Regulatory Guide 1.59

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)

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

OFFICE OF STANDARDS DEVELOPMENT

DESIGN

NUCLEAR PLANTS

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.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."

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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.

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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.

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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.)

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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.

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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.

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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

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(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