' wind spejeds andtI critical wind are made that the water surface is parallel to the average           directions assu.med coincident with mnxiiniini I'MI: or bed slope, any available floodplain geometry                        seismically i.'duced water levels should provide :t,,n; i rincc information is typical of the river reach under study, and          of virtually no risk to safety-reialed equipmientr icces.arnV
                                                                      Drain&#xa3;*e  Basin Average PMF Peak Project   State    River Basin          Stream           Area    (in inches)  Discharge (sq.mi.)  Prec. Runoff   (cfs)
   no upstream or downstream hydraulic controls affect                  to plant shutdowvn. The ('orps of' ngineecrs .uqiests the river reach fronting the site under study. Where such          (Refs. 26. 27) that average rmaximum %%-itnd siced% of'
Lf1 Success          Cal.   San Joaquin    Tule River                  38-  32.5    12.6    200,000
   computations can be shown to indicate conservatively                approximately 40 to (10 inph have occurred in miajor high flood levels, they may be used. However, the usual              windstorms in most regions of the United States. For method of estimating water surface profiles for flood                application to the safety analysis of nuclear facilities, the conditions that may be characterized as involving                    worst regional winds of record should le :ssnmned essentially steady flow is a technique called the                    coincident with the PMF. However. the postuhlted winds Itstandard-step method." This technique utilizes thle                should be meteorologically compatible with the i- .grated differential equation of steady fluid motion             conditions that induced tire PMF or with tlie flood commonly referred to as the Bernoulli equation                      conditions assunred coincident with seismically induced (References 22. 23, 24, and 25) where, depending on                  dam failures) such as the season of tfie year. the ntite whether supercritical or subcritical Rlow is tinder study,          required for the PMP storon to 11r0%'e our of the area and water levels in the direction of flow computation are                be replaced by meteorological conditions that could determined by the trial and error balance of upstream                produce the postulated winds, ard the restrictions on and downstream energy, respectively. Frictional and                  wind speed and direction produced by topography. As other types of head losses arc usually estimated in detail          an alternative to a detailed study of hitorical regional with the use of characteristic loss equations whose                  winds, a sustained 40-inph overland wind speed t'romr coefficients have been estimated from computational                  any. critical direction is an acceptable positulation.
    Terminus        Cal,   San Joaquin    Kaweah River                  560  40.1    24.8    290,000
    Tuolumne        Cal.   San Joaquin    Tuolumne River             1,533  25.1    20.?    602,000
    Whittier Narrows Cal.   San Gabriel    San Gabriel River            551+ 17.4    13.7    305,000


reconstitution of historical floods, and from detailed floodplain geometry information. Application of the                        Wind-generated set up (or wind tide) atd wave
APPENDIX C
  "standard-step method" has been developed into very action (runup and impact torces) may be estimated using sophisticated computerized models such as the one                   the techniques described in References 26 and 28. Tire described in Reference 23. Theoretical discussions of the            method for estimating wave action is based on stutistical techniques involved are presented in References 22, 24,              analyses of a wave spectrum. For nuclear power planrts.
                                                  SIMPLIFIED METHODS OF
                                      ESTIMATING PROBABLE MAXIMUM SURGES
                                                            TABLE OF CONTENTS
                                                                                                                                                        Page C.1 INTRODUCTION .................                                  ....................................                                          ..  1.59-55 C.2 SCOPE    . ............                                    ...                          ..................                                        1.59-55 C.3 PROBABLE MAXIMUM SURGE LEVELS FROM HURRICANES .....................                                                                              .1.59-55 C.3.1 Methods Used .........................................                                                                                        1.59-55 C.3.2 Use of Data in Estimating PMS .....                        .....      .......              ............................                      1.59-55 C.3.3 Wind-Wave Effects .......                .....        .....            ..................................                                    1.59-56 C.4 LIMITATIONS              . . . . . . . . . . . . . . . . . . . . .                                                                        . . . . 1.59-56 REFERENCES .......                .....    .....      ........................................                                                    .. 1.59-56 FIGURES ......          ...    .....    .......        ...........................................                                                    1.59-57 TABL E S    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . :                                                                    1.59-59 FIGURES
Figure C.1 - Probable Maximum Surge Estimates, Gulf Coast ....                                      .............                    . . . . . . . . 1.59-57 C.2 - Probable Maximum Surge Estimates, Atlantic Coast                                      ..........                          . . . . . . . . 1.59-58 TABLES
Table C. 1 -  Probable Maximum              Surge Data ......                    ....................                                                  1.59-59 C. 2 -  Probable Maximum              Hurricane, Surge,          and Water Level - Port Isabel                              . .                    1.59-60
      C. 3 -  Probable Maximum              Hurricane, Surge,          and Water Level - Freeport . . . .                                                1.59-61 C. 4 -  Probable Maximum              Hurricane, Surge,          and Water Level - Eugene Island .                                                  1.59-62 C. 5 -  Probable Maximum              Hurricane, Surge,          and Water Level.- Isle Dernieres                                                  1 .59-63 C. 6 -  Probable Maximum              Hurricane, Surge,          and Water Level - Biloxi                                                          1.59-64 C. 7 -  Probable Maximum              Hurricane, Surge,          and Water Level - Santarosa Island .                                              1.59-65 C. 8 -  Probable Maximum              Hurricane, Surge,          and Water Level - Pitts Creek                            . . .                    1.59-66 C. 9 -  Probable Maximum              Hurricane, Surge,          and Water Level - Naples .......                                                  1.59-67 C.10 -  Probable Maximum              Hurricane, Surge,          and Water Level - Miami                          .....                            1.59-68 C.1l-  Probable Maximum              Hurricane, Surge,          and Water Level - Jacksonville . . .                                              1.59-69 C.12 -  Probable Maximum              Hurricane, Surge,          and Water Level - JeckyUl Island...                                                1.59-70
      C.1 3 - Probable Maximum              Hurricane, Surge,          and Water Level - Folly Island . . .                                              1.59-71 C.14 -  Probable Maximum              Hurricane, Surge,          and Water Level - Raleigh Bay . . .                                                1.59-72 C.I 5 - Probable Maximum              Hurricane, Surge,          and Water Level - Ocean City . . .                                                1.59-73 C.1 6 - Probable Maximum              Hurricane, Surge,          and Water Level - Atlantic City                            . .                   1.59-74 C.17 -  Probable Maximum              Hurricane, Surge,          and Water Level - Long Island . . .                                                1.59-75 C. 18 - Probable Maximum              Hurricane, Surge,          and Water Level - Watch Hill Point                                                1.59-76 C.19 -  Probable Maximum              Hurricane, Surge,          and Water Level -- Hampton Beach                                                  1.59-77 C.20 - Probable Maximum              Hurricane, Surge,         and Water Level - Great Spruce Island                                              1.59-78 C.21 - Ocean Bed Profiles             . . . . . . .            . . . . . . . . . . . . . . . . .                                                  1.59-79
                                                                            1.59-53


and 25.                                                             protection against the maximuin wave, defincd in Refernce 28 as tire average of tire upper one percent ofl"
C.1 INTRODUCTION                                C.3.1 Methods Used This appendix presents timesaving methods of esti-                  All PMS determinations in Table C.A were made by mating the maximum stillwater level of the probable                NRC consultants for this study (Ref. 1), except Pass maximum surge (PMS) from hurricanes at open-coast                  Christian, Crystal River, St. Lucie, Brunswick, Chesa- sites on the Atlantic Ocean and Gulf of Mexico. Use of             peake Bay Entrance, Forked River-Oyster Creek, Mill- the methods herein will reduce both the time necessary              stone, Pilgrim, and Seabrook.
.       Unsteady-flow models may also be used to estimate water levels. Since steady flow may be consider,:d a class of unsteady flow, such models may also be used for the steady-flow water level estimaLion, Compnterized unsteady-flow models require generally the same the waves in the anticipated wave spectrumI , should bIe assumed.       Where depths of water ill tronitr0'
                                                                        safety-related structures are sufficient (Cusually about seven-tenths the wave height), the wave-induiced forces will be equal to the hydrostatic forces estimated frort
                                                                1.59-13


the maxilunm rurup level. Where the waves can be                  . In addition, assurance should be provided that
for applicants to prepare license applications and the NRC staff's review effort.                                             The computations by the consultants were made using the NRC surge computer program, which is The procedures are based on PMS values determined              adopted from References 2 and 3. Probable maximum by applicants for licenses that have been reviewed and              hurricane data were taken from Reference 4. Ocean accepted by the NRC staff and by the staff and its                  bottom topography for the computations was obtained consultants. The information in this appendix was                  from the most detailed available Nautical Charts pub- developed from a study made by Nunn, Snyder, and                   lished by the National Ocean Survey, NOAA. The Associates, through a contract with NRC (Ref. 1).                   traverse line used for the probable maximum hurricane surge estimate was drawn from the selected coastal point The PMS data are shown in Tables C.A through C.21              to the edge of the continental shelf or to an ocean depth and on maps of the Atlantic and Gulf Coasts (Figures                of 600 feet MLW, and was one hurricane radius to the C.A and C.2). Suggestions for interpolating between                right of the storm track. It was oriented perpendicular to these values are included.                                          the ocean bed contours near shore. The ocean bed profile along the traverse line was determined by Limitations on the use of these generalized methods             roughly averaging the topography of cross sections of estimating PMS are identified in Section C.4. These              perpendicular to the traverse line and extending a limitations should be considered in detail in assessing the        maximum of 5 nautical miles to either side. The 10-mile applicability of the methods at specific sites.                    wide cross sections were narrowed uniformly to zero at the selected site starting 10 nautical miles from shore. It Applicants for licenses for nuclear facilities at sites on     was assumed that the peak of the PMS coincided with the 10% exceedance high spring tide1 plus initial rise. 2 the open coast of the Atlantic Ocean or the Gulf of Mexico have the option of using these methods in lieu of more precise but laborious methods. The results of                      In each case the maximum water level resulted from application of the methods in this appendix will in many            use of the high translation speed for the hurricane in cases be accepted by the NRC staff with no further                  combination with the large radius to maximum wind, as verification.                                                      defined in Reference 4. Detailed data for the computed PMS values are shown in Tables C.1 through C.20. Ocean bed profile data for Pass Christian, Crystal River, St.
-tripped' and caused to break both before reaching and         safety systems ncessary for cold shutdown and on safeiy.related structures, dynamic Irces may. be            maintenance thereof are designed to withstand the static estimated from Reference 28. Where waves may induce             and dynamic effects resulting from frequent flood levels surging in intake structure sumps. pressures on walls and      coincident with the waves that would be produced by the underside of' exposed floors should be considered,          the nmaximumn gradient wind for the site (based on a particularly where such sumps are not vented and air            study of historical regional meteorology).
Colmpression call greatly increase dynamic forces.


1.59.14 I
C.2 SCOPE                                  Lucie, Chesapeake Bay Mouth, and Seabrook are shown in Table C.21.


V
The data and procedures in this appendix apply only to open-coast areas of the Gulf of Mexico and the                      The water levels resulting from these computations Atlantic Ocean.                                                     are open-coast stillwater levels upon which waves and wave runup should be superimposed.
6 4                                                        REFERENCES
      I. Precipitation station data and unpublished records            9. "Meteorology of Flood Producing Storms in the of Federal, State, municipal, and other agencies may              Ohio River Basin," Hydronieteorological Report be obtained from the U.S. Weather Bureau (now                    No. 38. U.S. Weather Bureau (now NOAA). 196L.


called National Weather Service). In addition, studies of some large storms are available in the           10. "Probable Maximum        and TVA Precipitation Over
Future studies are planned to determine the applica- bility of similar generalized methods and to develop such          C.3.2 Use of Data in Estimating PMS
          "Storm      Rainfall in the Un it ed States.                    the Tennessee River      Basin Above Chltllanooea."
methods, if feasible, for other areas. These studies, to be included in similar appendices, are anticipated for the                Estimates of the PMS stillwater level at open coast Great Lakes and the Pacific Coast, including Hawaii and            sites other than those shown in Tables C.1 through C.21 Alaska.                                                             and on Figures CA and C.2 may be obtained as follows:
          Depth.Area-Duration Data." summaries published                  Hydrometeorological    Report No. 43, U.S. Weather by Corps of Engineers, U.S. Army.                                Bureau (now NOAA),      1965.
      C.3 PROBABLE MAXIMUM SURGE LEVELS                                  1. Using topographic maps or maps showing sound- FROM HURRICANES                                  ings, such as the Nautical Charts, determine an ocean bed profile to a depth of 600 ft MLW, using the methods The data presented in this appendix consist of all determinations of hurricane-induced PMS peak levels at              'The 10% exceedance high spring tide is the predicted maximum open-coast locations computed by the NRC staff or their              monthly astronomical tide exceeded by 10% of the predicted consultants, or by applicants and accepted by the staff.             maximum monthly astronomical tides over a 21-year period.


2. Corps of Engineers publications, such as EM                  11. "Interim Report- -Probable Maximum Precipitation
The data are shown in Tables C.A through C.21 and on                2Initial rise talso called forerunner or sea level anomaly) is an Figures C.A and C.2. All represent stillwater levels for              anomalous departure of the tide level from the predicted open-coast conditions.                                               astronomical tide.
          1110-2-1405 dated 31 August 1959 and entitled,                  in California." Hydrometeorological Report No. 36.


"Engineering and Design-Flood Hydrograph                        U.S. Weather Bureau (now NOAA). 1961.
1.59-55


Analyses and Computations." provide excellent criteria for the necessary flood hydrograph analyses.       12. "Probable      Maximuni Precipitation, Northwest (Copies are for sale by Superintendent of                        States," Hydrometeorological Report No. 43. U.S.
outlined above. Compare this profile with the profiles of      obtained by the foregoing procedures.           Acceptable the locations shown in Tables C.2 through C.21. With          methods are given in Reference 2.


Documents. U.S. Government Printing Office,                      Weather Bureau (now NOAA), 1966.
particular emphasis on shallow water depths, select the location or locations in the general area with the most similar profiles. An estimate of the wind setup may be                            C.4 LIMITATIONS
interpolated from the wind setup data for these loca- tions.


Washington, D.C. 20402.) Isohyetal patterns and related precipitation data are in the files of the           13. "Probable Maximum Precipitation in the Hawaiian Chief of Engineering, Corps of Engineers.                          Islands," Hydrometeorological Report No. 39. U.S.
1. The NRC staff will continue to accept for review
  2. Pressure setup may be interpolated between loca-        detailed PMS analyses that result in less conservative tions on either side of the site.                             estimates. In addition, previously reviewed and approved detailed PMS analyses at specific sites will continue to be
    3. Initial rise, as shown in Table C1, may be              acceptable even though the data and procedures in this interpolated between locations on either side of the site.     appendix result in more conservative estimates.


Weather Bureau (now NOAA). 19)63.
4. The 10% exceedance high spring tide may be computed from predicted tide levels in Reference 5; it            2. The PMS estimates obtained as outlined in Section may be obtained from the Coastal Engineering Research          C.3.2 are maximum stillwater levels. Coincident wind- Center, U.S. Army Corps of Engineers, Ft. Belvoir, Va.;        wave effects should be added.


3. Two computerized models arc "Flood Hydrograph Package. HEC-I Generalized Computer Program,"                14. "Meteorological Conditions for the Probable available from the Corps of Engineers Hydrologic                  Maximum Flood on the Yukon River Above Engineering Center, Sacramento, California, dated                  Rampart, Alaska," Hydronieteorological Report No.
or it may be interpolated, using the tide relations in Reference 5.


October 1970 and "Hydrocomp Simulation                            42, U.S. Weather Bureau (now NOAA), 1966.
3. The PMS estimates obtained from the methods in
    5. An estimate of the PMS open-coast stillwater level      Section C.3.2 are valid only for open-coast sites, i.e., at at the desired site will be the sum of the values from        the point at which the surge makes initial landfall. If the Steps 1 through 4, above.                                      site of interest has appreciably different offshore bathy- metry, or if the coastal geometry differs or is complex, C.3.3 Wind-Wave Effects                                        such as for sites on an estuary, adjacent to an inlet, inshore of barrier islands, etc., detailed studies of the Coincident wave heights and wave runup should be            effect of such local conditions should be made. Refer- computed and superimposed on the PMS stillwater level          ence 2 provides guidance on such studies.


Programming-HSP," Hydrocomp Intl.. Stanford, Calif.                                                        15. "Meteorology of Flood-Producing Storms in the Mississippi River Basin." Hydrometeorological
APPENDIX C                                                            .
      4. One technique for the analysis of snowmelt is                      Report No. 34, U.S. Weather Bureau (now NOAA).
                                                    REFERENCES
          contained in Corps of Engineers EM 1100-2.406,                     1965.
1. Nunn, Snyder, and Associates, "Probable Maximum                Memorandum No. 35, U.S. Army Coastal Engineering Flood and Hurricane Surge Estimates," unpublished              Research Center, 1971.


"Engineering and Design-Runoff From Snowmelt,"
report to NRC, June 13, 1975 (available in the public document room).                                            4. U.S. Weather Bureau (now U.S. Weather Service, NOAA), "Meteorological Characteristics of the Probable Maximum Hurricane, Atlantic and Gulf
           January 5, 1960. Included in this reference is also           16. "Meteorology of Hypothetical Flood Sequences in an explanation of the derivation of probable                       the Mississippi River Basin," Hydrometeorological maximum and standard project snowmelt floods.                      Report No. 35, U.S. Weather Bureau (now NOAA),
2. U.S. Army Coastal Engineering Research Center,
                                                                             1959.
  "Shore Protection Manual," 1973.                                Coasts of the United States," Hurricane Research Interim Report, HUR 7-97 and HUR 7-97A, 1968.
 
3. B.R. Bodine, "Storm Surge on the Open Coast:                5. U.S. Department of Commerce,            NOAA,    "Tide Fundamental and Simplified Prediction," Technical              Tables," annual publications.
 
1.59-56
 
840  830  820    810    800  790    780
    360
    350
                                                                                                                                330
    340
                                                                                                                                320
    330
                                                                                                                                310
    310
                                    LOUISIANA
                                                                        -4 Z290
U300
                                                                                  0                      FLORIDA
                                                                            >          l                                      280
              29                            Wry z*                                                  270
    280  Z*
                                                                                                                                260
    270            _
                                                                                                    43                          250
    260
    250                                                                                                                        240
                                                                32.7 MAXIMUM STILLWATER LEVEL AT OPEN COAST, FT., MLW          230
        970    960  950 940    930    920    910  90&deg;  890    880    870  860    850  840      830    820    810
                              FIGURE C.1  PROBABLE MAXIMUM SURGE ESTIMATES - GULF COAST
 
830  820  810 800  790  780  770    760  750  740    730  720  710  700  690  680 670 660  650  640  630 620
                                                                                                                    (
                                    ___        " 32.7 MAXIMUM STILLWATER LEVEL AT OPEN COAST, FT., ML
  860    850  840    830    820      810  800    790    780    770    760  750  740  730    720  710  700
                    FIGURE C.2 PROBABLE MAXIMUM SURGE ESTIMATES - ATLANTIC COAST
                                                              1.59-58
 
TABLE C.1 PROBABLE MAXIMUM SURGE DATA
                                                                    (LOCATIONS INDICATED ON FIGURES C.] and C.2)
              DISTANCE FROM SHORELINE,    NAUTICAL MILES,    FOR SELECTED WATER DEPTHS,  FEET mLW            PROBABLE MAXIMUM  SURGE AT OPEN COAST SHORE LINE
    OPEN COAST LOCATION          TRAVERSE    J DEPTH, FEET, ALONG TRAVERSE FROM OPEN COAST SHORE LINE      WIND      PRESSURE    INITIAL 10% EXC. HIGH  TOTAL
      AND TRAVERSE                AZIMUTH          10        20        50    100        200        600  SETUP,      SETUP,      RISE,      TIDE,      SURGE,
                                DEG. - MIN.            DISTANCE, NAUTICAL MILES, TO DEPTH INDICATED          FT.        FT.        FT.      FT. MLW    FT. MLW
      PORT ISABEL                86      30      0.23      0.49      1.94    11.10      33.10      44.0  10.07        3.57        2.50      1.80        17.94 FREEPORT                152      00      0.20      0.55      5.50    24.0      55.5        70.9  15.99        2.89        2.40      2.90        24.18 EUGENE ISLAND            192      30      2.00      20.00    30.00    44.1      60.0        90.0  29.74        3.29        2.00      2.40        37.44 ISLE DERNIERES          165      00      0.62      1.75    11.90    30.4      45.3        58.5  18.61        3.29        2. 00      1.90        25.80
      PASS CHRISTIAN (a)                                                                            77.0  28.87        2.88        0.80      1.20        33.75 BILOXI                  160      00      3.40      11.20    30.00    50.1      69.2        78.0  27.77        2.98        1. 50      2.50        34.76 SANTAROSA ISLAND        183      00      0.09      0.18      0.48    11.9      20.9        45.0    9.12        3.25        1.50      1.80        15.67 PITTS CREEK              205      00      8.84      9.23    24.30    69.4      107.0      132.0    24.67        2.31        1.20      4.20        32.38 CRYSTAL RIVER (a)                          2.31                31.40                        127.0    26.55        2.65        0.60      4.30        34.10
      NAPLES                  248      00      0.17      0.79    15.70    45.6      85.8      145.0    18.47        2.90        1. 00      3.60        25.97 C-,.
      MIAMI                    100      00      0.17      0.94      2.01    2.2        2.7        3.9    2.51        3.90        0.90      3.60        10.91 STr. LUCIE(a)                              0.10                                                18.7    8.25        3.80        0.98      3.70        16.73 JACKSONVILLE              90      00      0.10      0.20      2.58    30.0      55.0        62.5  16.46        3.23        1.30      6.20        27.20
      JEKYLL ISLAND            108      00      2.60      4.00    15.60    39.6      64.3        72.6  20.63        3.34        1.20      7.50        32.67 FOLLY ISLAND            150      00      0.19      2.17    12.00    32.8      47.0        57.6  17.15 BRUNSWICK
                                                                                                                          3.23        I. 00      6.80        28.18
                                                                                                            12.94        2.20        1. 00      5.80        21.94 RALEIGH                  135      00      0.12      0.30      1.75    12.0      25.4        35.2    8.84        3.09        1 -00      5.20        18.13 CHESAPEAKE BAY
          ENTRANCE (a)                                                                              62.0    17.30(b)      (b)        1.10      3.50        21.90
      OCEAN CITY              110      00      0.12      0.26      3.67    17.8      45.0      59.0    14.30        2.83        1.14      5.10        23. 17 ATLANTIC CITY            146      00      0.20      0.85      5.00    23.1      58.4      70.0    15.32        2.57        1.10      5.80        24.80
      FORKED RIVER -
          OYSTER CREEK
                                                                                                            18.08(b)      (b)      1.00      2.70        21.78 LONG ISLAND              166      00      0.09      0.18      1.35    4.8      27.2      68.4    8.73        2.46        0.97      8.00        20.16 MILLSTONE
                                                                                                            12.41        2.20        1.00      3.56        19.17 WATCH HILL POINT        166      00      0.07      0.14      0.64    1.6      34.3      84.0    10.01        2.42        0.96      8.80        22.19 PILGRIM
      HAMPTON BEACH                                                                                                                                        19.6
                                115      00      0.22      0.31      0.71    2.0        7.2      40.0    4.25        2.23        0.83      11.70        19.01 SEABROOK(a)
                                                                                                    44.0    4.79        2.28        0.86      11.60        19.53.
 
GREAT SPRUCE ISLAND      148      00      0.04      0.08      0.20    1.1        6.3    178.0      9.73        1.82        0.56      18.40        30.51 ocean bedsetup.
 
for pressure C.H and profile.
 
a.  See Table wind b.
 
a.  Combined See Table C.21 for ocean bed profile.
 
b.  Combined wind and pressure setup.
 
TABLE C.2 SUMMARY-PERTINENT PROBABLE MAXIMUt.      hURRICANE (FMH),       STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL
                LOCATION PORT ISABEL [AT.      260o4.3'  LONG.    97 09.4': TRAVERSE-AZIMUTH86&deg;-30'DECREEi    LENGTH 42.1 NAUTICAL MILES
                          TEXAS
            PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS                    OCEAN BED PROFILE            PMH (CNPUTATIONAL COEFFICIENT
            ZONE C AT LOCATION        260    04' DEGREE NORTH
                                                                              TRAVERSE    WATER            AND WATER LEVEL (SURGE)  ESTIMATES
                                          SPEED OF TRANSLATION                DISTANCE    DEPTH
        PARAMETER DESIGNATIONS            SLOW    MODERATF      HIGH            FROM      BELOW
                                      _(ST)        (MT)        (.)_            SHORE      MLW
                                                                            (NAUT.MI.)    (FEET)                C 0 E F F I CI E N T S
  3ENTRAL PRESSURE INDEX
                        P0 INCHES        26.42      26.42    26.42&#xfd;              0          0              BOTfIOF FhICTION FACTOR 0.0030
  PER IPHERAL PRESSURE                                                            0.2        9.0
                        Pn INCAES        31.30      31.30    31.30        _      0.5      20.5          WIND STRESS CORRECTION FACTOR 1.10
                                                                                    1.0      35.0
  RADIUS TO MAXIMUM WIND                                                    _    1.5      43.0
        LARGE RADIUS NAUT. MI.            20        20        20                  2.0      51.0
  rRANSIATION SPEED                                                          _    3.0      58.5            WATER        LEVEL        DATA
                                                                            -      5.0      69.0
  Fv (FORWARD SPEED) KNOTS            1  4        11        28
0                                                                                10          95.5              (AT OPEN CCAST SHORELINE)
    WIAXMUM WIND SPEED                                                          15        116 V M.P.H.        147        151        161                  20        138 INITIAL DISTANCE-NAUT. MI, i/                                              _  30        171                            PMH SPEED OF TPANSLATION
  FROM 20 MPH WIND                    398        374        318                40        266          COMPONENTS          ST      MT        nIT
  6T SHORE TO MAX.        WIND                                                  44        600                                  F  E  E    T
                                                                                  50    1,850
    14ULe      Maximum wind  speed is  assumed  Lto  be on the traverse that is to right of storm track a                                                      WIND SETUP                              10.07 distance equal to the radius to maximum wind.
 
PRESSURE SETUP                          3.57
  -/Initial        distance is distance along traverse from shoreline to maximum wind when leading                                                  INITIAL WATER LEV.                      2.50
        20 mph isovel intersects shoreline.            Storm diameter between 20 mph-isovels is approxi-                                                  kSTRONONICAL                            1.80
      mately double the initial distanc
 
====e. FIDE LEVEL====
                                                                                                      rOTAL-SURGE
                                                                                                      STILL WATER LEV.                        17.9.4 FEET NLW
                                                                            LATITUDE
* 26&deg; 05'
                                                                            DEGREE AT TRAVERSE
                                                                            MID-POINT FROM SHORE
                                                                            TO 600-FOOT DEPTH
                                                                                  7]
 
TABLE C.3 SUMMARY-PERTINENT PROBABLE MAXIMU.      hURRICANE (FMH),    STORM SURGE COMPUTATIONAL LATA AND RESULTANT WATER LEVEL
                LOCATION FREEPORT,      LAT.  280    56' LONG. 95"   22' : 'PRAVERSE-AZIMUTH  152  DEGREEt LENGTH 70.9 NAUTICAL MILES
                            TEXAS
          PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS                OCEAN BED PROFILE              PMH OCPIPUTATIONAL COEFFICIENT
            ZONE C    AT LOCATION    280    56' DEGHEE NORI'H
                                                                          TRAVERSE    WATER          AND WATER LEVEL (SURGE)    ESTIMATES
        PARAMETER DESIGNATIONS
                                      I SLOW
                                          SPEED OF TRANSLATION
                                                  MODERATF    HIGH
                                                                          DISTANCE
                                                                            FROM
                                                                                        DErTH
                                                                                        BELOW
                                      S(ST)        (?Tr)      (*)T I        SHORE      MLW
                                                                        (NAUT.MI.)    (FEET)                C 0 E F F I C I E N T S
    MENTRAL PRESSURE INDEX                                    26.69 P 0 INCHES      26.69      26.69    26.69            0           0              BO'nUfM FRICTION FACTOR 0.0030
    PERIPHERAL PRESSURE                                                        1.0      30
                        P INCHES        31.25      31.25    31.25            2.0      32            WIND STRESS CORRECTION FACTOR 1.10
                                                                        _      3.0      37 RADIUS TO MAXIMUM WIND                                                      4.0      40
        LARGE RADIUS NAUT. MI.          26.0      26.0      26.0      _      5.0      47
                                                                              10.0        66              WA T E h    L EV E L      D A T A
    rRANS1ATION SPEED
U)
    F (FORWARD SPEED) KNOTS          I  4        11        28.0            15.0
                                                                              1          78
&                                                                            20.0        9o                  (AT OPEN CCAST SHORELINE)
      AIMUM WIND SPEED                                                        30.0      114 Vx M.P.H.      139        143      153        _    40&deg;.0      132 INITIAL DISTANCE-NAUT.MI.Y                                          _    50.0      168                              PMH SPEED OF TRANSLATION
    FROM 20 MPH WIND                    491                                  6o.o0      240          COMPONENTS
                                                  458      390                                                              ST I    MT  I HT
    AT SHORE TO MAX. WIND                                  I                  70.0      570                                    F  E    E  T
                                                                              70.9      600
  Note:        Maximum wind speed is assumed to be on the traverse that is to right of storm track a                                                WIND SETUP                              15.99 distance equal to the radius to maximum wind.
 
PRESSURE SETUP                            2.89
  -/Initial        distance is distance along traverse from shoreline to maximum wind when leading                                                INITIAL WATER LEV.                        2.40
        20 mph isovel intersects shoreline.          Storm diameter between 20 mph isovels is approxi-                                                kSTRONOMICAL                              2.90
        mately double the initial      distanc
 
====e. rIDE LEVEL====
                                                                                                  TOTAL-SURGE
                                                                                                  STILL WATER LEV.                        24.18 FEET MLW
                                                                        LATITUDE
* 28' 26'
                                                                        DEGREE AT TRAVERSE
                                                                        MID-POINT FROM SHORE
                                                                        TO 600-FOOT DEPTH
 
TABLE C4 SUMMARY-PERTINENT PROBABLE MAXIMUE hUHRICANE (FMH),               STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL
                                                                    1 :0                          2
                                                              21          'rTRAVERSE-AZIMUJTHl9    30 t DEG~REE, LENGTH  90  NAUTICAL MILES
          LOCATION EUGENE      LAT. 290    20'  LONG. 91 ISLAND, LOUISIANA
    PROBABLE MAXIMUM HURRICANE INDEX CHARACTEIISTICS                  OCEAN BED PROFILE                      PMH CCNPUTATIONAL COEFFICIENT
      ZONE    B  AT LOCATION    290    20' DEGREE NORTH                                                    AND WATER* LEVEL (SURGE) ESTIMATES
                                                                      TRAVERSE          WATER
                                    SPEED OF TRANSLATION              DISTANCE          DEPTH
  PARAMETER DESIGNATIONS        SLOW    MODERATF      HIGH                FROM        BEL40W
                              2  (ST)      (nT)      (HT)                SHORE        MLW
  MENMAL PRESSURE INDEX                                            (NAUT.MI.)          (FErT)
                  P INCHES      26.87      26.87    26.87              -    0.0          0  -              BOIOM FilICTION FACTOR 0.0030
PERIPHERAL PRESSURE                                                -          1.0
                                                                                2.0          105 -
                                                                                                -
                  P INCHES      31.24      31.24    31.24                                                WIND STRESS CORRECTION FACTOR 1.10
                                                                                3.0          12  -
RADIUS TO MAXIMUM WIND
  LARGE RADIUS NAUT. MI.        29.0        29.0    29.0      -            5.0          15  -
                                                                  -            10.0          15  -
rRANSLATION SPEED                                                -            15.0          18  -              WATER        LEVEL        DATA
Fv (FORWARD SPEED) KNOTS          4        11      28.0      -            20.0          20  -
                                                                  -            30.0          50  -                (AT OPEN CCAST SHORELINE)
MAXIMUM WIND SPEED                                              -            40            60  -
                  V M.P.H.      141        144      153        -            50          140  -
INITIAL DfSTANCE-NAUT. MI.i_                                      -          6o          200  -                            PMH SPEED OF TRANSLATION
FROM 20 MPH WIND                534        484      412          -          70          260  -          COMPONENTS            ST      M
                                                                                                                                          MT      HTI
4T SHORE TO MAX. WIND                                      .                80          320  -                                  F  E  E'  T
Note: Maximum wind speed is assumed to be on                      -          90          600  -
                                                                                                      WIND SETUP                                29.74 the traverse that is to right of storm track a distance equal to the radius to maximum wind.
 
PRESSURE SETUP                            3.29
-  Initial distance is distance along traverse from shoreline to maximum wind when leading                                                        INITIAL WATER LEV.                        2.00
  20 mph isovel intersects shoreline.        Storm diameter between 20 mph isovels is approxi-                                                        ASTRONOMICAL                              2.40
  mately double the initial    distanc
 
====e. TIDE LEVEL====
                                                                                                      TAL-SURGE
                                                                                                      STILL WATER LEV.                          37.44 FEET MLW                                        I
                                                                  IATITUDE          28  04 DEGREE AT TRAVERSE
                                                                  MID-POINT FROM SHORE
                                                                      (ro 600-FOOT DEPTH
                                                                                          -~-r..-
 
TABLE CA5 SUMMARY-PERTINENT PROBABLE MAXIMUE HU!RICANE (FMH),            STORM SURGE COMPUTATIONAL LATA AND RESULTANT WATE            LEVEL
          LOCATION ISLE          LAT. 29'02.9' LONG.      90'42.5': TRAVERSE-AZIMUTH        165    DEGREE,  LENGIH 58.5 NAUTICAL MILES
                    DERNIERES, LOUISIANA
    PROBABLE MAXIMUM HURRICANE INDEX CHARACTEIISTICS                  OCEAN BED PROFILE                  PMH OCXPUTATIONAL COBYFICIENT
      ZONE B    AT LOCATION    290    03' DEGREE NORTH
                                                                      TRAVERSE    WATER                AND WATER LEVEL (SURGE)      ESTIMATES
                                                                      DISTANCE    DEPTH
  PARAMETER DESIGNATIONS          SPEED OF
                                  SLOW        TRANSLATION
                                          I4ODERATF    HIGH          FROM      BELOW
                              _(ST)          (rT)          )          SHORE      MLW
                                                                    (NAUT.MI.)    (FEET)                      C 0 E F F I C I E N T S
JENTRAL PRESSURE INDEX
                P INCHES        26.88      26.88    26.88              0          0                    B(yJ']fj .FhICTION FACTOR 0.0030
                                                                    -      0.2        6.0
PER IPHERAL PRESSURE
                                                                            0.5        9.0
                P INCHES        31.25      31.25    31.25                                          WIND STRESS CORRECT*iON FACTOR 1.10
                  n            _        a            _                    1.0      13.0
RADIUS TO MAXIMUM WIND                                                      1.5      17.5 LARGE RADIUS NAUT. MI.          29          29        29                  2.0      22.5
                                                                            3.0      26.e rRANSLATION SPEED                                                                                        WATER          LEVEL        DATA
                                                                            5.0      32.0
F (FORWARD SPEED) KNOTS            4          11        28
                                                                            7.0      34.0
                                                                                                              (AT OPEN CCAST SHORELINE)
MAXIMUM WIND SPEED                                                          7.5      28.0
                V    M.P.H.    140          144      153        -        8.0      25.5
                                                                  -        8.5      25.0
INITIAL DISTANCE-NAUT.MI.1!                                                                                                PMH SPEED OF TANSIATIOI
FROM 20 MPH WIND                528          487      394                  9.0      28.5 COMPONENTS              ST      MT I    HT
                                                                          .9.5      34.0
&#xfd;T SHORE TO MAX. WIND                    I_                                                                                      F  E    E  T
                                                                          10.0
                                                                          1          42.5 Note: Maximum wind speed is assumed to be on                        -    15.0      62.0        WIND SETUP                                  18.61 the traverse that is to right of storm track a                      -    20.0        56.0
distance equal to the radius to maximum wind.                            30.0      97.9        PRESSURE SETUP                              3.29 y Initial  distance is distance along traverse                    -    40.0      152.0
  from shoreline to maximum wind when leading                            50.0      243          INITIAL WATER LEV.                           2.00
  20 mph isovel intersects shoreline.          Storm            -      58.5      600
  diameter between 20 mph isovels is approxi-                    -      60.o      688          kSTRONONICAL                                1.90
  mately double the initial    distanc
 
====e. rIDE LEVEL====
                                                                                                  TOTAL-SURGE
                                                                                                  STILL WATER LEV.                            25.aO
                                                                                                  FEET  MLW
                                                                  LATITUDE 0 28&deg; 3 4.4 DEGREE AT TRAVERSE
                                                                  MID-POINT FROM SHORE
                                                                  rO 600-FOOT DEPTH
                                                                                          I-..-.
 
TABLE C.6 SUMMARY-PERTINENT PROBABLE MAXIMUV. HURRICANE (PMH),            STORM SURGE COMPUTATIONAL DATA AND 'RESULTANT WATER LEVEL
                LOCATION    BILOXI        LAT. 30023.6'  LONG.  88"53.6': TRAVERSE-AZIMUTH      160  DEGREE,    LENGTH  77  NAUTICAL MILES
                            MISSISSIPPI
        PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS                    OCEAN BED PROFILE                PMH OCCPUTATIONAL COEFFICIENT
          ZONE    B AT LOCATION      300      24' DEGREE NORTH                                                                        ESTIMATES
                                                                            TRAVERSE    WATER              AND WATER LEVEL (SURGE)
                                          SPEED OF THRANS  TION           DISTANCE    DEPTH
      PARAMETER DESIGNATIONS              SLOW    MODERATF      HIGH          FROM      BELOW
                                        l  ST)'n    (n)        (HT)          SHORE      MLW
CENTRAL PRESSURE INDEX                                                    (NALT.MI.)    (FEET)                    C0 E F F I CI 9 N T S
                        P 0 INCHES        26.9      26.9    26.9                o          0                    BOT'1OYM FHICTION FACTOR 0.0030
PER IPHERAL PRESSURE                                                            0.2        3.0  -
                        P INCHES          31.23    31.23    31.23        _    0.5        2.0              WIND STRESS CORRECTION FACTOR 1.10
                          n__                                            _      1.0        6.5 RADIUS TO MAXIMUM WIND                                                    _      1.5        9.0"
      LARGE RADIUS NAUT. MI.              30        30      30                  2.0        9.0  -
TRANSLATION SPEED                                                        _      3.0        9.5 -              WATER          LEVEL        DATA
Fv (FORWARD SPEED) KNOTS                  4        11      28          _      5.0      12.0
                                                                          _      9.0        9.5                    (AT OPEN CCAST SHORELINE)
MAXIMUM WIND SPEED                                                        _    9.5      11.0
                      V M.P.H.        139        143      153                10.0        14.0
                        x INITIAL DISTANCE-NAUT.MI.i/                                            -    10.5        18.5                                PMH SPOED OF TRANSLATION
  FROM 20 MPH WIND                      525        498      396          _    11.0        17.5 -          COMPONENTS            ST I    MT    IHT
&T SHORE TO MAX, WIND                                                      _  11.5        23.0 j                                    F  E  E    T
                                                                              12.0        29.0
Note: Maximum wind speed is assumed to be on                              _    13        34.5_      WIND SETUP                                27.77 the traverse that is to right of storm track a                            _    15        41.5 distance equal to the radius to maximum wind.                                  20.        45.0        RESSURE SETUP                              2.98
-/Initial        distance is distance along traverse                    -    25        47.0
      from shoreline to maximum wind when leading                        _    30          50.0        INITIAL WATER LEV.                          1.50
      20 mph isovel intersects shoreline. Storm                                40          65.0
      diameter between 20 mph isovels is approxi-                        L      50        99.0              TNOMICAL                              2.50
      mately double the initial distance.                                      60        164    -
                                                                            S70          203
                                                                                          600o            rAL-SURGE
                                                                        L    '78 STILL WATER LU.                          34.76 BET  MLW
                                                                        LATITUDE
* 290 5'*
                                                                        DEfGREE AT TRAVERSE
                                                                        MID-POINT FROM SHORE
                                                                          rO 600-FOOT DEPTH
 
TABLE C.7 SUMMARY-PERTINENT PROBABLE MAXIMUV:        h1JRICANE (FMH),    STORM SURGE COMPUTATIONAL  DATA AND RESULTANT WATER LEVEL
                  LOCATION SANTA ROSA LAT.        30023.7'    LONG.    86 37.7': TRAVERSE-AZIMUTH  183  DEGXREEs LENGTH 44.7      NAUTICAL MILES
                              ISLAND, ALABAMA
            PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS                    OCEAN BED PROFILE              PMH    CNhPUTATIONAL COEFFICIENT
              ZONE B    AT LOCATION      300    24' DEGREE NORTH
                                                                              TRAVERSE    WATER            AND WATER LEVEL (SURGE)      ESTIMATES
                                            SPEED OF TRANSLATION              DISTANCE    DERPH
        PARAMETER DESIGNATIONS            SLOW      ,ODERATF      HIGH          FROM      BELOW
                                        _  (ST)      (MT)        (HT)        SHORE      MLW
                                                                              (NAUT.MI.)    (FEET)                  C 0 E F F I C I E N T S
    CTL          PRESSURE INDEX
                          P 0 INCHES        26.88      26.88      26.88            0          0                BO'i''0JM FilICTION FACTOR 0.0030
  PERIPHERAL PRESSURE                                                              0.2        22 P INCHES          31.20      31.20      31.20            0.5        52            WIND STRESS CORRECTiON FACTOR 1.10
                            n                                                      1.0        66 RADIUS TO MAXIMUM WIND                                                          1.5        66 LARGE RADIUS NAUT. MI.              29        29        29                "2.0      66 TRANSLATION SPEED                                                                3.0      73                WATEh          LEVEL        DATA
                                            4        ii        28                5.0        76 vi F (FORWARD SPEED) KNOTS
  MAXIMUM WIND SPEED"                                                            10        88                    (AT OPEN CCAST SHORELINE)
                                                                                  15        120
                        V    M.P.H.    140        144        153              20        182 INITIAL DISTANCE-NAUT.MI.I.i                                                  30        377                                PMH SPEED OF TRANSLATION
  FROM 20 MPH WIND                      528        487        394              40        510
                                                                                                            COMPO1ENTS              ST I    MT  I I-l'
  IT      SHORE TO MAX.    WIND                I          I
                                                                                  45
                                                                                  50
                                                                                            600
                                                                                            756 F  E    E  T
    Note: Maximum wind speed is assumed to be on WIND SETUP                                  9.12 the traverse that is to right of storm track a distance equal to the radius to maximumwind.
 
PRESSURE SETUP                              3.25
    -Initial        distance is distance along traverse from shoreline to maximum wind when leading                                                  INITIAL WATER LEV.                          1.50
          20 mph isovel intersects shoreline.            Storm diameter between 20 mph isovels is approxi-                                                ASTRONOMICAL                                  1.80
          mately double the initial        distanc
 
====e. TIDE LEVEL====
                                                                                                      TOTAL-SURGE
                                                                                                        STILL WATER LEV.                            15.67 FEET MLW
                                                                            LATITUDE;    30&deg;1.3'
                                                                            DEGREE AT TRAVERSE
                                                                            AID-POINT FROM SHORE
                                                                            iv 600-FOOT DEPTH
 
TABLE C.8 SUMMARY-PERTINENT PROBABLE MAXIMU.    hUhRRICANE (FMH),  STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL
                  LOCATIONPITTS CREEK LAT.    30&deg;01.1'  LONG.  83'  53' : TRAVERSE-AZIMUTH  205  DEGREEi LENGTH 110      NAUTICAL MILES
                            FLORIDA
            PROBABLE MAXIMUM HURRICANE INDEX CHARACTEIISTICS              OCEAN BED PROFILE              PMH    CDNPUTATIONAL COEFFICIENT
              ZONE A    AT LOCATION    300    01' DEGREE NORTH
                                                                          TRAVERSE    WATER            AND WATER LEVEL (SURGE)    ESTIMATES
        PARAMETER DESIGNATIONS      t  SPEED OF
                                        SLOW
                                        (ST)
                                                    TRANSLATION
                                                IODERATF      HIGH
                                                                          DISTANCE
                                                                            FROM
                                                                                      DEPTH
                                                                                      BELOW
                                                  (MT)      .HT            SHORE      MLW
                                                                        (NAUT.MI.)    (FEET)                  C0 E F F I C I E NT S
      ENTRAL PRESSURE INDEX
                          P INCHES      26.79      26.79    26.79            0          0                BOT'ION FlICTION FACTOR 0.0030
      ERIPHERAL      PRESSURE                                                  0.2        1.0
                          P  INCHES    30.22      30.22    30.22            0.5        2.0            WIND STRESS CORRECTION FACTOR 1.10
                                                                              1.0        3.0
  &#xfd;EDUS TO MAXIMUM WIND                                                      1.5        4.0
        LARGE RADIUS NAUT. MI.        26        26        26                2.0        5.0
/1  FRANSIATION SPEED                                                        3.0        6.5              WA T ER      LEVEL        DATA
  &#xfd;_ (FORWARD SPEED) KNOTS          1 4          11        21                5.0        9.0
                                                                            10          22.0                  (AT OPE12 CCAST SHOFELINE)
    MAXIMUM WIND SPEED                                                      15          31.0
                        V    M.P.H.  138        142      146
                                                                            20          41.0
    INITIAL DISTANCE-NRUT.MI.li                                              30          62.0                              PMH SPEED OF TPANSLATION
    FROM 20 MPH WIND                  354      322        278              40          78.0          COMPONENTS            ST I    MT        HTi'
            SHORE  TT_O
                      MAX.  WIND                                            50          81.0                                    F  E  E    T
    Note: Maximum wind speed is.assumed to be on                            6o          84.0
    the traverse that is to right of storm track a                          70        101.0      WIND SETUP                              24.67 distance equal to.the radius to maximum wind.                            80        117.0
                                                                            9o        144.0      PRESSURE SETUP                            2.31
    -/Initial      distance is distance along traverse
                                                                            100        180.0
          from shoreline to maximum wind when leading                       110        210.0      INITIAL WATER LEV.                        1.20
          20 mph isovel intersects shoreline.        Storm diameter between 20 mph isovels is approxi-                        120        280.0
        mately double the initial distance.                                130        543.0      ASTRONOMICAL                              4.20
                                                                            132        6oo.0      TIDE  LEVEL
                                                                            140        846        TOTAL-SURGE
                                                                                                  STILL WATER LEV.                        32.38 FEET MLW____
                                                                        LATITUDE $ 290 03'
                                                                        DEGREE AT TRAVESE
                                                                        MID-POINT FROM SHORE
                                                                        TO 600-FOOT DEPTH
 
TABLE C.9 SUMMARY-PERTINENT PROBABLE MAXIMUE hUJRRCANE (PMH),          STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL
              LOCATION  NAPLES      LAT.  26001.4' LONG.    81"46.2': TRAVERSE-AZIMUTH      2413    DELREE,      LENGTH 145      NAUTICAL MILES
                          FLORIDA
      PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS                  OCEAN BED PROFILE                    PMH CCNPUTATIONAL COEFFICIENT
        ZONE    A AT LOCATION      260    01' DEGREE NORTH
                                                                        TRAVERSE      WATER                AND WATER LEVEL (SURGE)          ESTIMATES
                                        SPEED OF TRANSLATION          DISTANCE      DEPTH
      PARAMETER    DESIGNATIONS      SLOW    IMODERATF    HIGH          FROM      BELOW
                                  _(ST)          (ni)      (HT)          SHORE      MLW
                                                                      (NAUT.MI.)    (FEET)                        C 0 E F F I C I E N T S
  CENTRAL PRESSURE INDEX
                                      26.24      26.24    26.24                0
                      P INCHES                                                                                BO'ITUr  FHICTION FACTOR 0.r1030
  PER IPHERAL PRESSURE                                                    -    0,.5    +/-8.0-
                      P INCHES      31.30      31.30    31.30                                          WIND STRESS CORRECTION FACTOR 1.10
                        n
                                                                                1.0
                                                                                -!.55 RADIUS TO MAXIMUM WIND
      LARGE RADIUS NAUT. MI.          15          1          I
                                                                                3.0      27.0
  TRANSLATION SPEED                                                                                          WATEh          LEVEL          DATA
                                                                                5.0
  F (FORWARD SPEED) KNOTS              4                17
                                                                              150        41.0
                                                                              151                                  (AT OPEN CCAST SHORELINE)
-I MAXIMUM WIND SPEED                                                                    48.
 
V  M.P.H.    150        1LL      158                20
  INITIAL DISTANCE-NAUT. MI.i/                                                                                                  PMH SPEED OF TRANSLATION
                                                                              4)        90.0            COMPONENTS                ST I
  FROM 20 MPH WIND                  292        270      256                                                                                  MT  I    HT
                                                                              50      108 AT SHORE TO MAX. WIND                                                                                                                F    E    E    T
                                                                    -        60        144 Note: Maximum wind speed is assumed to be on                              70        165        WIND SETUP                    13.49      15.87    18.47 the traverse that is to right of storm track a                            80        186 distance equal to the radius to maximum wind.                            90        210        PRESSURE SETUP                3.29      2.87      2.90
    -  Initial  distance is distance along traverse                        100        228
                                                                            110        249        INITIAL WATER LEV.            1.00      1.00      1.00
      from shoreline to maximum wind when leading
      20 mph isovel intersects shoreline.          Storm                    120        252 diameter between 20 mph isovels is approxi-                          130        432        ASTRONOMICAL                  3.60      3.60      3.60
      matelv double the initial    distance.                              140        452        TIDE LEVEL
                                                                    -      145        600            AOTKL-SURGE
                                                                            150      1,200        STILL WATER LEV.              21.38      23.35    25.97 FEE MLW                .. I          II              _I
                                                                      LATITUDE 0 250 35'
                                                                    DEGREE AT TRAVERSE
                                                                    MID-POINT FROM SHORE
                                                                    TO 600-FOOT DEPTH
 
TABLE C.10
          SU MMARY-PERTINENT PROBABLE MAXIMU.  hiUaRICANE (PMH),   STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL
          LOCATION  MIAMI      LAT. 25047.2'  LONG. 80"07.8' ; TRAVERSE-AZIMUTH    100    DBYGREEj LEN.GTH    3.9 NAUTICAL MILES
                    FLORIDA
  PROBABLE MA.XIMUM HURRICANE INDEX CHARACTEISTICS              OCEAN BED PROFILE                PMH OCMPUTATIONAL COEFFICIENT
    ZONE    1 AT LOCATION    250 47.2' DEXGREE NORTH
                                                              TRAVERSE    WATER              AND WATER LEVEL (SURGE)      ESTIMATES
                                                              DISTANCE    DEPTH
                                                                  FROM      BELOW
                                                                  SHORE      MLW
                                                              (NAUT.MI.)    (FEET)                    C0 E F F I C I E NT S
                                                                    0          0                    BOi7IFO FiRICTION FACIOR 0.0025
                                                                    0.2      12
                                                                    0.5      16              WIND STRESS CORRECTION FACTOR 1.10
                                                                    1.5      25
                                                                    2.0      47
                                                                  _3.0      266
                                                                    3.9      600                  WATER        LEVEL        DATA
                                                                    5.0      822 (AT OPEN CCAST SHORnELINE)
                                                                                                                  PMH SPEED OF TRANSLATION
                                                                                              COMPONENTS              ST    T MT    i    HI'
                                                                                                                        F  E    E    T
Note: Maximum wind speed is assumed to be on                                                                        2.06      2.37      2.51 WIND SETUP
the traverse that is to right of storm track a distance equal to the radius to maximum wind.
 
PRESSURE SETUP              3.97      3.82      3.90
- Initial    distance is distance along traverse from shoreline to maximum wind when leading                                          INITIAL WATER LE*.          0.90      0.90      0.90
  20 mph isovel intersects shoreline.      Storm diameter between 20 mph isovels is approxi-                                          ASTRONOMICAL                3.60      3.60      3.60
  mately double the initial    distance.                                                FIDE I*LEE________                          ____
                                                                                            AOTAL-SURGE
                                                                                        STILL WATER LER .          10.53    10.68    10.91 FEET MLW                          I
                                                            LATITUDE    0 25I46-.
                                                            DEGREE AT TRAVERSE
                                                            MID-POINT FROM SHORE
                                                            To 600-FOOT DEPTH
 
TABLE C.11 SUMN*ARRY-PERTINENT PROBAWLE NAXIMUI    h.HURRICANE (FMH),    STORM SURGE COMPUTATIONAL FATA AND RESULTANT WATER LEVEL
            LOCATION JACKSONVILLELAT.    300  21'  LONG. 81    24.3: TRAVERSE-AZIMUTH    90    DECREEt LENGTH 62.5 NAUTICAL MILES
                      FLORIDA
      PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS                  OCEAN BED PROFILE              PMH CCXNPUTATIONAL COEFFICIENT
      ZONE 2      AT LOCATION    300    21' DEGREE NORTH
                                                                      TRAVERSE    WATER            AND WATER LEVEL (SURGE)    ESTIMATES
                                    SPEED OF TRANSLATION              DISTANCE    DEPTH
    PARAMETER DESIGNATIONS          SLOW    MODERATF      HIGH          FROM      BELOW
                                  _(ST)        (T          HT          SHORE      MLW
                                                                      (NAUT.MI.)    (FEET)                C 0 E F F I C.1 E N T S
CENTRAL PRESSURE INDEX
                    P INCHES        26.67      26.67    26.67              0          0              BO)'Ir0N FkICTION FACTOR 0.0025 PERIPHERAL PRESSURE                                                        0.2      20
                    Pn INCHES      31.21      31.21    31.21              0.5      25            WIND STRESS CORRECTION FACTOR      1.10
                                                                            1.0      32 RADIUS TO MAXIMUM WIND                                                      1.5      37 LARGE RADIUS NAUT. MI.          38        38        38                2.0      43 TRANSIATION SPEED                I                                          3.0      55              WATER        LEVEL        DATA
F (FORWARD SPEED) KNOTS          1, 4          11        22                5.0      59
                                                                          10.0        66 (AT OPEN CCAST SHORELINE)
MIMUM WIND SPEED                                                          12.0        66 V M.P.H.      138        142      149              14.0        72 INITIAL DISTANCE-NAUT.MI.]_                                              15.0        73                              PMH SPEED OF TRANSLATION
FROM 20 MPH WIND                  407        372      334              20.0        80
                                                                                                    COMPONENTS            ST I    MT        M.HT
NT SHORE TO MAX.
 
30.0      100
                      WIND                I                                                                                F  E    E    T
                                                                          40.0      117 Note: Maximum wind speed is assumed to be on                              50.0      131      WIND SETUP                                16.46 the traverse that is to right of storm track a                    -    6o.o      270
distance equal to the radius to maximum wind.                      -    62.5      6oo      PRESSURE SETUP                              3.23 l/ Initial    distance is distance along traverse                        70.0      948 from shoreline to maximum wind when leading                                              INITIAL WATER LEV.                          1.30
    20 mph isovel intersects shoreline.        Storm diameter between 20 mph isovels is approxi-                                              ASTRONONICAL                                6.20
    mately double the initial    distanc
 
====e. TIDE LEVEL====
                                                                                              tOTAL-SURGE
                                                                                              STILL WATER LEV.                          27.20
                                                                                              FEET MLW
                                                                    LATITUDE
* 30' 21 DEGREE AT TRAVERSE
                                                                    MID-POINT FROM SHORE
                                                                    TO 600-FOOT DEPTH
                                                                                II
 
TABLE C.12 SUMMARY-PERTINENT PROBABLE MAXIMUk hURRICANE (FMH),            STORM SURGE COMPUTATIONAL rATA AND RESULTANT WATER LEVEL
              LOCATION JEKYLL        LAT.  310    05' LONG.    81" 24.5': TRAVERSE-AZIMUTH 108    DEGREE, LENGTH 72.6 NAUTICAL MILES
                        ISLAND, GEORGIA
        PROBABLE MAXIMUM HURRICANE INDEX CHARACTENISTICS                                                  PMH CCD]PUTATIONAL COEFFICIENT
        ZONE .2      AT LOCATION    310      05' DEGREE NORTH
                                                                                                        AND WATER LEVEL (SURGE)  ESTIMATES
                                  !    SPEED OF TRANSLATION
      PARAMETER DESIGNATIONS          SLOW    IIODERATF      HIGH
                                      (ST)        (NT)        (21L
                                                                                                              C 0 E F F I C I E N T S
  JENTRAL PRESSURE INDEX
                      P  INCHES        26.72      26.72    26.72 BOIU'ON FilICTION FACTOR G.C025 PER IPHERAL PRESSURE
                      Pn INCHES        31.19      31.19    31.].9                                    WIND STRESS CORRECTION FACTOR 1.10
  RADIUS TO MAXIMUM WIND
      LARGE RADIUS NAUT.      MI.      40          40        40
  rRANSLATION SPEED                                                                                      WA T Ei      LEVEL        DATA
0n F    (FORWARD
              VJ SPEED)    KNOTS  I    4          11      23 (AT OPEN CCAST SHORELINE)
  MAXIMUM WIND SPEED
                      V  M.P.H.      135        141      147 INITIAL DISTANCE-NAUT.MI.i/                                                                                          PMH SPEED OF TRANSLATION
  FROM 20 MPH WIND                  400          380      336                                        COMPONENTS          ST I    MT  I    H,
  &T SHORE TO MAX. WIND                                                                                                      F  E    E    T'
  Note:      Maximum wind speed is assumed to be on WIND SE'7UP                              20.63 the traverse that is to right of storm track a distance equal to the radius to maximum wind.
 
PRESSURE SETUP                            3.34
    -  Initial    distance is distance along traverse from shoreline to maximum wind when leading                                                INITIAL WATER LEV.                        1.20
      20 mph isovel intersects shoreline.          Storm diameter between 20 mph isovels is approxi-                                                ASTRONOMICAL                              7.50
      mately double the initial      distanc
 
====e. TIDE LEVEL====
                                                                                                  TOTAL-SURGE
                                                                                                  STILL WATER LEV.                          32.6.7 FEET MLW
 
TABLE C.13 SUMmARY-PERTINENT PROBAI.BLE NAXIML+k hURRICANE (FMH),          STORM SURGE COMPUTATIONAL LATA AND RESULTANT WATER LEVEL
          LOCATION FOLLY ISIANDLAT.      320    39'  LONG.  79 56.6'. TRAVERSE-AZIMUTH 150        DEGREEt LENGTH 57.6 NAUTICAL MILES
                      SOUTH CAROLINA
    PROBABLE MAXIMUM HURRICANE INDEX CHARACTE1ISTICS                    OCEAN BED PROFILE                  PMH OCHPUTATIONAL COEFICIENT
      ZONE  2  AT LOCATION      320    39' DEGREE NORTH
                                                                        TRAVERSE    WATER              AND WATER LEVEL (SURGE)    ESTIMATES
                                      SPEED OF THANSLATION          I DISTANCE      DEPTH      I
  PARAMETER DESIGNATIONS          SLOW    HODERATF      HIGH          FROM      BFELOW
                                    (ST)      (MT)        (HT)          SHORE        MLW
                                                                      (NAUT.MI.)    (FEET)                    C 0 E F F I C I E N T S
CENTRAL PRESSURE INDEX
                  P 0 INCHES      26.81      26.81    26.81              0          0                  BO1FI)FM FRICTION FACTOR 0.0025 PERIPHERAL PRESSURE                                                          0.2        10.5 P n INCHES      31.13      31.13    31.13      _      0.5        12.0  -          WIND STRESS CORRECTION FACTOR 1.10
                                                                            1.0        14.0  _
RADIUS TO MAXIMUM WIND                                                _      1.5        16.5 LARGE RADIUS NAUT. MI.          40        40        40                  2.0        18.0  _
TRANSLATION SPEED                                                    _      3.0        29.5                WA TER        LEVEL        DATA
F, (FORWARD SPEED) KNOTS              4        13        29          _      5.0        39.0
                                                                          10.0        46.0                  (AT OPEN CCAST SHORELINE)
MAXIMUM WIND SPEEDV M.P.H.        1134        139      14                  S1;. 0      56.0o X                                                _    20.0        65.0
INITIAL DISTANCE-NAUT.MI      .,/                                    _    30.0        85.0                              PMH SPEED OF TRANSLATIO]
FROM 20 MPH WIND                  400                              _    40.0        138.0  _        COMPONENTS            ST I      MT        H'
                                              364      311 fT  SHORE TO MAX.    WIND                                            _    50.0      227.0  _                                  F    E    E    T
                                                                    _      57.6      600.0
Note: Maximum wind speed is assumed to be on
                                                                      _    60.0    1,800.0      WIND SETUP                                  17.15 the traverse that is to right of storm track a distance equal to the radius to maximum wind.
 
PRESSURE SETUP                                3.23
-- Initial distance is distance along traverse from shoreline to maximum wind when leading                                                  INITIAL WATER LEV.                            1.00
    20 mph isovel intersects shoreline.          Storm diameter between 20 mph isovels is approxi-                                                  ASTRONOMICAL                                  6.80
    mately double the initial distanc
 
====e. TIDE  LEVEL====
                                                                                                  TOTAL-SURGE
                                                                                                  STILL WATER LEV.                            28.18 FEET  MLW                      I        I
                                                                    LATITUDE;      320 25'
                                                                    DEGREE AT TRAVERSE
                                                                    MID-POINT FROM SHORE
                                                                    TO 600-FOOT DEPTH
 
TABLE C.14 SUMMARY-PERTINENT PROBABLE MAXIMUE hUHRICA.NE (FMH),    STORM SURGE COMPUTATIONAL LATA AND RESULTANT WATER LEVEL
                  LOCATION RALEIGH BAY,LAT.    34  54' LONG. 7615.3;: TRAVERSE-AZIMUTH    135  DECXREi    LENG'i'H 35.2 NAUTICAL MILES
                            NORTH CAROLINA
            PROBABLE MAXIMUM HURRICANE INDEX CHARACTrEISTICS
                                                                    r  OCEAN BED PROFILE
                                                                                          1 PMH OCXPUTATIONAL COEFFICIENT
                                                                    I                    I
              ZONE 3    AT LOCATION    340    54' DEGREE NORTH
                                                                      TRAVERSE    WATER            AND WATER LEVEL (SbRGE)    ESTIMATES
                                          SPEED OF TRANSLATION        DISTANCE    DEPTH
        PARAMETER DESIGNATIONS          SLOW    MODERATF    HIGH      FROM      BELOW
                                      ,(ST)      (wT)      (HT)
                                                                        SHORE      MLW
                                                                    (NAUT.lI.)    (FEET)                  C0 E F F I C I E N T S
          "ENTRALPRESSURE INDEX
                          P INCHES      26.89    26.89    26.89          0          0                  BOT'XOM FhIlCTION FACTOR 0.0025
                                                                          0.2      16 PERIPHERAL PRESSURE
                                                                          0.5      28              WIND STRESS CORRECTION FACTOR 1.10
                          P INCHES      31.00    31.00    31.00
                                                                          1.0      40
    RADIUS TO MAXIMUM WIND                                                1.5      46 LARGE RADIUS NAUT. MI.          35        35      35            2.0      54
                                                                          3.0      64                WATEh          LEV E'L    DATA
    tRANSlATION SPEED
tJn                                                                        5.0      72 v (FORWARD SPEED) KNOTS            5      17      38 r'J                                                                      10.0      92                    (AT OPEN CLAST SHOR**LINE)
    FLAXfl4JM WIND SPEED                                                  15.0      112 V M.P.H.      130        137      149            20.0      124
                                                                          30.0      264 INITIAL DISTANCE-NAUT.MI.1/                                                                                        PMH SPEED OF TRANSLATION
    FROM 20 MPH WIND                  385                                35.2      6oo            COMPONENTS            ST      HI  I    HT
                                                  346      280
                                                                          40.0      900                                      F  E  E    T
    6T SHORE TO MAX. WIND
    Note: Maximum wind speed is assumed to be on                                              WIND SETUP                                  8.84 the traverse that is to right of storm track a distance equal to the radius to maximum wind.
 
PRESSURE SETUP                              3.09
    -/Initial      distance is distance along traverse from shoreline to maximum wind when leading                                          INITIAL WATER LEV.                          1.00
          20 mph isovel intersects shoreline.        Storm diameter between 20 mph isovels is approxi-                                          ASTRONONICAL                                5.20
        mately double the initial    distanc
 
====e. TIDE LEVEL====
                                                                                              TOTAL-SURGE
                                                                                              STILL WATER LEV.                          18.13 FEET  MLW                                        I
                                                                    LATITUDE # 34'41.A
                                                                    DEGREE AT TRAVERSE
                                                                    MID-POINT FROM SHORE
                                                                    TO 600-FOOT DEPTH
 
TABLE C.15 SUMMARY-PEYTINENT PROBABLE MAXIMUI.    hJURRICANE (FMH),       STORM SUHGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL
          LOCATION OCEAN CITY, LAT.    380    20' LONG.    75'04.9' : TRAVERSE-AZIMUTH 110      DEREEt LENGTH      59  NAUTICAL MILES
                    MARYLAND
    PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS                    OCEAN BED PROFILE            PMH CCINPUTATIONAL COEFFICIEN'
      ZONE 4    AT LOCATION    380    20' DEGREE NORTH
                                                                      TRAVERSE      WATER          AND WATER LEVEL (SURGE)    ESTIMATES
                                  SPEED OF TRANSLATION                DISTANCE      DEPTH
  PARAMETER DESIGNATIONS        SLOW      MODERATF      HIGH            FROM      BELOW
                              __(ST)        (NT)        (.Tf            SHORE      MLW
                                                                    (NAUT.MI.j      (FEET)              C 0 E F F I C I E N T S
CENTRAL PRESSURE INDEX
                  P  INCHES      27.05      27.05    27.05                0          0              BQ'I1ON FRICTION FACTOR 0.0025 PERIPHERAL PRESSURE                                                          0.2      17 P INCHES        30.77      30.77    30.77                0.5      32            WIND STRESS COiRRECTION FACTOR 1.10
                                                                             1.0      29 RADIUS TO MAXIMUM WIND                                              _      1.5      35 LARGE RADIUS NAUT. MI.        38        38        38                    2.0      45 TRANSLATION SPEED                                                              30      38              WA TER        LEVEL        DATA
F    (FORWARD  SPEED) KNOTS    1 10        26        48                  _ 0        56
                                                                    _      5.0      61                (AT OPEN CCAST SHORELINE)
MAXIMUM WIND SPEED                                                          6        71 V  M.P.H.    124        133      146                    7        56 INITIAL DISTANCE-NAUT. MI,.&#xfd;J                                                8        6o                              PMH SPEED CF TRANSLATION
FROM 20 MPH WIND                350        293      251                    9        58          COMPONENTS            ST I    MI      HT
6T SHORE TO MAX. WIND                    I                                10          59                                    F  E    E  T
                                                                          11          65 Note: Maximum wind speed is assumed to be on                              12          64      WIND SETUP                              14.30
the traverse that is to right of storm track a                            13          70
distance equal to the radius to maximum wind.                              14          62      PRESSURE SETUP                            2.83
1/Initial    distance is distance along traverse from shoreline to maximum wind when leading                        - 18                  INITIAL WATER LEV.                        1.14
                                                                          20        103
                                                                                      90
    20 mph isovel intersects shoreline.        Storm                    -
  diameter between 20 mph isovels is approxi-                    -      2      ~  114      ASTRONOMICAL                              5.10
  mately double the initial    distanc
 
====e. TIDE LEVEL====
                                                                  -                  146      TOTAL-SURGE
                                                                                              STILL WATER LEV.                        23.37
                                                                                      840      IEET NLW
                                                                    LATITUDE;      38o14, DEGREE AT TRAVERSE
                                                                    MID-POINT FROM SHORE
                                                                  To 600-FOOT DEPTH
                                                                                            I.
 
TABLE C.16 SUMNARY-PERTINENT  PRUbAPLE MAXIMUk hiJiRICANE (FMH),        STORM SURGE COMPUTATIONAL LATA AND RESULTANT WATER LEVEL
        LOCATION ATLANTIC        LAT. 39'  21' LONG.    74  25 : TRAVERSE-AZIMUTH        146  DEGREEt  LENGTH  70  NAUTICAL MILES
                    CITY, NEW JERSEY
    PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS                OCEAN BED PROFILU                PMH CCMPUTATIONAL COEFFICIENT
    ZONE 4    AT LOCATION    390    21' DEGREE NORTH
                                                                  TRAVERSE      WATER              AND WATER LEVEL (SURGE)      ESTIMATES
                                    S    OF TRANSLATION            DISTANCE    DEPTH
  PARAMETER DESIGNATIONS      5 SLOW    IHODERATF    HIGH          FROM      BELOW
                              _, (ST)      (MT)      (HT)          SHORE        MLW
                                                                (NAUT.MI.)      (FEET)                    C0 EF F I C I E N T S
CENTRAL PRESSURE INDEX
                P INCHES                            27.12      K        0          0                  B*0'1ION FhICTION FACTOR 0.002r5 PERIPHERAL PRESSURE                                                      0.2        10.0
                P    INCHES                        30.70                          15.0 _          WIND STRESS CORRECTION FACTOR 1.10
                  n            _____              ____0.70__            10,
                                                                                    22.0 _
RADIUS TO MAXIMUM WIND                                            _      2.0        38.0 _
  LARGE RADIUS NAUT. MI.                            40        -        5.0        50.0 _
                                                                  _    10.0        72.0 _            WATER        Lh V EL      DATA
TRANSLATION SPEED
Fv (FORWARD SPEED)    KNOTS                        4*9              20.0        90.0 -
                                                                -      30.0      120.0 _                  (AT OPEN CCAST SHOPELINE)
MAXIMUM WIND SPEED                                                _    40.0      138.0 _
                V    M.P.H.                      142 xX                                            -      50.0      162.0
INITIAL DISTANCE-NAUT. MI.Ii                                          6o.o        210.0 -                            PMH SPEED OF TRANSLATION
FROM420 MPH WIND                                                _    65.0      258.0 _          COMPONENTS            ST F I  mlE      MT
                                                                    _ 70.0      600.0
AT SHORE TO MAX.    WIND                                                                                                    I__ E    E    T
Note: Maximum wind speed is assumed to be on                                                  WIND SETUP                                15.32 the traverse that is to right of storm track a distance equal to the radius to maximum wind.
 
PRESSURE SETUP                              2.57 Initial distance is distance along traverse from shoreline to maximum wind when leading                                                  INITIAL WATER LEV.                          1.10
  20 mph isovel intersects shoreline.        Storm diameter between 20 mph isovels is approxi-                                                  ASTRONOMICAL                                5.80
  mately double the initial    distanc
 
====e. TIDE LEVEL====
                                                                                              TOTAL-SURGE
                                                                                              STILL WATER LEV.                          24.80
                                                                                                EET MLW
                                                                LATITUDE      # 38' 53'
                                                                DEGREE AT TRAVERSE
                                                                MID-POINT FROM SHORE
                                                                  o 600-FOOT DEPTH


5. "Technical Note No. 98-Estimation of Maximum Floods," WMO-No. 233.TP.126, World                           17. "Engineering and Design-Standard Project Flood Meteorological Organization, United Nations, 1969                  Determinations,"         Corps of Engineers EM
TABLE C.17 SULMPLAY-PERTINENT PROBAFLE MAXIMUE. hUR(RICANE (FMH),        STORM SURGE COMPU'ATIONAL LATA AND RESULTANT WATER LEVEL
          and "Manual for Depth-Area-Duration Analysis of                    1110.2-1411, March 1965, originally published as Storm Precipitation," WMO-No. 237.TP.129, World                   Civil Engineer Bulletin No. 52-8.26 March 1952.
                  LOCATION LONG ISLAND,LAT.    410    00' LONG. 72 01.8': TRAVERSE-AZIMUTH      166      DEBREEE      LENGqH 68.4 NAUTICAL MILES
                            CONNECTICUT
            PROBABLE MAXIMUM HUHRICANE INDEX CHARACTEISTICS                  OCEAN BED PROFILE                        PMH ccNPUTATIONAL COEFFICIENT
              ZONE 4    AT LOCATION    4.1    00' DEGREE NOBTH
                                                                              TRAVERSE    WATER                  AND WATER LEVEL (SURGE)        ESTIMATES
                                        - SPEED OF TRANSIATION              DISTANCE    DEPTH
          PARAMETER DESIGNATIONS          SLOW    HODERATF      HIGH          FROM      BELOW
                                        _ (ST)        (MT)      (HT()          SHORE      MLW
                                                                            (NAUT.MI.)    (FEET)                          C 0 E F F I C I E N T S
    CENTRAL PRESSURE INDEX
                          P INCHES        27.26      27.26    27.26              0          0
                           0            _                                                                              BO1J3'ON FriICTION FACTOR 0.0029 PERIPHERAL PRESSURE                                                            0.2      22 P INCHES        30.56      30.56    30.56      _      0.5      38                    WIND STRESS CORRECTiON FACTOH 1.10
                                                                          -        1.0      43 R          US TO MAXIMUM WIND                                          _      1.5        53 LARGE RADIUS NAUT.    MI.      48        48        48          _      2.0      67 TRANSLATION SPEED                                                    -       3.0      82                        WAT Eh         LE V E L    DATA
LA
            (FORWARD SPEED) KNOTS        15        34        51        -       5.0      102 LI'
            IMUM WIND SPEED                                            -       10.0      132                            (AT OPEN CCAST SHORELINE)
                        V    M.P.H.    115        126      136      -        15.0      145
                                                                            _    20.0      170
    INITIAL DISTANCE-NAUT.NI.i/                                          -     30.0      212                                        PMH SPEED OF TRANSLATION
    FROM 20 MPH WIND                    346          293      259                40.0      240                COMPONENTS                ST      MIT    I HT
    AT SHORE TO MAX.       WIND                  I          I                   50.0      260                                              F    E    E  T
                                                                                60.0      302 Note:        Maximum wind speed is assumed to be on                        68.4      6o0          WIND SETUP                                        8.73 the traverse that is to right of storm track a                            70.0
                                                                                7          870
    distance equal to the radius to maximum wind.                                                      PRESSURE SETUP                                    2.46
    -/Initial      distance is distance along traverse from shoreline to maximum wind when leading                                                  INITIAL WATER LEV.                                0.97
          20 mph isovel intersects shoreline.          Storm diameter between 20 mph isovels is approxi-                                                  ASTRONOMICAL                                      8.00
          mately double the initial      distanc


Meteorological Organization, United Nations, 1969.
====e. TIDE LEVEL====
                                                                                                          OTAL-SURGE
                                                                                                        STILL WATER LEV.                                20.16 VEE MLW                        _      I                I
                                                                          LATITUDE 0 400 27 DEGREE AT TRAVERSE
                                                                        MID-POINT FROM SHORE
                                                                        To 600-FOOT DEPTH
                                                                                      .4 I __I "  .1 . - . .---


18. "Probable Maximum Precipitation Over South Platte River, Colorado. and Minnesota River.
TABLE C.18 SU1I4AY-PERTINENT PROBABLE MAXIMUL. h1UJRICANE (FMH),      STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL
              LOCATION WATCH HILL    LAT.  410i18.9' LONG.  71 50 ; TRAVERSE-AZIMUTH        166    DECREEs LENGTH    84  NAUTICAL MILES
                        POINT,  RHODE ISLAND
        PROBABLE MAXIMUM HURRICANE INDEX CHARACTrISTICS                OCEAN BED PROFILE                  PMH CCNPUTATIONAL COEFFICIENT
          ZONE 4    AT LOCATION    410    19' DEGREE NORTH
                                                                      TRAVERSE      WATER              AND WATER LEVEL (SURGE)    ESTIMATES
                                      SPEED OF TRANSLATION            DISTANCE      DEPTH
      PARAMETER DESIGNATIONS        SLOW    MODERATF    HIGH          FROM        BELOW
                                  _ (ST)      (MT)      (HT)          SHORE        MLW
                                                                    (NAUT.MI.)      (FEET)                    C 0 E F F I C I E N T S
    CENTRAL PRESSURE INDEX
                      P  INCHES      27.29      27.29  27.29            o            0                  BO'T&#xb6;ON FRICTION FACTOR 0.0025 PERIPHERAL PRESSURE                                                    0.2        28 Pn INCHES      30.54      30.54    30.54            0.5        40              WIND STRESS CORRECTION FACTOR 1.10
                                                                          1.0        77 RADIUS TO MAXIMUM WIND                                          _      1.5        98 LARGE RADIUS NAUT. MI.        49        49      49                2.0        119 TRANSLATION SPEED                                              -      3.0        117                WATE h        LEVEL        DATA
    F (FORWARD SPEED) KNOTS          15        35      51                4.0        114
                                                                  -        5.0        128                      (AT OPEN CCAST SHORELINE)
0~' MAXIMUM WIND SPEED                                                    6.0        114 V  M.P.H.    113        126      134                7.0        113 INITIAL DISTANCE-NAUT.MI.i /                                          8.0        117                                PMH SPEED OF THANSLATION
    FROM 20 MPH WIND                                              -        9.0        118              COMP014ENTS          ST J    MT  i HT
                                    348        284      255 AT SHORE TO MAX. WIND                                                10.0          93                                      F  E    E  T
                                                                        11.0          70
    Note:    Maximum wind speed is assumed to be on
                                                                        12.0          65        WIND SETUP                                10.01 the traverse that is to right of storm track a
                                                                    _    13.0          51 distance equal to the radius to maximum wind.


6. "Meteorological          Estimation of Extreme                    Minnesota," Hydrometeorological Report No. 44.
14.0          56        PRESSURE SETUP                            2.42
      / Initial distance is distance along traverse                      15.0          77?
        from shoreline to maximum wind when leading
        20 mph isovel intersects shoreline.      Storm diameter between 20 mph isovels is approxi-
                                                                  -
                                                                        20.0
                                                                          0.  00    g
                                                                                      131
                                                                                      222 INITIAL WATER LEV.


Precipitation for Spillway Design Floods", Tech.                 U.S. Weather Bureau (now NOAA). 1961).
kSTRONOMICAL,
          Memo WBTM HYDRO-5. U.S. Weather Bureau (now NOAA) Office of Hydrology. 1967.                        19. "Unsteady       Flow Simulation      in Rivers and Reservoirs," by J. M. Garrison. J.  P. Granju and J.
                                                                                                                                            0.96
                                                                                                                                            8.80
                                                                            .0       240  -
        mately double the initial distanc


7. "Seasonal Variation of the Probable Maximum                        T. Price. pp 1559-1576, Vol.         95. No. IIYS,
====e. r IDE LEVEL====
          Precipitation East of the 105th Meridian for Areas                (September 1969), Journal of        the Ilyt'draulics from 10 to 1,000 Square Miles and Durations of 6,                Division. ASCE. (paper 6771).
                                                                  -      70                      rOTAL-SURGE
          12, 24, and 48 hours," Hydromneteorological Report No. 33, U.S. Weather Bureau (now NOAA), 1956.                20. "Handbook of Applied Hydrology." edited by Ven Te Chou, McGraw.Hill. 9)64. Chapter 25.
                                                                                      28g         STILL WATER LEV.                         22.1.9
                                                                        90.0      1.488          F'EET MLW                                        I__________
                                                                  LATITUDE 4 40&deg; 38 DE)REE AT TRAVERSE
                                                                  MID-POINT FROM SHORE
                                                                  TO 600-FOOT DEPTH


8. "Probable Maximum Precipitation. Susquehanna River Drainage Above Harrisburg, Pa.,                       21. "Routing of Floods Through River Channels." EM
TABLE C.19 SUMMARY-PERTINENT PROBA-PLE MAXIMUm. HURRICANE (FMH),         STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL
           "Hydrometeorological Report No. 40. U.S. Weather                    H 10-2-1408. U.S. Army Corps of Engineers. I
          LOCATION HAMPTON      LAT. 420    57' LONG.    70' 47.1'; TRAVERSE-AZIMUTH 115      D@CREE, LENGTH  40  NAUTICAL MILES
           Bureau (now NOAA), 1965.                                          March 1960.
                    BEACH, NEW HAMPSHIRE
    PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS                OCEAN BED PROFILE              PMH OCNPUTATIONAL COEFFICIENT
      ZONE  4  AT LOCATION    420    57'  DEGREE NORTH
                                                                    TRAVERSE    WATER            AND WATER LEVEL (SURGE)    ESTIMATES
                                  SPEED OF TRANSLATION              DISTANCE    DEPTH
  PARAMETER DESIGNATIONS        SLOW    1-ODERATF    HIGH            FROM      BELOW
                              _(ST)        (NT)      (HT)            SHORE
                                                                  INAUT.M1.)
                                                                                    MLW
                                                                                  (FFM)                C 0 E F F I C I E N T S
METRAL PRESSURE INDEX
                  P INCHES      27.44      27.44    27.44        -      0           0                BO7'OI- FRICTION FACTOR 0.0025 PERIPHERAL PRESSURE                                                      0.2        8 P INCHES      30.42      30.42  30.42        -      0.5        40           WIND STRESS CORRECTION FACTOR 1.10
                                                                  -.      1.0        64 RADIUS TO MAXIMUM WIND                                          -      1.5        82 LARGE RADIUS NAUT.    MI.     57        57      57          '-      2.0      100
[RANSIATION SPEED                                                -      3.0      105              WATE h        LE V EL      DATA
F (FORWARD SPEED) KNOTS        17        37      52          -      5.0      156
                                                                  -      10.0      258                  (Ar OPEN CCAST SHORELINE)
  WAXIMUM WIND SPEED                                              -     15.0      336 V  M.P.H.    107        118    127            -     20.0      266 INITIAL DISTAoCE-HAUT.MI.1/                                      -      25.0      210                              PMH SPEED OF TRANSIATION
FROM 20 MPH WIND              353        290    262            -    30.0        322          COMPONENTS           ST  I  MT        HI,
kT SHORE TO MAX.   WIND                                         -      35.0      433                                    F  E  E    T
Note: Maximum wind speed is assumed to be on                      -    40.o        6o0
                                                                                            WIND SETUP                                4.25 the traverse that is to right of storm track a distance equal to the radius to maximum wind.


1.59-15
PRESSURE SETUP                            2.23
- Initial  distance is distance along traverse from shoreline to maximum wind when leading                                              INITIAL WATER LEV.                        0.83
  20 mph isovel intersects shoreline.      Storm diameter between 20 mph isovels is approxi-                                              ASTRONOMICAL                            11.70
  mately double the initial    distanc


.2. "'l~nLiti .'riig 1 yvdiauilics". e.'dited hy Hlu tier Rouse.        2o. "Compiitation of Freeboard Allowances,fr Waves John WViley & Sons. l1tc. 19Q50.                                      in Reservoirs." I-ngineca Technic;al Leiter lTL
====e. TIDE LEVEL====
                                                                            I1 10-2-). U.S. Army Corps of lingineer
                                                                                            TOTAL-SURGE
                                                                                            STILL WATER LEV.                         19.01 FEET MLW
                                                                  LATITUDE   
* 420 48'
                                                                  DEGREE AT TRAVERSE
                                                                  MID-POINT FROM SHORE
                                                                      600-FOOT DEPTH


====s. I Augist====
TABLE C.20
                                                                            1960.*
                SUMMARY-PERTINENT PRUhABLE MAXIMUE hUJiRICANE (FMH),            STORM SURGE COMPU'IATlONAL    [ATA AND RESULTANT WATER LEVEL
           .. 1eW
                LOCATION GREAT        LAT.    44&deg;33.4' LONG.   67 30'; TRAVERSE-AZIMUTH          148  DEGREEs LFNGTH 178.6 NAUTICAL MILES
               c   Sil face Plroilies. HI.I-2 Genraliued Co nipmiaUt Program.' available from( tie Corps of
                          SPRUCE ISLAND,    MAINE
      1:-ni neers Hydrologic Engineering Center.                       27. "Policies     a nd Proceedures PerIaining to Sacrameilnito. C:ail.                                                 D)etermination of Spillway ('apaci ties anid Frecehoard Allowances for D)ams.'" lingincer Circular 1-C
        PROBABLE MAXIMUM HUHRICANE INDEX CHARACTERISTICS                  OCEAN BED PROFILE                    PMH CCMPUTATIONAL COEFFICIENT
_'4. "()pen    Chalnel Ilydratlic'" by Ven Te Choli;                      1110-2-27. LU.S. Arwy Corps or Engineer
          ZONE    4 AT LOCATION    440      3' DEGREE NORTH                                              ANL WATER LEVEL (SURGE)  ESTIMATES
                                                                        TRAVERSE          WATER
                                            SPEED
                                                OF TRANSLATION          DISTANCE        DEPTH
    PARAMETER DESIGNATIONS            SLOW      HODERATF    HIGH            FROM        BFLOW
                                        (ST)        (nT)      (HT)           SHORE        MLW
                                                                      (NAUT.MI.)          (FFET)                  C 0 E F F - C I E N T S
CENTRAL PRESSURE INDEX
                        P INCHES      27.61        27.61    27.61               0            0                BOTIOM 1i FICTION FACTOR 0.0025 PERIPHERAL PRESSURE                                                              0.2        50
                        P INCHES      30.25        30.25   30.25                0.5        96              WIND STRESS CORRECTION FACTOR 1.10
                                                                                  1.0        95 RADIUS TO MAXIMUM WIND                                                            1.5        125 LARGE RADIUS NAUT. MI.            64          64      64                  2.0        125 TRANSLATION SPEED                                                                3.0        165                W A T ER    L E V E L  DA T A
F (FORWARD SPEED) KNOTS                19          39      53                  4.o        247
                                                                      -           5.0        188                  (Ar OPEN CCAST SHORELINE)
MAXIMUM WIND SPEED                                                              10.0        233 V  M.P.H.    102          114      122        _        15.0        438 INITIAL DISTANCE-NAUT. *MI._ /                                                  20.0        570                              PMH SPEED OF TRANSLATION
FROM 20 MPH WIND                      352          288      262                  30.0        271            COMPONENTS          ST I    MT        HT
AT SHORE TO MAX. WIND                I                                          40.0        511                                    F  E  E    T
Note:         Maximum wind speed is assumed to be on
                                                                      -          50.0        443 the traverse that is to right of storm track a
                                                                            _    6o.0        374        WIND SETUP                              9.73 distance equal to the radius to maximum wind.                                  1100.0 0~
1/                                                                                                    PRESSURE SETUP                          1.82
                                                                              100.0        25
-/Initial        distance is distance along traverse from shoreline to maximum wind when leading                                                      INITIAL WATER LEV.                      0.56
                                                                      -
                                                                          - 120.0
                                                                              110.01        34O  -
      20 mph isovel intersects shoreline.             Storm diameter between 20 mph isovels is approxi-                                                       STRONONICAL                          18.40
      mately double the initial        distance.                              I                        IDE LEVEL
                                                                                                        TOT*L-SURGE
                                                                                                        STILL WATER LEV.                      30.51
                                                                      -        180.0      1,620
                                                                                                        EET MLW
                                                                      LATITUDE $43 17.8- DEGREE AT TRAVERSE
                                                                      MID-POINT FROM SHORE
                                                                        o 600-FOOT DEPTH


====s. I August====
TABLE C.21 OCEAN BED PROFILES
                                                                      28. "iShore Protect iot. !Il~amini*g and I)esign, Tedhnicil
              PASS                    CRYSTAL                                            CHESAPEAKE
       "lack%:%tlctr
          CHRISTIAN                  RIVER                      ST. LUCIE              BAY MOUTH                    SEABROOK
       -j                (Cirves in River (Channels." EM
    Nautical                Nautical                      Nautical                  Nautical                    Nautical Miles from      Depth, Miles from        Depth,    Miles from        Depth, Miles from        Depth,   Miles from       Depth, Shore        ft, MLW    Shore          ft, RLW        Shore        ft,  HLW    Shore        ft,  ffLW    Shore       ft, MLW
       II1        40-).I4. U.S. Ariny Corps of Elpgineeis.                  Relp)rt  No. 4. U.S. Arauy "Coastal Elngineering Dc),. a',:.cr "7. I*)g!                                              Research Cenler. 3rd edition. I906.
        1              3       0.55            3          0.1              10        5              44      0.5              20
        2            9        2.31          10          10                90      10                56      4              120
-4                                             14                            390        30              102      10              250
        5            12        6.25                      16
      10            13        8.33            9          18.7             600        50              178      25              250
        15            35        31.4            50                                      55              240    44                600
        20            36      100            180                                      62              600
        30            40      113            300
        40            52      127            600
        50            90
        60          160
        70          335
        77          600


1.59-16}}
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Revision as of 13:50, 10 March 2020

Design Basis Floods for Nuclear Power Plants
ML13038A102
Person / Time
Issue date: 04/30/1976
From:
Office of Nuclear Regulatory Research, NRC/OSD
To:
References
RG-1.059, Rev. 1
Download: ML13038A102 (80)
v • d • e


Revision 1 U.S. NUCLEAR REGULATORY COMMISSION April 1976 REGULATORY GUIDE

OFFICE OF STANDARDS DEVELOPMENT

DESIGN

NUCLEAR PLANTS

iA~

5,,.

.1 USNRC REGULATORY GUIDES Comments should be sent to the Secretary of the Commission. U S. Nuclear Regulatory Guides are issued to describe and make available to the public Regulatory Commission. Washington. D C 2055o. Attention Docketing and methods acceptable to the NRC staff of implementing specific parts of the Commission's regulations, to delineate techniques used by the staff in evalu The guides are issued in the following ten broad divisions"

ating specific problems or postulated accidents, or to provide guidance to appli cants. Regulatory Guides are not substitutes for regulations, and compliance t Power Reactors 6. Products with them is not required Methods and solutions different from those set out in 2. Research and Test Reactors 7. Transportation the guides wdi be acceptable if they provide a basis for the findings requisite to 3 Fuels and Materials Facilities 8 Occupational Health the issuance or continuance u Ia permit or license by the Commission 4 Environmental and Siting 9. Antitrust Review Comments and suggestions for improvenments in these guides are encouraged 5 Materials and Plant Protection 10 General at all times, and guides will lbe revised. as appropriate, to accommodate coa ments and to reflect new intormatn or eyperience However. comments on Copies of published guides may be obtained by written request indicating the this guide. if received within about Iwo months after its issuance, will be par divisions desired to the U S Nuclear Regulatory Commission. Washington. D.C

-culariyuseful in evaluating the need for an early revision 20655. Attention: Director. Office of Standards Development r'11 cx)--,7'-0" C."

66F(I

I

TABLE OF CONTENTS

Page A . IN TRO DUCTIO N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59-5

B. DISCUSSION

.......................... ......................... 595

C. REGULATORY POSITION

....................... ................................. 59-7

D. IMPLEMENTATION

......................... .................................... .59-8 APPENDIX A - Probable Maximum and Seismically Induced Floods on Streams ..... ............. .59-9 APPENDIX B - Alternative Methods of Estimating Probable Maximum Floods ....... ............. .59-23 *

APPENDIX C - Simplified Methods of Estimating Probable Maximum Surges ....... .............. .59-53

'LTines indicate substantive changes from previous issue.

1.59-3

A. INTRODUCTION

B. DISCUSSION

General Design Criterion 2, "Design Bases for Pro- Nuclear power plants should be designed to prevent tection Against Natural Phenomena," of Appendix A to the loss of capability for cold shutdown and mainten-

10 CFR Part 50, "General Design Criteria for Nuclear ance thereof resulting from the most severe flood Power Plants," requires, in part, that structures, systems, conditions that can reasonably be predicted to occur at a and components important to safety be designed to site as a result of severe hydrometeorological conditions, withstand the effects of natural phenomena such as seismic activity, or both.

floods, tsunami, and seiches without loss of capability to The Corps of Engineers for many years has studied perform their safety functions. Criterion 2 also requires that design bases for these structures, systems, and conditions and circumstances relating to floods and components reflect (1) appropriate consideration of the flood control. As a result of these studies, it has developed a definition for a Probable Maximum Flood most severe of the natural phenomena that have been (PMF)' and attendant analytical techniques for esti- historically reported for the site and surrounding region, mating, with an acceptable degree of conservatism, flood with sufficient margin for the limited accuracy and levels on streams resulting from hydrometeorological quantity of the historical data and the period of time in conditions. For estimating seismically induced flood which the data have been accumulated, (2) appropriate levels, an acceptable degree of conservatism for evalua- combinations of the effects of normal and accident ting the effects of the initiating event is provided by conditions with the effects of the natural phenomena, Appendix A to 10 CFR Part 100.

and (3) the importance of the safety functions to be performed. The conditions resulting from the worst site-related flood probable at the nuclear power plant (e.g., PMF,

Paragraph 100.10(c) of 10 CFR Part 100, "Reactor seismically induced flood, seiche, surge, severe local Site Criteria," requires that physical characteristics of precipitation) with attendant wind-generated wave activ- the site, including seismology, meteorology, geology, ity constitute the design basis flood conditions that and hydrology, be taken into account in determining the safety-related structures, systems, and components iden- acceptability of a site for a nuclear power reactor. tified in Regulatory Guide 1.292 should be designed to withstand and retain capability for cold shutdown and Section IV(c) of Appendix A, "Seismic and Geologic maintenance thereof.

'* Siting Criteria for Nuclear Power Plants," to 10 CFR

Part 100 suggests investigations for a detailed study of For sites along streams, the PMF generally provides seismically induced floods and water waves. The ap- the design basis flood. For sites along lakes or seashores, pendix also suggests [Section IV(c)(iii)] that the deter- a flood condition of comparable severity could be mination of design bases for seismically induced floods 'Corps of Engineers' Probable Maximum Flood definition ap- and water waves be based on the results of the required pears in many publications of that agency such as Engineering geologic and seismic investigations and that these design Circular EC 1110-2-27, Change 1, "Engineering and Design- bases be taken into account in the design of the nuclear Policies and Procedures Pertaining to Determination of Spill- power plant. way Capacities and Freeboard Allowances for Dams," dated 19 Feb. 1968. The Probable Maximum Flood is also directly analogous to the Corps of Engineers' "Spillway Design Flood"

as used for dams whose failures would result in a significant This guide discusses the design basis floods that loss of life and property.

nuclear power plants should be. designed to withstand 2Regulatory Guide 1.29, "Seismic Design Classification,"

without loss of capability for cold shutdown and identifies structures, systems, and components of light-water- maintenance thereof. The design requirements for flood cooled nuclear power plants that should be designed to protection are the subject of Regulatory Guide 1.102 withstand the effects of the Safe Shutdown Earthquake and

"Flood Protection for Nuclear Power Plants." remain functional. These structures, systems, and components are those necessary to ensure (1) the integrity of the reactor coolant pressure boundary, (2) the capability to shut down the reactor and maintain it in a safe shutdown condition, or (3) the Appendix A outlines the nature and scope of detailed capability to prevent or mitigate the consequences of accidents hydrologic engineering activities involved in determining which could result in potential offsite exposures comparable to estimates for the probable maximum flood and for the guideline exposures of 10 CFR Part 100. These same seismically induced floods resulting from dam failures structures, systems, and components should also be designed to withstand conditions resulting from the design basis flood and and describes the situations for which less extensive retain capability for cold shutdown and maintenance thereof of analyses are acceptable. Two new appendices have been other types of nuclear power plants. It is expected that added to this revision of the guide. Appendix B gives safety-related structures, systems, and components of other timesaving alternative methods of estimating the prob- types of nuclear power plants will be identified in future regulatory guides. In the interim, Regulatory Guide 1.29 should able maximum flood along streams and Appendix C 'be used as guidance when identifying safety-related structures, gives a simplified method of estimating probable maxi- systems, and components of other types of nuclear power mum surges on the Atlantic and Gulf coasts. plants.

1.59-5

produced by the most severe combination of hydro- waves that may be caused by multiple dam failures in a meteorological parameters reasonably possible, such as3 region where dams may be located close enough together may be produced by a Probable Maximum Hurricane, that a single seismic event can cause multiple failures.

or by a Probable Maximum Seiche. On estuaries, a Probable Maximum River Flood, a Probable Maximum Each of the severe flood types discussed above should Surge, a Probable Maximum Seiche, or a reasonable represent the upper limit of all potential phenomeno- combination of less severe phenomenologically caused logically caused flood combinations considered reason- flooding events should be considered in arriving at design ably possible. Analytical techniques are available and basis flood conditions comparable in frequency of should generally be used for prediction at individual occurrence with a PMF on streams. sites. Those techniques applicable to PMF and seismi- cally induced flood estimates on streams are presented in In addition to floods produced by severe hydro- Appendices A and B to this guide. Similar appendices for meteorological conditions, the most severe seismically coastal, estuary, and Great Lakes sites, reflecting com- induced floods reasonably possible should be considered parable levels of risk, will be issued as they become for each site. Along streams and estuaries, seismically available. Appendix C contains an acceptable method of induced floods may be produced by dam failures or estimating hurricane-induced surge levels on the open landslides. Along lakeshores, coastlines, and estuaries, coasts of the Gulf of Mexico and the Atlantic Ocean.

seismically induced or tsunami-type flooding shoUld be considered. Consideration of seismically induced floods Analyses of only the most severe flood conditions should include the same range of seismic events as is may not indicate potential threats to safety-related postulated for the design of the nuclear plant. For systems that might result from combinations of flood instance, the analysis of floods caused by dam failures, conditions thought to be less severe. Therefore, reason- landslides, or tsunami requires consideration of seismic able combinations of less-severe flood conditions should events of the severity of the Safe Shutdown Earthquake also be considered to the extent needed for a consistent occurring at the location that would produce the worst level of conservatism. Such combinations should be such flood at the nuclear power plant site. In the case of evaluated in cases where the probability of their existing seismically induced floods along rivers, lakes, and es- at the same time and having significant consequences is tuaries which may be produced by events less severe at least comparable to. that associated with the most than a Safe Shutdown Earthquake, consideration should severe hydrometeorological or seismically induced flood.

be given to the coincident occurrence of floods due to For example, a failure of relatively high levees adjacent (

severe hydrometeorological conditions, but only where to a plant could occur during floods less severe than the the effects on the plant are worse than and the worst site-related flood, but would produce conditions probability of such combined events may be greater than more severe than would result during a greater flood an individual occurrence of the most severe event of (where a levee failure elsewhere would produce less either type. For example, a seismically induced flood severe conditions at the plant site).

produced by an Operating Basis Earthquake (as defined in Appendix A to 10 CFR Part 100) coincident with a Wind-generated wave activity may produce severe runoff-type flood of Standard Project Flood4 severity flood-induced static and dynamic conditions either may be considered to have approximately the same independent of or coincident with severe hydrometeoro- severity as the seismically induced flood from an logical or seismic flood-producing mechanisms. For earthquake of Safe Shutdown severity coincident with example, along a lake, reservoir, river, or seashore, about a 25-year flood. For the specific case of seismi- reasonably severe wave action should be considered cally induced floods due to dam failures, an evaluation coincident with the probable maximum water level should be made of flood waves that may be caused by conditions.5 The coincidence of wave activity with domino-type dam failures triggered by a seismically probable maximum water level conditions should take induced failure of a critically located dam and of flood into account the fact that sufficient time can elapse between the occurrence of the assumed meteorological mechanism and the maximum water level to allow See References 2 and 4, Appendix C.

4 The Standard Project Flood (SPF) is the flood resulting from 'Probable Maximum Water Level is defined by the Corps of the most severe flood-producing rainfall depth-area-duration Engineers as "the maximum still water level (i.e., exclusive of relationship and isohyetal pattern of any storm that is local coincident wave runup) which can be produced by the considered reasonably characteristic of the region in which the most severe combination of hydrometeorological and/or watershed is located. If snowmelt may be substantial, appropri- seismic parameters reasonably possible for a particular location.

ate amounts are included with the Standard Project Storm Such phenomena are hurricanes, moving squall lines, other rainfall. Where floods are predominantly caused by snowmelt, cyclonic meteorological events, tsunami, etc., which, when the SPF is based on critical combinations of snow, temperature, combined with the physical response of a body of water and and water losses. See "Standard Project Flood Determina- severe ambient hydrological conditions, would produce a still tions," EM 1110-2-1411, Corps of Engineers, Departrlhent of water level that has virtually no risk of being exceeded." (See the Army (revised March 1965). Appendix A to this guide.)

1.59-6

subsequent meteorological activity to produce sub- establishing the design basis flood. A simplified analyti- stantial wind-generated waves coincident with the high cal technique for evaluating the hydrologic effects of water level. In addition, the most severe wave activity at seismically induced dam failures discussed herein is the site that can be generated by distant hydrometeoro- presented in Appendix A of this guide. Techniques for logical activity should be considered. For instance, evaluating the effects of tsunami will also be presented coastal locations may be subjected to severe wave action in a future appendix.

caused by a distant storm that, although not as severe as a local storm (e.g., a Probable Maximum Hurricane), d. Where upstream dams or other features which may produce more severe wave action because of a very provide flood protection are present, in addition to the long wave-generating fetch. The most severe wave analyses of the most severe floods that may be induced activity at the site that may be generated by conditions by either hydrometeorological or seismic mechanisms, at a distance from the site should be considered in such reasonable combinations of less-severe flood conditions cases. In addition, assurance should be provided that and seismic events should also be considered to the safety systems necessary for cold shutdown and main- extent needed for a consistent level of conservatism. The tenance thereof are designed to withstand the static and effect of such combinations on the flood conditions at dynamic effects resulting from frequent flood levels (i.e., the plant site should be evaluated in cases where the the maximum operating level in reservoirs and the probability of such combinations occurring at the same

10-year flood level in streams) coincident with the waves time and having significant consequences is at least that would be produced by the Probable Maximum comparable to the probability associated with the most Gradient Wind 6 for the site (based on a study of severe hydrometeorological or seismically induced flood.

historical regional meteorology). On relatively large streams, examples of acceptable combinations of runoff floods and seismic events that

C. REGULATORY POSITION

could affect the flood conditions at the plant include the Safe Shutdown Earthquake with the 25-year flood and

1. The conditions resulting from the worst site-re- the Operating Basis Earthquake with the Standard lated flood probable at a nuclear power plant (e.g., PMF, Project Flood. Less severe flood conditions, associated seismically induced flood, hurricane,. seiche, surge, heavy with the above seismic events, may be acceptable for local precipitation.) with attendant wind-generated wave small streams which exhibit relatively short periods of activity constitute the design basis flood conditions that flooding. The above combinations of independent events safety-related structures, systems, and components iden- are specified here only with respect to the determination fI

tified in Regulatory Guide 1.29 (see footnote 2) must be of the design basis flood level.

designed to withstand and retain capability for cold shutdown and maintenance thereof. e. The effects of coincident wind-generated wave activity to the water levels associated with the worst a. On streams the PMF, as defined by the Corps of site-related flood possible (as determined from para- Engineers and based on the analytical techniques sum- graphs a, b, c, or d above) should be added to generally marized in Appendices A and B of this guide, provides define the upper limit of flood . potential. An an acceptable level of conservatism for estimating flood acceptable analytical basis for wind-generated wave levels caused by severe hydrometeorological conditions. activity coincident with probable maximum water levels is the assumption of a 40-mph overland wind from the b. Along lakeshores, coastlines, and estuaries. most critical wind-wave-producing direction. However, if estimates of flood levels resulting from severe surges, historical windstorm data substantiate that the 40-mph seiches, and wave action caused by hydrometeorological event, including wind direction and speed, is more activity should be based on criteria comparable in extreme than has occurred regionally, historical data conservatism to those used for Probable -Maximum may be used. If the mechanism producing the maximum Floods. Criteria and analytical techniques providing this water level, such as a hurricane, would itself produce level of conservatism for the analysis of these events will higher waves, these higher waves should be used as the be summarized in subsequent appendices to this guide. design basis.

Appendix C of this guide presents an acceptable method for estimating the stillwater level of the Probable 2. As an alternative to designing hardened protec- Maximum Surge from hurricanes at open-coast sites on tion 7 for all safety-related structures, systems, and the Atlantic Ocean and Gulf of Mexico. components as specified in Regulatory Position 1 above, c. Flood conditions that could be caused by dam "Hardened protection means structural provisions incorporated in the plant design that will protect safety-related structures, failures from earthquakes should also be considered in systems, and components from the static and dynamic effects of floods. In addition, each component of the protection must

6 be passive and in place, as it is to be used for flood protection, Probable Maximum Gradient Wind is defined as a gradient wind during normal plant operation. Examples of the types of flood of a designated duration, which there is virtually no risk of protection to be provided for nuclear power plants are exceeding. contained in Regulatory Guide 1.102.

1.59-7

it is permissible not to provide hardened protection for effects of the increased flood. The following should be some of these features if: reported: 9 a. The type of investigation undertaken to a. Sufficient warning time is shown to be available identify changed or changing conditions in the site to shut the plant down and implement adequate environs.

emergency procedures;

b. The changed or changing conditions noted during the investigation.

b. All safety-related structures, systems, and com- c. The hydrologic engineering bases for estimating ponents identified in Regulatory Guide 1..29 (see foot- the effects of the changed conditions on the design basis note 2) are designed to withstand the flood conditions

8 flood.

I resulting from a Standard Project event with attendant wind-generated wave activity that may be produced by d. Safety-related structures, systems, or com- the worst winds of record and remain functional;

ponents (identified in paragraph 2.b above) affected by the changed conditions in the design basis flood should be identified along with modifications to the plant c. In addition to the analyses in paragraph 2.b facility necessary to afford protection during the in- above, reasonable combinations of less-severe flood creased flood conditions. If emergency operating pro- conditions are also considered to the extent needed for a cedures must be used to mitigate the effects of these consistent level of conservatism; and new flood conditions, the emergency procedures devel- oped or modifications to existing procedures should be provided.

d. In addition to paragraph 2.b above, at least those structures, systems, and components necessary for 4. Proper utilization of the data and procedures in cold shutdown and maintenance thereof are designed Appendices B and C will result in PMF peak discharges with hardened protective features to remain functional and PMS peak stillwater levels which will in many cases while withstanding the entire range of flood conditions be approved by the NRC staff with no further verifica- up to and including the worst site-related flood probable tion. The staff will continue to accept for review (e.g., PMF, seismically induced flood, hurricane, surge. detailed PMF and PMS analyses that result in less conservative estimates than those obtained by use of

( _4 seiche, heavy local precipitation) with coincident wind- generated wave action as discussed in Regulatory Posi- Appendices B and C. In addition, previously reviewed tion I above. and approved detailed PMF and PMS analyses will continue to be acceptable even though the data and procedures in Appendices B and C result in more

3. During the economic life of a nuclear power plant, conservative estimates.

unanticipated changes to the site environs which may

D. IMPLEMENTATION

affect the flood-producing characteristics of the environs are possible. Examples include construction of a dam The purpose of this section is to provide information upstream or downstream of the plant, or comparably, to license applicants and licensees regardirng the NRC

construction of a highway or railroad bridge and staff's plans for using this regulatory guide.

embankment that obstructs the flood flow of a river, and construction of a harbor or deepening of an existing This guide reflects current NRC practice. Therefore, harbor near a coastal or lake site plant. except in those cases in which the applicant or licensee proposes an acceptable alternative method for comply- ing with specified portions of the Commission's regula- Significant changes in the runoff or other flood- tions, the method described herein is being and will producing characteristics of the site environs, as they continue to be used in the evaluation of submittals for affect the design basis flood, should be identified and construction permit applications until this guide is used as the basis to develop or modify emergency revised as a result of suggestiQns from the public or operating procedures, if necessary, to mitigate the additional staff review.

8 For sites along streams, this event is characterized by the Corps 9 of Engineers' definition of a Standard Project Flood. (Also, see Reporting should be by special report to the appropriate NRC

footnote 4.) Such floods have been found to produce flow rates Regional Office and to the Director of the Office of Inspection generally 40 to 60 percent of the PMF. For sites along and Enforcement. Requirement for such reports should be seashores, this event may be characterized by the Corps of included in theTechnical Specifications (Appendix A) unless it Engineers' definition of a Standard Project Hurricane. For can be demonstrated that such reports will not be necessary other sites, a comparable level of risk should be assumed. during the life of the plant.

1.59-8

APPENDIX A

PROBABLE MAXIMUM AND SEISMICALLY INDUCED

FLOODS ON STREAMS

TABLE OF CONTENTS

Page A. 1 Introduction ......... ...................... 1.59-11 A. 2 Probable Maximum Flood ................ 1.59-11 A. 3 Hydrologic Characteristics . . . . . . . . . . . . . . . . 1.59-12 A. 4 Flood Hydrograph Analyses ............... 1.59-13 A. 5 Precipitation Losses and Base Flow ............ 1.59-13 A. 6 Runoff M odel . . . . . . . . . . . . .. . .. . . . . 1.59-14 A. 7 Probable Maximum Precipitation Estimates ......... 1.59-15 A. 8 Channel and Reservoir Routing .............. 1.59-17 A. 9 Probable Maximum Flood Hydrograph Estimates .......... 1.59-17 A.1O Seismically Induced Floods ..... ................. . . . . . . . . . . . . . . . . 1.59-18 A.] I Water Level Determinations ..... . .... .... . . . . . . . . . . . . . . . . . 1.59-18 A.12 Coincident Wind-Wave Activity .............. . . . . . . . . . . . . . . . . 1.59-19 REFERENCES ................... ..................................... ...1.59-20

1.59-9

(I

A.1 INTRODUCTION Three exceptions to use of the above-described analyses are considered acceptable as follows:

This appendix has been prepared to provide guidance for flood analyses required in support of applications for a. No flood analysis is required for nuclear facility licenses for nuclear facilities to be located on streams. sites where it is obvious that a PMF or seismically Because of the depth and diversity of presently available induced flood has no bearing. Examples of such sites are techniques, this appendix summarizes acceptable coastal locations (where it is obvious that surges, wave methods for estimating Probable Maximum Precipitation action, or tsunami would produce controlling water (PMP), for developing rainfall-runoff models, for analyz- levels and flood conditions) and hilltop or "dry" sites.

ing seismically induced dam failures, and for estimating the resulting water levels. b. Where PMF or seismically induced flood estimates of a quality comparable to that indicated herein exist for The Probable Maximum Flood (PMF) may be locations near the site of the nuclear facility, the estimates may be extrapolated directly to the site if such thought of as one generated by precipitation and a extrapolations do not introduce potential errors of more seismically induced flood as one caused by dam failure.

than about a foot in design basis water level estimates.

For many sites, however, these two types do not (See Appendix B.)

constitute the worst potential flood danger to the safety of the nuclear facilities. Subsequent appendices will present acceptable methods of analyzing other flood c. It is recognized that an in-depth PMF estimate types, such as tsunami, seiches, and surges (in addition may not be warranted because of the inherent capability to the surge method in Appendix C). of the design of some nuclear facilities to function safely with little or no special provisions or because the time and costs of making such an estimate are not com- The PMF on streams is compared with the upper limit mensurate with the cost of providing protection. In such of flood potential that may be caused by other cases, other means of estimating design basis floods are phenomena to develop a basis for the design of acceptable if it can be demonstrated that the technique safety-related structures and systems. This appendix utilized or the estimate itself is conservative. Similarly, outlines the nature and scope of detail.ed hydrologic conservative estimates of seismically induced flood engineering activities involved in determining estimates potential may provide adequate demonstration of for the PMF and for seismically induced floods resulting nuclear facility safety.

-- rom dam failures and describes the situations fdr which less extensive analyses are acceptable. A.2 PROBABLE MAXIMUM FLOOD

Estimation of the PMF requires the determination of Probable Maximum Flood studies should be com- the hydrologic response (losses, base flow, routing, and patible with the specific definitions and criteria sum- runoff model) of watersheds to intense rainfall, verifica- marized as follows:

tion based on historical storm and runoff data (flood hydrograph analysis), the most severe precipitation a. The Corps of Engineers defines the PMF as "the reasonably possible (PMP), minimum losses, maximum hypothetical flood characteristics (peak discharge, base flow, channel and reservoir routing, the adequacy volume, and hydrograph shape) that are considered to be of existing and proposed river control structures to the most severe reasonably possible at a particular safely pass a PMF, water level determinations, and the location, based on relatively comprehensive hydro- superposition of potential wind-generated wave activity. meteorological analysis of critical runoff-producing pre- Seismically induced floods, such as may be produced by cipitation (and snowmelt, if pertinent) and hydrologic dam failures or landslides, may be analytically evaluated factors favorable for maximum flood runoff." Detailed using many PMF estimating components (e.g., routing PMF determinations are usually prepared by estimating techniques, water level determinations) after conserva- the areal distribution of PMP (defined below) over the tive assumptions of flood wave initiation (such as dam subject drainage basin in critical periods of time and failures) have been made. Each potential flood com- computing the residual runoff hydrograph likely to ponent requires an in-depth analysis. The basic data and result with critical coincident conditions of ground results should be evaluated to ensure that the PMF wetness and related factors. PMF estimates are usually estimate is conservative. In addition, the flood potential based on the observed and deduced characteristics of from seismically induced causes should be compared historical flood-producing stormsý Associated hydrologic with the PMF to ensure selection of the appropriate factors are modified on the basis of hydrometeorological design basis flood. The seismically induced flood poten- analyses to represent the most severe runoff conditions tial may be evaluated by simplified methods when considered to be "reasonably possible" in the particular conservatively determined results provide acceptable drainage basin under study. The PMF should be deter- iesign bases. mined for adjacent large streams. In addition, a local

1.59-11

PMF should be estimated for each local drainage course records to "pre-project(s)" and "with project(s)" con- that can influence safety-related facilities, including ditions as follows:

drainage from the roofs of buildings, to assure that local intense precipitation cannot constitute a threat to the (1) The term "pre-project(s) conditions" refers to safety of the nuclear facility. all characteristics of watershed features and develop- ments that affect runoff characteristics. Existing con- b. Probable Maximum Precipitation is defined by the ditions are assumed to exist in the future if projects are Corps of Engineers and the National Oceanic and to be operated in a similar manner during the life of the Atmospheric Administration (NOAA) as "the theoreti- proposed nuclear facility and watershed runoff char- cally greatest depth of precipitation for a given duration acteristics are not expected to change due to develop- that is meteorologically possible over the applicable ment.

drainage area that would produce flood flows of which there is virtually no risk of being exceeded. These (2) The term "with project(s)" refers to the estimates usually involve detailed analyses of historical future effects of projects being analyzed, assuming they flood-producing storms in the general region of the will exist in the future and operate as specified. If drainage 'basin under study, and certain modifications existing projects were not operational during historical and extrapolations of historical data and reflect more floods and may be expected to be effective during the severe rainfall-runoff relations than actually recorded, lifetime of the nuclear facility, their effects on historical insofar as these are deemed reasonably possible of floods should be determined as part of the analyses occurrence on the basis of hydrometeorological reason- outlined in Sections A.5, A.6, and A.8.

ing." The PMP should represent the depth, time, and spade distribution of precipitation that approaches the c. Surface and subsurface characteristics that affect upper limit of what the atmosphere and regional runoff and streamflow to a major degree (e.g., large topography can produce. The critical PMP meteorologi- swamp areas, noncontributing drainage areas, ground- cal conditions are based on an analysis of air-mass water flow, and other watershed features of an unusual properties (e.g., effective precipitable water, depth of nature which cause unusual characteristics of stream- inflow layer, temperatures, winds), synoptic situations flow).

prevailing during recorded storms in the region, topo- graphical features, season of occurrence, and location of d. Topographic features of the watershed and histor- the geographic areas involved. The values thus derived ical flood profiles or high water marks, particularly in are designated as the PMP, since they are determined the vicinity of the nuclear facility. For some sites one or within the limitations of current meteorological theory more gaging stations may be required at or very near the and available data and are based on the most effective combination of critical controlling factors.

facility site as soon as a site is selected to establish (.

hydrologic parameters. (A regulatory guide is being prepared to provide guidance on hydrologic data collec- A.3 HYDROLOGIC CHARACTERISTICS tion.)

Hydrologic characteristics of the watershed and e. Stream channel distances between river control stream channels relative to the facility site should be structures, major tributaries, and the facility site.

determined from the following:

a. A topographic map of the drainage basin showing f. Data on major storms and resulting floods-of- watershed boundaries. for the entire basin and principal record in the drainage basin. Primary attention should be tributaries and other subbasins that are pertinent. The given to those events having a major bearing on map should include the location of principal stream hydrologic computations. It is usually necessary to gaging stations and other hydrologically related record analyze a few major floods-of-record in order to develop collection stations (e.g., streamflow, precipitation) and unit hydrograph relations, infiltration indices, base flow the locations of existing and proposed reservoirs. relationships, information on flood routing relationships, and flood profiles. Except in unusual cases, climatol- b. The drainage areas in each of the pertinent ogical data available from the Department of Commerce, watersheds or subbasins above gaging stations, reservoirs, the U.S. Army Corps of Engineers, National Oceanic and any river control structures, and any unusual terrain Atmospheric Administration, and other public sources features that could affect flood runoff. All .major are adequate to meet the data requirements for storm reservoirs and channel improvements that will have a precipitation histories. The data should include:

major influence on streamflow should be considered. In addition, the age of existing structures and. information (1) Hydrographs of major historical floods for concerning proposed projects affecting runoff character- pertinent locations in the basin from the U.S. Geological istics or streamflow are needed to adjust streamflow Survey or other sources, where available.

1.59-12

(2) Storm precipitation records, depth-area- A.5 PRECIPITATION LOSSES AND BASE FLOW

duration data, and any available isohyetal maps for the most severe local historical storms or floods that will be Determination of the absorption capability of the used to estimate basin hydrological characteristics. basin should consider antecedent and initial conditions and infiltration during each storm investigated. Antece- A.4 FLOOD HYDROGRAPH ANALYSES dent precipitation conditions affect precipitation losses and base flow. The assumed values should be verified by studies in the region or by detailed storm-runoff studies.

Flood hydrograph analyses and related computations The fundamental hydrologic factors would be derived by should be used to derive and verify the fundamental analyzing observed hydrographs of streamflow and hydrologic factors of precipitation losses (see Section related storms. A thorough study is essential to deter- A.5) and the runoff model (see Section A.6). The mine basin characteristics and meteorological influences analyses of observed flood hydrographs' of streamflow affecting runoff from a specific basin. Additional discus- and related storm precipitation (Ref. 1) use basic data sion and procedures for analyses are contained in various and information referred to in Section A.3 above. The publications such as Reference 2. The following discus- sizes and topographic features of the subbasin drainage sion briefly describes the considerations for determining areas upstream of the location of interest should be used the minimum losses applicable to the PMF.

to estimate runoff response for each individual hydro- logically similar subbasin utilized in the total basin runoff model. Subbasin runoff response characteristics a. Experience indicates that the capacity of a given are estimated from historical storm precipitation and soil and its cover to absorb rainfall applied continuously streamflow records where such are available, and by at high rate may rapidly decrease until a fairly definite synthetic means where no streamflow records are avail- minimum rate of infiltration is reached, usually within a able. Reference 2 and the following provide guidance for period of a few hours. Infiltration loss may include the analysis of flood hydrographs. initial conditions or may require separate determinations of initial losses. The order of decrease in infiltration a. The intensity, depth, and areal distribution of capacity and the minimum rate attained are primarily precipitation causing runoff for each historical storm dependent upon the type of ground cover, the size of (and rate of snowmelt, where this is significant) should soil pores within the zone of aeration, and the condi- be analyzed. Time distributions of storm precipitation tions affecting the rate of removal of capillary water

- k are generally based on recording rainfall gages. Total from the zone of aeration. Infiltration theory, with precipitation measurements (including data from non- certain approximations, offers a practical means of recording gages) are usually distributed, in time, using estimating the volume of surface runoff from intense precipitation recorders. Areal distributions of precipita- rainfall. However, in applying the theory to natural tion, for each time increment, are generally based on a drainage basins, several factors must be considered.

weighting procedure. The incremental precipitation over a particular drainage area is the sum of the precipitation

(1) The infiltration capacity of a given soil at the for each precipitation gage weighted by the percentage beginning of a storm is related to antecedent field of the drainage area considered to be represented by the moisture and the physical condition of the soil. There- rain gage. fore, the infiltration capacity for the same soil may vary appreciably from storm to storm.

b. Base flow is the time-distribution of the difference between gross runoff and net direct runoff. (2) The infiltration capacity of a soil is normally highest at the beginning of rainfall. Rainfall frequently c. Initial and infiltration losses are the time distrib- begins at relatively moderate rates, and a substantial uted differences between precipitation and net direct period of time may elapse before the rainfall intensity runoff. exceeds the prevailing infiltration capacity. It is gen- erally accepted that, a fairly substantial quantity of d. The combined effect of drainage area, channel infiltration is required to satisfy initial soil moisture characteristics, and reservoirs on the runoff character- deficiencies before runoff will occur, the amount of istics, herein referred to as the "runoff model," should initial loss depending upon antecedent conditions.

be established. (Channel and reservoir effects are dis- cussed separately in Section A.8.) (3) Rainfall does not normally cover the entire drainage basin during all periods of precipitation with Streamflow hydrographs (of major floods) are available in intensities exceeding infiltration capacities. Further- publications by the U.S. Geologic Survey, National Weather more, soils and infiltration capacities vary throughout a Service, State agencies, and other public sources. drainage basin. Therefore rational application of any

1.59-13

loss-rate technique must consider the varying nature of Basin runoff models for a PMF determination should rainfall intensities over the basin in order to determine provide a conservative estimate of the runoff that could the area covered by runoff-producing rainfall. be expected during the life of the nuclear facility. The basic analyses used in deriving the runoff model are not b. Initial loss is defined as the maximum amount of rigorous but may be conservatively undertaken by precipitation that can occur without producing runoff. considering the rate of runoff from unit rainfall (and Values of initial loss may range from a minimum of a snowmelt, if pertinent) of some unit duration and few tenths of an inch during relatively wet seasons to specific time-areal distribution (called a unit hydro- several inches during dry summer and fall months. Initial graph). The applicability of a unit hydrograph or other losses prevalent during major floods usually range from technique for use in computing the runoff from the about 0.2 to 0.5 inch and are relatively small in Probable Maximum Precipitation over a basin may be comparison with the flood runoff volume. Conse- partially verified by reproducing observed major flood quently, in estimating loss rates from data for major hydrographs. An estimated unit hydrograph is first floods, allowances for initial losses may be approximated applied to estimated historical rainfall-excess values to without introducing important errors into the results. obtain a hypothetical runoff hydrograph for comparison with the observed runoff hydrograph exclusive of base c. Base flow is defined herein as that portion of a flow (i.e., net runoff). The loss rate, the unit hydro- flood hydrograph which represents runoff from antece- graph, or both, are subsequently adjusted to provide dent storms and bank flow. Bank flow is storm accurate verification.

precipitation which infiltrates the ground surface and flows, possibly as groundwater, into stream channels. A study of the runoff response of a large number of Many techniques exist for estimating base flow. It is basins for several historical floods in which a variety of generally assumed that base flow which could exist valley storage characteristics, basin configurations, topo- during a PMF is high, the rationale being that a storm graphical features, and meteorological conditions are producing relatively high runoff could meteorologically represented provides the basis for estimating the relative occur over most watersheds about a week earlier than effects of predominating influences for use in PMF

that capable of producing a PMF. An acceptable method analyses. In detailed hydrological studies, each of the is to assume that a flood about half as severe as a PMF following procedures may be used to advantage:

occurred 3 to 5 days earlier for frontal-type storms and about 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for thunderstorms. The recession of this a. Analysis of rainfall-runoff records for major t- flood is the base flow for the PMF. storms;

A.6 RUNOFF MODEL b. Computation of synthetic runoff response models by (1) direct analogy with basins of similar character- The hydrologic response characteristics of the water- istics and/or (2) indirect analogy with a large number of shed to precipitation (i.e., runoff model) should be other basins through the application of empirical rela- determined and verified from historical flood records. tionships. In basins for which historical streamflow The model should include consideration of nonlinear and/or storm data are unavailable, synthetic techniques runoff response due to high rainfall intensities or are the only known means for estimating hydrologic unexplainable factors. In conjunction with data and response characteristics. However, care must be taken to analyses discussed above, a runoff model should be assure that a synthetic model conservatively reflects the developed, where data are available, by analytically runoff response expected from precipitation as severe as

"reconstituting" historical floods to substantiate its use the PMP.

for estimating a PMF. The rainfall-runoff-time-areal distribution of historical floods should be used to verify Detailed flood hydrograph analysis techniques and that the reconstituted hydrographs correspond reason- studies for specific basins are available from many ably well with flood hydrographs actually recorded at agencies. Published studies such as those by the Corps of selected gaging stations (Ref. 2). In most cases, reconsti- Engineers, Bureau of Reclamation, and Soil Conserva- tution studies should be made with respect to two or tion Service may be utilized directly where it can be more floods and possibly at two or more key locations, demonstrated that they are of a level of quality and particularly where possible errors in the determinations conservatism comparable with that indicated herein. In could have a serious impact on decisions required in the particular, the Corps of Engineers has developed analysis use of the runoff model for the PMF. In some cases the techniques (Refs. 2, 3) and has accomplished a large lack of stream gage records, the lack of sufficient time number of studies in connection with their water and areal precipitation definition, or unexplained causes resources development activities.

may prevent development of reliable predictive runoff models. In such cases a conservative PMF estimate Computerized runoff models (Ref. 3) offer an ex- should be ensured by other means such as conservatively tremely efficient tool for estimating PMF runoff rates developed synthetic unit hydrographs. and for evaluating the sensitivity of PMF estimates to

1.59-14

possible variations in parameters. Such techniques have mated by maximizing observed intense storm parameters been used successfully in making detailed flood esti- and transposing them to basins of interest. The param- mates. eters include storm duration, intensity, and the depth- area relation. The maximum storm should represent the Snowmelt may be a substantial runoff component for most critical rainfall depth-area-duration relation fo- *he both historical floods and the PMF. In cases where it is particular drainage area during various seasons oi -he necessary to provide for snowmelt in the runoff model, year (Refs. 7-10). In practice, the storm parameters additional hydrometeorological parameters must be in- considered are (1) the representative storm dewpoint corporated. The primary parameters are the depth of adjusted to inflow moisture producing the maximum assumed existing snowpack, the areal distribution of dewpoint (precipitable water), (2) seasonal variations in assumed existing snowpack, the snowpack temperature parameters, (3) the temperature contrast, (4) the geo- and moisture content, the type of soil or rock surface graphical relocation, and (5) the depth-area relation.

underlying the snowpack and the type and amount of Examples of these analyses are explained and utilized in forest cover of the snowpack and variation thereof, and a number of published reports (Refs. 7-10).

the time and elevation distribution of air temperatures and heat input during the storm and subsequent runoff This procedure, supported with an appropriate period. Techniques that have been developed to reconsti- analysis, is usually satisfactory where a sufficient num- tute historical snowmelt floods may be used in both ber of historical intense storms have been maximized historical flood hydrograph analysis and PMF determina- and transposed to the basin and where at least one of tions (Ref. 4). them contains a convergent wind "mechanism" very near the maximum that nature can be expected to A.7 PROBABLE MAXIMUM

PRECIPITATION ESTIMATES produce in the region (which is generally the case in the United States east of the Rocky Mountains). A general principle for PMP estimates is: The number and severity Probable Maximum Precipitation (PMP) estimates are of maximization steps must balance the adequacy of the the time and areal precipitation distributions compatible storm sample; additional maximization steps are re- with the definition of Section A.2 and are based on quired in regions of more limited storm samples.

detailed comprehensive meteorological analyses of severe storms of record. The analysis uses precipitation data and synoptic situations of major storms of record to b. PMP determinations in regions of orographic determine characteristic combinations of meteorological influences generally are for the high mountain regions.

conditions in a region surrounding the basin under Additional maximization steps from paragraph A.7.a study. Estimates are made of the increase in rainfall above are required in the use of the orographic model quantities that would have resulted if conditions during (Refs. 5, 6). The orographic model is used where severe the actual storm had been as critical as those considered precipitation is expected to be caused largely by the probable of occurrence in the region. Consideration is lifting imparted to the air by mountains. This orographic given to the modifications in meteorological conditions influence gives a basis for a wind model with maximized that would have been required for each of the record inflow. Laminar flow of air is assumed over any storms to have occurred over the drainage basin under particular mountain cross section. The "life" of the air, study, considering topographical features and location of the levels at which raindrops and snowflakes are formed, the region involved. and their drift with the air before they strike the ground may then be calculated.

The physical limitations in meteorological mecha- nisms for the maximum depth, time, and space distribu- Models are verified by reproducing the precipita- tion of precipitation over a basin are (1) humidity tion in observed storms and are then used for estimating (precipitable water) in the airflow over the watershed, PMP by introducing maximum values of moisture and

(2) the rate at which wind may carry the humid air into wind as inflow at the foot of the mountains. Maximum the basin, and (3) the fraction of the inflowing atmos- moisture is evaluated just as in nonorographic regions. In pheric water vapor that can be precipitated. Each of mountainous regions where storms cannot readily be these limitations is treated differently to estimate the transposed (paragraph A.7.a above) because of their PMP over a basin. The estimate is modified further for intimate relation to the immediate underlying topo- regions where topography causes marked orographic graphy, historical stor~ns are resolved into their convec- control on precipitation (designated as the orographic tive and orographic components and maximized. Maxi- model as opposed to the general model which embodies mum mroisture, maximum winds, and maximum values little topographic effect). Further details on the models of the orographic component and convective component and acceptable procedures are contained in References 5 (convective as in nonorographic areas) of precipitation and6. are considered to occur simultaneously. Some of the published reports that illustrate the combination of a. The PMP in regions of limited topographicinflu- orographic and convective components, including ence (mostly convergence precipitation) may be esti- seasonal variation, are References 11-13.

1.59-15

In some watersheds, major floods are often the result The position of the PMP, identified by "isohyetal of melting snowpack or of snowmelt combined with patterns" (lines of equal rainfall depth), may have a very rain. Accordingly, the PMP (rainfall) and maximum great effect on the regimen of runoff from a given associated runoff-producing snowpacks are both esti- volume of rainfall excess, particularly in large drainage mated on a seasonal and elevation basis. The probable basins in which a wide range of basin hydrologic runoff maximum seasonal snowpack water equivalent should be characteristics exist. Several trials may be necessary to determined by study of accumulations on local water- determine the critical position of the hypothetical PMP

sheds from historical records of the region. storm pattern (Refs. 8, 17) or the selected record storm pattern (Refs. .9, 16) to determine the critical isohyetal Several methods of estimating the upper limit of pattern that produces the maximum rate of runoff at the ultimate snowpack and melting are summarized in designated site. This may be accomplished by super- References 4 and 5. The methods have been applied in imposing the total-storm PMP isohyetal contour map on the Columbia River basin, the Yukon basin in Alaska, an outline of the drainage basin (above the site) in such a the upper Missouri River basin, and the upper Mississippi manner as to place the largest rainfall quantities in a in Minnesota and are described in a number of reports position that would result in the maximum flood runoff by the Corps of Engineers. In many intermediate- (see Section A.8 on Probable Maximum Flood runoff).

latitude basins, the greatest flood will likely result from The isohyetal pattern should be consistent with the a combination of critical snowpack (water equivalent) assumptions regarding the meteorological causes of the and PMP. The seasonal variation in both optimum snow storm.

depth (i.e., the greatest water equivalent in the snow- pack) and the associated PMP combination should be A considerable range in assumptions regarding rainfall meteorologically compatible. Temperature and winds patterns (Ref. II) and intensity variations can be made associated with PMP are two important snowmelt factors in developing PMP storm criteria for relatively small amenable to generalization for snowmelt computations basins without being inconsistent with meteorological (Ref. 14). The meteorological (e.g., wind, temperature, causes. For drainage basins less than a few thousand dewpoints) sequences prior to, during, and after the square miles in area (particularly if only one unit postulated PMP-producing storm should be compatible hydrograph is available), the rainfall may be expressed as (

with the sequential occurrence of the PMP. The user average depth over the drainage area. However, in should place the PMP over the basin and adjust the determining the PMP pattern for large drainage basins sequence of other parameters to give the most critical (with varying basin hydrologic characteristics, including runoff for the season considered. reservoir effects), runoff estimates are required for different storm pattern locations and orientations to The meteorological parameters for snowmelt compu- obtain the final PMF. Where historical rainfall patterns tations associated with PMP are discussed in more detail are not used for PMP, two other methods are generally in References 11, 12, and 14. employed.

Other items that need to be considered in deter- mining basin melt are optimum depth, areal extent and a. The average depth over the entire basin is based on type of snowpack, and other snowmelt factors (see the maximized areal distribution of the PMP.

Section A.8), all of which must be compatible with the most critical arrangement of the PMP and associated b. A hypothetical isohyetal pattern is assumed.

meteorological parameters. Studies of areal rainfall distribution from intense storms indicate that elliptical patterns may be assumed as Critical probable maximum storm estimates for very representative of such events. Examples are the typical large drainage areas are determined as above but may patterns presented in References 8, 14, 17, and 18.

differ somewhat in flood-producing storm rainfall from those encountered in preparing similar estimates for To compute a flood hydrograph from the probable small basins. As a general rule, the critical PMP in a small maximum storm, it is necessary to specify the time basin results primarily from extremely intense small-area sequence of precipitation in a feasible and critical storms, whereas in large basins the PMP usually results meteorological time sequence. Two meteorological from a series of less intense, large-area storms. In large factors must be considered in devising the time se- river basins (about 100,000 square miles or larger) such quences: (1) the time sequence in observed storms and.

as the Ohio and Mississippi River basins, it may be (2) the manner of deriving the PMP estimates. The first necessary to develop hypothetical PMP storm sequences imposes few limitations; the hyetographs (rainfall time (one storm period followed by another) and storm sequences) for observed storms are quite varied. There is tracks with an appropriate time interval between storms. some tendency for the two or three time increments The type of meteorological analyses required and typical with. the highest rainfall in a storm to bunch together, as examples thereof are contained in References 9, 15, and some time is required for the influence of a severe

16. precipitation-producing weather situation to pass a given

1.59-16

region. The second consideration uses meteorological Care should be taken to ensure that the characteristics parameters developed from PMP estimates. determined represent historical conditions (which may be verified by reconstituting historical floods) and also An example of 6-hour increments for obtaining a conservatively represent conditions to be expected dur- critical 24-hour PMP sequence would be that the most ing a PMF.

severe 6-hour increments should be adjacent to each other in time (Ref. 17). In this arrangement the second Channel and reservoir routing methods of many types highest increment should precede the highest, the third have been developed to model the progressive down- highest should be immediately after this 12-hour se- stream translation of flood waves. The same theoretical quence, and the fourth highest should be before the relationships hold for both channel and reservoir rout-

18-hour sequence. This procedure may also be used in ing. However, in the case of flood wave translation the distribution of the lesser, second (24-48 hours) and through reservoirs, simplified procedures have been third (48-72 hours), 24-hour periods. These arrange- developed that are generally not used for channel ments are permissible because separate bursts of precipi- routing because of the inability of such simplified tation could have 'occurred within each 24-hour period methods to model frictional effects. The simplified (Ref. 7). The three 24-hour precipitation periods are channel routing procedures that have been developed interchangeable. Other arrangements that fulfill the have been found useful in modeling historical floods, but sequential requirements would be equally reasonable. care should be exercised in using such models for severe The hyetograph selected should be the most severe hypothetical floods such as the PMF. The coefficients reasonably possible that would produce critical runoff at developed from analysis of historical floods may not the project location based on the general appraisal of the conservatively reflect flood wave translation for more hydrometeorologic conditions in the project basin. severe events.

Examples of PMP time sequences fulfilling the sequential requirements are illustrated in References 11, 12, and Most of the older procedures were basically attempts

17. For small areas maximized local records should be to model unsteady-flow phenomena using simplifying considered to ensure that the selected PMP time approximations. The digital computer has allowed sequence is as severe as has occurred. development of analysis techniques that permit direct solution of basic unsteady flow equations utilizing The Corps of Engineers and the Hydrometeorological numerical analysis techniques (Ref. 19). Most of the Branch of NOAA (under a cooperative -arrangement older techniques have also been adapted for computer since 1939) have made comprehensive meteorological use (Ref. 3).

studies of extreme flood-producing storms (Ref. 1) and have developed a number of estimates of PMP. The PMP For all routing techniques, care should be exercised estimates are presented in various unpublished memo- to ensure that parameters selected for model verification randa and published reports. The series of published are based on several historical floods (whenever possible)

reports is listed on the fly sheet of referenced Hydro- and that their application to the PMF will result in meteorological Reports such as Reference 18. The conservative estimates of flow rates, water levels, veloci- unpublished memoranda reports may be obtained from ties, and impact forces. Theoretical discussions of the the Corps of Engineers or Hydrometeorological Branch, many methods available for such analyses are contained NOAA. These reports and memoranda present general in References2 and 19-22.

techniques and several contain generalized estimates of PMP for different river basins. The generalized studies (Refs. 7-13, 18, 29) are based on coordinated studies of A.9 PROBABLE MAXIMUM FLOOD

all available data, supplemented by thorough meteoro- HYDROGRAPH ESTIMATES

logical analyses and usually assure reliable and consistent estimates for various locations in the region for which Probable Maximum Flood (PMF) net runoff hydro- they have been developed. In some cases, however, graph estimates are made by sequentially applying additional detailed analyses are needed for specific river critically located and distributed PMP estimates using basins (Refs. 7, 8) to take into account unusually large the runoff model, conservatively low estimates of areas, storm series, topography, or orientation of drain- precipitation losses, and conservatively high estimates of age basins not fully reflected in the generalized esti- base flow and antecedent reservoir levels.

mates. In many river basins, available studies may be utilized to obtain the PMP without the in-depth analysis In PMF determinations it is generally assumed that discussed herein. short-term reservoir flood control storage would be depleted by antecedent floods. An exception would be when it can be demonstrated that a reasonably severe A.8 CHANNEL AND RESERVOIR ROUTING flood (e.g., about one-half of a PMF) less than a week (usually a minrimm of 3 to 5 days; 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if the PMP

Channel and reservoir routing of floods is generally an is a thunderstorm) prior to a PMF can be evacuated from integral part of the runoff model for subdivided basins. the reservoir before the arrival of a PMF. However, it is

1.59-17

unusual to use an antecedent storage level of less than flood are assumed coincident with the Safe Shutdown one-half the available flood control storage. Earthquake. (An acceptable method of determining the

25-year flood is contained in Reference 30.) Also, The application of PMP in basins whose hydrologic consideration should be given to the occurrence of a features vary from location to location requires the Standard Project Flood with full flood control reservoirs determination that the estimated PMF hydrograph repre- coincident with the Operating Basis Earthquake to sent the most critical centering of the PMP storm with maintain a consistent level of analysis with other respect to the site. Care must be taken in basins with combinations of such events. As with failures due to substantial headwater flood control storage to ensure inadequate flood- control capacity, domino and essen- that a more highly concentrated PMP over a smaller area tially simultaneous multiple failures may also require downstream of the reservoirs would not produce a consideration. If the arbitrarily assumed total instan- greater PMF than a total basin storm that is partially taneous failure of the most critically located (from a controlled. In such cases more than one PMP runoff hydrologic standpoint) structures indicates flood risks at analysis would be required. Usually, only a few trials of the nuclear facility site more severe than a PMF, a a total basin PMP are required to determine the most progressively more detailed analysis of the seismic critical centering. capability of the dam is warranted. In lieu of detailed geologic and seismic investigations at the site of the river Antecedent snowpack is included when it ýs deter- control structure, the flood potential at the nuclear mined that snowmelt significantly contributes to the facility may be evaluated assuming the most probable PMF (see Section A.7). mechanistic-type failure of the questioned structures. If the flood effects of this assumed failure cannot be safely Runoff hydrographs should be prepared at key accommodated at the nuclear facility site in an accept- hydrologic locations (e.g., streamgages and dams) as well able manner, the seismic potential at the site of each as at the site of nuclear facilities. For all reservoirs questioned structure is then evaluated in detail. The involved, inflow, outflow, and pool elevation hydro- structural capability is evaluated in the same depth as for graphs should be prepared. the nuclear facility. If the capability is not sufficient to ensure survival of the structure, its failure is assumed, Many existing and proposed dams and other river and the resulting seismically induced flood is routed to control structures may not be capable of safely passing the site of the nuclear power plant. This last detailed floods as severe as a PMF. The capability of river control analysis is not generally required since intermediate structures to safely pass a PMF and local coincident investigations usually provide sufficient conservative wind-generated wave activity must be determined as part information to allow determination of an adequate of the PMF analysis. Where it is possible that such design basis flood.

structures may not safely survive floods as severe as a PMF, the worst such condition with respect to down- A.11 WATER LEVEL DETERMINATIONS

stream nuclear facilities is assumed (but should be substantiated by analysis of upstream PMF potential) to The preceding discussion has been concerned pri- be their failure during a PMF, and the PMF determina- marily with determinations of flow rates. The flow rate tion should include the resultant effects. This analysis or discharge must be converted to water surface eleva- also requires that the consequences of upstream dam tion for use in design. This may involve determination of failures on downstream dams (domino effects) be elevation-discharge relations for natural stream valleys or considered. reservoir conditions. The, reservoir elevation estimates involve the spillway discharge capacity and peak reser- A.10 SEISMICALLY INDUCED FLOODS voir level likely to be attained during the PMF as governed by the inflow hydrograph, the reservoir level at Seismically induced floods on streams and rivers may the beginning of the PMF, and the reservoir regulation be caused by landslides or dam failures. Where river plan with respect to total releases while the reservoir is control structures are widely spaced, their arbitrarily rising to peak stage. Most river water level determina:

assumed individual, total, instantaneous failure and tions involve the assumption of steady, or nonvarying, conservative flood wave routing may be sufficient to flow for which standard methods are used to estimate show that no threat exists to nuclear facilities. However, flood levels.

where the relative size, location, or proximity of dams to potential seismic generators indicates a threat to nuclear Where little floodplain geometry definition exists, a facilities, the capability of such structures (either singly technique called "slope-area" may be employed wherein or in combination) to resist severe earthquakes (critically the assumptions are made that (1) the water surface is located) should be considered. In river basins where the parallel to the average -bed slope, (2) any available flood runoff season may constitute a significant portion floodplain geometry information is typical of the river of the year (such as the Mississippi, Columbia, or Ohio reach under study, and (3) no upstream or downstream River basins), full flood control reservoirs with a 25-year hydraulic controls affect the river reach fronting the site

1.59-48

ander study. Where such computations can be shown to The 'selection of windspeeds and critical wind indicate conservatively high flood levels, they may be directions assumed coincident with maximum PMF or used. However, the usual method of estimating water seismically induced water levels should provide assurance surface profiles for flood conditions that may be of virtually no risk to safety-related equipment. The characterized as involving essentially steady flow is Corps of Engineers suggests (Refs. 26, 27) that average called the "standard-step method." This method utilizes maximum windspeeds of approximately 40 to 60 mph the integrated differential equation of steady fluid have occurred in major windstorms in most regions of motion commonly referred to as the Bernoulli equation the United States. For application to the safety analysis (Refs. 22-25). Water levels in the direction of flow of nuclear facilities, the worst regional winds of record computation are determined by the trial and error should be assumed coincident with the PMF. However, balance of upstream and downstream energy. Frictional the postulated winds should be meteorologically com- and other types of head losses are usually estimated in patible with the conditions that induced the PMF (or detail using characteristic loss equations whose coeffi- with the flood conditions assumed coincident with cients have been estimated from computational reconsti- seismically induced dam failures). The cqnditions in- tution of historical floods and from detailed floodplain clude the season of the year, the time required for the geometry information. Where no data exist to reconsti- PMP storm to move out of the area and be replaced by tute water levels from historical floods, conservative meteorological conditions that could produce the postu- values of the various loss coefficients should be used. lated winds, and the restrictions on windspeed and Application of the standard-step method has been direction produced by topography. As an alternative to a developed into very sophisticated computerized models detailed study of historical regional winds, a sustained such as the one described in Reference 23. Theoretical 40-mph overland windspeed from any critical direction discussions of the techniques involved are presented in is an acceptable postulation.

References 22, 24, and 25.

Unsteady-flow models may also be used to estimate Wind-generated setup (or windtide) and wave action water levels since steady flow may be considered a class (runup and impact forces) may be estimated using the of unsteady flow. Computerized unsteady-flow models techniques described in References 26 and 28. The require generally the same floodplain geometry defini- method for estimating wave action is based on statistical tion as steady-flow models, and their use may allow analyses of a wave spectrum. For nuclear facilities, more accurate water surface level estimates for cases protection against the one-percent wave, defined in where steady-flow approximations are made. One such Reference 28 as the average of the upper one percent of unsteady-flow computer model is discussed in Reference the waves in the anticipated wave spectrum, should be

19. assumed. Where depths of water in front of safety- related structures are sufficient (usually about seven- All reasonably accurate water level estimation models tenths of the wave height), the wave-induced forces will require detailed floodplain definition, especially of areas be equal to the hydrostatic forces estimated from the that can materially affect water levels. The models maximum runup level. Where the waves can be should be calibrated by mathematical reconstitution of "tripped" and caused to break, both before reaching and historical floods (or the selection of calibration coeffici- on safety-related structures, dynamic forces may be ents based on the conservative transfer of information estimated from Reference 28. Where waves may induce derived from similar studies. of other river reaches). surging in intake structures, the pressures on walls and Particular care should be exercised to ensure that the underside of exposed floors should be considered, controlling flood level estimates are always conserva- particularly where such structures are not vented and air tively high. compression can greatly increase dynamic forces.

A.12 COINCIDENT WIND-WAVE ACTIVITY

In addition, assurance should be provided that safety The superposition of wind-wave activity on PMF or systems are designed to withstand the static and seismically induced water level determinations is re- dynamic effects resulting from frequent (10-year) flood quired to ensure that, in the event either condition did levels coincident with the waves that would be produced occur, ambient meteorological activity would not cause by the Probable Maximum Gradient Wind for the site a loss of any safety-related functions due to wave action. (based on a study of historical regional meteorology).

1.59-19

APPENDIX A

REFERENCES

1. Precipitation station data and unpublished records Square Miles and Durations from 6 to 72 Hours,"

of Federal, State, municipal, and other agencies may draft report, National Weather Service, ESSA (now be obtained from the National Weather Service U.S. Weather Service, NOAA), 1972.

(formerly called the U.S. Weather Bureau). In addition, studies of some large storms are available 8. "Probable Maximum Precipitation, Susquehanna in the "Storm Rainfall in the United States, River Drainage Above Harrisburg, Pa.," Hydro- Depth-Area-Duration Data," summaries published meteorological Report No. 40, U.S. Weather Bureau by Corps of Engineers, U.S. Army. A list of (now U.S. Weather Service, NOAA), 1965.

references is contained in Section 2.4 of

"Regulatory-Standard Review Plan," U.S. Nuclear 9. "Meteorology of Flood Producing Storms in the Regulatory Commission, October 1974. Ohio River Basin," Hydrometeorological Report No. 38, U.S. Weather Bureau (now NOAA), 1961.

2. Corps of Engineers publications, such as EM

1110-2-1405, August 31, 1959, "Engineering and 10. "Probable Maximum and TVA Precipitation Over Design-Flood Hydrograph Analyses and Computa- the Tennessee River Basin Above Chattanooga,"

tions," provide excellent criteria for the necessary Hydrometeorological Report No. 43, U.S. Weather flood hydrograph analyses. (Copies are for sale by Bureau (now NOAA), 1965.

Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.) Isohyetal 11. "Interim Report-Probable Maximum Precipitation patterns and related precipitation data. are in the in California," Hydrometeorological Report No. 36, files of the Chief of Engineers, Corps of Engineers.

3. A publicly available model is "Flood Hydrograph U.S. Weather Bureau (now NOAA), 1961; revised

196

9. I

Package, HEC-l Generalized Computer Program," 12. "Probable Maximum Precipitation, Northwest available from the Corps of Engineers Hydrologic States," Hydrometeorological Report No. 43, U.S.

Engineering Center, Davis, California, October Weather Bureau (now NOAA), 1966.

1970. 1

13. "Probable Maximum Precipitation in the Hawaiian

4. One technique for the analysis of snowmelt is Islands," Hydrometeorological Report No. 39, U.S.

contained in Corps of Engineers EM 1100-2-406, Weather Bureau (now NOAA), 1963.

"Engineering and Design-Runoff From Snowmelt,"

January 5, 1960. Included in this reference is also 14. "Meteorological Conditions for the Probable Maxi- an explanation of the derivation of probable maxi- mum Flood on the Yukon River Above Rampart, mum and standard project snowmelt floods. Alaska," Hydrometeorological Report No. 42, U.S.

Weather Bureau (now NOAA), 1966.

5. "Technical Note No. 98-Estimation of Maximum'

Floods," WMO-No. 233.TP.126, World Meteorologi- 15. "Meteorology of Flood-Producing Storms in the cal Organization, United Nations, 1969, and Mississippi River Basin," Hydrometeorological

"Manual for Depth-Area-Duration Analysis of Report No. 34, U.S. Weather Bureau (now NOAA),

Storm Precipitation," WMO-No. 237.TP. 129, World 1965.

Meteorological Organization, United Nations, 1969.

16. "Meteorology of Hypothetical Flood Sequences in

6. "Meteorological Estimation of Extreme Precipita- the Mississippi River Basin," Hydrometeorological tion for Spillway Design Floods," Tech. Memo Report No. 35, U.S. Weather Bureau (now NOAA),

WBTM HYDRO-5, U.S. Weather Bureau (now 1959.

NOAA) Office of Hydrology, 1967.

17. "Engineering and Design-Standard Project Flood

7. "Seasonal Variation of the Probable Maximum Determinations," Corps of Engineers EM

Precipitation East of the 105th Meridian for Areas 1110-2-1411, March 1965, originally published as from 10 to 1,000 Square Miles and Durations of 6, Civil Engineer Bulletin No. 52-8, 26 March 1952.

12, 24, and 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />." Hydrometeorological Report No. 33, U.S. Weather Bureau (now U.S. Weather 18. "Probable Maximum Precipitation Over South Service, NOAA), 1956; and "All-Season Probable Platte River, Colorado, and Minnesota River, Minne- Maximum Precipitation-United States East of the sota," Hydrometeorological Report No. 44, U.S.

105th Meridian, for Areas from 1,000 to 20,000 Weather Bureau (now NOAA), 1969.

1.59-20

19. "Unsteady Flow Simulation in Rivers and Reser- 26. "Coxlnutation of Freeboard Allowances for Waves voirs," by J.M. Garrison, J.P. Granju, and J.T. Price, in Reservoirs," Engineer Technical Letter ETL

pp. 1559-1576, Vol. 95, No. HY5, (September 1110-2-9, U.S. Army Corps of Engineers, August 1,

1969), Journal of the Hydraulics Division, ASCE, 1966.

(paper 6771).

20. "Handbook of Applied Hydrology," edited by Ven 27. "Policies and Procedures Pertaining to Deter- Te Chow, McGraw-Hill, 1964, Chapter 25. mination of Spillway Capacities and Freeboard Allowances for Dams," Engineer Circular EC

21. "Routing of Floods Through River Channels," EM 1110-2-27, U.S. Army Corps of Engineers, August

1110-2-1408, U.S. Army Corps of Engineers, March 1, 1966.

1, 1960.

22. "Engineering Hydraulics," edited by Hunter Rouse, 28. "Shore Protection Manual," U.S. Army Coastal John Wiley & Sons, Inc., 1950. Engineering Research Center. 1973.

23. "Water Surface Profiles, HEC-2 Generalized Com- puter Program," available from the Corps of Engi- 29. "Probable Maximum and TVA Precipitation for neers Hydrologic Engineering Center, Davis, Calif. Tennessee River Basins up to 3,000 Square Miles in Area and Durations to 72 Hours," Hydrometeoro- logical Report No. 45, U.S. Weather Bureau (now

24. "Open Channel Hydraulics" by Ven Te Chow, NOAA), 1969.

McGraw-Hill, 1959.

25. "Backwater Curves in River Channels," EM 30. "Floods in the United States, Magnitude and Fre-

1110-2-1409, U.S. Army Corps of Engineers, quency, (Basin)," series of Water-Supply Papers.

December 7, 1959. U.S. Geological Survey, various dates.

1.59-21

ft -i-i APPENDIX B

ALTERNATIVE METHODS OF

ESTIMATING PROBABLE MAXIMUM FLOODS

TABLE OF CONTENTS

Page B.1 INTRODUCTION ............... 1.59-25 B.2 SCOPE ........ .................... 1.59-25 B.3 PROBABLE MAXIMUM FLOOD PEAK DISCHARGE ......... ..................... 1.59-25 B.3.1 Use of PMF Discharge Determinations .... . . . . . . . . . . . . . . . . . . . . 1.5 9 -2 5 B.3.2 Enveloping isolines of PMF Peak Discharge . . . . . . . . . . . . . . . . . . . . . . . 1.5 9 -2 5 B.3.2.1 Preparation of Maps ... .. .. . . . . . . . . . . . . . . . . . . . . . 1.59 -2 5 B.3.2.2 Use of Maps . . . . . . . . . . . . ...... . . . . . . . . . . . I. . 1.59-26 B.3.3 Probable Maximum Water Level ....... . . . . . . . . . . . . . . . . . . . . 1.5 9 -2 6 B.3.4 Wind-Wave Effects . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 9 -26 B.4 LIMITATIONS . . . . . . . . . .. . . . . . . 1.59-26 REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . *. . . 1.59-27 FIG UR ES . . . . . . . . . . . . . . . . . . . .. . . . . . 1.59-28 TABLE 1.59-36 FIGURES

Figure B.I - Water Resources Regions. ................ 1.59-28 B.2 - Probable Maximum Flood (Enveloping Isolines) - 100 Sq. Mi. . 1.59-29 B.3 - Probable. Maximum Flood (Enveloping Isolines) - 500 Sq. Mi.. 1.59-30

B.4 - Probable Maximum Flood (Enveloping Isolines) - 1,000 Sq. Mi. 1.59-31 B.5 - Probable Maximum Flood (Enveloping Isolines) - 5,000 Sq. Mi. 1.59-32 B.6 - Probable Maximum Flood (Enveloping Isolines) - 10,000 Sq. Mi. 1.59-33 B.7 - Probable Maximum Flood (Enveloping Isolines) - 20,000 Sq. Mi. 1 .59-34 B.8 - Example of Use of Enveloping Isolines .... ........... 1.59-35 TABLE

Table B. I - Probable Maximum Flood Data 1.59-36

1.59-23

r B.1 INTRODUCTION * B.3 PROBABLE MAXIMUM FLOOD

PEAK DISCHARGE

This appendix presents timesaving alternative methods of estimating the probable maximum flood The data presented in this section are as follows:

(PMF) peak discharge for nuclear facilities on nontidal streams in the contiguous United States. Use of the 1. A tabulation of PMF peak discharge determina- methods herein will reduce both the time necessary for tions at specific locations throughout the contiguous applicants to prepare license applications and the NRC United States. These data are subdivided into water staff's review effort. resources regions, delineated on Figure B.1, and are tabulated in Table B.1.

The procedures are based on PMF values determined by the U.S. Army Corps of Engineers, by applicants for 2. A set of six maps, Figures B.2 through B.7, licenses that have been reviewed and accepted by the covering index drainage areas of 100, 500, 1,000, 5,000,

NRC staff, and by the staff and its consultants. The 10,000, and 20.000 square miles, containing isolines of information in this appendix was developed from a equal PMF peak discharge for drainage areas of those study made by Nunn, Snyder, and Associates, through a sizes east of the 103rd meridian.

contract with NRC (Ref. 1).

B.3.1 Use of PMF Discharge Determinations PMF peak discharge determinations for the entire contiguous United States are presented in Table B.1. The PMF peak discharge determinations listed in Under some conditions, these may be used directly to Table B.1 are those computed by the Corps of Engi- evaluate the PMF at specific sites. In addition, maps neers, by the NRC staff and their consultants, or showing enveloping isolines of PMF discharge for several computed by applicants and accepted by the staff.

index drainage areas are presented in Figures B.2 through B.7 for the contiguous United States east of the For a nuclear facility located near or adjacent to one

103rd meridian, including instructions for and an of the streams listed in the table and reasonably close to example of their use (see Figure B.8). Because of the the location of the PMF determination, that PMF may enveloping procedures used in preparing the maps, be transposed, with proper adjustment, or routed to the results from their use are highly conservative. nuclear facility site. Methods of transposition, adjust- ment, and routing are given in standard hydrology texts Limitations on the use of these generalized methods and are not repeated here. Limits for acceptable trans- of estimating PMFs are identified in Section B.4. These positions are contained in Appendix A, Section A.I .b.

limitations should be considered in detail in assessing the applicability of the methods at specific sites. B.3.2 Enveloping lsolines of PMF Peak Discharge Applicants for licenses for nuclear facilities at sites on B.3.2.1 Preparation of Maps nontidal streams in the contiguous United States have the option of using these methods in lieu of the more For each of the water resources regions, each PMF

precise but laborious methods of Appendix A. The determination in Table B.1 was plotted on logarithmic results of application of the methods in this appendix paper (cubic feet per second per square mile versus will in many cases be accepted by the NRC staff with no drainage area). It was found that there were insufficient further verification. data and too much scatter west of about the 103rd meridian, caused by variations in precipitation from B.2 SCOPE orographic effects or by melting snowpack. Accordingly, the rest of the study was confined to the United States The data and procedures in this appendix apply only east of the 103rd meridian. For sites west of the 103rd to nontidal streams in the contiguous United States. meridian, the methods of the preceding section may be Two procedures are included for nontidal streams east of used.

the 103rd meridian.

Envelope curves were drawn for each region east of Future studies are planned to determine the applica- the 103rd meridian. It was found that the envelope bility of similar generalized methods and to develop such curves generally paralleled the Creager curve (Ref. 2),

methods, if feasible, for other areas. These studies, to be defined as included in similar appendices, are anticipated for the main steins of large rivers and the United States west of 0 4 8 )-l the 103rd meridian, including Hawaii and Alaska. Q = 46.0 CA(0.894A-O'

1.59-25

where 4. Plot the six PMF peak discharges so obtained on logarithmic paper against drainage area, as shown on Q is the discharge in cubic feet per second (cfs) Figure B.8.

C is a constant, taken as 100 for this study A is the drainage area in square miles. 5. Draw a smooth curve through the points. Reason- able extrapolations above and below the defined curve Each PMF discharge determination of 50 square miles may be made.

or more was adjusted to one or more of the six selected 6. Read the PMF peak discharge at the site from the index drainage areas in accordance with the slope of the curve at the appropriate drainage area.

Creager *curve. Such adjustments were made as follows:

B.3.3 Probable Maximum Water Level PMF Within Drainage Adjusted to Index When the PMF peak discharge has been obtained as Area Range, sq. mi. Drainage Area, sq. mi. outlined in the foregoing sections, the PMF stillwater level should be determine

d. The methods given in

50 to 500 100 Appendix A, Section A.11, are acceptable for this

100 to 1,000 500 purpose.

500 to 5,000 1,000

1,000 to 10,000 5,000

B.3.4 Wind-Wave Effects

5,000 to 50,000 10,000

10,000 or greater 20,000 Wind-wave effects should be superimposed on the PMF stillwater level. Criteria and acceptable methods are The PMF values so adjusted were plotted on maps of given in Appendix A, Section A.12.

the United States east of the 103rd meridian, one map for each of the six index drainage areas. It was found B.4 LIMITATIONS

that there were areas on each map with insufficient points to define isolines. To fill in such gaps, conserva- 1. The NRC staff will continue to accept for review tive computations of approximate PMF peak discharge detailed PMF analyses that result in less conservative were made for each two-degree latitude-longitude inter- estimates. In addition, previously reviewed and appruved section on each map. This was done by using enveloped detailed PMF analyses at specific sites will continue to relations between drainage area and PMF peak discharge be acceptable even though the data and procedures in I

(in cfs per inch of runoff), and applying appropriate this appendix result in more conservative estimates.

probable maximum precipitation (PMP) at each two- degree latitude-longitude intersection. PMP values, ob- 2. The PMF estimates obtained as outlined in Sec- tained from References 3 and 4, were assumed to be for tions B.3.1 and 13.3.2 are peak discharges that should be a 48-hour storm to which losses of 0.05 inch per hour converted to water level to which appropriate wind-wave were applied. These approximate PMF values were also effects should be added.

plotted on the maps for each index drainage area and the enveloping isolines were drawn as shown on Figures B.2 3. If there are one or more reservoirs in the drainage through B.7. area upstream of the site, seismic and hydrologic dam failure' flood analyses should be made to determine B.3.2.2 Use of Maps whether such a flood will produce the design basis water level. Criteria and acceptable methods are included in The maps may be used to determine PMF peak Appendix A, Section A.10.

discharge at a given site with a known drainage area as follows: 4. Because of the enveloping procedures used, PMF

peak discharges estimated as outlined in Section B.3.2

1. Locate the site on the 100-square-mile map, have a high degree of conservatism. If the PMF so Figure B.2. estimated casts doubt on the suitability of a site, or if protection from a flood of that magnitude would not be

2. Read and record the 100-square-mile PMF peak physically or economically feasible, consideration should discharge by straight-line interpolation between the be given to performing a detailed PMF analysis, as isolines. outlined in Appendix A. It is likely that such an analysis will result in appreciably lower PMF.levels.

3. Repeat Steps 1 and 2 for 500, 1,000, 5,000,

10.000, and 20,000 square miles from Figures B.3 In this context, "hydrologic dam failure" means a failure through B.7. caused by a flood from the drainage area upstream of the dam.

1.59-26

APPENDIX B

REFERENCES

1. Nunn, Snyder, and Associates, "Probable Maximum Maximum Precipitation East of the 105th Meridian,"

Flood and Hurricane Surge Estimates," unpublished Hydrometeorological Report No. 33, 1956.

report to NRC, June 13, 1975 (available in the public document room).

2. W.P. Creager, J.D. Justin, and J. Hinds, "Engineering 4. U.S. Department of Commerce, N.OAA, "All-Season For Dams," J. Wiley and Sons, Inc., New York, 1945. Probable Maximum Precipitation-United States East of the 105th Meridian, for Areas from 1,000 to

3. U.S. Weather Bureau (now U.S. Weather Service, 20,000 Square Miles and Durations From 6 to 72 NOAA), "Seasonal Variation of the Probable Hours," draft report, July 1972.

1.59-27

450'

410

'l0 CALIFORNIA-

t'.)00SOUTH PACIFIC

133'

ROGRANDEmis

290 TEXAS-GULF I 290

1250

1170 1130 1090 1050 1010 970 930 890 850 810

FIGURE B.1 WATER RESOURCES REGIONS

F

t ISOLINE REPRESENTING PEAK FLOW OF

PMF IN 1,000 CFS.

NOTE: PMF ISOLINES ON THIS CHART REPRESENT ENVELOPED

VALUES OF PEAK RUNOFF FROM 100-SQUARE MILE DRAINAGE 160

AREA UNDER NATURAL RIVER CONDITIONS. ACCORDINGLY,

I PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU-

TIONS TO PEAK FLOW THAT WOULD RESULT FROM 140

UPSTREAM DAM FAILURES OR OTHER UNNATURAL EVENTS. 1

1190 1170 1150 113' 111° 1090 1070 1050 1030 101' 990

FIGURE B.2 PROBABLE MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 100 SOUARE MILES

470

450

430

410

390

370

350

'.

330

310

290

,-ISOLINE REPRESENTING PEAK FLOW OF

PMF IN 1,000 CFS.

270

NOTE: PMF ISOLINES ON THIS CHART REPRESENT ENVELOPED

VALUES OF PEAK RUNOFF FROM 500-SQUARE MILE DRAINAGE

AREA UNDER NATURAL RIVER CONDITIONS. ACCORDINGLY,

PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU- 250

TIONS TO PEAK FLOW THAT WOULD RESULT FROM UPSTREAM

DAM FAILURES OR OTHER UNNATURAL EVENTS.

I I 1 I I I T -

FIGURE B.3 PROBABLE MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 500 SQUARE MILES

470

470

450 14 45'

430 200 250 43'

4300

410 1 2 410

3 9 0

0 4 04 3 9.0

0

370 370

4.5 350

330 330

31040 5 310

290 290.

270 PMF IN 1 000 CFS. 503020270

NOTE: PMF ISOLINES ON THIS CHART REPRESENT ENVELOPED

VALUES OF PEAK RUNOFF FROM 1,000-SQUARE MILE DRAINAGE 500 350

AREA UNDER NATURAL RIVER CONDITIONS. ACCORDINGLY, ___I

25 PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU- 250

I *,;^,* ....

TIONS TO PEAK FLOW THAT WOULD RESULT FROM UPSTREAM45 I 045ol1 I

DAM FAILURES OR OTHER UNNATURAL EVENTS.0

1210 1190 1170 1150 113" 111' 1090 1070 105" 103" 101l 97' 95" 93" 91" 89" 87' 850 83' 81, FIGURE B.4 PROBABLE MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 1.000 SQUARE MILES

470

450

410

390

350

700 6000,.

330 29°I800

2900

3106

27~ IN 1,000 CFS.000

_1PMF

25° PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU9 TIONS TO PEAK FLOW. THAT WOULD RESULT FROM UPSTREAM DAM

FAILURE OR OTHERUNARLEVTS

121° 1190 1170 1150 T13° 1110 1090 1070 1Q05 1030 j01° gg0 970 950 930 910 890 870 850

830

FIGURE B.5 PROBABLE MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 5,000 SQUAR

E MILES

470

450

430

410

390

370

.J1 350

330

310

290

ISOLINE REPRESENTING PEAK FLOW OF

PMF IN 1,000 CFS.

"..# ,. I 270

NOTE: PMF ISOLINES ON THIS CHART REPRESENT ENVELOPED

/ VALUES OF PEAK RUNOFF FROM 10,000-SOUARE MILE DRAINAGE

AREA UNDER NATURAL RIVER CONDITIONS. ACCORDINGLY,

PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU. 250

TIONS TO PEAK FLOW THAT WOULD RESULT FROM UPSTREAM DAM

FAILURES OR OTHER UNNATURAL EVENTS.

1210 1190 1170 1150 1130 1110 1090 1070 1050 1030 1010 990 970 950 930 910 890 870 850 830 810

FIGURE B.6 PROBABLE MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 10,000 SQUARE MILES

~100

350

4ý 100 400 1600 1800

330°50

311

2900

TIN T ISOLINE REPRESENTING PEAK FLOW OF DAM 1200

C O DN L 1300 16

250 AR AU D RN T R LRV R O DTO S

PMDF IN 1,000 C FSO

2?

NOTE: PMF ISOLINES ON THIS CHART REPRESENTMILE

20,000-SQUARE ENVELOPED

DRAINAGE . 1400MI 1100

VALUES OF PEAK RUNOFF FROM

. . 1310

250 AREA UNDER NATURAL RIVER CONDITIONS. ACCORDINGLY.

1 3 0 0 0 0

0g 9 9 0 8 0 8 0 8 0 3 9 7

1270PMF110 VALUES 17OBTAINED NOT INCLUDE

15 DO 13 11 0 9 0 0CONTRIBU-

1POSSIBLE . 00 g 0 9 300

25 T'IONS TO PEAK FLOW THAT WOULD RESULT FROM UPSTREAM DAM 10

DAM FAILURES OR OTHER UNNATURAL EVENTS. .

121° 119° 1170 1150 113° Ili, 109° 107' "1050 103° 101' 99° 97o 95' 93° 91° 89' B7' 85° 83o 810 79° 77'

75' 73'

FIGURE B.7 PROBABL E MAXIMUM FLOOD (ENVELOPING PMF ISOLINES) FOR 20,000 SQUARE MILES

I

r*V

I I I I III

I I I SI I I lfl ý I I I I I I I

LLf I I I T I I I I I I I

-EXAMPLE: .1 Li L

-FOR DRAINAGE AREA OF

-2,300 SQ. MI. AT LAT. 95",

LONG. 430, DETERMINE PMF -1-4. -SOLUTION:

PEAK

I

DISCHARGE.

II I I III! I I

I I I I I

- FOR DRAINAGE AREA OF

-2,300 SQ. MI., PMF PEAK =

Lci il-HI -

400,000 CFS.

[ i I

POINTS FROM

0 FIGURES B.2-B. J

0

'C 11flai IL

~flh1IEl3~

. _W=I

0 i i I I I I I1'r Z i i I

0

Cc

1 01 .

.10

100 1000 10,000 100,000

DRAINAGE AREA, SQUARE MILES

FIGURE B.8 EXAMPLE OF USE OF ENVELOPING ISOLINES

TABLE B.1 PROBABLE MAXIMUM FLOOD DATA ( )

Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge (sq.mi.) Prec. Runoff (cfs)

North.Atlantic Region (Northeast Atlantic Sub-region)

Ball Mountain Vt, Connecticut West River 172 20.6 18.1 190,000

Barre Falls Mass. Connecticut Ware River 55 20.1 18.9 61,000

Beaver Brook N. H. Connecticut Beaver Brook 6.0 21.3 19.7 10,400

Birch Hill Mass. Connecticut Millers River 175 18.3 17.1 88.500

Black Rock Conn. Housatonic Branch Brook 20 22.2 20.6 35,000

Blackwater N. H. Merrimack Blackwater River 128 18.3 16.4 95,000

Buffumville Mass. Thames Little River 26 26.6 25.3 36,500

Colebrook Conn. Connecticut Farmington River 118 22.7 21.1 165,000

Conant Brook Mass. Connecticut Conant Brook 7.8 24.4 23.2 11,900

East Barre Vt. Winooski Jail Branch 39 21.5 18.6 52,500

East Branch Conn. Housatonic Naugatuck River 9.2 24.0 22.8 15,500

East Brimfield Mass. Thames Quinebaug River 68 24.2 22.9 73,900

W*

0\

CYN Edward McDowell N. H. Merrimack Nubanusit River 44 19.5 18.3 43,000

Everett N. H. Merrimack Piscataquog River 64 20.7 18.2 68,000

Franklin Falls N.H. Merrimack Pemigewasset River 1,000 15.8 13.3 300,000

Hall Meadow Conn. Connecticut Hall Meadow Brook 17 24.o 22.8 26,600

Hancock Corn. Housatonic Hancock Brook 12 24.0 22.8 20,700

Hodges Village Mass. Thames French River 31 26.2 22.3 35,600

Hop Brook Conn. Housatonic Hop Brook 16 25.0 23.8 26,400

Hopkinton N. H. Merrimack Contoocook River 426 17.4 14.7 135,000

Knightville Mass. Connecticut Westfield River 162 18.8 17. 6 160,000

Littleville Mass. Connecticut Westfield River 52 25.1 22.4 98,000

Mad River Conn. Connecticut Mad River 18 24.0 22.8 30,000

Mansfield Hollow Conn. Thames Natchaug River 159 19.8 18.5 125,000

Nookagee Mass. Merrimack Phillips Brook 11 21.8 20.2 17,750

Northfield Conn. Housatonic Northfield Brook 5.7 24.4 23.2 9,000

North Hartland Vt. Connecticut Ottauquechee River 220 19.3 17,2 199,000

North Springfield Vt. Connecticut Black River 158 20.0 18.3 157,000

Otter Brook N. H. Connecticut Otter Brook 47 19.1 17.9 45,000

Phillips Mass. Merrimack Phillips Brook 5.0 24.2 23.0 7,700

Sucker Brook Conn. Connecticut Sucker Brook 3.4 22.4 21.4 6,500

Surry Mountain N. H. Connecticut Ashuelot River 100 22.2 19.6 63,000

Thomaston Conn. Housatonic Naugatuck River 97 24.5 22.4 158,000

TABLE B.1 (Page 2 of 17)

Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge Prec.., Runoff (cfs)

(sa mi L .

Townshend Vt. Connecticut West River 278 21.3 17.2 228,000

Trumbull Conn. Pequonnook Pequonnook River 14 23.0 21.8 26,700

Tully Mass. Connecticut Tully River 50 20.0 16.6 47,000

Union Village Vt. Connecticut Ompompanoosuc River 126 1760 15.8 110,000

Vermont-Yankee Vt. Connecticut Connecticut River 6,266 48O,O00

Waterbury Vt. Winooski Waterbury River 109 18.9 16.0 128,000

West Hill Mass. Blackstone West River 28 28.0 25.6 26,000

West Thompson Conn. Thames Quinebaug River 74 2064 17.5 85,000

Westville Mass. Thames Quinebaug River 32 25,4 22.8 38,400

Merrimack Whitman River 18 21.4 19.8 25,000

Whitemanville Mass.

Wrightsville Vt. Winooski North Branch 68 2092 17.3 74,000

North Atlantic Region (Mid-Atlantic Sub-region)

Almond N. Y. Susquehanna Canacadea Creek 56 22.0 18.8 59,000

Alvin R. Bush Pa. Susquehanna Kettle Creek 226 24.0 21.1 154,000

Aquashicola Pa. Delaware Aquashicola Creek 66 28.0 24.2 42,500

Arkport N. Y. Susquehanna Canister River 31 22.5 17.7 33,400

Aylesworth Pa. Susquehanna Aylesworth Creek 6.2 23.8 22.0 13,700

Baird W. Va. Potomac Buffalo Creek 10 34.0 30.2 14,600

Beltzville Pa. Delaware Pohopoco Creek 97 27.1 25.6 68,000

Bloomington Md. Potomac North Branch 263 22.2 17.6 196,000

Blue Marsh Pa. Delaware Tulpehockan Creek 175 24.0 21.3 110,600

Burketown Va. Potomac North River 375 24.3 21.2 272,200

Cabins W. Va. Potomac South Branch 314 20.8 16.8 195,900

Chambersburg Md. Potomac Conococheague River 141 28.9 26.0 81,400

Christiana Del. Delaware Christiana River 41 32.1 28.3 39,200

Cootes Store Va. Potomac North Fork River 215 22.5 19.1 140,200

Cowanesque Pa. Susquehanna Cowanesque River 298 21.9 18.5 285,000

Curwensville Pa. Susquehanna Susquehanna River 36,; 22.0 18.9 205,000

Dawsonville Md. Pot ciMac Seneca Creek 206.I 2?.1 i61,900

Douglas Point Md. Potomac Potomac River 13.4 10.2 1,490,000

East Sidney N. Y. Susquehanna Oulelot River 102 24.0 22.1 99, 900

Edes Fort W. Va. Potomac Cacapon River 679 21.2 17.3 410,800

Fairview Md. Potomac Conococleaque Creek 494 22..9 18.8 150,100

Foster Joseph Say( ers Pa. Susquehanna Bald Eagle Creek 339 21,8 19.0 251,000

Francis E. Walter Pa. Delaware Lehigh River 288 2264 19.8 170,000

.4

TABLE B.1 ( )

Drainage Basin Average P1* Peak Project State River Basin Stream Area (in inches) Discharge (sn.mi.) Prec. Runoff (cfsR

Franklin W. Va. Potomac South Branch 182 24.2 20.6 174,000

Frederick Md. Potomac Monocacy River 817 23.2 20.9 363,400

Front Royal Va. Potomac S.Fk.Shenandoah River 1,638 18.0 14.3 419,000

Fulton (Harrisburg) Pa. Susquehanna Susquehanna River 24,100 12.7 8.2 1,750,000

Gathright Va. James Jackson River 344 24.4 21.3 246,0OO

Gen. Edgar Jadwin Pa. Delaware Dyberry Creek 65 24.8 24.0 119,700

Great Cacapon W. Va. Potomac Cacapon River 677 21*2 17.3 373,400

Harriston Va. Potomac South River 222 29.6 26.5 153,700

Hawk Mountain Pa. Delaware E.Br. Delaware River 812 16.5 12.7 202,000

Headsville W. Va. Potomac Patterson Creek 219 23.4 19.0 176,000

John H. Kerr Va. Roanoke Roanoke River 7,800 16.8 12,9 1,000,000

W. Va. South Branch 1,577 18.9 14.9 430,000

Karo Potomac Keyser W. Va. Potomac North Branch 495 21.5 16.3 279,200

Kitzmiller Md. Potomac North Branch 225 22,3 17,1 120,200

Leesburg Va. Potomac Goose Creek 338 26.5 24.2 340,900

Lewistown Md. Potomac Fishing Creek 7.1 34.8 32.7 12,200

Licking Creek W. Va. Potomac Licking Creek 158 29.0 26.1 125,800

Little Cacapon W. Va. Potomac Little Cacapon River 101 29.7 27o4 122,700

Maiden Creek Pa. Delaware Maiden Creek 161 27.3 23.5 118,000

Martinsburg W. Va. Potomac Opequon Creek 272 27.2 24.1 174,600

Mikville W, Va. Potomac Shenandoah River 3,040 16.2 11.7 592,000

Moorefield W. Va. Potomac South Branch 1,173 18.0 14.0 389,700

Moorefield W. Va. Potomac So. Fk. South Branch 283 21,1 17.1 173,800

Newark Del. Delaware White Clay River 66 29.8 26.0 103,000

North Anna Va. Pamunkey(York) North Anna River 343 25.0 21.3 220,000

North Mountain W. Va. Potomac Back Creek 231 27.9 24.8 256,000

Peach Bottom Pa. Susquehanna Susquehanna River 27,000 12.7 8.2 1,750,000

Perryman Md. Chesapeake Bay Bush River 118 87,400

Petersburg W. Va. Potomac South Branch 642 19,3 15.3 208,700

Philpott Va. Roanoke Smith River 212 27.5 24.3 160,000

Prompton Pa, Delaware Lackawaxen River 60 25.0 24.2 87,190

Raystown Pa. Susquehanna Juniata River (Br.) 960 21-4 17.5 353,400

Royal Glen Md. Potomac South Branch 640 19.3 15.3 208,700

Salem Church Va. Rappahannock Rappahannock River 1,598 23.6 19.6 552,000

Savage River Md. Potomac Savage River 105 26.3 22.2 107,400

Seneca Md. Potomac Potomac River 11,400 13.5 10.3 1,393,000

Sharpsburg Md. Potomac Antietem Creek 281 26.6 23.5 154,900

TABLE B.1 ( )

Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge (sq.mi.) Prec. Runoff (cfs) -w Sherrill Drive Md. Potomac Rock Creek 62 30.6 28,3 111,900

Six Bridge Md. Potomac Monocacy River 308 27.1 24.0 225,000

Springfield W. Va. Potomac South Branch 1,471 17.5 15,5 405,000

Staunton Va. Potomac South Branch Shen. 325 25.0 21.3 226,000

Stillwater Pa. Susquehanna Lacawanna River 37 27.3 24.1 39,600

Summit N. J. Delaware Delaware River 11,100 1,000,000

Surry Va. James James River 9,517 1,000,000

Tioga-Hammond Pa. Susquehanna Tioga River 402 23.5 19.2 318,000

Tocks Island N. J. Delaware Delaware River 3,827 13.3 10.5 576,300

Tonoloway Md. Potomac Tonoloway Creek 112 29.9 26.8 117,600

Town Creek Md. Potomac Town Creek 144 27.5 25.2 102,900

Trenton N. J. Delaware Delaware River 6,780 830,000

Trexler Pa. Delaware Jordon Creek 52 25.2 22.6 55,500

Tri-Towns W. Va. Potomac North Branch 478 21.6 16.4 268,000

Verplanck N. Y, Hudson Hudson River 12,650 14.0 9.7 1,100,000

Washington, D. C. Md. Potomac Potomac River 11,560 13.4 10.2 1,280,000

Waynesboro Va. Potomac South River 136 29.6 26 .5 116,000

West Branch W. Va. Potomac Conococheague River 78 30.7 27.0 78,700

Whitney Point N. Y. Susquehanna Otselie River 255 20.7 19.1 102,000

Winchester Va. Potomac Opeqnon Creek 120 28.9 25.8 142,100

York Indian Rock Pa. Susquehanna Codorus Creek 94 22,1 17.7 74,300

South Atlantic-Gulf Region Allatoona Ga. Alabama-Coosa Etowah River 1,110 22.2 19.8 440,000

Alvin W. Vogtle Ga. Savannah Savannah River 6,144 21.8 14.5 1,001,000

Bridgewater N. C. Santee Catawba River 380 187,000

Buford Ga. Apalachicola Chattahoochee River 1,040 21.7 19.7 428,900

Carters Ga. Alabama-Coosa Coosawattee River 376 26.6 22.3 203,100

Catawba N. C. Santee Catawba River 3,020 16.6 674,000

Cherokee N. C. Congaree-Santee Broad River 1, 550 560,000

Claiborne Ala. Alabama-Coosa Alabama River 21,520 14.9 12.3 682,500

Clark Hill Ga. Savannah Savannah River 6,144 21.8 14.5 1,140,000

Coffeeville Ala. Tombigbee Black Warrior River 18,600 13.6 11.2 743,400

Cowans Ford N. C. Santee Catawba River 1,790 636,000

Demopolis Ala. Tombigbee Tombigbee River 15,300 16.7 14.3 1,068,000

Falls Lake N. C. Neuse Neuse River 760 23.2 21.2 323,000

TABLE B.1 ( )

Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge (sq.mi.) Prec. Runoff (cfs)

Gainsville Ala. Tombigbee Tombigbee River 7,142 19.6 16.8 702,400

Hartwell Ga. Savannah Savannah River 2,088 24.8 18.8 875,000

Holt Ala. Warrior Warrior River 4,232 22.1 19.2 650,000

Howards Mill N. C. Cape Fear Deep River . 626 26.8 24.2 305,000

Jim Woodruff Fla. Apalachicola Apalachicola River 17,150 17,6 12.3 1,133,800

John H. Bankhead Ala. Tombigbee Black Warrior River 3,900 22.3 19.4 670,300

Jones Bluff Ala. Alabama Alabama River 16,300 14.2 11.6 664,000

Lazer Creek Ca. Apalachicola Lazer Creek i,41O 24.6 20.7 303,600

Lookout Shoals N. C, Santee Catawba River 1,450 492,000

Lower Auchumpkee Ga. Apalachicola Flint River 1,970 23.7 19.8 355,600

McGuire N. C, Santee Catawba River 1,770 750,000

Millers Ferry Ala. Alabama Alabama River 20,700 14.7 12.1 844,000

Mountain Island N. C. Santee Catawba River i, 860 362,000

New Hope N. C. Cape Fear New Hope River 1,69o 22.0 19.4 511,000

Oconee S. C. Savannah Keowee River 439 26.5 23.5 450,000

0 Oconee S. C. Savannah Little River 26.6 245,000

Okatibbee Miss. Pascagoula 9katibbee Creek 154 33.0 28.4 8?, 700

Oxford N. C. Santee Catawba River 1,31.0 479,000

Perkins N. C. Pee Dee Yadkin River 2,4?3 440,600

Randleman N, C. Cape Fear Deep River 169 28.6 26.0 126,000

Reddies N. C. Pee Dee Reddies River 94 28.0 24.8 174,200

Rhodhiss N. C, Santee Catawba River 1,090 379,000

Shearon Harris N. C. Cape Fear White Oak Creek 79 163, 500

Sprewell Bluff Ca. Apalachicola Flint River 1,210 25.8 21.3 318,000

Trotters Shoals Ga. Savannah Savannah River 2,900 24.0 19.1 800,000

Walter F. George Ga. Apalachicola Chattahoochee River 7,4460 16.6 15.2 843,000

Warrior Ala. Tombigbee Black Warrior River 5,828 19.5 16.6 554,000

West Point Ga. Apalachicola Chattahoochee River 3,44o 21.9 17.4 440,000

W. Kerr Scott N. C. Pee Dee Yadkin River 348 25.6 21.5 318,000

Great Lakes Region Bedford Ohio Cuyahoga Tinkers Creek 91 28.6 25.9 79,000

Bristol N. Y. Oswego Mud Creek 29 29.9 28.1 64,900

N. Y. 16. 1 63,400

Fall Creek Oswego Fall Creek 123 17.1 Ithaca N. Y. Oswego Six Mile Creek 43 26.9 25.1 77,900

Jamesville N. Y. Oswego Butternut Creek 37 26.0 24.1 35,200

Linden N. Y. Niagara Little Tonawanda Creek 22 30.8 29.0 64,400

TABLE B.1 ( )

Drainage Basin Average PMF Peak Pr,,ject State River Basin Stream Area _Lin inches) Discharge (sq.mi.) Prec. Runoff (cfs)

Mount Morris N. Y. Genesee River Genesee River 1,077 17.0 14.6 385,000

Onondago N. Y. Lake Ontario Onondago Creek 68 24.2 23.3 61,800

Oran N. Y. Oswego Limestone Creek 47 25.1 23.4 80,790

Portageville N. Y. Genesee Genesee River 983 17.8 15.8 359,000

Quanicassee Mich. Saginaw Bay Saginaw River 6,260 440,000

Quanicassee Mich. Saginaw Bay Tittabawassee River 2,400 270,000

Quanicassee Mich. Saginaw Bay Quanicassee River 70 46,000

Standard Corners N. Y. Genesee Genesee River 265 22.3 20.3 189,900

Ohio Region Alum Creek Ohio Ohio Alum Creek 123 24.6 21.8 110,000

Barkley Ky. Ohio Cumberland River 8,700 22.6 21.5 1,000,000

Barren Ky. Ohio Barren River 940 17.6 16.9 531,000

Beaver Valley Pa. Ohio Ohio River 23,000 1,500,000

Beech Fork W. Va. Ohio Twelve Pole Creek 78 26.4 23.5 84,000

Big Blue Ind. Ohio Big Blue River 269 23.5 21.2 161,000

Big Darby Ohio Ohio Big Darby Creek 441 24.1 21.3 294,000

Big Pine Ind. Ohio Big Pine Creek 326 22.4 20.4 174,000

Big Walnut Ind. Ohio Big Walnut Creek 19? 24.0 22.0 144,000

Birch W. Va. Ohio Birch River 142 28.4 25.2 102,000

Bluestone W. Va. Ohio New River 4,565 13.8 410,000

Booneville Ky. Ohio So. Fk. Kentucky River 665 23.2 21.0 425,000

Brookville Ind. Ohio Whitewater River 379 24.2 22.1 272,000

Buckhorn Ky. Ohio M. Fk.Kentucky River 408 23.8 21.5 239,000

Burnsville W. Va. Ohio Little Kanawha River 165 24.8 22.3 138,800

Caesar Creek Ohio Ohio Caesar Creek 237 24.1 21.9 230,200

Cagles Mill Ind. Ohio Mill Creek 295 24.6 22.7 159,000

Carr Fork Ky. Ohio No. Fk. Kentucky River 58 27.4 25.0 132,500

Cave Run Ky. Ohio Licking River 826 22.8 20.6 510,000

Center Hill Tenn. Ohio Caney Fork 2,174 22.3 21.8 696,000

Clarence J. Brown Ohio Ohio Buck Creek 82 29.0 26.7 121,000

Claytor Va. Ohio New River 2,382 22.3 18.0 1,109,000

Clifty Creek Ind. Ohio Clifty Creek 145 24.9 23.0 112,900

Dale Hollow Tenn. Ohio Obey River 935 23.8 2303 435,000

Deer Creek Ohio Ohio Deer Creek 278 22.9 20,1 160,000

Delaware Ohio Ohio Olentangy River 381 22.7 20.4 296,000

Dewey Ky. Ohio Big Sandy River 207 25.0 22.6 75,500

1;

TABLE B.1 ( )

Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge (sa.mi.) Prec. Runoff (cfs)

Dillon Ohio Ohio Licking River 748 19.8 16.3 246,000

Dyes Ohio Ohio Dyes Fork 44 30.7 27.8 49,500

Eagle Creek Ky. Ohio Eagle Creek 292 24.? 22.1 172,800

E. Br. Clarion Pa. Ohio E. Br. Clarion River 72 22.7 18.9 41,500

East Fork Ohio Ohio E. Fk. Little Miami River 342 23.8 21.2 313,200

East Lynn W. Va. Ohio Twelve Pole Creek 133 29.4 26.5 72,000

Fishtrap Ky. Ohio Levisa Fk. Sandy River 395 26.1 23.2 320,000

Grayson Ky. Ohio Little Sandy River 196 27.5 24.7 83,300

Green River Ky. Ohio Green River 682 26.5 23.9 409,000

Helm Ill. Ohio Skillet Fk. Wabash River 2LO 24.8 22.6 152,800

John W. Flannagan Va. Ohio Pound River 222 27.6 24.9 235,800

J. Percy Priest Tenn. Ohio Stones River 892 25.9 18.8 430,000

Kehoe Ky. Ohio Tygarts Creek 127 26.0 23.4 105,900

Kinzua Pa. Ohio Allegheny River 2,180 16.4 12.8 115,000

Lafayette Ind. Ohio Wildcat Creek 791 20.6 18.5 182,000

'.0

Laurel Ky. Ohio Laurel River 282 25.9 20.7 120,000

Leading Creek W. Va. Ohio Leading Creek 146 25.0 22.5 131,000

Lincoln Ill. Ohio Embarras River 915 21.2 19.0 502,000

Logan Ohio Ohio Clear Creek 84 29.5 27.0 78,000

Louisville Ill. Ohio Little Wabash River 661 22.1 19.9 310,000

Mansfield Ind. Ohio Raccoon Creek 216 25.9 23.0 175,800

Martins Fork Ky. Ohio Cumberland River 56 27.9 22.7 61,800

Meigs Ohio Ohio Meigs Creek 72 29.5 26.6 72,100

Meigs Ohio Ohio Meigs Creek 27 32.2 29.3 45,500

Mill Creek Ohio Ohio Mill Creek 181 24.0 2i.4 92,000

Mississinewa Ind. Ohio Mississinewa River 809 20.6 18.4 196,000

Michael J. Kirwin Ohio Ohio Mahoning River 80 26.0 20.1 51,800

Monroe Ind. Ohio Salt Creek 441 25.9 25.4 366,000

Pa. Ohio Muddy Creek 61 22.8 19.6 59,300

Muddy Creek Nolin Ky. Ohio Nolin River 703 14.2 13.2 158,000

Ohio Ohio N. Br. Kokosing River 44 25.4 22.6 50,000

N. Br. Kokosing Va. Ohio N. Fk. Pound River 18 35.3 32.2 51,200

N. Fk. Pound River Ohio Ohio Paint Creek 573 21.8 18.8 305,000

Paint Creek Ky. Ohio Paint Creek 92 26.3 23.8 77,500

Paintsville Panthers Creek W. Va. Ohio Panther Creek 24 36.7 3309 59,800

Patoka Ind. Ohio Patoka River 168 25.6 23.5 292,000

R. D. Bailey W. Va. Ohio Guyandotte River 540 23.1 20.3 349,000

Rough River Ky. Ohio Rough River 454 27.6 25.1 358,000

1

TABLE B.1 ( )

Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge Prec Runoff (cfs)

Rowlesburg W. Va. Ohio Cheat River 936 21.2 18.4 331,000

Salamonia Ind. Ohio Salamonia River 553 2143 19.0 201,000

Stonewall Jackson W. Va. Ohio West Fork River 10? 22.2 85, 500

Summersville W. Va. Ohio Gauley River 80, 23.8 21.1 412,000

Sutton W. Va. Ohio Elk River 53? 20.4 20.4 222,400

Taylorville Ky. Ohio Salt River 353 24.8 22.2 426, 000

Tom Jenkins Ohio Ohio Hocking River 33 26. 7 25.8 43,000

Union City Pa. Ohio French Creek 222 20.3 17.8 87, 500

Utica Ohio Ohio N. Fk. Licking River 112 24.7 22.1 73,700

West Fork W. Va. Ohio W. Fk. Little Kanawha 238 24.4 21.8 156,400

West Fk. Mill Ck. Ohio Ohio Mill Creek 30 31.9 30.0 81,600

Whiteoak Ohio Ohio Whiteoak Creek 214 24.5 21.6 134,000

Wolf Creek Ky. Ohio Cumberland River 5,789 20.6 20.0 996,000

Woodcock Pa. Ohio Woodcock Creek 46 23.5 20.9 37,700

Yatesville Ky. Ohio Blaine Creek 208 25.2 22.6 118,000

Youghiogheny Pa. Ohio Youghiogheny River 434 25.4 151,000

-J~. Zimmer, Wm. H. Ohio Ohio Ohio River 70,800 2,150,000

Tennessee Region Bellefonte Ala. Ohio Tennessee River 23,340 1,160,000

Browns Ferry Tenn. Ohio Tennessee River 29,130 1,200,000

Sequoyah Tenn. Ohio Tennessee River 20,650 1,205,000

Upper Mississippi Region Ames Iowa Upper Miss. Skunk River 314 21.3 18.4 87,200

Bryon Ill. Upper Miss. Rock River 8,000 308,000

Bear Creek Mo. Upper Miss. Bear Creek 28 29.0 26.2 38,000

Blue Earth Minn. Upper Miss. Minnesota River 11,250 14.2 10.9 283,000

Blue Earth Minn. Upper Miss. Blue Earth River 3,550 18.4 14.8 206,000

Carlyle Ill. Upper Miss. Kaskaskia River 2,680 19.2 15.8 246,000

Clarence Cannon Mo. Upper Miss. Salt River 2,318 21.8 15.7 476,200

Clinton Ill. Upper Miss. Salt Creek 296 99,500

Coralville Iowa Upper Miss. Iowa River 3,084 20.8 14.4 326,000

Duane Arnold Iowa Upper Miss. Cedar River 6,250 316,000

Farmdal e Ill. Upper Miss. Farm Creek 26 24.0 22.1 67,300

Fondulac Ill. Upper Miss. Fondulac Creek 5.4 21.4 19.9 21,200

Friends Creek Ill. Upper Miss. Friends Creek 133 27.8 21.6 83,160

TABLE Bi1 ( )

17)

B.I 9 of (Page TABLE Drainage Basin Ave-age PMF Peak Project State River Basin Stream Area (in inches) Discharge (sq.mi.) Prec.. Runoff (cfs)

Jefferson Iowa Upper Miss. Raccoon River 1,532 21.7 19.0 267,300

LaFarge Wisc. Upper Miss. Kickapoo River 266 22.8 18.9 128,000

Mankato Minn. Upper Miss. Minnesota River 14,900 13.9 10.6 329,000

Meramec Park Mo. Upper Miss. Meramec River 1,497 22.9 17.5 552,000

Montevideo Minn. Upper Miss. Minnesota River 6,180 15.2 11.6 263,000

Monticello Minn. Upper Miss. Mississippi River 13,900 365,000

New Ulm Minn. Upper Miss. Minnesota River 9,500 14.4 11.1 263,000

New Ulm Minn. Upper Miss. Cottonwood River 1,280 21.2 17.6 128,000

Oakley Ill. Upper Miss. Sangamon River 808 23.5 17.2 178,000

Prairie Island Minn. Upper Miss. Mississinpi River 44,755 910,000

Red Rock Iowa Upper Miss. Des Moines River 12,323 12,1 7.5 613,000

Rend Ill. Upper Miss. Big Muddy River 488 27.5 21.5 308,200

Saylorville Iowa Upper Miss. Des Moines River 5,823 13.8 10.3 277,800

Shelbyville Ill. Upper Miss. Kaskaskia River 1,030 22.1 .19.1 142,000

Lower Mississippi Regaon Arkabutla Miss. Lower Miss. Coldwater River 1, 000 22.5 21.2 430, 000

Enid Miss. Lower Miss. Yacona River 560 25.4 24.7 204,900

Grenada Miss. Lower Miss. Yalobusha River 1,320 24.0 23.1 390,800

Sardis Miss. Lower Miss. Tallahatchia River 1, 545 32.5 26.0 290,400

Union Mo. Lower Miss. Bourbeuse River 771 25.0 19.9 264,000

Wappapello Mo. Lower Miss. St. Francis River 1,310 13.0 11.7 344,000

Souris-Red-Rainy Region Burlington N. D. Souris Souris River 9,490 13.2 5.7 89,100

Fox Hole N. D. Souris Des Lacs River 939 19.9 12.4 52,700

Homme N. D. Red of North Park River 229 15.2 12.3 35,000

Kindred N. D. Red of North Sheyenne River 3,020 13.4 8.6 68,700

Lake Ashtabula N. D. Red of North Sheyenne River 983 12.4 9.5 86,500

Orwell Minn. hid of North Otter Tail River 1,820 17.1 14.7 25,500

Missouri Region Bear Creek Colo. Missouri Bear Creek 236 24.4 6.7 225,000

Big Bend S. D. Missouri Missouri River 5,840 9.0 725,000

Blue Springs Mo. Missouri Blue Springs Creek 33 26.5 23.8 42,4OO

Blue Stem Nebr. Missouri Olive Br. Salt Creek 17 25.0 21.7 69,200

Bowman-Haley N. D. Missouri Grand River 446 15.5 12.7 113,000

Branched Oak Nebr. Missouri Oak Creek 89 20.1 16.8 93,600

.~ ~ F I

TABLE 8.1 ( )

Drainage Basin Average PMF Peak Project State River basin Stream Area (in inches) Discharge (an ml.) Pre.~ RInnff (eflf (s mi Prec Runoff (cfs)

Braymer Mo. Missouri Shoal Creek 390 24.7 22.2 173,800

Brookfield Mo. Missouri West Yellow Creek 140 24.5 22.0 64, 500

Bull Hook Mont. Missouri Bull Hook Creek 54 10.8 26,200

Chatfield Colo. Missouri South Platte River 3,018 13.2 2.0 584, 500

Cherry Creek Colo. Missouri Cherry Creek 385 23.9 9.5 350,000

Clinton Kans. Missouri Wakarusa River 367 23.6 22.4 153,500

Cold Brook S. D. Missouri Cold Brook 70 6.4 95,700

Conestoga Nebr. Missouri Holmes Creek 15 25.2 21.9 52,000

Cottonwood Springs S. D. Missouri Cheyenne River 26 18.7 11.1 74,700

Dry Fork Mo. Missouri Fishing River 3.2 26.1 22.5 19,460

East Fork Mo. Missouri Fishing River 19 25.7 24.1 62,700

Fort Scott Kans. Missouri Marmaton River 279 23.8 22.7 198,000

Fort Peck Mont. Missouri Missouri River 57,725 3.2 360,000

Port Randall S. D. Missouri Missouri River 14,150 3.7 849,000

Fort St. Vrain Colo. Missouri South Platte River 4,700 500,000

(J* Garrison N. D. Missouri Missouri River 123,215 2.7 1,026,000

(I' Gavins Point Nebr. Missouri Missouri River 16,000 3.3 642,000

Grove Kans. Missouri Soldier Creek 259 23.8 22.? 79,800

Harlan County Nebr. Missouri Republican River 7, 142 7.6 2.8 485,000

Harry S. Truman Mo. Missouri Osage River 7,856 13.1 1,060,000

Hillsdale Kans. Missouri Big Bull Creek 144 25.4 24.3 190,500

Holmes Nebr. Missouri Antelope Creek 5.4 27.1 23.8 41,600

Kanopolis Kans. Missouri Smoky Hill River 2,560 6.9 3.6 456,300

Linneus Mo. Missouri Locust River 5446 23.7 21.2 242,300

Long Branch Mo. Missouri E. Fk. Little Chariton 109 24.5 21.9 66,500

Longview Mo. Missouri Blue River 50 26.2 23.4 74,800

Melvern Kans. Missouri Marias des Cygnes River 349 23.1 22.1 182,000

Mercer Mo. Missouri Weldon River 427 21.0 17.8 274,000

Milford Kans. Missouri Republican River 3,620 8.8 5.0 757,400

Mill Lake Mo. Missouri Mill Creek 9.5 27.7 26.4 13,000

Oahe S. D. Missouri Missouri River 62,550 6.5 946,000

Olive Creek Nebr. Missouri Olive Br. Salt Creek 8.2 26.0 22.7 36,650

Onag Kans. Missouri Vermillion Creek 301 23.5 22.2 251,000

Pattonsburg Mo. Missouri Grand River 2,232 18.8 16.3 40o0,100

Pawnee Nebr. Missouri Pawnee Br. Salt Creek 36 23.5 20.2 59,000

Perry Kans. Missouri Delaware River 1,117 21.5 18.4 387,400

Pioneer Colo. Missouri Republican River 918 15.0 8.3 390,000

Pomme de Terre Mo. Missouri Pomme de Terre River 611 23.9 21.6 362,000

TABLE B.1 ( )

Drainage Basin Average PFY Peak Project State River Basin Stre:an Aren ' ir. 4nchesq_ Discharge (sa.'ni.) Prec. Runcff (cf s)

Pomona Kans. Missouri 110 Mile Creek 322 26.2 25.2 186,000

Rathbun Iowa Missouri Chariton River 23.7 21.1 188,000

Smithville Mo. Missouri Little Platte River 213 23.9 20.2 185,000

Stagecoach Nebr. Missouri Hickman Br. Salt Creek 9.7 26.0 22.7 50,500

Stockton Mo. Missouri Sac River 1,160 19.7 18.9 470,000

Thomas Hill Mo. Missouri Little Chariton River 1a47 25.0 23.0 79,000

Tomahawk Kans. Missouri Tomahawk Creek 24 26.4 24.8 26,800

Trenton Mo. Missouri Thompson River 1,079 22.6 20.1 342,400

Tuttle Creek Kans. Missouri Big Blue River 9,556 14.5 8.1 798,000

Twin Lakes Nebr. Missouri S. Br. Middle Creek 11 25.9 22.6 56,000

Wagon Train Nebr. Missouri Hickman Br. Salt Creek 16 25.2 21.9 53,500

Wilson Kans. Missouri Saline River 1, q1? 20.2 10.8 252,000

Wolf-Coffee Kans. Missouri Blue River 45 26.1 24.5 58,000

Yankee Hill Nebr. Missouri Cardwell Br. Salt Creek 8.4 26.0 22.? 58,400

Arkansas-White-Red Region Arcadia Okla. Arkansas Deep Fork River 105 28.5 24.9 1i44,000

Bayou Bodcau La. lied Bayou Bodcau 656 35.3 33.6 168,?00

Beaver Ark. White White River 1,186 24.3 22.4 480,000

Bell Foley Ark. Arkansas Strawberry River 78 26.4 23.5 57,000

Big Hifl Kans. Arkansas Big Hill Creek 3? 25.4 23.6 47, 500

Big Pine Tex. Red Big Pine Creek 31.3 29.3 86,ooo Okla. Arkansas Birch Creek

66 29.0 26.0 91,000

Birch Blakely Mountain Ark. Red Ouachita River 1,105 21.5 19.6 418,000

Blue Mountain Ark. Arkansas Petit Jean River 500 21.8 18.2 258,000

Boswell Okla. Red Boggy Creek 2,273 27.6 20.8 405,000

Broken Bow Okla. Red Mountain Fork 754 32.5 29.4 569,000

Bull Shoals Ark. White White River 6,036 15.2 1ý.0 765, 000

Candy Okla. Arkansas Candy Creek 43 29.-3 27 5 67, 500

Canton Okla. Arkansas North Canadian River 7,600 12.4 4.1 371,000

Cedar Point Kans. Arkansas Cedar Creek 119 25.4 22.6 208,000

Clayton Okla. Red Jackfort Creek 275 31.3 29.3 24O0,oo Clearwater Mo. White Black River 898 16.0 13.8 432,000

Conchas N. Mex. Arkansas South Canadian River 7,409 4.8 3.0 582,000

Cooper Tex. Red South Sulphur River 476 30.9 29.2 194,40o Copan Okla. Arkansas Little Caney River 505 26.2 21.1 169,000

Council Grove Kans. Arkansas Grand River 246 25.5 22.7 250,000

County Line Mo. White James River 153 27.2 25.3 133,000

TABLE B.1 ( )

Drainage Basin Average PMF Peak Project State River Bas in Stream Area (in inches) Discharge (sq.mi.) Prec. Runoff _(cfs) _

DeGray Ark. Red Caddo River 453 28.4 26.0 397,000

Denison Okla. Red Red River 33,783 12.9 6.5 1,830,000

DeQueen Ark. Red Rolling Fork 169 35. 5 32. 5 254,000

Dierks Ark. Red Saline River 113 36.2 33.2 202,000

Douglas Kans. Arkansas Little Walnut Creek 238 26.7 22.9 156,000

El Dorado Kans. Arkansas Walnut River 234 22.8 196,000

Elk City Kans. Arkansas Elk River 634 23.0 20.3 319,000

Eufaula Okla. Arkansas Canadian River 8,405 15.9 10.9 700,000

Fall River Kans. Arkansas Fall River 556 27.1 23.0 442,000

Ferrells Bridge Tex. Red Cypress Creek 880 31.1 28.1 367,000

Fort Gibson Okla. Arkansas Grand River 9,477 15.2 12.6 865,000

Fort Supply Okla. Arkansas Wolf Creek 1,494 20. 5 15.7 547,000

Gillham Ark. Red Cossatot River 271 34.6 31.5 355,000

Great Salt Plains Okla. Arkansas Salt Fk. Arkansas River 3,200 i6ý? 9.3 412,000

Greers Ferry Ark. Red Little Red River 1, !i46 17.9 17.5 630,000

Heyburn Okla. Arkansas Polecat Creek 123 26.3 24.2 151,000

1,709 27.1 25.8 339,000

Lu Hugo Okla. Red Kiamichi River Hulah Okla. Arkansas Caney River 732 16. 5 13.5 239,000

--1 Arkansas Arkansas River 18,130 7.4 2.0 630,000

John Martin Colo.

John Redmond Kans. Arkansas Grand River 3,015 16.2 ;56 038,000

Kaw Okla. Arkansas Arkansas River 7,250 14.5 9.9 774,000

Keystone Okla. Arkansas Arkansas River 22,351 12.9 6.7 1,035,000

Lake Kemp Tex. Red Wichita River 2,056 23.7 19.2 566,000

Lukfata Okla. Red Glover Greek 291 34.6 31.5 349,0o0

Marion Kans. Arkansas Cottonwood River 200 24.8 2J..9 160,000

Millwood Ark. Red Little River 4,104 25.3 442,o00

Narrows Ark. Red Little Missouri River 23? 25.0 23.0 194,000

Neodesha Kans, Arkansas Verdigris River 1,100 18.7 16.6 287,000

Nimrod Ark. Arkansas Fourche La Fave River 68o 20.2 17.2 228,000

Norfolk Ark. White North Fork White River 1,765 15.7 12.8 372,000

Oologah Okla. Arkansas Verdigris River 4,339 17.8 13.9 451,000

Optima Arkansas North Canadian hiver 2,341 13.8 9.0 386,000

Okla.

Pat Mayse Tex. Red Sanders Creek 175 31.8 29.4 150,000

Pine Creek Okla. Red Little River 635 32.8 29.8 523,000

Okla. Arkansas Arkansas River 64,386 10.0 5.8 1,884,000

Robert S. Kerr Sand Okla. Arkansas Sand Creek 137 31.3 28.3 154,000

Shidler Okla. Arkansas Salt Creek 99 27.3 24.0 104,100

Skiatook Okla. Arkansas Hominy Creek 354 23.8 147,800

rable Rock No. White White River 4,020 18.3 15.4 657,000

TABLE B.1 ( )

Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge (s .mi.) Prec. Runoff (cfs)

Tenkiller Ferry Okla. Arkansas Illinois River 1,61o 20.4 17.6 406,ooo Texarkana Tex. Red Sulphur River 3,400 26.6 20.1 451,000

Toronto Kans. Arkansas Verdigris River 730 23.9 21.1 400,000

Towanda Kans. Arkansas Whitewater River 422 24.3 20.5 198,000

Trinidad Colo. Arkansas Purgatorie River 671 10.0 4.5 296,000

Tuskahoma Okla. Red Kiamichi River 347 16.5 14.6 188,400

Wallace Lake La. Red Cypress Bayou 260 38.4 35.6 197,000

Waurika Okla. Red Beaver Creek 562 26.5 22.2 354,ooo Webbers Falls Okla. Arkansas Arkansas River 48,127 10.7 6.1 1,518,000

Wister Okla. Arkansas Poteau River 993 25.9 23.2 339,000

Texas-Gulf Region Addicks Tex. San Jacinto South Mayde Creek 129 2q.7 27.9 68,670

Aquilla Tex. Brazos Aquilla Creek 294 31.2 28.6 283,800

Aubrey Tex. Trinity Elm Fork Trinity Hiver 692 28.5 26.0 445,300

L1A 178 28. 3 163,500

Bardwell Tex. Trinity Waxahachie Creek 31.1

00 Barker Tex. San Jacinto Buffalo Bayou 150 29.4 29.9 55,900

Belton Tex. Brazos Leon River 3,560 29.4 20.6 608,400

Benbrook Tex. Trinity Clear Fork Trinity River 429 28.2 21.1 290,100

Big Sandy Tex. Sabine Big Sandy Creek 196 36.2 32.2 125,200

Blieders Creek Tex. Guadalupe Blieders Creek 15 431.8 34.6 70,300

Brownwood Tex. Colorado Pecan Bayou 1,544 27.8 21.0 676,200

Canyon Lake Tex. Guadalupe Guadalupe River 1,432 24.5 16.9 687,000

Carl L. Estes Tex. Sabine Sabine River 1,146 34.5 30.4 277,000

Coleman Tex. Colorado Colorado River 287 30.9 24.1 267,800

Comanche Peak Tex. Brazos Squaw Creek 64 39.1 34.1 149,000

Ferguson Tex. Brazos Navasota River 1,782 26.0 22.4 355,800

Gonzales Tex. Guadalupe San Marcos River 1,344 24.9 15.4 633,900

Grapevine Tex. Trinity Denton Creek 695 26.5 21.5 319,400

Hords Creek Tex. Colorado Hords Creek 4b 28.9 23.4 92,400

Lake Fork Tex. Sabine Lake Fork Creek 507 33.8 29.7 247,600

Lakeview Tex. Trinity Mountain Creek 232 31.b 28.8 335,0o0

Tex. Brazos San Gatriel Piv-r eC9 28 .9 23?7 52i,'00

Laneport Lavon Tex. Trinity East Fork, Trinity River 770 26.2 23.4 430,300

Lewisville Tex. Trinity Elm Fork, Trinity River i,66o 23.2 20.5 632,200

Millican Tex. Brazos Navasota River 2,120 25.5 22.4 393,400

Navarro Mills Tex. Trinity Richland Creek 320 33.6 30.5 280,500

Navasota Tex. Brazos Navasota River 1,341 27.2 24.2 327,400

TABLE B.1 ( )

Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge (so.mi.) Prec. Runoff (cfs)

North Fork Tex. Brazos N. Fk. San Gabriel River 246 31.7 26.6 265,800

Pecan Bayou Tex. Colorado Pecan Bayou 316 30.7 23.8 236,200

Proctor Tex. Brazos Leon River 1,265 27.*0 21.4 459,200

Denton Creek 604 28.9  ;>',. I 313,600

Roanoke Tex. Trinity Rockland Tex. Neches Neches River 3,557 21.0 150, 00

23.7 Sam Rayburn Tex. Neches Angelina River 3,449 20.6 395,600

San Angelo Tex. Colorado North Concho River 1,511 21.2 13.1 (14,-00

Somerville Tex. Brazos Yogua Creek 1,006 22.0 13.6 415,700

32.6 27.*4 South Fork Tex. Brazos S. Fk. San Gabriel River 123 145,300

Lampasas River 1,318 27 *7 686,400

Stillhouse Hollow Tex. Brazos 22.5 Tennessee Colony Tex. Trinity Trinity River 12,687 20.4 575,600

2?. 7

18.9 Town Bluff Tex. Necnes Neches River 7, 573 25.7 15.7 326,000

Waco Lake Tex. Braazos Bosque River i, 670 25. 7 20.6 622,900

Whitney Tex. Brazos Brazos River 17,656 7.7 700,000

Rio Grande Region Abiquiu N. Me Rio Grande Rio Grande 3,159 8.2 130,000

3,917 Alamogordo N. M. Rio Grande Pecos River 1.9 277,000

Cochita N. M. Rio Grande Rio Grande 4,065 4.6 1.9 320,000

Jemez Canyon N. M. Rio Grande Jemez Canyon 1,034 9.2 3.7 220,000

Los Esteros N. M. Rio Grande Peccs River 2,434 12.2 4.7 352,000

Two Rivers N. M. Rio Grande Rio Hondo 1,027 282,400

Lower Colorado RegLon Alamo Ariz. Colorado Bill Williams River 4,770 12.0 3.5 580,000

McMicken Ariz. Colorado Aqua Fria River 247 3,3 52,000

Whitlow Ranch Ariz. Colorado Queen Creek 143 11 .5 9.7 230,000

Painted Rock Ariz. Colorado Gila River 50,600 7.7 2.8 620,000

Great Basin Region Little Dell Utah Jordon (Great) Dell Creek 36 6.1 6.0 23,000

Mathews Canyon Nev. Great Basin Mathews Canyon 34 8.6 7.4 35,000

Pine Canyon Nev. Great Basin Pine Canyon 4ý5 8.2 6.6 38,000

Columbia-North Pacific Region Applegate Oreg. Rogue Applegate River 223 28.9 99,500

Blue River Oreg. Columbia S. Fk. McKenzie River 88 22.7 39,500

TABLE B.1 ( )

Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge (sa.mi.) Prec. Runoff (cfs)

Bonneville Oreg. Columbia Columbia River 240,000 22,1 2,720,000

Cascadia Oreg. Columbia South Santiam River 179 42,2 115,000

Chief Joseph Wash. Columbia Columbia River 75,000 29.0 1,550,000

Cottage Grove Oreg. Columbia Coast Fk. Willamette River 104 29.7 45,000

Cougar Oreg. Columbia S. Fk. McKenzie River 208 34.2 98,000

Detroit Oreg. Columbia North Santiam River 438 36.0 203,000

Dorena Oreg. Columbia Row River 2hc 34.6 131,600

Dworshak Ida. Columbia N. Fk. Clearwater River 2,440O 70.5 280,000

Elk Creek Oreg. Rogue Elk Creek 132 32.6 63,500

Fall Creek Oreg. Columbia Willamette River 184 33.8 100,000

Fern Ridge Oreg. Columbia Long Tom River 252 20.3 4,8,600

Foster Oreg. Columbia South Santiam River 4c!4 40 .8 260,000

Green Peter Oreg. Columbia Middle Santiam River 277 41.1 160,0oo Gate Creek Oreg. Columbia Gate Ck. McKenzie River 50 4*.3 37,000

Hills Creek Oreg. (2olum bia Middle Fk. Willamette River 38q 33.0 197,000

Holley Oreg. Columbia Gala.pooia River 105 35.8 59,000

Howard A. Hanson Wash. Green Green River 22* 26. 8 164,000

Ice Harbor Wash. Columbia Snake River 109,000 13.a 954,000

C)

JOhn Day Oreg. Columbia Columbia River 226,000 21.1 2,650,000

3r:.5 Libby Mont. Columbia Kootenai River 9,070 282,000

Little Goose Wash. Columbia Snake River 3.03.900 14.6 850,000

Lookout Point Oreg. Columbia MiddJe Fk. Wilamette ?iver 9ga -40.8 360,000

Lost Fork Oreg. Rogue Lost Fk. Howie River 6L 22.7 169,OOC

Lower Granite Wash. Columbia Snake River 10*,400 14.7 850,000

Lower Monumental Wash. Columbia Snake River 1.08,500 14.0 850,000

Lucky Peak Ida, Columbia Boise River 2,650 32. 5 123,000

McNary Oreg. Columbia Columbia River 21.4,000 23.0 2,610,000

Mud Mountain Wash. Puyallup White River '400 33.9 386,000

Ririe Ida. Columbia Willow Ck. Snake River 620 *,4 4?, 000

The Dalles Oreg. Columbia Columbia River 237,000 2i.1 2,660,000

Wynoochee Wash. Chechalis Wynoochee River 4i 69.9 52, 500

Zintel Wash. Columbia Zintel Canyon Snake River 1Q 7.8 40, '500

California Region Bear Cal. San Joaquin Bear Creek 72 I 3.b 13.6 30,400

Big Dry Creek Cal. San Joaquin Big Dry Creek 91. 19.0 13.8 17,000

Black Butte Cal. Sacramento Stony Creek 741 19.7 12,3 254,000

Brea Cal. Santa Ana Brea Creek 23 10. LL 6.6 37,000

K-

TABLE B.1 ( )

Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge (sq.mi.) Prec. Runoff (cfs)

Buchanan Cal. San Joaquin Chowchilla River 235 26.0 20.1 127,000

Burns Cal. San Joaquin Burns Creek 74 17.4 10.6 26,800

-Butler Valley Cal. Mad Mad River 352 35.2 137,000

Carbon Canyon Cal. Santa Ana Santa Ana River 19 10.4 10.3 56,000

Cherry Valley Cal. San Joaquin Cherry Creek 117 24.3 23.1 60,000

Comanche Cal. San Joaquin Mokelumne River 618 25.0 19.9 261,000

Coyote Valley Cal. Russian East Fk. Russian River 105 22.9 57,000

Dry Creek Cal. Russian Dry Creek 82 21.3 15.6 4-5,000

Farmington Cal. San Joaquin Little John Creek 212 11.3 10.9 56, 000

Folsom Cal. Sacramento American River 1,875 21.2 17.5 615,000

Fullerton Cal. Santa Ana Fullerton .Creek 5.0 9.0 6.8 16,000

tJ*

Hansen Cal. Los Angeles Tujunga Wash 147 9.8 130,000

Hidden Lake Cal. San Joaquin Fresno River 234 29.9 18.4 114,000

Isabella Cal. San Joaquin Kern River 2,073 27.1 6-5 235,000

Knights Valley Cal. Russian Franz-Maacama Creek 59 31.6 28.9 44,300

Lakeport Cal. Sacramento Scotts Creek 52 30.9 24.0 36,100

Lopez Cal. Los Angeles Pacoima Creek 34 20.8 32,000

Mariposa Cal. San Joaquin Mariposa Creek 108 18.6 13.0 43,000

Martis Creek Cal. Truckee Martis Creek 39 26.5 12.7 12,400

Marysville Cal. Sacramento Yuba River 1,324 38.9 27.0 460,000

Mojave River Cal. Mojave Mojave River 215 40.4 30.4 186,000

New Bullards Bar Cal. Sacramento North Yuba River 489 38.9 25.7 226,000

New Exchequer Cal. San Joaquin Merced River 1,031 27.1 15.9 396,000

New Hogan Cal. San Joaquin Calaveras River 362 18.3 132,000

New Melones Cal. San Joaquin Stanislaus River 897 25.8 16.3 355,000

Oroville Cal. Sacramento Feather River 2,600 23.3 22.8 720,000

Owens Cal. San Joaquin Owens Creek 26 14.4 9.2 11,400

Pine Flat Cal. San Joaquin Kings River 1,542 28.5 14.4 437,000

Prado Cal. Santa Ana Santa Ana River 2,233 26.3 13.0 700,000

San Antonio Cal. Santa Ana San Antonio Creek 27 13.0 60,000

Santa Fe Cal. San.Gabriel San Gabriel River 236 35.5 194,000

Sepulveda Cal. Los Angeles Los Angeles River 152 15.0 220,000

I -- - - - -

TABLE B.] ( )

Drain£*e Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge (sq.mi.) Prec. Runoff (cfs)

Lf1 Success Cal. San Joaquin Tule River 38- 32.5 12.6 200,000

Terminus Cal, San Joaquin Kaweah River 560 40.1 24.8 290,000

Tuolumne Cal. San Joaquin Tuolumne River 1,533 25.1 20.? 602,000

Whittier Narrows Cal. San Gabriel San Gabriel River 551+ 17.4 13.7 305,000

APPENDIX C

SIMPLIFIED METHODS OF

ESTIMATING PROBABLE MAXIMUM SURGES

TABLE OF CONTENTS

Page C.1 INTRODUCTION ................. .................................... .. 1.59-55 C.2 SCOPE . ............ ... .................. 1.59-55 C.3 PROBABLE MAXIMUM SURGE LEVELS FROM HURRICANES ..................... .1.59-55 C.3.1 Methods Used ......................................... 1.59-55 C.3.2 Use of Data in Estimating PMS ..... ..... ....... ............................ 1.59-55 C.3.3 Wind-Wave Effects ....... ..... ..... .................................. 1.59-56 C.4 LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 1.59-56 REFERENCES ....... ..... ..... ........................................ .. 1.59-56 FIGURES ...... ... ..... ....... ........................................... 1.59-57 TABL E S . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . : 1.59-59 FIGURES

Figure C.1 - Probable Maximum Surge Estimates, Gulf Coast .... ............. . . . . . . . . 1.59-57 C.2 - Probable Maximum Surge Estimates, Atlantic Coast .......... . . . . . . . . 1.59-58 TABLES

Table C. 1 - Probable Maximum Surge Data ...... .................... 1.59-59 C. 2 - Probable Maximum Hurricane, Surge, and Water Level - Port Isabel . . 1.59-60

C. 3 - Probable Maximum Hurricane, Surge, and Water Level - Freeport . . . . 1.59-61 C. 4 - Probable Maximum Hurricane, Surge, and Water Level - Eugene Island . 1.59-62 C. 5 - Probable Maximum Hurricane, Surge, and Water Level.- Isle Dernieres 1 .59-63 C. 6 - Probable Maximum Hurricane, Surge, and Water Level - Biloxi 1.59-64 C. 7 - Probable Maximum Hurricane, Surge, and Water Level - Santarosa Island . 1.59-65 C. 8 - Probable Maximum Hurricane, Surge, and Water Level - Pitts Creek . . . 1.59-66 C. 9 - Probable Maximum Hurricane, Surge, and Water Level - Naples ....... 1.59-67 C.10 - Probable Maximum Hurricane, Surge, and Water Level - Miami ..... 1.59-68 C.1l- Probable Maximum Hurricane, Surge, and Water Level - Jacksonville . . . 1.59-69 C.12 - Probable Maximum Hurricane, Surge, and Water Level - JeckyUl Island... 1.59-70

C.1 3 - Probable Maximum Hurricane, Surge, and Water Level - Folly Island . . . 1.59-71 C.14 - Probable Maximum Hurricane, Surge, and Water Level - Raleigh Bay . . . 1.59-72 C.I 5 - Probable Maximum Hurricane, Surge, and Water Level - Ocean City . . . 1.59-73 C.1 6 - Probable Maximum Hurricane, Surge, and Water Level - Atlantic City . . 1.59-74 C.17 - Probable Maximum Hurricane, Surge, and Water Level - Long Island . . . 1.59-75 C. 18 - Probable Maximum Hurricane, Surge, and Water Level - Watch Hill Point 1.59-76 C.19 - Probable Maximum Hurricane, Surge, and Water Level -- Hampton Beach 1.59-77 C.20 - Probable Maximum Hurricane, Surge, and Water Level - Great Spruce Island 1.59-78 C.21 - Ocean Bed Profiles . . . . . . . . . . . . . . . . . . . . . . . . 1.59-79

1.59-53

C.1 INTRODUCTION C.3.1 Methods Used This appendix presents timesaving methods of esti- All PMS determinations in Table C.A were made by mating the maximum stillwater level of the probable NRC consultants for this study (Ref. 1), except Pass maximum surge (PMS) from hurricanes at open-coast Christian, Crystal River, St. Lucie, Brunswick, Chesa- sites on the Atlantic Ocean and Gulf of Mexico. Use of peake Bay Entrance, Forked River-Oyster Creek, Mill- the methods herein will reduce both the time necessary stone, Pilgrim, and Seabrook.

for applicants to prepare license applications and the NRC staff's review effort. The computations by the consultants were made using the NRC surge computer program, which is The procedures are based on PMS values determined adopted from References 2 and 3. Probable maximum by applicants for licenses that have been reviewed and hurricane data were taken from Reference 4. Ocean accepted by the NRC staff and by the staff and its bottom topography for the computations was obtained consultants. The information in this appendix was from the most detailed available Nautical Charts pub- developed from a study made by Nunn, Snyder, and lished by the National Ocean Survey, NOAA. The Associates, through a contract with NRC (Ref. 1). traverse line used for the probable maximum hurricane surge estimate was drawn from the selected coastal point The PMS data are shown in Tables C.A through C.21 to the edge of the continental shelf or to an ocean depth and on maps of the Atlantic and Gulf Coasts (Figures of 600 feet MLW, and was one hurricane radius to the C.A and C.2). Suggestions for interpolating between right of the storm track. It was oriented perpendicular to these values are included. the ocean bed contours near shore. The ocean bed profile along the traverse line was determined by Limitations on the use of these generalized methods roughly averaging the topography of cross sections of estimating PMS are identified in Section C.4. These perpendicular to the traverse line and extending a limitations should be considered in detail in assessing the maximum of 5 nautical miles to either side. The 10-mile applicability of the methods at specific sites. wide cross sections were narrowed uniformly to zero at the selected site starting 10 nautical miles from shore. It Applicants for licenses for nuclear facilities at sites on was assumed that the peak of the PMS coincided with the 10% exceedance high spring tide1 plus initial rise. 2 the open coast of the Atlantic Ocean or the Gulf of Mexico have the option of using these methods in lieu of more precise but laborious methods. The results of In each case the maximum water level resulted from application of the methods in this appendix will in many use of the high translation speed for the hurricane in cases be accepted by the NRC staff with no further combination with the large radius to maximum wind, as verification. defined in Reference 4. Detailed data for the computed PMS values are shown in Tables C.1 through C.20. Ocean bed profile data for Pass Christian, Crystal River, St.

C.2 SCOPE Lucie, Chesapeake Bay Mouth, and Seabrook are shown in Table C.21.

The data and procedures in this appendix apply only to open-coast areas of the Gulf of Mexico and the The water levels resulting from these computations Atlantic Ocean. are open-coast stillwater levels upon which waves and wave runup should be superimposed.

Future studies are planned to determine the applica- bility of similar generalized methods and to develop such C.3.2 Use of Data in Estimating PMS

methods, if feasible, for other areas. These studies, to be included in similar appendices, are anticipated for the Estimates of the PMS stillwater level at open coast Great Lakes and the Pacific Coast, including Hawaii and sites other than those shown in Tables C.1 through C.21 Alaska. and on Figures CA and C.2 may be obtained as follows:

C.3 PROBABLE MAXIMUM SURGE LEVELS 1. Using topographic maps or maps showing sound- FROM HURRICANES ings, such as the Nautical Charts, determine an ocean bed profile to a depth of 600 ft MLW, using the methods The data presented in this appendix consist of all determinations of hurricane-induced PMS peak levels at 'The 10% exceedance high spring tide is the predicted maximum open-coast locations computed by the NRC staff or their monthly astronomical tide exceeded by 10% of the predicted consultants, or by applicants and accepted by the staff. maximum monthly astronomical tides over a 21-year period.

The data are shown in Tables C.A through C.21 and on 2Initial rise talso called forerunner or sea level anomaly) is an Figures C.A and C.2. All represent stillwater levels for anomalous departure of the tide level from the predicted open-coast conditions. astronomical tide.

1.59-55

outlined above. Compare this profile with the profiles of obtained by the foregoing procedures. Acceptable the locations shown in Tables C.2 through C.21. With methods are given in Reference 2.

particular emphasis on shallow water depths, select the location or locations in the general area with the most similar profiles. An estimate of the wind setup may be C.4 LIMITATIONS

interpolated from the wind setup data for these loca- tions.

1. The NRC staff will continue to accept for review

2. Pressure setup may be interpolated between loca- detailed PMS analyses that result in less conservative tions on either side of the site. estimates. In addition, previously reviewed and approved detailed PMS analyses at specific sites will continue to be

3. Initial rise, as shown in Table C1, may be acceptable even though the data and procedures in this interpolated between locations on either side of the site. appendix result in more conservative estimates.

4. The 10% exceedance high spring tide may be computed from predicted tide levels in Reference 5; it 2. The PMS estimates obtained as outlined in Section may be obtained from the Coastal Engineering Research C.3.2 are maximum stillwater levels. Coincident wind- Center, U.S. Army Corps of Engineers, Ft. Belvoir, Va.; wave effects should be added.

or it may be interpolated, using the tide relations in Reference 5.

3. The PMS estimates obtained from the methods in

5. An estimate of the PMS open-coast stillwater level Section C.3.2 are valid only for open-coast sites, i.e., at at the desired site will be the sum of the values from the point at which the surge makes initial landfall. If the Steps 1 through 4, above. site of interest has appreciably different offshore bathy- metry, or if the coastal geometry differs or is complex, C.3.3 Wind-Wave Effects such as for sites on an estuary, adjacent to an inlet, inshore of barrier islands, etc., detailed studies of the Coincident wave heights and wave runup should be effect of such local conditions should be made. Refer- computed and superimposed on the PMS stillwater level ence 2 provides guidance on such studies.

APPENDIX C .

REFERENCES

1. Nunn, Snyder, and Associates, "Probable Maximum Memorandum No. 35, U.S. Army Coastal Engineering Flood and Hurricane Surge Estimates," unpublished Research Center, 1971.

report to NRC, June 13, 1975 (available in the public document room). 4. U.S. Weather Bureau (now U.S. Weather Service, NOAA), "Meteorological Characteristics of the Probable Maximum Hurricane, Atlantic and Gulf

2. U.S. Army Coastal Engineering Research Center,

"Shore Protection Manual," 1973. Coasts of the United States," Hurricane Research Interim Report, HUR 7-97 and HUR 7-97A, 1968.

3. B.R. Bodine, "Storm Surge on the Open Coast: 5. U.S. Department of Commerce, NOAA, "Tide Fundamental and Simplified Prediction," Technical Tables," annual publications.

1.59-56

840 830 820 810 800 790 780

360

350

330

340

320

330

310

310

LOUISIANA

-4 Z290

U300

0 FLORIDA

> l 280

29 Wry z* 270

280 Z*

260

270 _

43 250

260

250 240

32.7 MAXIMUM STILLWATER LEVEL AT OPEN COAST, FT., MLW 230

970 960 950 940 930 920 910 90° 890 880 870 860 850 840 830 820 810

FIGURE C.1 PROBABLE MAXIMUM SURGE ESTIMATES - GULF COAST

830 820 810 800 790 780 770 760 750 740 730 720 710 700 690 680 670 660 650 640 630 620

(

___ " 32.7 MAXIMUM STILLWATER LEVEL AT OPEN COAST, FT., ML

860 850 840 830 820 810 800 790 780 770 760 750 740 730 720 710 700

FIGURE C.2 PROBABLE MAXIMUM SURGE ESTIMATES - ATLANTIC COAST

1.59-58

TABLE C.1 PROBABLE MAXIMUM SURGE DATA

(LOCATIONS INDICATED ON FIGURES C.] and C.2)

DISTANCE FROM SHORELINE, NAUTICAL MILES, FOR SELECTED WATER DEPTHS, FEET mLW PROBABLE MAXIMUM SURGE AT OPEN COAST SHORE LINE

OPEN COAST LOCATION TRAVERSE J DEPTH, FEET, ALONG TRAVERSE FROM OPEN COAST SHORE LINE WIND PRESSURE INITIAL 10% EXC. HIGH TOTAL

AND TRAVERSE AZIMUTH 10 20 50 100 200 600 SETUP, SETUP, RISE, TIDE, SURGE,

DEG. - MIN. DISTANCE, NAUTICAL MILES, TO DEPTH INDICATED FT. FT. FT. FT. MLW FT. MLW

PORT ISABEL 86 30 0.23 0.49 1.94 11.10 33.10 44.0 10.07 3.57 2.50 1.80 17.94 FREEPORT 152 00 0.20 0.55 5.50 24.0 55.5 70.9 15.99 2.89 2.40 2.90 24.18 EUGENE ISLAND 192 30 2.00 20.00 30.00 44.1 60.0 90.0 29.74 3.29 2.00 2.40 37.44 ISLE DERNIERES 165 00 0.62 1.75 11.90 30.4 45.3 58.5 18.61 3.29 2. 00 1.90 25.80

PASS CHRISTIAN (a) 77.0 28.87 2.88 0.80 1.20 33.75 BILOXI 160 00 3.40 11.20 30.00 50.1 69.2 78.0 27.77 2.98 1. 50 2.50 34.76 SANTAROSA ISLAND 183 00 0.09 0.18 0.48 11.9 20.9 45.0 9.12 3.25 1.50 1.80 15.67 PITTS CREEK 205 00 8.84 9.23 24.30 69.4 107.0 132.0 24.67 2.31 1.20 4.20 32.38 CRYSTAL RIVER (a) 2.31 31.40 127.0 26.55 2.65 0.60 4.30 34.10

NAPLES 248 00 0.17 0.79 15.70 45.6 85.8 145.0 18.47 2.90 1. 00 3.60 25.97 C-,.

MIAMI 100 00 0.17 0.94 2.01 2.2 2.7 3.9 2.51 3.90 0.90 3.60 10.91 STr. LUCIE(a) 0.10 18.7 8.25 3.80 0.98 3.70 16.73 JACKSONVILLE 90 00 0.10 0.20 2.58 30.0 55.0 62.5 16.46 3.23 1.30 6.20 27.20

JEKYLL ISLAND 108 00 2.60 4.00 15.60 39.6 64.3 72.6 20.63 3.34 1.20 7.50 32.67 FOLLY ISLAND 150 00 0.19 2.17 12.00 32.8 47.0 57.6 17.15 BRUNSWICK

3.23 I. 00 6.80 28.18

12.94 2.20 1. 00 5.80 21.94 RALEIGH 135 00 0.12 0.30 1.75 12.0 25.4 35.2 8.84 3.09 1 -00 5.20 18.13 CHESAPEAKE BAY

ENTRANCE (a) 62.0 17.30(b) (b) 1.10 3.50 21.90

OCEAN CITY 110 00 0.12 0.26 3.67 17.8 45.0 59.0 14.30 2.83 1.14 5.10 23. 17 ATLANTIC CITY 146 00 0.20 0.85 5.00 23.1 58.4 70.0 15.32 2.57 1.10 5.80 24.80

FORKED RIVER -

OYSTER CREEK

18.08(b) (b) 1.00 2.70 21.78 LONG ISLAND 166 00 0.09 0.18 1.35 4.8 27.2 68.4 8.73 2.46 0.97 8.00 20.16 MILLSTONE

12.41 2.20 1.00 3.56 19.17 WATCH HILL POINT 166 00 0.07 0.14 0.64 1.6 34.3 84.0 10.01 2.42 0.96 8.80 22.19 PILGRIM

HAMPTON BEACH 19.6

115 00 0.22 0.31 0.71 2.0 7.2 40.0 4.25 2.23 0.83 11.70 19.01 SEABROOK(a)

44.0 4.79 2.28 0.86 11.60 19.53.

GREAT SPRUCE ISLAND 148 00 0.04 0.08 0.20 1.1 6.3 178.0 9.73 1.82 0.56 18.40 30.51 ocean bedsetup.

for pressure C.H and profile.

a. See Table wind b.

a. Combined See Table C.21 for ocean bed profile.

b. Combined wind and pressure setup.

TABLE C.2 SUMMARY-PERTINENT PROBABLE MAXIMUt. hURRICANE (FMH), STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL

LOCATION PORT ISABEL [AT. 260o4.3' LONG. 97 09.4': TRAVERSE-AZIMUTH86°-30'DECREEi LENGTH 42.1 NAUTICAL MILES

TEXAS

PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS OCEAN BED PROFILE PMH (CNPUTATIONAL COEFFICIENT

ZONE C AT LOCATION 260 04' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

SPEED OF TRANSLATION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW MODERATF HIGH FROM BELOW

_(ST) (MT) (.)_ SHORE MLW

(NAUT.MI.) (FEET) C 0 E F F I CI E N T S

3ENTRAL PRESSURE INDEX

P0 INCHES 26.42 26.42 26.42ý 0 0 BOTfIOF FhICTION FACTOR 0.0030

PER IPHERAL PRESSURE 0.2 9.0

Pn INCAES 31.30 31.30 31.30 _ 0.5 20.5 WIND STRESS CORRECTION FACTOR 1.10

1.0 35.0

RADIUS TO MAXIMUM WIND _ 1.5 43.0

LARGE RADIUS NAUT. MI. 20 20 20 2.0 51.0

rRANSIATION SPEED _ 3.0 58.5 WATER LEVEL DATA

- 5.0 69.0

Fv (FORWARD SPEED) KNOTS 1 4 11 28

0 10 95.5 (AT OPEN CCAST SHORELINE)

WIAXMUM WIND SPEED 15 116 V M.P.H. 147 151 161 20 138 INITIAL DISTANCE-NAUT. MI, i/ _ 30 171 PMH SPEED OF TPANSLATION

FROM 20 MPH WIND 398 374 318 40 266 COMPONENTS ST MT nIT

6T SHORE TO MAX. WIND 44 600 F E E T

50 1,850

14ULe Maximum wind speed is assumed Lto be on the traverse that is to right of storm track a WIND SETUP 10.07 distance equal to the radius to maximum wind.

PRESSURE SETUP 3.57

-/Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 2.50

20 mph isovel intersects shoreline. Storm diameter between 20 mph-isovels is approxi- kSTRONONICAL 1.80

mately double the initial distanc

e. FIDE LEVEL

rOTAL-SURGE

STILL WATER LEV. 17.9.4 FEET NLW

LATITUDE

  • 26° 05'

DEGREE AT TRAVERSE

MID-POINT FROM SHORE

TO 600-FOOT DEPTH

7]

TABLE C.3 SUMMARY-PERTINENT PROBABLE MAXIMU. hURRICANE (FMH), STORM SURGE COMPUTATIONAL LATA AND RESULTANT WATER LEVEL

LOCATION FREEPORT, LAT. 280 56' LONG. 95" 22' : 'PRAVERSE-AZIMUTH 152 DEGREEt LENGTH 70.9 NAUTICAL MILES

TEXAS

PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS OCEAN BED PROFILE PMH OCPIPUTATIONAL COEFFICIENT

ZONE C AT LOCATION 280 56' DEGHEE NORI'H

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

PARAMETER DESIGNATIONS

I SLOW

SPEED OF TRANSLATION

MODERATF HIGH

DISTANCE

FROM

DErTH

BELOW

S(ST) (?Tr) (*)T I SHORE MLW

(NAUT.MI.) (FEET) C 0 E F F I C I E N T S

MENTRAL PRESSURE INDEX 26.69 P 0 INCHES 26.69 26.69 26.69 0 0 BO'nUfM FRICTION FACTOR 0.0030

PERIPHERAL PRESSURE 1.0 30

P INCHES 31.25 31.25 31.25 2.0 32 WIND STRESS CORRECTION FACTOR 1.10

_ 3.0 37 RADIUS TO MAXIMUM WIND 4.0 40

LARGE RADIUS NAUT. MI. 26.0 26.0 26.0 _ 5.0 47

10.0 66 WA T E h L EV E L D A T A

rRANS1ATION SPEED

U)

F (FORWARD SPEED) KNOTS I 4 11 28.0 15.0

1 78

& 20.0 9o (AT OPEN CCAST SHORELINE)

AIMUM WIND SPEED 30.0 114 Vx M.P.H. 139 143 153 _ 40°.0 132 INITIAL DISTANCE-NAUT.MI.Y _ 50.0 168 PMH SPEED OF TRANSLATION

FROM 20 MPH WIND 491 6o.o0 240 COMPONENTS

458 390 ST I MT I HT

AT SHORE TO MAX. WIND I 70.0 570 F E E T

70.9 600

Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a WIND SETUP 15.99 distance equal to the radius to maximum wind.

PRESSURE SETUP 2.89

-/Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 2.40

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- kSTRONOMICAL 2.90

mately double the initial distanc

e. rIDE LEVEL

TOTAL-SURGE

STILL WATER LEV. 24.18 FEET MLW

LATITUDE

  • 28' 26'

DEGREE AT TRAVERSE

MID-POINT FROM SHORE

TO 600-FOOT DEPTH

TABLE C4 SUMMARY-PERTINENT PROBABLE MAXIMUE hUHRICANE (FMH), STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL

1 :0 2

21 'rTRAVERSE-AZIMUJTHl9 30 t DEG~REE, LENGTH 90 NAUTICAL MILES

LOCATION EUGENE LAT. 290 20' LONG. 91 ISLAND, LOUISIANA

PROBABLE MAXIMUM HURRICANE INDEX CHARACTEIISTICS OCEAN BED PROFILE PMH CCNPUTATIONAL COEFFICIENT

ZONE B AT LOCATION 290 20' DEGREE NORTH AND WATER* LEVEL (SURGE) ESTIMATES

TRAVERSE WATER

SPEED OF TRANSLATION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW MODERATF HIGH FROM BEL40W

2 (ST) (nT) (HT) SHORE MLW

MENMAL PRESSURE INDEX (NAUT.MI.) (FErT)

P INCHES 26.87 26.87 26.87 - 0.0 0 - BOIOM FilICTION FACTOR 0.0030

PERIPHERAL PRESSURE - 1.0

2.0 105 -

-

P INCHES 31.24 31.24 31.24 WIND STRESS CORRECTION FACTOR 1.10

3.0 12 -

RADIUS TO MAXIMUM WIND

LARGE RADIUS NAUT. MI. 29.0 29.0 29.0 - 5.0 15 -

- 10.0 15 -

rRANSLATION SPEED - 15.0 18 - WATER LEVEL DATA

Fv (FORWARD SPEED) KNOTS 4 11 28.0 - 20.0 20 -

- 30.0 50 - (AT OPEN CCAST SHORELINE)

MAXIMUM WIND SPEED - 40 60 -

V M.P.H. 141 144 153 - 50 140 -

INITIAL DfSTANCE-NAUT. MI.i_ - 6o 200 - PMH SPEED OF TRANSLATION

FROM 20 MPH WIND 534 484 412 - 70 260 - COMPONENTS ST M

MT HTI

4T SHORE TO MAX. WIND . 80 320 - F E E' T

Note: Maximum wind speed is assumed to be on - 90 600 -

WIND SETUP 29.74 the traverse that is to right of storm track a distance equal to the radius to maximum wind.

PRESSURE SETUP 3.29

- Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 2.00

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- ASTRONOMICAL 2.40

mately double the initial distanc

e. TIDE LEVEL

TAL-SURGE

STILL WATER LEV. 37.44 FEET MLW I

IATITUDE 28 04 DEGREE AT TRAVERSE

MID-POINT FROM SHORE

(ro 600-FOOT DEPTH

-~-r..-

TABLE CA5 SUMMARY-PERTINENT PROBABLE MAXIMUE HU!RICANE (FMH), STORM SURGE COMPUTATIONAL LATA AND RESULTANT WATE LEVEL

LOCATION ISLE LAT. 29'02.9' LONG. 90'42.5': TRAVERSE-AZIMUTH 165 DEGREE, LENGIH 58.5 NAUTICAL MILES

DERNIERES, LOUISIANA

PROBABLE MAXIMUM HURRICANE INDEX CHARACTEIISTICS OCEAN BED PROFILE PMH OCXPUTATIONAL COBYFICIENT

ZONE B AT LOCATION 290 03' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

DISTANCE DEPTH

PARAMETER DESIGNATIONS SPEED OF

SLOW TRANSLATION

I4ODERATF HIGH FROM BELOW

_(ST) (rT) ) SHORE MLW

(NAUT.MI.) (FEET) C 0 E F F I C I E N T S

JENTRAL PRESSURE INDEX

P INCHES 26.88 26.88 26.88 0 0 B(yJ']fj .FhICTION FACTOR 0.0030

- 0.2 6.0

PER IPHERAL PRESSURE

0.5 9.0

P INCHES 31.25 31.25 31.25 WIND STRESS CORRECT*iON FACTOR 1.10

n _ a _ 1.0 13.0

RADIUS TO MAXIMUM WIND 1.5 17.5 LARGE RADIUS NAUT. MI. 29 29 29 2.0 22.5

3.0 26.e rRANSLATION SPEED WATER LEVEL DATA

5.0 32.0

F (FORWARD SPEED) KNOTS 4 11 28

7.0 34.0

(AT OPEN CCAST SHORELINE)

MAXIMUM WIND SPEED 7.5 28.0

V M.P.H. 140 144 153 - 8.0 25.5

- 8.5 25.0

INITIAL DISTANCE-NAUT.MI.1! PMH SPEED OF TANSIATIOI

FROM 20 MPH WIND 528 487 394 9.0 28.5 COMPONENTS ST MT I HT

.9.5 34.0

ýT SHORE TO MAX. WIND I_ F E E T

10.0

1 42.5 Note: Maximum wind speed is assumed to be on - 15.0 62.0 WIND SETUP 18.61 the traverse that is to right of storm track a - 20.0 56.0

distance equal to the radius to maximum wind. 30.0 97.9 PRESSURE SETUP 3.29 y Initial distance is distance along traverse - 40.0 152.0

from shoreline to maximum wind when leading 50.0 243 INITIAL WATER LEV. 2.00

20 mph isovel intersects shoreline. Storm - 58.5 600

diameter between 20 mph isovels is approxi- - 60.o 688 kSTRONONICAL 1.90

mately double the initial distanc

e. rIDE LEVEL

TOTAL-SURGE

STILL WATER LEV. 25.aO

FEET MLW

LATITUDE 0 28° 3 4.4 DEGREE AT TRAVERSE

MID-POINT FROM SHORE

rO 600-FOOT DEPTH

I-..-.

TABLE C.6 SUMMARY-PERTINENT PROBABLE MAXIMUV. HURRICANE (PMH), STORM SURGE COMPUTATIONAL DATA AND 'RESULTANT WATER LEVEL

LOCATION BILOXI LAT. 30023.6' LONG. 88"53.6': TRAVERSE-AZIMUTH 160 DEGREE, LENGTH 77 NAUTICAL MILES

MISSISSIPPI

PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS OCEAN BED PROFILE PMH OCCPUTATIONAL COEFFICIENT

ZONE B AT LOCATION 300 24' DEGREE NORTH ESTIMATES

TRAVERSE WATER AND WATER LEVEL (SURGE)

SPEED OF THRANS TION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW MODERATF HIGH FROM BELOW

l ST)'n (n) (HT) SHORE MLW

CENTRAL PRESSURE INDEX (NALT.MI.) (FEET) C0 E F F I CI 9 N T S

P 0 INCHES 26.9 26.9 26.9 o 0 BOT'1OYM FHICTION FACTOR 0.0030

PER IPHERAL PRESSURE 0.2 3.0 -

P INCHES 31.23 31.23 31.23 _ 0.5 2.0 WIND STRESS CORRECTION FACTOR 1.10

n__ _ 1.0 6.5 RADIUS TO MAXIMUM WIND _ 1.5 9.0"

LARGE RADIUS NAUT. MI. 30 30 30 2.0 9.0 -

TRANSLATION SPEED _ 3.0 9.5 - WATER LEVEL DATA

Fv (FORWARD SPEED) KNOTS 4 11 28 _ 5.0 12.0

_ 9.0 9.5 (AT OPEN CCAST SHORELINE)

MAXIMUM WIND SPEED _ 9.5 11.0

V M.P.H. 139 143 153 10.0 14.0

x INITIAL DISTANCE-NAUT.MI.i/ - 10.5 18.5 PMH SPOED OF TRANSLATION

FROM 20 MPH WIND 525 498 396 _ 11.0 17.5 - COMPONENTS ST I MT IHT

&T SHORE TO MAX, WIND _ 11.5 23.0 j F E E T

12.0 29.0

Note: Maximum wind speed is assumed to be on _ 13 34.5_ WIND SETUP 27.77 the traverse that is to right of storm track a _ 15 41.5 distance equal to the radius to maximum wind. 20. 45.0 RESSURE SETUP 2.98

-/Initial distance is distance along traverse - 25 47.0

from shoreline to maximum wind when leading _ 30 50.0 INITIAL WATER LEV. 1.50

20 mph isovel intersects shoreline. Storm 40 65.0

diameter between 20 mph isovels is approxi- L 50 99.0 TNOMICAL 2.50

mately double the initial distance. 60 164 -

S70 203

600o rAL-SURGE

L '78 STILL WATER LU. 34.76 BET MLW

LATITUDE

  • 290 5'*

DEfGREE AT TRAVERSE

MID-POINT FROM SHORE

rO 600-FOOT DEPTH

TABLE C.7 SUMMARY-PERTINENT PROBABLE MAXIMUV: h1JRICANE (FMH), STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL

LOCATION SANTA ROSA LAT. 30023.7' LONG. 86 37.7': TRAVERSE-AZIMUTH 183 DEGXREEs LENGTH 44.7 NAUTICAL MILES

ISLAND, ALABAMA

PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS OCEAN BED PROFILE PMH CNhPUTATIONAL COEFFICIENT

ZONE B AT LOCATION 300 24' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

SPEED OF TRANSLATION DISTANCE DERPH

PARAMETER DESIGNATIONS SLOW ,ODERATF HIGH FROM BELOW

_ (ST) (MT) (HT) SHORE MLW

(NAUT.MI.) (FEET) C 0 E F F I C I E N T S

CTL PRESSURE INDEX

P 0 INCHES 26.88 26.88 26.88 0 0 BO'i0JM FilICTION FACTOR 0.0030

PERIPHERAL PRESSURE 0.2 22 P INCHES 31.20 31.20 31.20 0.5 52 WIND STRESS CORRECTiON FACTOR 1.10

n 1.0 66 RADIUS TO MAXIMUM WIND 1.5 66 LARGE RADIUS NAUT. MI. 29 29 29 "2.0 66 TRANSLATION SPEED 3.0 73 WATEh LEVEL DATA

4 ii 28 5.0 76 vi F (FORWARD SPEED) KNOTS

MAXIMUM WIND SPEED" 10 88 (AT OPEN CCAST SHORELINE)

15 120

V M.P.H. 140 144 153 20 182 INITIAL DISTANCE-NAUT.MI.I.i 30 377 PMH SPEED OF TRANSLATION

FROM 20 MPH WIND 528 487 394 40 510

COMPO1ENTS ST I MT I I-l'

IT SHORE TO MAX. WIND I I

45

50

600

756 F E E T

Note: Maximum wind speed is assumed to be on WIND SETUP 9.12 the traverse that is to right of storm track a distance equal to the radius to maximumwind.

PRESSURE SETUP 3.25

-Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 1.50

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- ASTRONOMICAL 1.80

mately double the initial distanc

e. TIDE LEVEL

TOTAL-SURGE

STILL WATER LEV. 15.67 FEET MLW

LATITUDE; 30°1.3'

DEGREE AT TRAVERSE

AID-POINT FROM SHORE

iv 600-FOOT DEPTH

TABLE C.8 SUMMARY-PERTINENT PROBABLE MAXIMU. hUhRRICANE (FMH), STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL

LOCATIONPITTS CREEK LAT. 30°01.1' LONG. 83' 53' : TRAVERSE-AZIMUTH 205 DEGREEi LENGTH 110 NAUTICAL MILES

FLORIDA

PROBABLE MAXIMUM HURRICANE INDEX CHARACTEIISTICS OCEAN BED PROFILE PMH CDNPUTATIONAL COEFFICIENT

ZONE A AT LOCATION 300 01' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

PARAMETER DESIGNATIONS t SPEED OF

SLOW

(ST)

TRANSLATION

IODERATF HIGH

DISTANCE

FROM

DEPTH

BELOW

(MT) .HT SHORE MLW

(NAUT.MI.) (FEET) C0 E F F I C I E NT S

ENTRAL PRESSURE INDEX

P INCHES 26.79 26.79 26.79 0 0 BOT'ION FlICTION FACTOR 0.0030

ERIPHERAL PRESSURE 0.2 1.0

P INCHES 30.22 30.22 30.22 0.5 2.0 WIND STRESS CORRECTION FACTOR 1.10

1.0 3.0

ýEDUS TO MAXIMUM WIND 1.5 4.0

LARGE RADIUS NAUT. MI. 26 26 26 2.0 5.0

/1 FRANSIATION SPEED 3.0 6.5 WA T ER LEVEL DATA

ý_ (FORWARD SPEED) KNOTS 1 4 11 21 5.0 9.0

10 22.0 (AT OPE12 CCAST SHOFELINE)

MAXIMUM WIND SPEED 15 31.0

V M.P.H. 138 142 146

20 41.0

INITIAL DISTANCE-NRUT.MI.li 30 62.0 PMH SPEED OF TPANSLATION

FROM 20 MPH WIND 354 322 278 40 78.0 COMPONENTS ST I MT HTi'

SHORE TT_O

MAX. WIND 50 81.0 F E E T

Note: Maximum wind speed is.assumed to be on 6o 84.0

the traverse that is to right of storm track a 70 101.0 WIND SETUP 24.67 distance equal to.the radius to maximum wind. 80 117.0

9o 144.0 PRESSURE SETUP 2.31

-/Initial distance is distance along traverse

100 180.0

from shoreline to maximum wind when leading 110 210.0 INITIAL WATER LEV. 1.20

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- 120 280.0

mately double the initial distance. 130 543.0 ASTRONOMICAL 4.20

132 6oo.0 TIDE LEVEL

140 846 TOTAL-SURGE

STILL WATER LEV. 32.38 FEET MLW____

LATITUDE $ 290 03'

DEGREE AT TRAVESE

MID-POINT FROM SHORE

TO 600-FOOT DEPTH

TABLE C.9 SUMMARY-PERTINENT PROBABLE MAXIMUE hUJRRCANE (PMH), STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL

LOCATION NAPLES LAT. 26001.4' LONG. 81"46.2': TRAVERSE-AZIMUTH 2413 DELREE, LENGTH 145 NAUTICAL MILES

FLORIDA

PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS OCEAN BED PROFILE PMH CCNPUTATIONAL COEFFICIENT

ZONE A AT LOCATION 260 01' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

SPEED OF TRANSLATION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW IMODERATF HIGH FROM BELOW

_(ST) (ni) (HT) SHORE MLW

(NAUT.MI.) (FEET) C 0 E F F I C I E N T S

CENTRAL PRESSURE INDEX

26.24 26.24 26.24 0

P INCHES BO'ITUr FHICTION FACTOR 0.r1030

PER IPHERAL PRESSURE - 0,.5 +/-8.0-

P INCHES 31.30 31.30 31.30 WIND STRESS CORRECTION FACTOR 1.10

n

1.0

-!.55 RADIUS TO MAXIMUM WIND

LARGE RADIUS NAUT. MI. 15 1 I

3.0 27.0

TRANSLATION SPEED WATEh LEVEL DATA

5.0

F (FORWARD SPEED) KNOTS 4 17

150 41.0

151 (AT OPEN CCAST SHORELINE)

-I MAXIMUM WIND SPEED 48.

V M.P.H. 150 1LL 158 20

INITIAL DISTANCE-NAUT. MI.i/ PMH SPEED OF TRANSLATION

4) 90.0 COMPONENTS ST I

FROM 20 MPH WIND 292 270 256 MT I HT

50 108 AT SHORE TO MAX. WIND F E E T

- 60 144 Note: Maximum wind speed is assumed to be on 70 165 WIND SETUP 13.49 15.87 18.47 the traverse that is to right of storm track a 80 186 distance equal to the radius to maximum wind. 90 210 PRESSURE SETUP 3.29 2.87 2.90

- Initial distance is distance along traverse 100 228

110 249 INITIAL WATER LEV. 1.00 1.00 1.00

from shoreline to maximum wind when leading

20 mph isovel intersects shoreline. Storm 120 252 diameter between 20 mph isovels is approxi- 130 432 ASTRONOMICAL 3.60 3.60 3.60

matelv double the initial distance. 140 452 TIDE LEVEL

- 145 600 AOTKL-SURGE

150 1,200 STILL WATER LEV. 21.38 23.35 25.97 FEE MLW .. I II _I

LATITUDE 0 250 35'

DEGREE AT TRAVERSE

MID-POINT FROM SHORE

TO 600-FOOT DEPTH

TABLE C.10

SU MMARY-PERTINENT PROBABLE MAXIMU. hiUaRICANE (PMH), STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL

LOCATION MIAMI LAT. 25047.2' LONG. 80"07.8' ; TRAVERSE-AZIMUTH 100 DBYGREEj LEN.GTH 3.9 NAUTICAL MILES

FLORIDA

PROBABLE MA.XIMUM HURRICANE INDEX CHARACTEISTICS OCEAN BED PROFILE PMH OCMPUTATIONAL COEFFICIENT

ZONE 1 AT LOCATION 250 47.2' DEXGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

DISTANCE DEPTH

FROM BELOW

SHORE MLW

(NAUT.MI.) (FEET) C0 E F F I C I E NT S

0 0 BOi7IFO FiRICTION FACIOR 0.0025

0.2 12

0.5 16 WIND STRESS CORRECTION FACTOR 1.10

1.5 25

2.0 47

_3.0 266

3.9 600 WATER LEVEL DATA

5.0 822 (AT OPEN CCAST SHORnELINE)

PMH SPEED OF TRANSLATION

COMPONENTS ST T MT i HI'

F E E T

Note: Maximum wind speed is assumed to be on 2.06 2.37 2.51 WIND SETUP

the traverse that is to right of storm track a distance equal to the radius to maximum wind.

PRESSURE SETUP 3.97 3.82 3.90

- Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LE*. 0.90 0.90 0.90

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- ASTRONOMICAL 3.60 3.60 3.60

mately double the initial distance. FIDE I*LEE________ ____

AOTAL-SURGE

STILL WATER LER . 10.53 10.68 10.91 FEET MLW I

LATITUDE 0 25I46-.

DEGREE AT TRAVERSE

MID-POINT FROM SHORE

To 600-FOOT DEPTH

TABLE C.11 SUMN*ARRY-PERTINENT PROBAWLE NAXIMUI h.HURRICANE (FMH), STORM SURGE COMPUTATIONAL FATA AND RESULTANT WATER LEVEL

LOCATION JACKSONVILLELAT. 300 21' LONG. 81 24.3: TRAVERSE-AZIMUTH 90 DECREEt LENGTH 62.5 NAUTICAL MILES

FLORIDA

PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS OCEAN BED PROFILE PMH CCXNPUTATIONAL COEFFICIENT

ZONE 2 AT LOCATION 300 21' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

SPEED OF TRANSLATION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW MODERATF HIGH FROM BELOW

_(ST) (T HT SHORE MLW

(NAUT.MI.) (FEET) C 0 E F F I C.1 E N T S

CENTRAL PRESSURE INDEX

P INCHES 26.67 26.67 26.67 0 0 BO)'Ir0N FkICTION FACTOR 0.0025 PERIPHERAL PRESSURE 0.2 20

Pn INCHES 31.21 31.21 31.21 0.5 25 WIND STRESS CORRECTION FACTOR 1.10

1.0 32 RADIUS TO MAXIMUM WIND 1.5 37 LARGE RADIUS NAUT. MI. 38 38 38 2.0 43 TRANSIATION SPEED I 3.0 55 WATER LEVEL DATA

F (FORWARD SPEED) KNOTS 1, 4 11 22 5.0 59

10.0 66 (AT OPEN CCAST SHORELINE)

MIMUM WIND SPEED 12.0 66 V M.P.H. 138 142 149 14.0 72 INITIAL DISTANCE-NAUT.MI.]_ 15.0 73 PMH SPEED OF TRANSLATION

FROM 20 MPH WIND 407 372 334 20.0 80

COMPONENTS ST I MT M.HT

NT SHORE TO MAX.

30.0 100

WIND I F E E T

40.0 117 Note: Maximum wind speed is assumed to be on 50.0 131 WIND SETUP 16.46 the traverse that is to right of storm track a - 6o.o 270

distance equal to the radius to maximum wind. - 62.5 6oo PRESSURE SETUP 3.23 l/ Initial distance is distance along traverse 70.0 948 from shoreline to maximum wind when leading INITIAL WATER LEV. 1.30

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- ASTRONONICAL 6.20

mately double the initial distanc

e. TIDE LEVEL

tOTAL-SURGE

STILL WATER LEV. 27.20

FEET MLW

LATITUDE

  • 30' 21 DEGREE AT TRAVERSE

MID-POINT FROM SHORE

TO 600-FOOT DEPTH

II

TABLE C.12 SUMMARY-PERTINENT PROBABLE MAXIMUk hURRICANE (FMH), STORM SURGE COMPUTATIONAL rATA AND RESULTANT WATER LEVEL

LOCATION JEKYLL LAT. 310 05' LONG. 81" 24.5': TRAVERSE-AZIMUTH 108 DEGREE, LENGTH 72.6 NAUTICAL MILES

ISLAND, GEORGIA

PROBABLE MAXIMUM HURRICANE INDEX CHARACTENISTICS PMH CCD]PUTATIONAL COEFFICIENT

ZONE .2 AT LOCATION 310 05' DEGREE NORTH

AND WATER LEVEL (SURGE) ESTIMATES

! SPEED OF TRANSLATION

PARAMETER DESIGNATIONS SLOW IIODERATF HIGH

(ST) (NT) (21L

C 0 E F F I C I E N T S

JENTRAL PRESSURE INDEX

P INCHES 26.72 26.72 26.72 BOIU'ON FilICTION FACTOR G.C025 PER IPHERAL PRESSURE

Pn INCHES 31.19 31.19 31.].9 WIND STRESS CORRECTION FACTOR 1.10

RADIUS TO MAXIMUM WIND

LARGE RADIUS NAUT. MI. 40 40 40

rRANSLATION SPEED WA T Ei LEVEL DATA

0n F (FORWARD

VJ SPEED) KNOTS I 4 11 23 (AT OPEN CCAST SHORELINE)

MAXIMUM WIND SPEED

V M.P.H. 135 141 147 INITIAL DISTANCE-NAUT.MI.i/ PMH SPEED OF TRANSLATION

FROM 20 MPH WIND 400 380 336 COMPONENTS ST I MT I H,

&T SHORE TO MAX. WIND F E E T'

Note: Maximum wind speed is assumed to be on WIND SE'7UP 20.63 the traverse that is to right of storm track a distance equal to the radius to maximum wind.

PRESSURE SETUP 3.34

- Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 1.20

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- ASTRONOMICAL 7.50

mately double the initial distanc

e. TIDE LEVEL

TOTAL-SURGE

STILL WATER LEV. 32.6.7 FEET MLW

TABLE C.13 SUMmARY-PERTINENT PROBAI.BLE NAXIML+k hURRICANE (FMH), STORM SURGE COMPUTATIONAL LATA AND RESULTANT WATER LEVEL

LOCATION FOLLY ISIANDLAT. 320 39' LONG. 79 56.6'. TRAVERSE-AZIMUTH 150 DEGREEt LENGTH 57.6 NAUTICAL MILES

SOUTH CAROLINA

PROBABLE MAXIMUM HURRICANE INDEX CHARACTE1ISTICS OCEAN BED PROFILE PMH OCHPUTATIONAL COEFICIENT

ZONE 2 AT LOCATION 320 39' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

SPEED OF THANSLATION I DISTANCE DEPTH I

PARAMETER DESIGNATIONS SLOW HODERATF HIGH FROM BFELOW

(ST) (MT) (HT) SHORE MLW

(NAUT.MI.) (FEET) C 0 E F F I C I E N T S

CENTRAL PRESSURE INDEX

P 0 INCHES 26.81 26.81 26.81 0 0 BO1FI)FM FRICTION FACTOR 0.0025 PERIPHERAL PRESSURE 0.2 10.5 P n INCHES 31.13 31.13 31.13 _ 0.5 12.0 - WIND STRESS CORRECTION FACTOR 1.10

1.0 14.0 _

RADIUS TO MAXIMUM WIND _ 1.5 16.5 LARGE RADIUS NAUT. MI. 40 40 40 2.0 18.0 _

TRANSLATION SPEED _ 3.0 29.5 WA TER LEVEL DATA

F, (FORWARD SPEED) KNOTS 4 13 29 _ 5.0 39.0

10.0 46.0 (AT OPEN CCAST SHORELINE)

MAXIMUM WIND SPEEDV M.P.H. 1134 139 14 S1;. 0 56.0o X _ 20.0 65.0

INITIAL DISTANCE-NAUT.MI .,/ _ 30.0 85.0 PMH SPEED OF TRANSLATIO]

FROM 20 MPH WIND 400 _ 40.0 138.0 _ COMPONENTS ST I MT H'

364 311 fT SHORE TO MAX. WIND _ 50.0 227.0 _ F E E T

_ 57.6 600.0

Note: Maximum wind speed is assumed to be on

_ 60.0 1,800.0 WIND SETUP 17.15 the traverse that is to right of storm track a distance equal to the radius to maximum wind.

PRESSURE SETUP 3.23

-- Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 1.00

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- ASTRONOMICAL 6.80

mately double the initial distanc

e. TIDE LEVEL

TOTAL-SURGE

STILL WATER LEV. 28.18 FEET MLW I I

LATITUDE; 320 25'

DEGREE AT TRAVERSE

MID-POINT FROM SHORE

TO 600-FOOT DEPTH

TABLE C.14 SUMMARY-PERTINENT PROBABLE MAXIMUE hUHRICA.NE (FMH), STORM SURGE COMPUTATIONAL LATA AND RESULTANT WATER LEVEL

LOCATION RALEIGH BAY,LAT. 34 54' LONG. 7615.3;: TRAVERSE-AZIMUTH 135 DECXREi LENG'i'H 35.2 NAUTICAL MILES

NORTH CAROLINA

PROBABLE MAXIMUM HURRICANE INDEX CHARACTrEISTICS

r OCEAN BED PROFILE

1 PMH OCXPUTATIONAL COEFFICIENT

I I

ZONE 3 AT LOCATION 340 54' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SbRGE) ESTIMATES

SPEED OF TRANSLATION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW MODERATF HIGH FROM BELOW

,(ST) (wT) (HT)

SHORE MLW

(NAUT.lI.) (FEET) C0 E F F I C I E N T S

"ENTRALPRESSURE INDEX

P INCHES 26.89 26.89 26.89 0 0 BOT'XOM FhIlCTION FACTOR 0.0025

0.2 16 PERIPHERAL PRESSURE

0.5 28 WIND STRESS CORRECTION FACTOR 1.10

P INCHES 31.00 31.00 31.00

1.0 40

RADIUS TO MAXIMUM WIND 1.5 46 LARGE RADIUS NAUT. MI. 35 35 35 2.0 54

3.0 64 WATEh LEV E'L DATA

tRANSlATION SPEED

tJn 5.0 72 v (FORWARD SPEED) KNOTS 5 17 38 r'J 10.0 92 (AT OPEN CLAST SHOR**LINE)

FLAXfl4JM WIND SPEED 15.0 112 V M.P.H. 130 137 149 20.0 124

30.0 264 INITIAL DISTANCE-NAUT.MI.1/ PMH SPEED OF TRANSLATION

FROM 20 MPH WIND 385 35.2 6oo COMPONENTS ST HI I HT

346 280

40.0 900 F E E T

6T SHORE TO MAX. WIND

Note: Maximum wind speed is assumed to be on WIND SETUP 8.84 the traverse that is to right of storm track a distance equal to the radius to maximum wind.

PRESSURE SETUP 3.09

-/Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 1.00

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- ASTRONONICAL 5.20

mately double the initial distanc

e. TIDE LEVEL

TOTAL-SURGE

STILL WATER LEV. 18.13 FEET MLW I

LATITUDE # 34'41.A

DEGREE AT TRAVERSE

MID-POINT FROM SHORE

TO 600-FOOT DEPTH

TABLE C.15 SUMMARY-PEYTINENT PROBABLE MAXIMUI. hJURRICANE (FMH), STORM SUHGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL

LOCATION OCEAN CITY, LAT. 380 20' LONG. 75'04.9' : TRAVERSE-AZIMUTH 110 DEREEt LENGTH 59 NAUTICAL MILES

MARYLAND

PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS OCEAN BED PROFILE PMH CCINPUTATIONAL COEFFICIEN'

ZONE 4 AT LOCATION 380 20' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

SPEED OF TRANSLATION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW MODERATF HIGH FROM BELOW

__(ST) (NT) (.Tf SHORE MLW

(NAUT.MI.j (FEET) C 0 E F F I C I E N T S

CENTRAL PRESSURE INDEX

P INCHES 27.05 27.05 27.05 0 0 BQ'I1ON FRICTION FACTOR 0.0025 PERIPHERAL PRESSURE 0.2 17 P INCHES 30.77 30.77 30.77 0.5 32 WIND STRESS COiRRECTION FACTOR 1.10

1.0 29 RADIUS TO MAXIMUM WIND _ 1.5 35 LARGE RADIUS NAUT. MI. 38 38 38 2.0 45 TRANSLATION SPEED 30 38 WA TER LEVEL DATA

F (FORWARD SPEED) KNOTS 1 10 26 48 _ 0 56

_ 5.0 61 (AT OPEN CCAST SHORELINE)

MAXIMUM WIND SPEED 6 71 V M.P.H. 124 133 146 7 56 INITIAL DISTANCE-NAUT. MI,.ýJ 8 6o PMH SPEED CF TRANSLATION

FROM 20 MPH WIND 350 293 251 9 58 COMPONENTS ST I MI HT

6T SHORE TO MAX. WIND I 10 59 F E E T

11 65 Note: Maximum wind speed is assumed to be on 12 64 WIND SETUP 14.30

the traverse that is to right of storm track a 13 70

distance equal to the radius to maximum wind. 14 62 PRESSURE SETUP 2.83

1/Initial distance is distance along traverse from shoreline to maximum wind when leading - 18 INITIAL WATER LEV. 1.14

20 103

90

20 mph isovel intersects shoreline. Storm -

diameter between 20 mph isovels is approxi- - 2 ~ 114 ASTRONOMICAL 5.10

mately double the initial distanc

e. TIDE LEVEL

- 146 TOTAL-SURGE

STILL WATER LEV. 23.37

840 IEET NLW

LATITUDE; 38o14, DEGREE AT TRAVERSE

MID-POINT FROM SHORE

To 600-FOOT DEPTH

I.

TABLE C.16 SUMNARY-PERTINENT PRUbAPLE MAXIMUk hiJiRICANE (FMH), STORM SURGE COMPUTATIONAL LATA AND RESULTANT WATER LEVEL

LOCATION ATLANTIC LAT. 39' 21' LONG. 74 25 : TRAVERSE-AZIMUTH 146 DEGREEt LENGTH 70 NAUTICAL MILES

CITY, NEW JERSEY

PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS OCEAN BED PROFILU PMH CCMPUTATIONAL COEFFICIENT

ZONE 4 AT LOCATION 390 21' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

S OF TRANSLATION DISTANCE DEPTH

PARAMETER DESIGNATIONS 5 SLOW IHODERATF HIGH FROM BELOW

_, (ST) (MT) (HT) SHORE MLW

(NAUT.MI.) (FEET) C0 EF F I C I E N T S

CENTRAL PRESSURE INDEX

P INCHES 27.12 K 0 0 B*0'1ION FhICTION FACTOR 0.002r5 PERIPHERAL PRESSURE 0.2 10.0

P INCHES 30.70 15.0 _ WIND STRESS CORRECTION FACTOR 1.10

n _____ ____0.70__ 10,

22.0 _

RADIUS TO MAXIMUM WIND _ 2.0 38.0 _

LARGE RADIUS NAUT. MI. 40 - 5.0 50.0 _

_ 10.0 72.0 _ WATER Lh V EL DATA

TRANSLATION SPEED

Fv (FORWARD SPEED) KNOTS 4*9 20.0 90.0 -

- 30.0 120.0 _ (AT OPEN CCAST SHOPELINE)

MAXIMUM WIND SPEED _ 40.0 138.0 _

V M.P.H. 142 xX - 50.0 162.0

INITIAL DISTANCE-NAUT. MI.Ii 6o.o 210.0 - PMH SPEED OF TRANSLATION

FROM420 MPH WIND _ 65.0 258.0 _ COMPONENTS ST F I mlE MT

_ 70.0 600.0

AT SHORE TO MAX. WIND I__ E E T

Note: Maximum wind speed is assumed to be on WIND SETUP 15.32 the traverse that is to right of storm track a distance equal to the radius to maximum wind.

PRESSURE SETUP 2.57 Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 1.10

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- ASTRONOMICAL 5.80

mately double the initial distanc

e. TIDE LEVEL

TOTAL-SURGE

STILL WATER LEV. 24.80

EET MLW

LATITUDE # 38' 53'

DEGREE AT TRAVERSE

MID-POINT FROM SHORE

o 600-FOOT DEPTH

TABLE C.17 SULMPLAY-PERTINENT PROBAFLE MAXIMUE. hUR(RICANE (FMH), STORM SURGE COMPU'ATIONAL LATA AND RESULTANT WATER LEVEL

LOCATION LONG ISLAND,LAT. 410 00' LONG. 72 01.8': TRAVERSE-AZIMUTH 166 DEBREEE LENGqH 68.4 NAUTICAL MILES

CONNECTICUT

PROBABLE MAXIMUM HUHRICANE INDEX CHARACTEISTICS OCEAN BED PROFILE PMH ccNPUTATIONAL COEFFICIENT

ZONE 4 AT LOCATION 4.1 00' DEGREE NOBTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

- SPEED OF TRANSIATION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW HODERATF HIGH FROM BELOW

_ (ST) (MT) (HT() SHORE MLW

(NAUT.MI.) (FEET) C 0 E F F I C I E N T S

CENTRAL PRESSURE INDEX

P INCHES 27.26 27.26 27.26 0 0

0 _ BO1J3'ON FriICTION FACTOR 0.0029 PERIPHERAL PRESSURE 0.2 22 P INCHES 30.56 30.56 30.56 _ 0.5 38 WIND STRESS CORRECTiON FACTOH 1.10

- 1.0 43 R US TO MAXIMUM WIND _ 1.5 53 LARGE RADIUS NAUT. MI. 48 48 48 _ 2.0 67 TRANSLATION SPEED - 3.0 82 WAT Eh LE V E L DATA

LA

(FORWARD SPEED) KNOTS 15 34 51 - 5.0 102 LI'

IMUM WIND SPEED - 10.0 132 (AT OPEN CCAST SHORELINE)

V M.P.H. 115 126 136 - 15.0 145

_ 20.0 170

INITIAL DISTANCE-NAUT.NI.i/ - 30.0 212 PMH SPEED OF TRANSLATION

FROM 20 MPH WIND 346 293 259 40.0 240 COMPONENTS ST MIT I HT

AT SHORE TO MAX. WIND I I 50.0 260 F E E T

60.0 302 Note: Maximum wind speed is assumed to be on 68.4 6o0 WIND SETUP 8.73 the traverse that is to right of storm track a 70.0

7 870

distance equal to the radius to maximum wind. PRESSURE SETUP 2.46

-/Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 0.97

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- ASTRONOMICAL 8.00

mately double the initial distanc

e. TIDE LEVEL

OTAL-SURGE

STILL WATER LEV. 20.16 VEE MLW _ I I

LATITUDE 0 400 27 DEGREE AT TRAVERSE

MID-POINT FROM SHORE

To 600-FOOT DEPTH

.4 I __I " .1 . - . .---

TABLE C.18 SU1I4AY-PERTINENT PROBABLE MAXIMUL. h1UJRICANE (FMH), STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL

LOCATION WATCH HILL LAT. 410i18.9' LONG. 71 50 ; TRAVERSE-AZIMUTH 166 DECREEs LENGTH 84 NAUTICAL MILES

POINT, RHODE ISLAND

PROBABLE MAXIMUM HURRICANE INDEX CHARACTrISTICS OCEAN BED PROFILE PMH CCNPUTATIONAL COEFFICIENT

ZONE 4 AT LOCATION 410 19' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

SPEED OF TRANSLATION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW MODERATF HIGH FROM BELOW

_ (ST) (MT) (HT) SHORE MLW

(NAUT.MI.) (FEET) C 0 E F F I C I E N T S

CENTRAL PRESSURE INDEX

P INCHES 27.29 27.29 27.29 o 0 BO'T¶ON FRICTION FACTOR 0.0025 PERIPHERAL PRESSURE 0.2 28 Pn INCHES 30.54 30.54 30.54 0.5 40 WIND STRESS CORRECTION FACTOR 1.10

1.0 77 RADIUS TO MAXIMUM WIND _ 1.5 98 LARGE RADIUS NAUT. MI. 49 49 49 2.0 119 TRANSLATION SPEED - 3.0 117 WATE h LEVEL DATA

F (FORWARD SPEED) KNOTS 15 35 51 4.0 114

- 5.0 128 (AT OPEN CCAST SHORELINE)

0~' MAXIMUM WIND SPEED 6.0 114 V M.P.H. 113 126 134 7.0 113 INITIAL DISTANCE-NAUT.MI.i / 8.0 117 PMH SPEED OF THANSLATION

FROM 20 MPH WIND - 9.0 118 COMP014ENTS ST J MT i HT

348 284 255 AT SHORE TO MAX. WIND 10.0 93 F E E T

11.0 70

Note: Maximum wind speed is assumed to be on

12.0 65 WIND SETUP 10.01 the traverse that is to right of storm track a

_ 13.0 51 distance equal to the radius to maximum wind.

14.0 56 PRESSURE SETUP 2.42

/ Initial distance is distance along traverse 15.0 77?

from shoreline to maximum wind when leading

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi-

-

20.0

0. 00 g

131

222 INITIAL WATER LEV.

kSTRONOMICAL,

0.96

8.80

.0 240 -

mately double the initial distanc

e. r IDE LEVEL

- 70 rOTAL-SURGE

28g STILL WATER LEV. 22.1.9

90.0 1.488 F'EET MLW I__________

LATITUDE 4 40° 38 DE)REE AT TRAVERSE

MID-POINT FROM SHORE

TO 600-FOOT DEPTH

TABLE C.19 SUMMARY-PERTINENT PROBA-PLE MAXIMUm. HURRICANE (FMH), STORM SURGE COMPUTATIONAL DATA AND RESULTANT WATER LEVEL

LOCATION HAMPTON LAT. 420 57' LONG. 70' 47.1'; TRAVERSE-AZIMUTH 115 D@CREE, LENGTH 40 NAUTICAL MILES

BEACH, NEW HAMPSHIRE

PROBABLE MAXIMUM HURRICANE INDEX CHARACTERISTICS OCEAN BED PROFILE PMH OCNPUTATIONAL COEFFICIENT

ZONE 4 AT LOCATION 420 57' DEGREE NORTH

TRAVERSE WATER AND WATER LEVEL (SURGE) ESTIMATES

SPEED OF TRANSLATION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW 1-ODERATF HIGH FROM BELOW

_(ST) (NT) (HT) SHORE

INAUT.M1.)

MLW

(FFM) C 0 E F F I C I E N T S

METRAL PRESSURE INDEX

P INCHES 27.44 27.44 27.44 - 0 0 BO7'OI- FRICTION FACTOR 0.0025 PERIPHERAL PRESSURE 0.2 8 P INCHES 30.42 30.42 30.42 - 0.5 40 WIND STRESS CORRECTION FACTOR 1.10

-. 1.0 64 RADIUS TO MAXIMUM WIND - 1.5 82 LARGE RADIUS NAUT. MI. 57 57 57 '- 2.0 100

[RANSIATION SPEED - 3.0 105 WATE h LE V EL DATA

F (FORWARD SPEED) KNOTS 17 37 52 - 5.0 156

- 10.0 258 (Ar OPEN CCAST SHORELINE)

WAXIMUM WIND SPEED - 15.0 336 V M.P.H. 107 118 127 - 20.0 266 INITIAL DISTAoCE-HAUT.MI.1/ - 25.0 210 PMH SPEED OF TRANSIATION

FROM 20 MPH WIND 353 290 262 - 30.0 322 COMPONENTS ST I MT HI,

kT SHORE TO MAX. WIND - 35.0 433 F E E T

Note: Maximum wind speed is assumed to be on - 40.o 6o0

WIND SETUP 4.25 the traverse that is to right of storm track a distance equal to the radius to maximum wind.

PRESSURE SETUP 2.23

- Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 0.83

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- ASTRONOMICAL 11.70

mately double the initial distanc

e. TIDE LEVEL

TOTAL-SURGE

STILL WATER LEV. 19.01 FEET MLW

LATITUDE

  • 420 48'

DEGREE AT TRAVERSE

MID-POINT FROM SHORE

600-FOOT DEPTH

TABLE C.20

SUMMARY-PERTINENT PRUhABLE MAXIMUE hUJiRICANE (FMH), STORM SURGE COMPU'IATlONAL [ATA AND RESULTANT WATER LEVEL

LOCATION GREAT LAT. 44°33.4' LONG. 67 30'; TRAVERSE-AZIMUTH 148 DEGREEs LFNGTH 178.6 NAUTICAL MILES

SPRUCE ISLAND, MAINE

PROBABLE MAXIMUM HUHRICANE INDEX CHARACTERISTICS OCEAN BED PROFILE PMH CCMPUTATIONAL COEFFICIENT

ZONE 4 AT LOCATION 440 3' DEGREE NORTH ANL WATER LEVEL (SURGE) ESTIMATES

TRAVERSE WATER

SPEED

OF TRANSLATION DISTANCE DEPTH

PARAMETER DESIGNATIONS SLOW HODERATF HIGH FROM BFLOW

(ST) (nT) (HT) SHORE MLW

(NAUT.MI.) (FFET) C 0 E F F - C I E N T S

CENTRAL PRESSURE INDEX

P INCHES 27.61 27.61 27.61 0 0 BOTIOM 1i FICTION FACTOR 0.0025 PERIPHERAL PRESSURE 0.2 50

P INCHES 30.25 30.25 30.25 0.5 96 WIND STRESS CORRECTION FACTOR 1.10

1.0 95 RADIUS TO MAXIMUM WIND 1.5 125 LARGE RADIUS NAUT. MI. 64 64 64 2.0 125 TRANSLATION SPEED 3.0 165 W A T ER L E V E L DA T A

F (FORWARD SPEED) KNOTS 19 39 53 4.o 247

- 5.0 188 (Ar OPEN CCAST SHORELINE)

MAXIMUM WIND SPEED 10.0 233 V M.P.H. 102 114 122 _ 15.0 438 INITIAL DISTANCE-NAUT. *MI._ / 20.0 570 PMH SPEED OF TRANSLATION

FROM 20 MPH WIND 352 288 262 30.0 271 COMPONENTS ST I MT HT

AT SHORE TO MAX. WIND I 40.0 511 F E E T

Note: Maximum wind speed is assumed to be on

- 50.0 443 the traverse that is to right of storm track a

_ 6o.0 374 WIND SETUP 9.73 distance equal to the radius to maximum wind. 1100.0 0~

1/ PRESSURE SETUP 1.82

100.0 25

-/Initial distance is distance along traverse from shoreline to maximum wind when leading INITIAL WATER LEV. 0.56

-

- 120.0

110.01 34O -

20 mph isovel intersects shoreline. Storm diameter between 20 mph isovels is approxi- STRONONICAL 18.40

mately double the initial distance. I IDE LEVEL

TOT*L-SURGE

STILL WATER LEV. 30.51

- 180.0 1,620

EET MLW

LATITUDE $43 17.8- DEGREE AT TRAVERSE

MID-POINT FROM SHORE

o 600-FOOT DEPTH

TABLE C.21 OCEAN BED PROFILES

PASS CRYSTAL CHESAPEAKE

CHRISTIAN RIVER ST. LUCIE BAY MOUTH SEABROOK

Nautical Nautical Nautical Nautical Nautical Miles from Depth, Miles from Depth, Miles from Depth, Miles from Depth, Miles from Depth, Shore ft, MLW Shore ft, RLW Shore ft, HLW Shore ft, ffLW Shore ft, MLW

1 3 0.55 3 0.1 10 5 44 0.5 20

2 9 2.31 10 10 90 10 56 4 120

-4 14 390 30 102 10 250

5 12 6.25 16

10 13 8.33 9 18.7 600 50 178 25 250

15 35 31.4 50 55 240 44 600

20 36 100 180 62 600

30 40 113 300

40 52 127 600

50 90

60 160

70 335

77 600

UNITED STATES

NUCLEAR REGULATORY COMMISSION

WASHINGTON, D. C. 20555 POSTAGE AND FEES PAID

U.S. NUCLEAR REGULATORY

OFFICIAL BUSINESS COMMISSION

PENALTY FOR PRIVATE USE, $300


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