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)

U.S. NUCLEAR REGULATORY

COMMISSION

REGULATORY

GUIDE OFFICE OF STANDARDS

DEVELOPMENT

Revision 1 April 1976 DESIGN NUCLEAR PLANTS iA~5,,..1 USNRC REGULATORY

GUIDES Comments should be sent to the Secretary of the Commission.

U S. Nuclear Regulatory Guides are issued to describe and make available to the public Regulatory Commission.

Washington.

D C 2055o. Attention Docketing and methods acceptable to the NRC staff of implementing specific parts of the Commission's regulations, to delineate techniques used by the staff in evalu The guides are issued in the following ten broad divisions" ating specific problems or postulated accidents, or to provide guidance to appli cants. Regulatory Guides are not substitutes for regulations, and compliance t Power Reactors 6. Products with them is not required Methods and solutions different from those set out in 2. Research and Test Reactors 7. Transportation the guides wdi be acceptable if they provide a basis for the findings requisite to 3 Fuels and Materials Facilities

8 Occupational Health the issuance or continuance u Ia permit or license by the Commission

4 Environmental and Siting 9. Antitrust Review Comments and suggestions for improvenments in these guides are encouraged

5 Materials and Plant Protection

10 General at all times, and guides will lbe revised. as appropriate, to accommodate coa ments and to reflect new intormatn or eyperience However. comments on Copies of published guides may be obtained by written request indicating the this guide. if received within about Iwo months after its issuance, will be par divisions desired to the U S Nuclear Regulatory Commission.

Washington.

D.C-culariy useful in evaluating the need for an early revision 20655. Attention:

Director.

Office of Standards Development

--7 0 C." r'11 cx) , '- " I 66 F(I

TABLE OF CONTENTS Page A .IN TRO DUCTIO N .....................................59-5

B. DISCUSSION

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595 C. REGULATORY

POSITION .......................

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59-7

D. IMPLEMENTATION

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.59-8 APPENDIX A -Probable Maximum and Seismically Induced Floods on Streams ..... .............

.59-9 APPENDIX B -Alternative Methods of Estimating Probable Maximum Floods ....... .............

.59-23 *APPENDIX C -Simplified Methods of Estimating Probable Maximum Surges ....... ..............

.59-53'LTines indicate substantive changes from previous issue.1.59-3

B. DISCUSSION

General Design Criterion 2, "Design Bases for Pro-tection Against Natural Phenomena," of Appendix A to 10 CFR Part 50, "General Design Criteria for Nuclear Power Plants," requires, in part, that structures, systems, and components important to safety be designed to withstand the effects of natural phenomena such as floods, tsunami, and seiches without loss of capability to perform their safety functions.

Criterion

2 also requires that design bases for these structures, systems, and components reflect (1) appropriate consideration of the most severe of the natural phenomena that have been historically reported for the site and surrounding region, with sufficient margin for the limited accuracy and quantity of the historical data and the period of time in which the data have been accumulated, (2) appropriate combinations of the effects of normal and accident conditions with the effects of the natural phenomena, and (3) the importance of the safety functions to be performed.

Paragraph

100.10(c)

of 10 CFR Part 100, "Reactor Site Criteria," requires that physical characteristics of the site, including seismology, meteorology, geology, and hydrology, be taken into account in determining the acceptability of a site for a nuclear power reactor.Section IV(c) of Appendix A, "Seismic and GeologicSiting Criteria for Nuclear Power Plants," to 10 CFR Part 100 suggests investigations for a detailed study of seismically induced floods and water waves. The ap-pendix also suggests [Section IV(c)(iii)]

that the deter-mination of design bases for seismically induced floods and water waves be based on the results of the required geologic and seismic investigations and that these design bases be taken into account in the design of the nuclear power plant.This guide discusses the design basis floods that nuclear power plants should be. designed to withstand without loss of capability for cold shutdown and maintenance thereof. The design requirements for flood protection are the subject of Regulatory Guide 1.102"Flood Protection for Nuclear Power Plants." Appendix A outlines the nature and scope of detailed hydrologic engineering activities involved in determining estimates for the probable maximum flood and for seismically induced floods resulting from dam failures and describes the situations for which less extensive analyses are acceptable.

Two new appendices have been added to this revision of the guide. Appendix B gives timesaving alternative methods of estimating the prob-able maximum flood along streams and Appendix C gives a simplified method of estimating probable maxi-mum surges on the Atlantic and Gulf coasts.Nuclear power plants should be designed to prevent the loss of capability for cold shutdown and mainten-ance thereof resulting from the most severe flood conditions that can reasonably be predicted to occur at a site as a result of severe hydrometeorological conditions, seismic activity, or both.The Corps of Engineers for many years has studied conditions and circumstances relating to floods and flood control. As a result of these studies, it has developed a definition for a Probable Maximum Flood (PMF)' and attendant analytical techniques for esti-mating, with an acceptable degree of conservatism, flood levels on streams resulting from hydrometeorological conditions.

For estimating seismically induced flood levels, an acceptable degree of conservatism for evalua-ting the effects of the initiating event is provided by Appendix A to 10 CFR Part 100.The conditions resulting from the worst site-related flood probable at the nuclear power plant (e.g., PMF, seismically induced flood, seiche, surge, severe local precipitation)

with attendant wind-generated wave activ-ity constitute the design basis flood conditions that safety-related structures, systems, and components iden-tified in Regulatory Guide 1.292 should be designed to withstand and retain capability for cold shutdown and maintenance thereof.For sites along streams, the PMF generally provides the design basis flood. For sites along lakes or seashores, a flood condition of comparable severity could be'Corps of Engineers'

Probable Maximum Flood definition ap-pears in many publications of that agency such as Engineering Circular EC 1110-2-27, Change 1, "Engineering and Design-Policies and Procedures Pertaining to Determination of Spill-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 loss of life and property.2Regulatory Guide 1.29, "Seismic Design Classification," identifies structures, systems, and components of light-water- cooled nuclear power plants that should be designed to withstand the effects of the Safe Shutdown Earthquake and 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 capability to prevent or mitigate the consequences of accidents which could result in potential offsite exposures comparable to the guideline exposures of 10 CFR Part 100. These same structures, systems, and components should also be designed to withstand conditions resulting from the design basis flood and retain capability for cold shutdown and maintenance thereof of other types of nuclear power plants. It is expected that safety-related structures, systems, and components of other types of nuclear power plants will be identified in future regulatory guides. In the interim, Regulatory Guide 1.29 should'be used as guidance when identifying safety-related structures, systems, and components of other types of nuclear power plants.1.59-5 produced by the most severe combination of hydro-meteorological parameters reasonably possible, such as may be produced by a Probable Maximum Hurricane, 3 or by a Probable Maximum Seiche. On estuaries, a Probable Maximum River Flood, a Probable Maximum Surge, a Probable Maximum Seiche, or a reasonable combination of less severe phenomenologically caused flooding events should be considered in arriving at design basis flood conditions comparable in frequency of occurrence with a PMF on streams.In addition to floods produced by severe hydro-meteorological conditions, the most severe seismically induced floods reasonably possible should be considered for each site. Along streams and estuaries, seismically induced floods may be produced by dam failures or landslides.

Along lakeshores, coastlines, and estuaries, seismically induced or tsunami-type flooding shoUld be considered.

Consideration of seismically induced floods should include the same range of seismic events as is postulated for the design of the nuclear plant. For instance, the analysis of floods caused by dam failures, landslides, or tsunami requires consideration of seismic events of the severity of the Safe Shutdown Earthquake occurring at the location that would produce the worst such flood at the nuclear power plant site. In the case of seismically induced floods along rivers, lakes, and es-tuaries which may be produced by events less severe than a Safe Shutdown Earthquake, consideration should be given to the coincident occurrence of floods due to severe hydrometeorological conditions, but only where the effects on the plant are worse than and the probability of such combined events may be greater than an individual occurrence of the most severe event of either type. For example, a seismically induced flood produced by an Operating Basis Earthquake (as defined in Appendix A to 10 CFR Part 100) coincident with a runoff-type flood of Standard Project Flood 4 severity may be considered to have approximately the same severity as the seismically induced flood from an earthquake of Safe Shutdown severity coincident with about a 25-year flood. For the specific case of seismi-cally induced floods due to dam failures, an evaluation should be made of flood waves that may be caused by domino-type dam failures triggered by a seismically induced failure of a critically located dam and of flood See References

2 and 4, Appendix C.4 The Standard Project Flood (SPF) is the flood resulting from the most severe flood-producing rainfall depth-area-duration relationship and isohyetal pattern of any storm that is considered reasonably characteristic of the region in which the watershed is located. If snowmelt may be substantial, appropri-ate amounts are included with the Standard Project Storm rainfall.

Where floods are predominantly caused by snowmelt, the SPF is based on critical combinations of snow, temperature, and water losses. See "Standard Project Flood Determina- tions," EM 1110-2-1411, Corps of Engineers, Departrlhent of the Army (revised March 1965).waves that may be caused by multiple dam failures in a region where dams may be located close enough together that a single seismic event can cause multiple failures.Each of the severe flood types discussed above should represent the upper limit of all potential phenomeno- logically caused flood combinations considered reason-ably possible.

Analytical techniques are available and should generally be used for prediction at individual sites. Those techniques applicable to PMF and seismi-cally induced flood estimates on streams are presented in Appendices A and B to this guide. Similar appendices for coastal, estuary, and Great Lakes sites, reflecting com-parable levels of risk, will be issued as they become available.

Appendix C contains an acceptable method of estimating hurricane-induced surge levels on the open coasts of the Gulf of Mexico and the Atlantic Ocean.Analyses of only the most severe flood conditions may not indicate potential threats to safety-related systems that might result from combinations of flood conditions thought to be less severe. Therefore, reason-able combinations of less-severe flood conditions should also be considered to the extent needed for a consistent level of conservatism.

Such combinations should be evaluated in cases where the probability of their existing at the same time and having significant consequences is at least comparable to. that associated with the most severe hydrometeorological or seismically induced flood.For example, a failure of relatively high levees adjacent (to a plant could occur during floods less severe than the worst site-related flood, but would produce conditions more severe than would result during a greater flood (where a levee failure elsewhere would produce less severe conditions at the plant site).Wind-generated wave activity may produce severe flood-induced static and dynamic conditions either independent of or coincident with severe hydrometeoro- logical or seismic flood-producing mechanisms.

For example, along a lake, reservoir, river, or seashore, reasonably severe wave action should be considered coincident with the probable maximum water level conditions.

5 The coincidence of wave activity with probable maximum water level conditions should take into account the fact that sufficient time can elapse between the occurrence of the assumed meteorological mechanism and the maximum water level to allow'Probable Maximum Water Level is defined by the Corps of Engineers as "the maximum still water level (i.e., exclusive of local coincident wave runup) which can be produced by the most severe combination of hydrometeorological and/or seismic parameters reasonably possible for a particular location.Such phenomena are hurricanes, moving squall lines, other cyclonic meteorological events, tsunami, etc., which, when combined with the physical response of a body of water and severe ambient hydrological conditions, would produce a still water level that has virtually no risk of being exceeded." (See Appendix A to this guide.)1.59-6 subsequent meteorological activity to produce sub-stantial wind-generated waves coincident with the high water level. In addition, the most severe wave activity at the site that can be generated by distant hydrometeoro- logical activity should be considered.

For instance, coastal locations may be subjected to severe wave action caused by a distant storm that, although not as severe as a local storm (e.g., a Probable Maximum Hurricane), may produce more severe wave action because of a very long wave-generating fetch. The most severe wave activity at the site that may be generated by conditions at a distance from the site should be considered in such cases. In addition, assurance should be provided that safety systems necessary for cold shutdown and main-tenance thereof are designed to withstand the static and dynamic effects resulting from frequent flood levels (i.e., the maximum operating level in reservoirs and the 10-year flood level in streams) coincident with the waves that would be produced by the Probable Maximum Gradient Wind 6 for the site (based on a study of historical regional meteorology).

C. REGULATORY

POSITION 1. The conditions resulting from the worst site-re-lated flood probable at a nuclear power plant (e.g., PMF, seismically induced flood, hurricane,.

seiche, surge, heavy local precipitation.)

with attendant wind-generated wave activity constitute the design basis flood conditions that safety-related structures, systems, and components iden-tified in Regulatory Guide 1.29 (see footnote 2) must be designed to withstand and retain capability for cold shutdown and maintenance thereof.a. On streams the PMF, as defined by the Corps of Engineers and based on the analytical techniques sum-marized in Appendices A and B of this guide, provides an acceptable level of conservatism for estimating flood levels caused by severe hydrometeorological conditions.

b. Along lakeshores, coastlines, and estuaries.

estimates of flood levels resulting from severe surges, seiches, and wave action caused by hydrometeorological activity should be based on criteria comparable in conservatism to those used for Probable -Maximum Floods. Criteria and analytical techniques providing this level of conservatism for the analysis of these events will be summarized in subsequent appendices to this guide.Appendix C of this guide presents an acceptable method for estimating the stillwater level of the Probable Maximum Surge from hurricanes at open-coast sites on the Atlantic Ocean and Gulf of Mexico.c. Flood conditions that could be caused by dam failures from earthquakes should also be considered in 6 Probable Maximum Gradient Wind is defined as a gradient wind of a designated duration, which there is virtually no risk of exceeding.

establishing the design basis flood. A simplified analyti-cal technique for evaluating the hydrologic effects of seismically induced dam failures discussed herein is presented in Appendix A of this guide. Techniques for evaluating the effects of tsunami will also be presented in a future appendix.d. Where upstream dams or other features which provide flood protection are present, in addition to the analyses of the most severe floods that may be induced by either hydrometeorological or seismic mechanisms, reasonable combinations of less-severe flood conditions and seismic events should also be considered to the extent needed for a consistent level of conservatism.

The effect of such combinations on the flood conditions at the plant site should be evaluated in cases where the probability of such combinations occurring at the same time and having significant consequences is at least comparable to the probability associated with the most severe hydrometeorological or seismically induced flood.On relatively large streams, examples of acceptable combinations of runoff floods and seismic events that could affect the flood conditions at the plant include the Safe Shutdown Earthquake with the 25-year flood and the Operating Basis Earthquake with the Standard Project Flood. Less severe flood conditions, associated with the above seismic events, may be acceptable for small streams which exhibit relatively short periods of flooding.

The above combinations of independent events are specified here only with respect to the determination of the design basis flood level.e. The effects of coincident wind-generated wave activity to the water levels associated with the worst site-related flood possible (as determined from para-graphs a, b, c, or d above) should be added to generally define the upper limit of flood .potential.

An acceptable analytical basis for wind-generated wave activity coincident with probable maximum water levels is the assumption of a 40-mph overland wind from the most critical wind-wave-producing direction.

However, if historical windstorm data substantiate that the 40-mph event, including wind direction and speed, is more extreme than has occurred regionally, historical data may be used. If the mechanism producing the maximum water level, such as a hurricane, would itself produce higher waves, these higher waves should be used as the design basis.2. As an alternative to designing hardened protec-tion 7 for all safety-related structures, systems, and components as specified in Regulatory Position 1 above,"Hardened protection means structural provisions incorporated in the plant design that will protect safety-related structures, systems, and components from the static and dynamic effects of floods. In addition, each component of the protection must be passive and in place, as it is to be used for flood protection, during normal plant operation.

Examples of the types of flood protection to be provided for nuclear power plants are contained in Regulatory Guide 1.102.fI 1.59-7 I it is permissible not to provide hardened protection for some of these features if: a. Sufficient warning time is shown to be available to shut the plant down and implement adequate emergency procedures;

b. All safety-related structures, systems, and com-ponents identified in Regulatory Guide 1..29 (see foot-note 2) are designed to withstand the flood conditions resulting from a Standard Project event 8 with attendant wind-generated wave activity that may be produced by the worst winds of record and remain functional;

c. In addition to the analyses in paragraph

2.b above, reasonable combinations of less-severe flood conditions are also considered to the extent needed for a consistent level of conservatism;

and d. In addition to paragraph

2.b above, at least those structures, systems, and components necessary for cold shutdown and maintenance thereof are designed with hardened protective features to remain functional while withstanding the entire range of flood conditions up to and including the worst site-related flood probable (e.g., PMF, seismically induced flood, hurricane, surge.seiche, heavy local precipitation)

with coincident wind-generated wave action as discussed in Regulatory Posi-tion I above.3. During the economic life of a nuclear power plant, unanticipated changes to the site environs which may affect the flood-producing characteristics of the environs are possible.

Examples include construction of a dam upstream or downstream of the plant, or comparably, construction of a highway or railroad bridge and embankment that obstructs the flood flow of a river, and construction of a harbor or deepening of an existing harbor near a coastal or lake site plant.Significant changes in the runoff or other flood-producing characteristics of the site environs, as they affect the design basis flood, should be identified and used as the basis to develop or modify emergency operating procedures, if necessary, to mitigate the 8 For sites along streams, this event is characterized by the Corps of Engineers'

definition of a Standard Project Flood. (Also, see footnote 4.) Such floods have been found to produce flow rates generally

40 to 60 percent of the PMF. For sites along seashores, this event may be characterized by the Corps of Engineers'

definition of a Standard Project Hurricane.

For other sites, a comparable level of risk should be assumed.a. The type of investigation undertaken to identify changed or changing conditions in the site environs.b. The changed or changing conditions noted during the investigation.

c. The hydrologic engineering bases for estimating the effects of the changed conditions on the design basis flood.d. Safety-related structures, systems, or com-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 facility necessary to afford protection during the in-creased flood conditions.

If emergency operating pro-cedures must be used to mitigate the effects of these new flood conditions, the emergency procedures devel-oped or modifications to existing procedures should be provided.4. Proper utilization of the data and procedures in Appendices B and C will result in PMF peak discharges and PMS peak stillwater levels which will in many cases be approved by the NRC staff with no further verifica-tion. The staff will continue to accept for review detailed PMF and PMS analyses that result in less conservative estimates than those obtained by use of Appendices B and C. In addition, previously reviewed 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 conservative estimates.

D. IMPLEMENTATION

The purpose of this section is to provide information to license applicants and licensees regardirng the NRC staff's plans for using this regulatory guide.This guide reflects current NRC practice.

Therefore, 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-tions, the method described herein is being and will continue to be used in the evaluation of submittals for construction permit applications until this guide is revised as a result of suggestiQns from the public or additional staff review.9 Reporting should be by special report to the appropriate NRC Regional Office and to the Director of the Office of Inspection and Enforcement.

Requirement for such reports should be included in theTechnical Specifications (Appendix A) unless it can be demonstrated that such reports will not be necessary during the life of the plant._4 effects of the increased flood. The following should be reported:

9 (1.59-8 APPENDIX A PROBABLE MAXIMUM AND SEISMICALLY

INDUCED FLOODS ON STREAMS TABLE OF CONTENTS Page A. 1 Introduction

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A. 2 Probable Maximum Flood ................

A. 3 Hydrologic Characteristics

................A. 4 Flood Hydrograph Analyses ...............

A. 5 Precipitation Losses and Base Flow ............

A. 6 Runoff M odel .............. ... ....A. 7 Probable Maximum Precipitation Estimates

.........A. 8 Channel and Reservoir Routing ..............

A. 9 Probable Maximum Flood Hydrograph Estimates

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A.1O Seismically Induced Floods ..... .................

A.] I Water Level Determinations

..... ..... .... .A.12 Coincident Wind-Wave Activity ..............

1.59-11 1.59-11 1.59-12 1.59-13 1.59-13 1.59-14 1.59-15 1.59-17 1.59-17 1.59-18 1.59-18 1.59-19................................................REFERENCES

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.. .1.59-20 1.59-9 (I

A.1 INTRODUCTION

This appendix has been prepared to provide guidance for flood analyses required in support of applications for licenses for nuclear facilities to be located on streams.Because of the depth and diversity of presently available techniques, this appendix summarizes acceptable methods for estimating Probable Maximum Precipitation (PMP), for developing rainfall-runoff models, for analyz-ing seismically induced dam failures, and for estimating the resulting water levels.The Probable Maximum Flood (PMF) may be thought of as one generated by precipitation and a seismically induced flood as one caused by dam failure.For many sites, however, these two types do not constitute the worst potential flood danger to the safety of the nuclear facilities.

Subsequent appendices will present acceptable methods of analyzing other flood types, such as tsunami, seiches, and surges (in addition to the surge method in Appendix C).The PMF on streams is compared with the upper limit of flood potential that may be caused by other phenomena to develop a basis for the design of safety-related structures and systems. This appendix outlines the nature and scope of detail.ed hydrologic engineering activities involved in determining estimates for the PMF and for seismically induced floods resulting--rom dam failures and describes the situations fdr which less extensive analyses are acceptable.

Estimation of the PMF requires the determination of the hydrologic response (losses, base flow, routing, and runoff model) of watersheds to intense rainfall, verifica-tion based on historical storm and runoff data (flood hydrograph analysis), the most severe precipitation reasonably possible (PMP), minimum losses, maximum base flow, channel and reservoir routing, the adequacy of existing and proposed river control structures to safely pass a PMF, water level determinations, and the superposition of potential wind-generated wave activity.Seismically induced floods, such as may be produced by dam failures or landslides, may be analytically evaluated using many PMF estimating components (e.g., routing techniques, water level determinations)

after conserva-tive assumptions of flood wave initiation (such as dam failures)

have been made. Each potential flood com-ponent requires an in-depth analysis.

The basic data and results should be evaluated to ensure that the PMF estimate is conservative.

In addition, the flood potential from seismically induced causes should be compared with the PMF to ensure selection of the appropriate design basis flood. The seismically induced flood poten-tial may be evaluated by simplified methods when conservatively determined results provide acceptable iesign bases.Three exceptions to use of the above-described analyses are considered acceptable as follows: a. No flood analysis is required for nuclear facility sites where it is obvious that a PMF or seismically induced flood has no bearing. Examples of such sites are coastal locations (where it is obvious that surges, wave action, or tsunami would produce controlling water levels and flood conditions)

and hilltop or "dry" sites.b. Where PMF or seismically induced flood estimates of a quality comparable to that indicated herein exist for locations near the site of the nuclear facility, the estimates may be extrapolated directly to the site if such extrapolations do not introduce potential errors of more than about a foot in design basis water level estimates.(See Appendix B.)c. It is recognized that an in-depth PMF estimate may not be warranted because of the inherent capability 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-mensurate with the cost of providing protection.

In such cases, other means of estimating design basis floods are acceptable if it can be demonstrated that the technique utilized or the estimate itself is conservative.

Similarly, conservative estimates of seismically induced flood potential may provide adequate demonstration of nuclear facility safety.A.2 PROBABLE MAXIMUM FLOOD Probable Maximum Flood studies should be com-patible with the specific definitions and criteria sum-marized as follows: a. The Corps of Engineers defines the PMF as "the hypothetical flood characteristics (peak discharge, volume, and hydrograph shape) that are considered to be the most severe reasonably possible at a particular location, based on relatively comprehensive hydro-meteorological analysis of critical runoff-producing pre-cipitation (and snowmelt, if pertinent)

and hydrologic factors favorable for maximum flood runoff." Detailed PMF determinations are usually prepared by estimating the areal distribution of PMP (defined below) over the subject drainage basin in critical periods of time and computing the residual runoff hydrograph likely to result with critical coincident conditions of ground wetness and related factors. PMF estimates are usually based on the observed and deduced characteristics of historical flood-producing stormsý Associated hydrologic factors are modified on the basis of hydrometeorological analyses to represent the most severe runoff conditions considered to be "reasonably possible" in the particular drainage basin under study. The PMF should be deter-mined for adjacent large streams. In addition, a local 1.59-11 PMF should be estimated for each local drainage course that can influence safety-related facilities, including drainage from the roofs of buildings, to assure that local intense precipitation cannot constitute a threat to the safety of the nuclear facility.b. Probable Maximum Precipitation is defined by the Corps of Engineers and the National Oceanic and Atmospheric Administration (NOAA) as "the theoreti-cally greatest depth of precipitation for a given duration that is meteorologically possible over the applicable drainage area that would produce flood flows of which there is virtually no risk of being exceeded.

These estimates usually involve detailed analyses of historical flood-producing storms in the general region of the drainage 'basin under study, and certain modifications and extrapolations of historical data and reflect more severe rainfall-runoff relations than actually recorded, insofar as these are deemed reasonably possible of occurrence on the basis of hydrometeorological reason-ing." The PMP should represent the depth, time, and spade distribution of precipitation that approaches the upper limit of what the atmosphere and regional topography can produce. The critical PMP meteorologi- cal conditions are based on an analysis of air-mass properties (e.g., effective precipitable water, depth of inflow layer, temperatures, winds), synoptic situations prevailing during recorded storms in the region, topo-graphical features, season of occurrence, and location of the geographic areas involved.

The values thus derived are designated as the PMP, since they are determined within the limitations of current meteorological theory and available data and are based on the most effective combination of critical controlling factors.A.3 HYDROLOGIC

CHARACTERISTICS

Hydrologic characteristics of the watershed and stream channels relative to the facility site should be determined from the following:

a. A topographic map of the drainage basin showing watershed boundaries.

for the entire basin and principal tributaries and other subbasins that are pertinent.

The map should include the location of principal stream gaging stations and other hydrologically related record collection stations (e.g., streamflow, precipitation)

and the locations of existing and proposed reservoirs.

b. The drainage areas in each of the pertinent watersheds or subbasins above gaging stations, reservoirs, any river control structures, and any unusual terrain features that could affect flood runoff. All .major reservoirs and channel improvements that will have a major influence on streamflow should be considered.

In addition, the age of existing structures and. information concerning proposed projects affecting runoff character- istics or streamflow are needed to adjust streamflow records to "pre-project(s)" and "with project(s)" con-ditions as follows: (1) The term "pre-project(s)

conditions" refers to all characteristics of watershed features and develop-ments that affect runoff characteristics.

Existing con-ditions are assumed to exist in the future if projects are to be operated in a similar manner during the life of the proposed nuclear facility and watershed runoff char-acteristics are not expected to change due to develop-ment.(2) The term "with project(s)" refers to the future effects of projects being analyzed, assuming they will exist in the future and operate as specified.

If existing projects were not operational during historical floods and may be expected to be effective during the lifetime of the nuclear facility, their effects on historical floods should be determined as part of the analyses outlined in Sections A.5, A.6, and A.8.c. Surface and subsurface characteristics that affect runoff and streamflow to a major degree (e.g., large swamp areas, noncontributing drainage areas, ground-water flow, and other watershed features of an unusual nature which cause unusual characteristics of stream-flow).d. Topographic features of the watershed and histor-ical flood profiles or high water marks, particularly in the vicinity of the nuclear facility.

For some sites one or more gaging stations may be required at or very near the 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-tion.)e. Stream channel distances between river control structures, major tributaries, and the facility site.f. Data on major storms and resulting floods-of- record in the drainage basin. Primary attention should be given to those events having a major bearing on hydrologic computations.

It is usually necessary to analyze a few major floods-of-record in order to develop unit hydrograph relations, infiltration indices, base flow relationships, information on flood routing relationships, and flood profiles.

Except in unusual cases, climatol-ogical data available from the Department of Commerce, the U.S. Army Corps of Engineers, National Oceanic and Atmospheric Administration, and other public sources are adequate to meet the data requirements for storm precipitation histories.

The data should include: (1) Hydrographs of major historical floods for pertinent locations in the basin from the U.S. Geological Survey or other sources, where available.

(.1.59-12

(2) Storm precipitation records, depth-area- duration data, and any available isohyetal maps for the most severe local historical storms or floods that will be used to estimate basin hydrological characteristics.

A.4 FLOOD HYDROGRAPH

ANALYSES Flood hydrograph analyses and related computations should be used to derive and verify the fundamental hydrologic factors of precipitation losses (see Section A.5) and the runoff model (see Section A.6). The analyses of observed flood hydrographs'

of streamflow and related storm precipitation (Ref. 1) use basic data and information referred to in Section A.3 above. The sizes and topographic features of the subbasin drainage areas upstream of the location of interest should be used to estimate runoff response for each individual hydro-logically similar subbasin utilized in the total basin runoff model. Subbasin runoff response characteristics are estimated from historical storm precipitation and streamflow records where such are available, and by synthetic means where no streamflow records are avail-abl

e. Reference

2 and the following provide guidance for the analysis of flood hydrographs.

a. The intensity, depth, and areal distribution of precipitation causing runoff for each historical storm (and rate of snowmelt, where this is significant)

should be analyzed.

Time distributions of storm precipitation

-k are generally based on recording rainfall gages. Total precipitation measurements (including data from non-recording gages) are usually distributed, in time, using precipitation recorders.

Areal distributions of precipita- tion, for each time increment, are generally based on a weighting procedure.

The incremental precipitation over a particular drainage area is the sum of the precipitation for each precipitation gage weighted by the percentage of the drainage area considered to be represented by the rain gage.b. Base flow is the time-distribution of the difference between gross runoff and net direct runoff.c. Initial and infiltration losses are the time distrib-uted differences between precipitation and net direct runoff.d. The combined effect of drainage area, channel characteristics, and reservoirs on the runoff character- istics, herein referred to as the "runoff model," should be established. (Channel and reservoir effects are dis-cussed separately in Section A.8.)Streamflow hydrographs (of major floods) are available in publications by the U.S. Geologic Survey, National Weather Service, State agencies, and other public sources.A.5 PRECIPITATION

LOSSES AND BASE FLOW Determination of the absorption capability of the basin should consider antecedent and initial conditions and infiltration during each storm investigated.

Antece-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.The fundamental hydrologic factors would be derived by analyzing observed hydrographs of streamflow and related storms. A thorough study is essential to deter-mine basin characteristics and meteorological influences affecting runoff from a specific basin. Additional discus-sion and procedures for analyses are contained in various publications such as Reference

2. The following discus-sion briefly describes the considerations for determining the minimum losses applicable to the PMF.a. Experience indicates that the capacity of a given soil and its cover to absorb rainfall applied continuously at high rate may rapidly decrease until a fairly definite minimum rate of infiltration is reached, usually within a period of a few hours. Infiltration loss may include initial conditions or may require separate determinations of initial losses. The order of decrease in infiltration capacity and the minimum rate attained are primarily dependent upon the type of ground cover, the size of soil pores within the zone of aeration, and the condi-tions affecting the rate of removal of capillary water from the zone of aeration.

Infiltration theory, with certain approximations, offers a practical means of estimating the volume of surface runoff from intense rainfall.

However, in applying the theory to natural drainage basins, several factors must be considered.

(1) The infiltration capacity of a given soil at the beginning of a storm is related to antecedent field moisture and the physical condition of the soil. There-fore, the infiltration capacity for the same soil may vary appreciably from storm to storm.(2) The infiltration capacity of a soil is normally highest at the beginning of rainfall.

Rainfall frequently begins at relatively moderate rates, and a substantial period of time may elapse before the rainfall intensity exceeds the prevailing infiltration capacity.

It is gen-erally accepted that, a fairly substantial quantity of infiltration is required to satisfy initial soil moisture deficiencies before runoff will occur, the amount of initial loss depending upon antecedent conditions.

(3) Rainfall does not normally cover the entire drainage basin during all periods of precipitation with intensities exceeding infiltration capacities.

Further-more, soils and infiltration capacities vary throughout a drainage basin. Therefore rational application of any 1.59-13 loss-rate technique must consider the varying nature of rainfall intensities over the basin in order to determine the area covered by runoff-producing rainfall.b. Initial loss is defined as the maximum amount of precipitation that can occur without producing runoff.Values of initial loss may range from a minimum of a few tenths of an inch during relatively wet seasons to several inches during dry summer and fall months. Initial losses prevalent during major floods usually range from about 0.2 to 0.5 inch and are relatively small in comparison with the flood runoff volume. Conse-quently, in estimating loss rates from data for major floods, allowances for initial losses may be approximated without introducing important errors into the results.c. Base flow is defined herein as that portion of a flood hydrograph which represents runoff from antece-dent storms and bank flow. Bank flow is storm precipitation which infiltrates the ground surface and flows, possibly as groundwater, into stream channels.Many techniques exist for estimating base flow. It is generally assumed that base flow which could exist during a PMF is high, the rationale being that a storm producing relatively high runoff could meteorologically occur over most watersheds about a week earlier than that capable of producing a PMF. An acceptable method is to assume that a flood about half as severe as a PMF 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 flood is the base flow for the PMF.A.6 RUNOFF MODEL The hydrologic response characteristics of the water-shed to precipitation (i.e., runoff model) should be determined and verified from historical flood records.The model should include consideration of nonlinear runoff response due to high rainfall intensities or unexplainable factors. In conjunction with data and analyses discussed above, a runoff model should be developed, where data are available, by analytically"reconstituting" historical floods to substantiate its use for estimating a PMF. The rainfall-runoff-time-areal distribution of historical floods should be used to verify that the reconstituted hydrographs correspond reason-ably well with flood hydrographs actually recorded at selected gaging stations (Ref. 2). In most cases, reconsti-tution studies should be made with respect to two or more floods and possibly at two or more key locations, particularly where possible errors in the determinations could have a serious impact on decisions required in the use of the runoff model for the PMF. In some cases the lack of stream gage records, the lack of sufficient time and areal precipitation definition, or unexplained causes may prevent development of reliable predictive runoff models. In such cases a conservative PMF estimate should be ensured by other means such as conservatively developed synthetic unit hydrographs.

Basin runoff models for a PMF determination should provide a conservative estimate of the runoff that could be expected during the life of the nuclear facility.

The basic analyses used in deriving the runoff model are not rigorous but may be conservatively undertaken by considering the rate of runoff from unit rainfall (and snowmelt, if pertinent)

of some unit duration and specific time-areal distribution (called a unit hydro-graph). The applicability of a unit hydrograph or other technique for use in computing the runoff from the Probable Maximum Precipitation over a basin may be partially verified by reproducing observed major flood hydrographs.

An estimated unit hydrograph is first applied to estimated historical rainfall-excess values to obtain a hypothetical runoff hydrograph for comparison with the observed runoff hydrograph exclusive of base flow (i.e., net runoff). The loss rate, the unit hydro-graph, or both, are subsequently adjusted to provide accurate verification.

A study of the runoff response of a large number of basins for several historical floods in which a variety of valley storage characteristics, basin configurations, topo-graphical features, and meteorological conditions are represented provides the basis for estimating the relative effects of predominating influences for use in PMF analyses.

In detailed hydrological studies, each of the following procedures may be used to advantage:

a. Analysis of rainfall-runoff records for major storms;b. Computation of synthetic runoff response models by (1) direct analogy with basins of similar character- istics and/or (2) indirect analogy with a large number of other basins through the application of empirical rela-tionships.

In basins for which historical streamflow and/or storm data are unavailable, synthetic techniques are the only known means for estimating hydrologic response characteristics.

However, care must be taken to assure that a synthetic model conservatively reflects the runoff response expected from precipitation as severe as the PMP.Detailed flood hydrograph analysis techniques and studies for specific basins are available from many agencies.

Published studies such as those by the Corps of Engineers, Bureau of Reclamation, and Soil Conserva-tion Service may be utilized directly where it can be demonstrated that they are of a level of quality and conservatism comparable with that indicated herein. In particular, the Corps of Engineers has developed analysis techniques (Refs. 2, 3) and has accomplished a large number of studies in connection with their water resources development activities.

Computerized runoff models (Ref. 3) offer an ex-tremely efficient tool for estimating PMF runoff rates and for evaluating the sensitivity of PMF estimates to t-1.59-14 possible variations in parameters.

Such techniques have been used successfully in making detailed flood esti-mates.Snowmelt may be a substantial runoff component for both historical floods and the PMF. In cases where it is necessary to provide for snowmelt in the runoff model, additional hydrometeorological parameters must be in-corporated.

The primary parameters are the depth of assumed existing snowpack, the areal distribution of assumed existing snowpack, the snowpack temperature and moisture content, the type of soil or rock surface underlying the snowpack and the type and amount of forest cover of the snowpack and variation thereof, and the time and elevation distribution of air temperatures and heat input during the storm and subsequent runoff period. Techniques that have been developed to reconsti-tute historical snowmelt floods may be used in both historical flood hydrograph analysis and PMF determina- tions (Ref. 4).A.7 PROBABLE MAXIMUM PRECIPITATION

ESTIMATES Probable Maximum Precipitation (PMP) estimates are the time and areal precipitation distributions compatible with the definition of Section A.2 and are based on detailed comprehensive meteorological analyses of severe storms of record. The analysis uses precipitation data and synoptic situations of major storms of record to determine characteristic combinations of meteorological conditions in a region surrounding the basin under study. Estimates are made of the increase in rainfall quantities that would have resulted if conditions during the actual storm had been as critical as those considered probable of occurrence in the region. Consideration is given to the modifications in meteorological conditions that would have been required for each of the record storms to have occurred over the drainage basin under study, considering topographical features and location of the region involved.The physical limitations in meteorological mecha-nisms for the maximum depth, time, and space distribu-tion of precipitation over a basin are (1) humidity (precipitable water) in the airflow over the watershed, (2) the rate at which wind may carry the humid air into the basin, and (3) the fraction of the inflowing atmos-pheric water vapor that can be precipitated.

Each of these limitations is treated differently to estimate the PMP over a basin. The estimate is modified further for regions where topography causes marked orographic control on precipitation (designated as the orographic model as opposed to the general model which embodies little topographic effect). Further details on the models and acceptable procedures are contained in References

5 and6.a. The PMP in regions of limited topographic influ-ence (mostly convergence precipitation)

may be esti-mated by maximizing observed intense storm parameters and transposing them to basins of interest.

The param-eters include storm duration, intensity, and the depth-area relation.

The maximum storm should represent the most critical rainfall depth-area-duration relation fo- *he particular drainage area during various seasons oi -he year (Refs. 7-10). In practice, the storm parameters considered are (1) the representative storm dewpoint adjusted to inflow moisture producing the maximum dewpoint (precipitable water), (2) seasonal variations in parameters, (3) the temperature contrast, (4) the geo-graphical relocation, and (5) the depth-area relation.Examples of these analyses are explained and utilized in a number of published reports (Refs. 7-10).This procedure, supported with an appropriate analysis, is usually satisfactory where a sufficient num-ber of historical intense storms have been maximized and transposed to the basin and where at least one of them contains a convergent wind "mechanism" very near the maximum that nature can be expected to 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 of maximization steps must balance the adequacy of the storm sample; additional maximization steps are re-quired in regions of more limited storm samples.b. PMP determinations in regions of orographic influences generally are for the high mountain regions.Additional maximization steps from paragraph A.7.a above are required in the use of the orographic model (Refs. 5, 6). The orographic model is used where severe precipitation is expected to be caused largely by the lifting imparted to the air by mountains.

This orographic influence gives a basis for a wind model with maximized inflow. Laminar flow of air is assumed over any particular mountain cross section. The "life" of the air, the levels at which raindrops and snowflakes are formed, and their drift with the air before they strike the ground may then be calculated.

Models are verified by reproducing the precipita- tion in observed storms and are then used for estimating PMP by introducing maximum values of moisture and wind as inflow at the foot of the mountains.

Maximum moisture is evaluated just as in nonorographic regions. In mountainous regions where storms cannot readily be transposed (paragraph A.7.a above) because of their intimate relation to the immediate underlying topo-graphy, historical stor~ns are resolved into their convec-tive and orographic components and maximized.

Maxi-mum mroisture, maximum winds, and maximum values of the orographic component and convective component (convective as in nonorographic areas) of precipitation are considered to occur simultaneously.

Some of the published reports that illustrate the combination of orographic and convective components, including seasonal variation, are References

11-13.1.59-15 In some watersheds, major floods are often the result of melting snowpack or of snowmelt combined with rain. Accordingly, the PMP (rainfall)

and maximum associated runoff-producing snowpacks are both esti-mated on a seasonal and elevation basis. The probable maximum seasonal snowpack water equivalent should be determined by study of accumulations on local water-sheds from historical records of the region.Several methods of estimating the upper limit of ultimate snowpack and melting are summarized in References

4 and 5. The methods have been applied in the Columbia River basin, the Yukon basin in Alaska, the upper Missouri River basin, and the upper Mississippi in Minnesota and are described in a number of reports by the Corps of Engineers.

In many intermediate- latitude basins, the greatest flood will likely result from a combination of critical snowpack (water equivalent)

and PMP. The seasonal variation in both optimum snow depth (i.e., the greatest water equivalent in the snow-pack) and the associated PMP combination should be meteorologically compatible.

Temperature and winds associated with PMP are two important snowmelt factors amenable to generalization for snowmelt computations (Ref. 14). The meteorological (e.g., wind, temperature, dewpoints)

sequences prior to, during, and after the postulated PMP-producing storm should be compatible with the sequential occurrence of the PMP. The user should place the PMP over the basin and adjust the sequence of other parameters to give the most critical runoff for the season considered.

The meteorological parameters for snowmelt compu-tations associated with PMP are discussed in more detail in References

11, 12, and 14.Other items that need to be considered in deter-mining basin melt are optimum depth, areal extent and type of snowpack, and other snowmelt factors (see Section A.8), all of which must be compatible with the most critical arrangement of the PMP and associated meteorological parameters.

Critical probable maximum storm estimates for very large drainage areas are determined as above but may differ somewhat in flood-producing storm rainfall from those encountered in preparing similar estimates for small basins. As a general rule, the critical PMP in a small basin results primarily from extremely intense small-area storms, whereas in large basins the PMP usually results from a series of less intense, large-area storms. In large river basins (about 100,000 square miles or larger) such as the Ohio and Mississippi River basins, it may be necessary to develop hypothetical PMP storm sequences (one storm period followed by another) and storm tracks with an appropriate time interval between storms.The type of meteorological analyses required and typical examples thereof are contained in References

9, 15, and 16.The position of the PMP, identified by "isohyetal patterns" (lines of equal rainfall depth), may have a very great effect on the regimen of runoff from a given volume of rainfall excess, particularly in large drainage basins in which a wide range of basin hydrologic runoff characteristics exist. Several trials may be necessary to determine the critical position of the hypothetical PMP storm pattern (Refs. 8, 17) or the selected record storm pattern (Refs. .9, 16) to determine the critical isohyetal pattern that produces the maximum rate of runoff at the designated site. This may be accomplished by super-imposing the total-storm PMP isohyetal contour map on an outline of the drainage basin (above the site) in such a manner as to place the largest rainfall quantities in a position that would result in the maximum flood runoff (see Section A.8 on Probable Maximum Flood runoff).The isohyetal pattern should be consistent with the assumptions regarding the meteorological causes of the storm.A considerable range in assumptions regarding rainfall patterns (Ref. II) and intensity variations can be made in developing PMP storm criteria for relatively small basins without being inconsistent with meteorological causes. For drainage basins less than a few thousand square miles in area (particularly if only one unit hydrograph is available), the rainfall may be expressed as average depth over the drainage area. However, in determining the PMP pattern for large drainage basins (with varying basin hydrologic characteristics, including reservoir effects), runoff estimates are required for different storm pattern locations and orientations to obtain the final PMF. Where historical rainfall patterns are not used for PMP, two other methods are generally employed.a. The average depth over the entire basin is based on the maximized areal distribution of the PMP.b. A hypothetical isohyetal pattern is assumed.Studies of areal rainfall distribution from intense storms indicate that elliptical patterns may be assumed as representative of such events. Examples are the typical patterns presented in References

8, 14, 17, and 18.To compute a flood hydrograph from the probable maximum storm, it is necessary to specify the time sequence of precipitation in a feasible and critical meteorological time sequence.

Two meteorological factors must be considered in devising the time se-quences: (1) the time sequence in observed storms and.(2) the manner of deriving the PMP estimates.

The first imposes few limitations;

the hyetographs (rainfall time sequences)

for observed storms are quite varied. There is some tendency for the two or three time increments with. the highest rainfall in a storm to bunch together, as some time is required for the influence of a severe precipitation-producing weather situation to pass a given (1.59-16 region. The second consideration uses meteorological parameters developed from PMP estimates.

An example of 6-hour increments for obtaining a critical 24-hour PMP sequence would be that the most severe 6-hour increments should be adjacent to each other in time (Ref. 17). In this arrangement the second highest increment should precede the highest, the third highest should be immediately after this 12-hour se-quence, and the fourth highest should be before the 18-hour sequence.

This procedure may also be used in the distribution of the lesser, second (24-48 hours) and third (48-72 hours), 24-hour periods. These arrange-ments are permissible because separate bursts of precipi-tation could have 'occurred within each 24-hour period (Ref. 7). The three 24-hour precipitation periods are interchangeable.

Other arrangements that fulfill the sequential requirements would be equally reasonable.

The hyetograph selected should be the most severe reasonably possible that would produce critical runoff at the project location based on the general appraisal of the hydrometeorologic conditions in the project basin.Examples of PMP time sequences fulfilling the sequential requirements are illustrated in References

11, 12, and 17. For small areas maximized local records should be considered to ensure that the selected PMP time sequence is as severe as has occurred.The Corps of Engineers and the Hydrometeorological Branch of NOAA (under a cooperative -arrangement since 1939) have made comprehensive meteorological studies of extreme flood-producing storms (Ref. 1) and have developed a number of estimates of PMP. The PMP estimates are presented in various unpublished memo-randa and published reports. The series of published reports is listed on the fly sheet of referenced Hydro-meteorological Reports such as Reference

18. The unpublished memoranda reports may be obtained from the Corps of Engineers or Hydrometeorological Branch, NOAA. These reports and memoranda present general 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 all available data, supplemented by thorough meteoro-logical analyses and usually assure reliable and consistent estimates for various locations in the region for which they have been developed.

In some cases, however, additional detailed analyses are needed for specific river basins (Refs. 7, 8) to take into account unusually large areas, storm series, topography, or orientation of drain-age basins not fully reflected in the generalized esti-mates. In many river basins, available studies may be utilized to obtain the PMP without the in-depth analysis discussed herein.A.8 CHANNEL AND RESERVOIR

ROUTING Channel and reservoir routing of floods is generally an integral part of the runoff model for subdivided basins.Care should be taken to ensure that the characteristics determined represent historical conditions (which may be verified by reconstituting historical floods) and also conservatively represent conditions to be expected dur-ing a PMF.Channel and reservoir routing methods of many types have been developed to model the progressive down-stream translation of flood waves. The same theoretical relationships hold for both channel and reservoir rout-ing. However, in the case of flood wave translation through reservoirs, simplified procedures have been developed that are generally not used for channel routing because of the inability of such simplified methods to model frictional effects. The simplified channel routing procedures that have been developed have been found useful in modeling historical floods, but care should be exercised in using such models for severe hypothetical floods such as the PMF. The coefficients developed from analysis of historical floods may not conservatively reflect flood wave translation for more severe events.Most of the older procedures were basically attempts to model unsteady-flow phenomena using simplifying approximations.

The digital computer has allowed development of analysis techniques that permit direct solution of basic unsteady flow equations utilizing numerical analysis techniques (Ref. 19). Most of the older techniques have also been adapted for computer use (Ref. 3).For all routing techniques, care should be exercised to ensure that parameters selected for model verification are based on several historical floods (whenever possible)and that their application to the PMF will result in conservative estimates of flow rates, water levels, veloci-ties, and impact forces. Theoretical discussions of the many methods available for such analyses are contained in References2 and 19-22.A.9 PROBABLE MAXIMUM FLOOD HYDROGRAPH

ESTIMATES Probable Maximum Flood (PMF) net runoff hydro-graph estimates are made by sequentially applying critically located and distributed PMP estimates using the runoff model, conservatively low estimates of precipitation losses, and conservatively high estimates of base flow and antecedent reservoir levels.In PMF determinations it is generally assumed that 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 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 is a thunderstorm)

prior to a PMF can be evacuated from the reservoir before the arrival of a PMF. However, it is 1.59-17 unusual to use an antecedent storage level of less than one-half the available flood control storage.The application of PMP in basins whose hydrologic features vary from location to location requires the determination that the estimated PMF hydrograph repre-sent the most critical centering of the PMP storm with respect to the site. Care must be taken in basins with substantial headwater flood control storage to ensure that a more highly concentrated PMP over a smaller area downstream of the reservoirs would not produce a greater PMF than a total basin storm that is partially controlled.

In such cases more than one PMP runoff analysis would be required.

Usually, only a few trials of a total basin PMP are required to determine the most critical centering.

Antecedent snowpack is included when it ýs deter-mined that snowmelt significantly contributes to the PMF (see Section A.7).Runoff hydrographs should be prepared at key hydrologic locations (e.g., streamgages and dams) as well as at the site of nuclear facilities.

For all reservoirs involved, inflow, outflow, and pool elevation hydro-graphs should be prepared.Many existing and proposed dams and other river control structures may not be capable of safely passing floods as severe as a PMF. The capability of river control structures to safely pass a PMF and local coincident wind-generated wave activity must be determined as part of the PMF analysis.

Where it is possible that such structures may not safely survive floods as severe as a PMF, the worst such condition with respect to down-stream nuclear facilities is assumed (but should be substantiated by analysis of upstream PMF potential)

to be their failure during a PMF, and the PMF determina- tion should include the resultant effects. This analysis also requires that the consequences of upstream dam failures on downstream dams (domino effects) be considered.

A.10 SEISMICALLY

INDUCED FLOODS Seismically induced floods on streams and rivers may be caused by landslides or dam failures.

Where river control structures are widely spaced, their arbitrarily assumed individual, total, instantaneous failure and conservative flood wave routing may be sufficient to show that no threat exists to nuclear facilities.

However, where the relative size, location, or proximity of dams to potential seismic generators indicates a threat to nuclear facilities, the capability of such structures (either singly or in combination)

to resist severe earthquakes (critically located) should be considered.

In river basins where the flood runoff season may constitute a significant portion of the year (such as the Mississippi, Columbia, or Ohio River basins), full flood control reservoirs with a 25-year flood are assumed coincident with the Safe Shutdown Earthquake. (An acceptable method of determining the 25-year flood is contained in Reference

30.) Also, consideration should be given to the occurrence of a Standard Project Flood with full flood control reservoirs coincident with the Operating Basis Earthquake to maintain a consistent level of analysis with other combinations of such events. As with failures due to inadequate flood- control capacity, domino and essen-tially simultaneous multiple failures may also require consideration.

If the arbitrarily assumed total instan-taneous failure of the most critically located (from a hydrologic standpoint)

structures indicates flood risks at the nuclear facility site more severe than a PMF, a progressively more detailed analysis of the seismic capability of the dam is warranted.

In lieu of detailed geologic and seismic investigations at the site of the river control structure, the flood potential at the nuclear facility may be evaluated assuming the most probable mechanistic-type failure of the questioned structures.

If the flood effects of this assumed failure cannot be safely accommodated at the nuclear facility site in an accept-able manner, the seismic potential at the site of each questioned structure is then evaluated in detail. The structural capability is evaluated in the same depth as for the nuclear facility.

If the capability is not sufficient to ensure survival of the structure, its failure is assumed, and the resulting seismically induced flood is routed to the site of the nuclear power plant. This last detailed analysis is not generally required since intermediate investigations usually provide sufficient conservative information to allow determination of an adequate design basis flood.A.11 WATER LEVEL DETERMINATIONS

The preceding discussion has been concerned pri-marily with determinations of flow rates. The flow rate or discharge must be converted to water surface eleva-tion for use in design. This may involve determination of elevation-discharge relations for natural stream valleys or reservoir conditions.

The, reservoir elevation estimates involve the spillway discharge capacity and peak reser-voir level likely to be attained during the PMF as governed by the inflow hydrograph, the reservoir level at the beginning of the PMF, and the reservoir regulation plan with respect to total releases while the reservoir is rising to peak stage. Most river water level determina:

tions involve the assumption of steady, or nonvarying, flow for which standard methods are used to estimate flood levels.Where little floodplain geometry definition exists, a technique called "slope-area" may be employed wherein the assumptions are made that (1) the water surface is parallel to the average -bed slope, (2) any available floodplain geometry information is typical of the river reach under study, and (3) no upstream or downstream hydraulic controls affect the river reach fronting the site 1.59-48 ander study. Where such computations can be shown to indicate conservatively high flood levels, they may be used. However, the usual method of estimating water surface profiles for flood conditions that may be characterized as involving essentially steady flow is called the "standard-step method." This method utilizes the integrated differential equation of steady fluid motion commonly referred to as the Bernoulli equation (Refs. 22-25). Water levels in the direction of flow computation are determined by the trial and error balance of upstream and downstream energy. Frictional and other types of head losses are usually estimated in detail using characteristic loss equations whose coeffi-cients have been estimated from computational reconsti-tution of historical floods and from detailed floodplain geometry information.

Where no data exist to reconsti-tute water levels from historical floods, conservative values of the various loss coefficients should be used.Application of the standard-step method has been developed into very sophisticated computerized models such as the one described in Reference

23. Theoretical discussions of the techniques involved are presented in References

22, 24, and 25.Unsteady-flow models may also be used to estimate water levels since steady flow may be considered a class of unsteady flow. Computerized unsteady-flow models require generally the same floodplain geometry defini-tion as steady-flow models, and their use may allow more accurate water surface level estimates for cases where steady-flow approximations are made. One such unsteady-flow computer model is discussed in Reference 19.All reasonably accurate water level estimation models require detailed floodplain definition, especially of areas that can materially affect water levels. The models should be calibrated by mathematical reconstitution of historical floods (or the selection of calibration coeffici-ents based on the conservative transfer of information derived from similar studies. of other river reaches).Particular care should be exercised to ensure that controlling flood level estimates are always conserva-tively high.A.12 COINCIDENT

WIND-WAVE

ACTIVITY The superposition of wind-wave activity on PMF or seismically induced water level determinations is re-quired to ensure that, in the event either condition did occur, ambient meteorological activity would not cause a loss of any safety-related functions due to wave action.The 'selection of windspeeds and critical wind directions assumed coincident with maximum PMF or seismically induced water levels should provide assurance of virtually no risk to safety-related equipment.

The Corps of Engineers suggests (Refs. 26, 27) that average maximum windspeeds of approximately

40 to 60 mph have occurred in major windstorms in most regions of the United States. For application to the safety analysis of nuclear facilities, the worst regional winds of record should be assumed coincident with the PMF. However, the postulated winds should be meteorologically com-patible with the conditions that induced the PMF (or with the flood conditions assumed coincident with seismically induced dam failures).

The cqnditions in-clude the season of the year, the time required for the PMP storm to move out of the area and be replaced by meteorological conditions that could produce the postu-lated winds, and the restrictions on windspeed and direction produced by topography.

As an alternative to a detailed study of historical regional winds, a sustained 40-mph overland windspeed from any critical direction is an acceptable postulation.

Wind-generated setup (or windtide)

and wave action (runup and impact forces) may be estimated using the techniques described in References

26 and 28. The method for estimating wave action is based on statistical analyses of a wave spectrum.

For nuclear facilities, protection against the one-percent wave, defined in Reference

28 as the average of the upper one percent of the waves in the anticipated wave spectrum, should be assumed. Where depths of water in front of safety-related structures are sufficient (usually about seven-tenths of the wave height), the wave-induced forces will be equal to the hydrostatic forces estimated from the maximum runup level. Where the waves can be"tripped" and caused to break, both before reaching and on safety-related structures, dynamic forces may be estimated from Reference

28. Where waves may induce surging in intake structures, the pressures on walls and the underside of exposed floors should be considered, particularly where such structures are not vented and air compression can greatly increase dynamic forces.In addition, assurance should be provided that safety systems are designed to withstand the static and dynamic effects resulting from frequent (10-year)

flood levels coincident with the waves that would be produced by the Probable Maximum Gradient Wind for the site (based on a study of historical regional meteorology).

1.59-19 APPENDIX A REFERENCES

1. Precipitation station data and unpublished records of Federal, State, municipal, and other agencies may be obtained from the National Weather Service (formerly called the U.S. Weather Bureau). In addition, studies of some large storms are available in the "Storm Rainfall in the United States, Depth-Area-Duration Data," summaries published by Corps of Engineers, U.S. Army. A list of references is contained in Section 2.4 of"Regulatory-Standard Review Plan," U.S. Nuclear Regulatory Commission, October 1974.2. Corps of Engineers publications, such as EM 1110-2-1405, August 31, 1959, "Engineering and Design-Flood Hydrograph Analyses and Computa-tions," provide excellent criteria for the necessary flood hydrograph analyses. (Copies are for sale by Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.) Isohyetal patterns and related precipitation data. are in the files of the Chief of Engineers, Corps of Engineers.

3. A publicly available model is "Flood Hydrograph Package, HEC-l Generalized Computer Program," available from the Corps of Engineers Hydrologic Engineering Center, Davis, California, October 1970.4. One technique for the analysis of snowmelt is contained in Corps of Engineers EM 1100-2-406,"Engineering and Design-Runoff From Snowmelt," January 5, 1960. Included in this reference is also an explanation of the derivation of probable maxi-mum and standard project snowmelt floods.5. "Technical Note No. 98-Estimation of Maximum'Floods," WMO-No. 233.TP.126, World Meteorologi- cal Organization, United Nations, 1969, and"Manual for Depth-Area-Duration Analysis of Storm Precipitation," WMO-No. 237.TP. 129, World Meteorological Organization, United Nations, 1969.6. "Meteorological Estimation of Extreme Precipita- tion for Spillway Design Floods," Tech. Memo WBTM HYDRO-5, U.S. Weather Bureau (now NOAA) Office of Hydrology, 1967.7. "Seasonal Variation of the Probable Maximum Precipitation East of the 105th Meridian for Areas from 10 to 1,000 Square Miles and Durations of 6, 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 Service, NOAA), 1956; and "All-Season Probable Maximum Precipitation-United States East of the 105th Meridian, for Areas from 1,000 to 20,000 Square Miles and Durations from 6 to 72 Hours," draft report, National Weather Service, ESSA (now U.S. Weather Service, NOAA), 1972.8. "Probable Maximum Precipitation, Susquehanna River Drainage Above Harrisburg, Pa.," Hydro-meteorological Report No. 40, U.S. Weather Bureau (now U.S. Weather Service, NOAA), 1965.9. "Meteorology of Flood Producing Storms in the Ohio River Basin," Hydrometeorological Report No. 38, U.S. Weather Bureau (now NOAA), 1961.10. "Probable Maximum and TVA Precipitation Over the Tennessee River Basin Above Chattanooga," Hydrometeorological Report No. 43, U.S. Weather Bureau (now NOAA), 1965.11. "Interim Report-Probable Maximum Precipitation in California," Hydrometeorological Report No. 36, U.S. Weather Bureau (now NOAA), 1961; revised 1969.12. "Probable Maximum Precipitation, Northwest States," Hydrometeorological Report No. 43, U.S.Weather Bureau (now NOAA), 1966.1 13. "Probable Maximum Precipitation in the Hawaiian Islands," Hydrometeorological Report No. 39, U.S.Weather Bureau (now NOAA), 1963.14. "Meteorological Conditions for the Probable Maxi-mum Flood on the Yukon River Above Rampart, Alaska," Hydrometeorological Report No. 42, U.S.Weather Bureau (now NOAA), 1966.15. "Meteorology of Flood-Producing Storms in the Mississippi River Basin," Hydrometeorological Report No. 34, U.S. Weather Bureau (now NOAA), 1965.16. "Meteorology of Hypothetical Flood Sequences in the Mississippi River Basin," Hydrometeorological Report No. 35, U.S. Weather Bureau (now NOAA), 1959.17. "Engineering and Design-Standard Project Flood Determinations," Corps of Engineers EM 1110-2-1411, March 1965, originally published as Civil Engineer Bulletin No. 52-8, 26 March 1952.18. "Probable Maximum Precipitation Over South Platte River, Colorado, and Minnesota River, Minne-sota," Hydrometeorological Report No. 44, U.S.Weather Bureau (now NOAA), 1969.I 1.59-20

19. "Unsteady Flow Simulation in Rivers and Reser-voirs," by J.M. Garrison, J.P. Granju, and J.T. Price, pp. 1559-1576, Vol. 95, No. HY5, (September

1969), Journal of the Hydraulics Division, ASCE, (paper 6771).20. "Handbook of Applied Hydrology," edited by Ven Te Chow, McGraw-Hill, 1964, Chapter 25.21. "Routing of Floods Through River Channels," EM 1110-2-1408, U.S. Army Corps of Engineers, March 1, 1960.22. "Engineering Hydraulics," edited by Hunter Rouse, John Wiley & Sons, Inc., 1950.23. "Water Surface Profiles, HEC-2 Generalized Com-puter Program," available from the Corps of Engi-neers Hydrologic Engineering Center, Davis, Calif.24. "Open Channel Hydraulics" by Ven Te Chow, McGraw-Hill, 1959.25. "Backwater Curves in River Channels," EM 1110-2-1409, U.S. Army Corps of Engineers, December 7, 1959.26. "Coxlnutation of Freeboard Allowances for Waves in Reservoirs," Engineer Technical Letter ETL 1110-2-9, U.S. Army Corps of Engineers, August 1, 1966.27. "Policies and Procedures Pertaining to Deter-mination of Spillway Capacities and Freeboard Allowances for Dams," Engineer Circular EC 1110-2-27, U.S. Army Corps of Engineers, August 1, 1966.28. "Shore Protection Manual," U.S. Army Coastal Engineering Research Center. 1973.29. "Probable Maximum and TVA Precipitation for 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 NOAA), 1969.30. "Floods in the United States, Magnitude and Fre-quency, (Basin)," series of Water-Supply Papers.U.S. Geological Survey, various dates.1.59-21 f t-i-i APPENDIX B ALTERNATIVE

METHODS OF ESTIMATING

PROBABLE MAXIMUM FLOODS TABLE OF CONTENTS Page B.1 INTRODUCTION

...............

B.2 SCOPE ........ ....................

1.59-25 1.59-25 B.3 PROBABLE MAXIMUM FLOOD PEAK DISCHARGE

.........

.....................

1.59-25 B.3.1 Use of PMF Discharge Determinations

....B.3.2 Enveloping isolines of PMF Peak Discharge

...B.3.2.1 Preparation of Maps ... .. .. .B.3.2.2 Use of Maps ............B.3.3 Probable Maximum Water Level .......B.3.4 Wind-Wave Effects .... .........B.4 LIMITATIONS

........... ..........................1.5 9 -2 5....................1.5 9 -2 5....................1.59 -2 5...... ...........I. .1.59-26....................1.5 9 -2 6....................1.5 9 -2 6 1.59-26 REFERENCES

........................FIG U R ES ..........................TABLE FIGURES Figure B.I -Water Resources Regions. ................

B.2 -Probable Maximum Flood (Enveloping Isolines)

-100 Sq. Mi. .B.3 -Probable.

Maximum Flood (Enveloping Isolines)

-500 Sq. Mi..B.4 -Probable Maximum Flood (Enveloping Isolines)

-1,000 Sq. Mi.B.5 -Probable Maximum Flood (Enveloping Isolines)

-5,000 Sq. Mi.B.6 -Probable Maximum Flood (Enveloping Isolines)

-10,000 Sq. Mi.B.7 -Probable Maximum Flood (Enveloping Isolines)

-20,000 Sq. Mi.B.8 -Example of Use of Enveloping Isolines .... ...........

TABLE*. ..1.59-27 1.59-28 1.59-36 1.59-28 1.59-29 1.59-30 1.59-31 1.59-32 1.59-33 1 .59-34 1.59-35..--Table B. I -Probable Maximum Flood Data 1.59-36 1.59-23 r

B.1 INTRODUCTION

• This appendix presents timesaving alternative methods of estimating the probable maximum flood (PMF) peak discharge for nuclear facilities on nontidal streams in the contiguous United States. Use of the methods herein will reduce both the time necessary for applicants to prepare license applications and the NRC staff's review effort.The procedures are based on PMF values determined by the U.S. Army Corps of Engineers, by applicants for licenses that have been reviewed and accepted by the NRC staff, and by the staff and its consultants.

The information in this appendix was developed from a study made by Nunn, Snyder, and Associates, through a contract with NRC (Ref. 1).PMF peak discharge determinations for the entire contiguous United States are presented in Table B.1.Under some conditions, these may be used directly to evaluate the PMF at specific sites. In addition, maps showing enveloping isolines of PMF discharge for several index drainage areas are presented in Figures B.2 through B.7 for the contiguous United States east of the 103rd meridian, including instructions for and an example of their use (see Figure B.8). Because of the enveloping procedures used in preparing the maps, results from their use are highly conservative.

Limitations on the use of these generalized methods of estimating PMFs are identified in Section B.4. These limitations should be considered in detail in assessing the applicability of the methods at specific sites.Applicants for licenses for nuclear facilities at sites on nontidal streams in the contiguous United States have the option of using these methods in lieu of the more precise but laborious methods of Appendix A. The results of application of the methods in this appendix will in many cases be accepted by the NRC staff with no further verification.

B.2 SCOPE The data and procedures in this appendix apply only to nontidal streams in the contiguous United States.Two procedures are included for nontidal streams east of the 103rd meridian.Future studies are planned to determine the applica-bility of similar generalized methods and to develop such methods, if feasible, for other areas. These studies, to be included in similar appendices, are anticipated for the main steins of large rivers and the United States west of the 103rd meridian, including Hawaii and Alaska.B.3 PROBABLE MAXIMUM FLOOD PEAK DISCHARGE The data presented in this section are as follows: 1. A tabulation of PMF peak discharge determina- tions at specific locations throughout the contiguous United States. These data are subdivided into water resources regions, delineated on Figure B.1, and are tabulated in Table B.1.2. A set of six maps, Figures B.2 through B.7, covering index drainage areas of 100, 500, 1,000, 5,000, 10,000, and 20.000 square miles, containing isolines of equal PMF peak discharge for drainage areas of those sizes east of the 103rd meridian.B.3.1 Use of PMF Discharge Determinations The PMF peak discharge determinations listed in Table B.1 are those computed by the Corps of Engi-neers, by the NRC staff and their consultants, or computed by applicants and accepted by the staff.For a nuclear facility located near or adjacent to one of the streams listed in the table and reasonably close to the location of the PMF determination, that PMF may be transposed, with proper adjustment, or routed to the nuclear facility site. Methods of transposition, adjust-ment, and routing are given in standard hydrology texts and are not repeated here. Limits for acceptable trans-positions are contained in Appendix A, Section A.I .b.B.3.2 Enveloping lsolines of PMF Peak Discharge B.3.2.1 Preparation of Maps For each of the water resources regions, each PMF determination in Table B.1 was plotted on logarithmic paper (cubic feet per second per square mile versus drainage area). It was found that there were insufficient data and too much scatter west of about the 103rd meridian, caused by variations in precipitation from orographic effects or by melting snowpack.

Accordingly, the rest of the study was confined to the United States east of the 103rd meridian.

For sites west of the 103rd meridian, the methods of the preceding section may be used.Envelope curves were drawn for each region east of the 103rd meridian.

It was found that the envelope curves generally paralleled the Creager curve (Ref. 2), defined as Q = 46.0 CA(0.894A-O'

0 4 8)-l 1.59-25 where Q is the discharge in cubic feet per second (cfs)C is a constant, taken as 100 for this study A is the drainage area in square miles.Each PMF discharge determination of 50 square miles or more was adjusted to one or more of the six selected index drainage areas in accordance with the slope of the Creager *curve. Such adjustments were made as follows: PMF Within Drainage Area Range, sq. mi.50 to 500 100 to 1,000 500 to 5,000 1,000 to 10,000 5,000 to 50,000 10,000 or greater Adjusted to Index Drainage Area, sq. mi.100 500 1,000 5,000 10,000 20,000 The PMF values so adjusted were plotted on maps of the United States east of the 103rd meridian, one map for each of the six index drainage areas. It was found that there were areas on each map with insufficient points to define isolines.

To fill in such gaps, conserva-tive computations of approximate PMF peak discharge were made for each two-degree latitude-longitude inter-section on each map. This was done by using enveloped relations between drainage area and PMF peak discharge (in cfs per inch of runoff), and applying appropriate probable maximum precipitation (PMP) at each two-degree latitude-longitude intersection.

PMP values, ob-tained from References

3 and 4, were assumed to be for a 48-hour storm to which losses of 0.05 inch per hour were applied. These approximate PMF values were also plotted on the maps for each index drainage area and the enveloping isolines were drawn as shown on Figures B.2 through B.7.B.3.2.2 Use of Maps The maps may be used to determine PMF peak discharge at a given site with a known drainage area as follows: 1. Locate the site on the 100-square-mile map, Figure B.2.2. Read and record the 100-square-mile PMF peak discharge by straight-line interpolation between the isolines.3. Repeat Steps 1 and 2 for 500, 1,000, 5,000, 10.000, and 20,000 square miles from Figures B.3 through B.7.4. Plot the six PMF peak discharges so obtained on logarithmic paper against drainage area, as shown on Figure B.8.5. Draw a smooth curve through the points. Reason-able extrapolations above and below the defined curve may be made.6. Read the PMF peak discharge at the site from the curve at the appropriate drainage area.B.3.3 Probable Maximum Water Level When the PMF peak discharge has been obtained as outlined in the foregoing sections, the PMF stillwater level should be determined.

The methods given in Appendix A, Section A.11, are acceptable for this purpose.B.3.4 Wind-Wave Effects Wind-wave effects should be superimposed on the PMF stillwater level. Criteria and acceptable methods are given in Appendix A, Section A.12.B.4 LIMITATIONS

1. The NRC staff will continue to accept for review detailed PMF analyses that result in less conservative estimates.

In addition, previously reviewed and appruved detailed PMF analyses at specific sites will continue to be acceptable even though the data and procedures in this appendix result in more conservative estimates.

2. The PMF estimates obtained as outlined in Sec-tions B.3.1 and 13.3.2 are peak discharges that should be converted to water level to which appropriate wind-wave effects should be added.3. If there are one or more reservoirs in the drainage area upstream of the site, seismic and hydrologic dam failure' flood analyses should be made to determine whether such a flood will produce the design basis water level. Criteria and acceptable methods are included in Appendix A, Section A.10.4. Because of the enveloping procedures used, PMF peak discharges estimated as outlined in Section B.3.2 have a high degree of conservatism.

If the PMF so estimated casts doubt on the suitability of a site, or if protection from a flood of that magnitude would not be physically or economically feasible, consideration should be given to performing a detailed PMF analysis, as outlined in Appendix A. It is likely that such an analysis will result in appreciably lower PMF.levels.

In this context, "hydrologic dam failure" means a failure caused by a flood from the drainage area upstream of the dam.I 1.59-26 APPENDIX B REFERENCES

1. Nunn, Snyder, and Associates, "Probable Maximum Flood and Hurricane Surge Estimates," unpublished report to NRC, June 13, 1975 (available in the public document room).2. W.P. Creager, J.D. Justin, and J. Hinds, "Engineering For Dams," J. Wiley and Sons, Inc., New York, 1945.3. U.S. Weather Bureau (now U.S. Weather Service, NOAA), "Seasonal Variation of the Probable Maximum Precipitation East of the 105th Meridian," Hydrometeorological Report No. 33, 1956.4. U.S. Department of Commerce, N.OAA, "All-Season Probable Maximum Precipitation-United States East of the 105th Meridian, for Areas from 1,000 to 20,000 Square Miles and Durations From 6 to 72 Hours," draft report, July 1972.1.59-27

450'410'l0 CALIFORNIA-

t'.)00SOUTH

PACIFIC ROGRANDEmis

290 TEXAS-GULF

1170 1130 1090 1050 1010 970 930 890 850 810 FIGURE B.1 WATER RESOURCES

REGIONS F 133'I 290 1250

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'.450 430 410 390 370 350 330 310 290 270 250 ,-ISOLINE

REPRESENTING

PEAK FLOW OF PMF IN 1,000 CFS.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-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 3 9.0 0 4 04 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 TIONS TO PEAK FLOW THAT WOULD RESULT FROM UPSTREAM45 DAM FAILURES OR OTHER UNNATURAL

EVENTS.0 I ....0 I 45o l1 I 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

470 450 410 390 350 330 3106 700 6000,.29°I800 2900 27~ _1PMF IN 1,000 CFS.000 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 FIGURE B.5 PROBABLE MAXIMUM FLOOD (ENVELOPING

PMF ISOLINES)

FOR 5,000 SQUAR 830 E MILES

470.J1 450 430 410 390 370 350 330 310 290 270 250 ISOLINE REPRESENTING

PEAK FLOW OF PMF IN 1,000 CFS."..# ,. I 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.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°50 311 250 AR AU D RN T R LRV R O DTO S C O DN L 1300 16 2900 TIN T ISOLINE REPRESENTING

PEAK FLOW OF DAM 1200 PMDF IN 1,000 C FSO 127 0 110 17 15 13 11 0 1 9 0 0 .0 0 1 3 0 0 g 0 9 0 0g 0 9 300 9 0 8 0 8 0 8 0 3 9 7 NOTE: PMF ISOLINES ON THIS CHART REPRESENT

ENVELOPED

1400M 1100 VALUES OF PEAK RUNOFF FROM 20,000-SQUARE

MILE DRAINAGE .I 250 AREA UNDER NATURAL RIVER CONDITIONS.

ACCORDINGLY.

10 ..13 PMF VALUES OBTAINED DO NOT INCLUDE POSSIBLE CONTRIBU-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'FIGURE B.7 PROBABL E MAXIMUM FLOOD (ENVELOPING

PMF ISOLINES)

FOR 20,000 SQUARE MILES 2?25 75' 73'

I I I I I III'C LLf 0 0 IL 0 Cc r -EXAMPLE:-FOR DRAINAGE AREA OF-2,300 SQ. MI. AT LAT. 95", LONG. 430, DETERMINE

PMF PEAK DISCHARGE.

I II I I III! I I I I SI I I I I I T I I I I I I I.1 Li L I-1-4. I I I I I--SOLUTION:

FOR DRAINAGE AREA OF-2,300 SQ. MI., PMF PEAK =400,000 CFS.il-HI I Lci 0 POINTS FROM FIGURES B.2-B.-; [ i J lfl ý I I I I I I I 11 flai._W=I i i I I I I I1'r Z i i~flh1IEl3~

I 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)

0\CYN Ball Mountain Barre Falls Beaver Brook Birch Hill Black Rock Blackwater Buffumville Colebrook Conant Brook East Barre East Branch East Brimfield Edward McDowell Everett Franklin Falls Hall Meadow Hancock Hodges Village Hop Brook Hopkinton Knightville Littleville Mad River Mansfield Hollow Nookagee Northfield North Hartland North Springfield Otter Brook Phillips Sucker Brook Surry Mountain Thomaston Vt, Mass.N. H.Mass.Conn.N. H.Mass.Conn.Mass.Vt.Conn.Mass.N. H.N. H.N.H.Conn.Corn.Mass.Conn.N. H.Mass.Mass.Conn.Conn.Mass.Conn.Vt.Vt.N. H.Mass.Conn.N. H.Conn.Connecticut Connecticut Connecticut Connecticut Housatonic Merrimack Thames Connecticut Connecticut Winooski Housatonic Thames Merrimack Merrimack Merrimack Connecticut Housatonic Thames Housatonic Merrimack Connecticut Connecticut Connecticut Thames Merrimack Housatonic Connecticut Connecticut Connecticut Merrimack Connecticut Connecticut Housatonic West River Ware River Beaver Brook Millers River Branch Brook Blackwater River Little River Farmington River Conant Brook Jail Branch Naugatuck River Quinebaug River Nubanusit River Piscataquog River Pemigewasset River Hall Meadow Brook Hancock Brook French River Hop Brook Contoocook River Westfield River Westfield River Mad River Natchaug River Phillips Brook Northfield Brook Ottauquechee River Black River Otter Brook Phillips Brook Sucker Brook Ashuelot River Naugatuck River 172 55 6.0 175 20 128 26 118 7.8 39 9.2 68 44 64 1,000 17 12 31 16 426 162 52 18 159 11 5.7 220 158 47 5.0 3.4 100 97 20.6 20.1 21.3 18.3 22.2 18.3 26.6 22.7 24.4 21.5 24.0 24.2 19.5 20.7 15.8 24.o 24.0 26.2 25.0 17.4 18.8 25.1 24.0 19.8 21.8 24.4 19.3 20.0 19.1 24.2 22.4 22.2 24.5 18.1 18.9 19.7 17.1 20.6 16.4 25.3 21.1 23.2 18.6 22.8 22.9 18.3 18.2 13.3 22.8 22.8 22.3 23.8 14.7 17. 6 22.4 22.8 18.5 20.2 23.2 17,2 18.3 17.9 23.0 21.4 19.6 22.4 190,000 61,000 10,400 88.500 35,000 95,000 36,500 165,000 11,900 52,500 15,500 73,900 43,000 68,000 300,000 26,600 20,700 35,600 26,400 135,000 160,000 98,000 30,000 125,000 17,750 9,000 199,000 157,000 45,000 7,700 6,500 63,000 158,000

TABLE B.1 ( )Project State River Basin Stream Drainage Area Basin Average (in inches)Prec. Runoff PMF Peak Discharge (cfs)(sa mi., L .Townshend Trumbull Tully Union Village Vermont-Yankee Waterbury West Hill West Thompson Westville Whitemanville Wrightsville Vt.Conn.Mass.Vt.Vt.Vt.Mass.Conn.Mass.Mass.Vt.Connecticut Pequonnook Connecticut Connecticut Connecticut Winooski Blackstone Thames Thames Merrimack Winooski West River Pequonnook River Tully River Ompompanoosuc River Connecticut River Waterbury River West River Quinebaug River Quinebaug River Whitman River North Branch 278 14 50 126 6,266 109 28 74 32 18 68 North Atlantic Region (Mid-Atlantic Sub-region)

Almond Alvin R. Bush Aquashicola Arkport Aylesworth Baird Beltzville Bloomington Blue Marsh Burketown Cabins Chambersburg Christiana Cootes Store Cowanesque Curwensville Dawsonville Douglas Point East Sidney Edes Fort Fairview Foster Joseph Say(Francis E. Walter N. Y.Pa.Pa.N. Y.Pa.W. Va.Pa.Md.Pa.Va.W. Va.Md.Del.Va.Pa.Pa.Md.Md.N. Y.W. Va.Md.ers Pa.Pa.Susquehanna Susquehanna Delaware Susquehanna Susquehanna Potomac Delaware Potomac Delaware Potomac Potomac Potomac Delaware Potomac Susquehanna Susquehanna Pot ciMac Potomac Susquehanna Potomac Potomac Susquehanna Delaware Canacadea Creek Kettle Creek Aquashicola Creek Canister River Aylesworth Creek Buffalo Creek Pohopoco Creek North Branch Tulpehockan Creek North River South Branch Conococheague River Christiana River North Fork River Cowanesque River Susquehanna River Seneca Creek Potomac River Oulelot River Cacapon River Conococleaque Creek Bald Eagle Creek Lehigh River 56 226 66 31 6.2 10 97 263 175 375 314 141 41 215 298 36,;102 679 494 339 288 21.3 23.0 20.0 1760 18.9 28.0 2064 25,4 21.4 2092 22.0 24.0 28.0 22.5 23.8 34.0 27.1 22.2 24.0 24.3 20.8 28.9 32.1 22.5 21.9 22.0 206 .I 13.4 24.0 21.2 22..9 21,8 2264 17.2 21.8 16.6 15.8 16.0 25.6 17.5 22.8 19.8 17.3 18.8 21.1 24.2 17.7 22.0 30.2 25.6 17.6 21.3 21.2 16.8 26.0 28.3 19.1 18.5 18.9 2?.1 10.2 22.1 17.3 18.8 19.0 19.8 59,000 154,000 42,500 33,400 13,700 14,600 68,000 196,000 110,600 272,200 195,900 81,400 39,200 140,200 285,000 205,000 i61,900 1,490,000 99, 900 410,800 150,100 251,000 170,000 228,000 26,700 47,000 110,000 48O,O00 128,000 26,000 85,000 38,400 25,000 74,000.4 TABLE B.1 ( )Project State River Basin Stream Drainage Basin Average Area (in inches)(sn.mi.) Prec. Runoff P1* Peak Discharge (cfsR Franklin Frederick Front Royal Fulton (Harrisburg)

Gathright Gen. Edgar Jadwin Great Cacapon Harriston Hawk Mountain Headsville John H. Kerr Karo Keyser Kitzmiller Leesburg Lewistown Licking Creek Little Cacapon Maiden Creek Martinsburg Mikville Moorefield Moorefield Newark North Anna North Mountain Peach Bottom Perryman Petersburg Philpott Prompton Raystown Royal Glen Salem Church Savage River Seneca Sharpsburg W. Va.Md.Va.Pa.Va.Pa.W. Va.Va.Pa.W. Va.Va.W. Va.W. Va.Md.Va.Md.W. Va.W. Va.Pa.W. Va.W, Va.W. Va.W. Va.Del.Va.W. Va.Pa.Md.W. Va.Va.Pa, Pa.Md.Va.Md.Md.Md.Potomac Potomac Potomac Susquehanna James Delaware Potomac Potomac Delaware Potomac Roanoke Potomac Potomac Potomac Potomac Potomac Potomac Potomac Delaware Potomac Potomac Potomac Potomac Delaware Pamunkey(York)

Potomac Susquehanna Chesapeake Bay Potomac Roanoke Delaware Susquehanna Potomac Rappahannock Potomac Potomac Potomac South Branch Monocacy River S.Fk.Shenandoah River Susquehanna River Jackson River Dyberry Creek Cacapon River South River E.Br. Delaware River Patterson Creek Roanoke River South Branch North Branch North Branch Goose Creek Fishing Creek Licking Creek Little Cacapon River Maiden Creek Opequon Creek Shenandoah River South Branch So. Fk. South Branch White Clay River North Anna River Back Creek Susquehanna River Bush River South Branch Smith River Lackawaxen River Juniata River (Br.)South Branch Rappahannock River Savage River Potomac River Antietem Creek 182 817 1,638 24,100 344 65 677 222 812 219 7,800 1, 577 495 225 338 7.1 158 101 161 272 3,040 1,173 283 66 343 231 27,000 118 642 212 60 960 640 1, 598 105 11,400 281 24.2 23.2 18.0 12.7 24.4 24.8 21*2 29.6 16.5 23.4 16.8 18.9 21.5 22,3 26.5 34.8 29.0 29.7 27.3 27.2 16.2 18.0 21,1 29.8 25.0 27.9 12.7 19,3 27.5 25.0 21-4 19.3 23.6 26.3 13.5 26.6 20.6 20.9 14.3 8.2 21.3 24.0 17.3 26.5 12.7 19.0 12,9 14.9 16.3 17,1 24.2 32.7 26.1 27o4 23.5 24.1 11.7 14.0 17.1 26.0 21.3 24.8 8.2 15.3 24.3 24.2 17.5 15.3 19.6 22.2 10.3 23.5 174,000 363,400 419,000 1,750,000 246,0OO 119,700 373,400 153,700 202,000 176,000 1,000,000 430,000 279,200 120,200 340,900 12,200 125,800 122,700 118,000 174,600 592,000 389,700 173,800 103,000 220,000 256,000 1,750,000 87,400 208,700 160,000 87,190 353,400 208,700 552,000 107,400 1,393,000 154,900

TABLE B.1 ( )Project State River Basin Stream Sherrill Drive Six Bridge Springfield Staunton Stillwater Summit Surry Tioga-Hammond Tocks Island Tonoloway Town Creek Trenton Trexler Tri-Towns Verplanck Washington, D. C.Waynesboro West Branch Whitney Point Winchester York Indian Rock Allatoona Alvin W. Vogtle Bridgewater Buford Carters Catawba Cherokee Claiborne Clark Hill Coffeeville Cowans Ford Demopolis Falls Lake Md.Md.W. Va.Va.Pa.N. J.Va.Pa.N. J.Md.Md.N. J.Pa.W. Va.N. Y, Md.Va.W. Va.N. Y.Va.Pa.Ga.Ga.N. C.Ga.Ga.N. C.N. C.Ala.Ga.Ala.N. C.Ala.N. C.Potomac Potomac Potomac Potomac Susquehanna Delaware James Susquehanna Delaware Potomac Potomac Delaware Delaware Potomac Hudson Potomac Potomac Potomac Susquehanna Potomac Susquehanna Rock Creek Monocacy River South Branch South Branch Shen.Lacawanna River Delaware River James River Tioga River Delaware River Tonoloway Creek Town Creek Delaware River Jordon Creek North Branch Hudson River Potomac River South River Conococheague River Otselie River Opeqnon Creek Codorus Creek Drainage Area (sq.mi.)62 308 1,471 325 37 11,100 9,517 402 3,827 112 144 6,780 52 478 12,650 11,560 136 78 255 120 94 Basin Average (in inches)Prec. Runoff PMF Peak Discharge (cfs)30.6 27.1 17.5 25.0 27.3 23.5 13.3 29.9 27.5 25.2 21.6 14.0 13.4 29.6 30.7 20.7 28.9 22,1 28,3 24.0 15,5 21.3 24.1 19.2 10.5 26.8 25.2 22.6 16.4 9.7 10.2 26 .5 27.0 19.1 25.8 17.7 111,900 225,000 405,000 226,000 39,600 1,000,000 1,000,000 318,000 576,300 117,600 102,900 830,000 55,500 268,000 1,100,000 1,280,000 116,000 78,700 102,000 142,100 74,300 440,000 1,001,000 187,000 428,900 203,100 674,000 560,000 682,500 1,140,000 743,400 636,000 1,068,000 323,000-w South Atlantic-Gulf Region Alabama-Coosa Savannah Santee Apalachicola Alabama-Coosa Santee Congaree-Santee Alabama-Coosa Savannah Tombigbee Santee Tombigbee Neuse Etowah River Savannah River Catawba River Chattahoochee River Coosawattee River Catawba River Broad River Alabama River Savannah River Black Warrior River Catawba River Tombigbee River Neuse River 1, 110 6,144 380 1,040 376 3,020 1, 550 21,520 6,144 18,600 1,790 15,300 760 22.2 19.8 21.8 14.5 21.7 19.7 26.6 22.3 16.6 14.9 21.8 13.6 16.7 23.2 12.3 14.5 11.2 14.3 21.2 TABLE B.1 ( )Drainage Basin Average PMF Peak Project State River Basin Stream Area (in inches) Discharge (sq.mi.) Prec. Runoff (cfs)0 Gainsville Hartwell Holt Howards Mill Jim Woodruff John H. Bankhead Jones Bluff Lazer Creek Lookout Shoals Lower Auchumpkee McGuire Millers Ferry Mountain Island New Hope Oconee Oconee Okatibbee Oxford Perkins Randleman Reddies Rhodhiss Shearon Harris Sprewell Bluff Trotters Shoals Walter F. George Warrior West Point W. Kerr Scott Ala.Ga.Ala.N. C.Fla.Ala.Ala.Ca.N. C, Ga.N. C, Ala.N. C.N. C.S. C.S. C.Miss.N. C.N. C.N, C.N. C.N. C, N. C.Ca.Ga.Ga.Ala.Ga.N. C.Ohio N. Y.N. Y.N. Y.N. Y.N. Y.Tombigbee Savannah Warrior Cape Fear Apalachicola Tombigbee Alabama Apalachicola Santee Apalachicola Santee Alabama Santee Cape Fear Savannah Savannah Pascagoula Santee Pee Dee Cape Fear Pee Dee Santee Cape Fear Apalachicola Savannah Apalachicola Tombigbee Apalachicola Pee Dee Tombigbee River Savannah River Warrior River Deep River Apalachicola River Black Warrior River Alabama River Lazer Creek Catawba River Flint River Catawba River Alabama River Catawba River New Hope River Keowee River Little River 9katibbee Creek Catawba River Yadkin River Deep River Reddies River Catawba River White Oak Creek Flint River Savannah River Chattahoochee River Black Warrior River Chattahoochee River Yadkin River Great Lakes Region Tinkers Creek Mud Creek Fall Creek Six Mile Creek Butternut Creek Little Tonawanda Creek 7,142 2,088 4,232.626 17,150 3,900 16,300 i,41O 1,450 1,970 1,770 20,700 i, 860 1,69o 439 154 1,31.0 2,4?3 169 94 1,090 79 1,210 2,900 7,4460 5,828 3,44o 348 19.6 24.8 22.1 26.8 17,6 22.3 14.2 24.6 23.7 19.8 14.7 12.1 22.0 19.4 26.5 23.5 26.6 33.0 28.4 28.6 26.0 28.0 24.8 16.8 18.8 19.2 24.2 12.3 19.4 11.6 20.7 702,400 875,000 650,000 305,000 1,133,800 670,300 664,000 303,600 492,000 355,600 750,000 844,000 362,000 511,000 450,000 245,000 8?, 700 479,000 440,600 126,000 174,200 379,000 163, 500 318,000 800,000 843,000 554,000 440,000 318,000 25.8 24.0 16.6 19.5 21.9 25.6 28.6 29.9 17.1 26.9 26.0 30.8 21.3 19.1 15.2 16.6 17.4 21.5 25.9 28.1 16. 1 25.1 24.1 29.0 Bedford Bristol Fall Creek Ithaca Jamesville Linden Cuyahoga Oswego Oswego Oswego Oswego Niagara 91 29 123 43 37 22 79,000 64,900 63,400 77,900 35,200 64,400

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

TABLE B.1 ( )Project State River Basin Stream Drainage Basin Average PMF Peak Area (in inches) Discharge (sa.mi.) Prec. Runoff (cfs)'.0 Dillon Dyes Eagle Creek E. Br. Clarion East Fork East Lynn Fishtrap Grayson Green River Helm John W. Flannagan J. Percy Priest Kehoe Kinzua Lafayette Laurel Leading Creek Lincoln Logan Louisville Mansfield Martins Fork Meigs Meigs Mill Creek Mississinewa Michael J. Kirwin Monroe Muddy Creek Nolin N. Br. Kokosing N. Fk. Pound River Paint Creek Paintsville Panthers Creek Patoka R. D. Bailey Rough River Ohio Ohio Ky.Pa.Ohio W. Va.Ky.Ky.Ky.Ill.Va.Tenn.Ky.Pa.Ind.Ky.W. Va.Ill.Ohio Ill.Ind.Ky.Ohio Ohio Ohio Ind.Ohio Ind.Pa.Ky.Ohio Va.Ohio Ky.W. Va.Ind.W. Va.Ky.Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Licking River Dyes Fork Eagle Creek E. Br. Clarion River E. Fk. Little Miami River Twelve Pole Creek Levisa Fk. Sandy River Little Sandy River Green River Skillet Fk. Wabash River Pound River Stones River Tygarts Creek Allegheny River Wildcat Creek Laurel River Leading Creek Embarras River Clear Creek Little Wabash River Raccoon Creek Cumberland River Meigs Creek Meigs Creek Mill Creek Mississinewa River Mahoning River Salt Creek Muddy Creek Nolin River N. Br. Kokosing River N. Fk. Pound River Paint Creek Paint Creek Panther Creek Patoka River Guyandotte River Rough River 748 44 292 72 342 133 395 196 682 2LO 222 892 127 2,180 791 282 146 915 84 661 216 56 72 27 181 809 80 441 61 703 44 18 573 92 24 168 540 454 19.8 30.7 24.?22.7 23.8 29.4 26.1 27.5 26.5 24.8 27.6 25.9 26.0 16.4 20.6 25.9 25.0 21.2 29.5 22.1 25.9 27.9 29.5 32.2 24.0 20.6 26.0 25.9 22.8 14.2 25.4 35.3 21.8 26.3 36.7 25.6 23.1 27.6 16.3 27.8 22.1 18.9 21.2 26.5 23.2 24.7 23.9 22.6 24.9 18.8 23.4 12.8 18.5 20.7 22.5 19.0 27.0 19.9 23.0 22.7 26.6 29.3 2i.4 18.4 20.1 25.4 19.6 13.2 22.6 32.2 18.8 23.8 3309 23.5 20.3 25.1 246,000 49,500 172,800 41,500 313,200 72,000 320,000 83,300 409,000 152,800 235,800 430,000 105,900 115,000 182,000 120,000 131,000 502,000 78,000 310,000 175,800 61,800 72,100 45,500 92,000 196,000 51,800 366,000 59,300 158,000 50,000 51,200 305,000 77,500 59,800 292,000 349,000 358,000 1 TABLE B.1 ( )Stream Project State River Basin Drainage Area Basin Average (in inches)PMF Peak Discharge Prec Runoff (cfs)-J~.Rowlesburg Salamonia Stonewall Jackson Summersville Sutton Taylorville Tom Jenkins Union City Utica West Fork West Fk. Mill Ck.Whiteoak Wolf Creek Woodcock Yatesville Youghiogheny Zimmer, Wm. H.Bellefonte Browns Ferry Sequoyah Ames Bryon Bear Creek Blue Earth Blue Earth Carlyle Clarence Cannon Clinton Coralville Duane Arnold Farmdal e Fondulac Friends Creek W. Va.Ind.W. Va.W. Va.W. Va.Ky.Ohio Pa.Ohio W. Va.Ohio Ohio Ky.Pa.Ky.Pa.Ohio Ala.Tenn.Tenn.Iowa Ill.Mo.Minn.Minn.Ill.Mo.Ill.Iowa Iowa Ill.Ill.Ill.Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Ohio Cheat River Salamonia River West Fork River Gauley River Elk River Salt River Hocking River French Creek N. Fk. Licking River W. Fk. Little Kanawha Mill Creek Whiteoak Creek Cumberland River Woodcock Creek Blaine Creek Youghiogheny River Ohio River Tennessee Region Tennessee River Tennessee River Tennessee River Upper Mississippi Region Skunk River Rock River Bear Creek Minnesota River Blue Earth River Kaskaskia River Salt River Salt Creek Iowa River Cedar River Farm Creek Fondulac Creek Friends Creek 936 553 10?80, 53?353 33 222 112 238 30 214 5,789 46 208 434 70,800 21.2 2143 23.8 20.4 24.8 26. 7 20.3 24.7 24.4 31.9 24.5 20.6 23.5 25.2 18.4 19.0 22.2 21.1 20.4 22.2 25.8 17.8 22.1 21.8 30.0 21.6 20.0 20.9 22.6 25.4 331,000 201,000 85, 500 412,000 222,400 426, 000 43,000 87, 500 73,700 156,400 81,600 134,000 996,000 37,700 118,000 151,000 2,150,000 1,160,000 1,200,000 1,205,000 23,340 29,130 20,650 Upper Upper Upper Upper Upper Upper Upper Upper Upper Upper Upper Upper Upper Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.314 8,000 28 11,250 3,550 2,680 2,318 296 3,084 6,250 26 5.4 133 21.3 18.4 29.0 26.2 14.2 10.9 18.4 14.8 19.2 15.8 21.8 15.7 20.8 14.4 87,200 308,000 38,000 283,000 206,000 246,000 476,200 99,500 326,000 316,000 67,300 21,200 83,160 24.0 21.4 27.8 22.1 19.9 21.6 TABLE Bi1 ( )TABLE B.I ( )Project State River Basin Stream Drainage Basin Ave-age Area (in inches)(sq.mi.) Prec.. Runoff PMF Peak Discharge (cfs)Jefferson LaFarge Mankato Meramec Park Montevideo Monticello New Ulm New Ulm Oakley Prairie Island Red Rock Rend Saylorville Shelbyville Iowa Upper Miss.Wisc. Upper Miss.Arkabutla Enid Grenada Sardis Union Wappapello Minn.Mo.Minn.Minn.Minn.Minn.Ill.Minn.Iowa Ill.Iowa Ill.Miss.Miss.Miss.Miss.Mo.Mo.N. D.N. D.N. D.N. D.N. D.Minn.Colo.S. D.Mo.Nebr.N. D.Nebr.Upper Upper Upper Upper Upper Upper Upper Upper Upper Upper Upper Upper Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.Miss.Lower Lower Lower Lower Lower Lower Raccoon River Kickapoo River Minnesota River Meramec River Minnesota River Mississippi River Minnesota River Cottonwood River Sangamon River Mississinpi River Des Moines River Big Muddy River Des Moines River Kaskaskia River Miss.Miss.Miss.Miss.Miss.Miss.Burlington Fox Hole Homme Kindred Lake Ashtabula Orwell Bear Creek Big Bend Blue Springs Blue Stem Bowman-Haley Branched Oak Souris Souris Red of Red of Red of hid of Lower Mississippi Regaon Coldwater River Yacona River Yalobusha River Tallahatchia River Bourbeuse River St. Francis River Souris-Red-Rainy Region Souris River Des Lacs River Park River Sheyenne River Sheyenne River Otter Tail River Missouri Region Bear Creek Missouri River Blue Springs Creek Olive Br. Salt Creek Grand River Oak Creek 1,532 266 14,900 1,497 6,180 13,900 9,500 1,280 808 44,755 12,323 488 5,823 1,030 1, 000 560 1,320 1, 545 771 1,310 9,490 939 229 3,020 983 1,820 236 5,840 33 17 446 89 21.7 22.8 13.9 22.9 15.2 14.4 21.2 23.5 12,1 27.5 13.8 22.1 22.5 25.4 24.0 32.5 25.0 13.0 13.2 19.9 15.2 13.4 12.4 17.1 19.0 18.9 10.6 17.5 11.6 11.1 17.6 17.2 7.5 21.5 10.3.19.1 21.2 24.7 23.1 26.0 19.9 11.7 5.7 12.4 12.3 8.6 9.5 14.7 267,300 128,000 329,000 552,000 263,000 365,000 263,000 128,000 178,000 910,000 613,000 308,200 277,800 142,000 430, 000 204,900 390,800 290,400 264,000 344,000 89,100 52,700 35,000 68,700 86,500 25,500 225,000 725,000 42,4OO 69,200 113,000 93,600 North North North North Missouri Missouri Missouri Missouri Missouri Missouri 24.4 6.7 9.0 26.5 23.8 25.0 21.7 15.5 12.7 20.1 16.8.~ ~ F I

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

TABLE B.1 ( )Project State River Basin Stre:an Drainage Basin Average Aren ' ir. 4nchesq_(sa.'ni.)

Prec. Runcff PFY Peak Discharge (cf s)Pomona Rathbun Smithville Stagecoach Stockton Thomas Hill Tomahawk Trenton Tuttle Creek Twin Lakes Wagon Train Wilson Wolf-Coffee Yankee Hill Kans.Iowa Mo.Nebr.Mo.Mo.Kans.Mo.Kans.Nebr.Nebr.Kans.Kans.Nebr.Arcadia Bayou Bodcau Beaver Bell Foley Big Hifl Big Pine Birch Blakely Mountain Blue Mountain Boswell Broken Bow Bull Shoals Candy Canton Cedar Point Clayton Clearwater Conchas Cooper Copan Council Grove County Line Okla.La.Ark.Ark.Kans.Tex.Okla.Ark.Ark.Okla.Okla.Ark.Okla.Okla.Kans.Okla.Mo.N. Mex.Tex.Okla.Kans.Mo.Missouri Missouri Missouri Missouri Missouri Missouri Missouri Missouri Missouri Missouri Missouri Missouri Missouri Missouri Arkansas lied White Arkansas Arkansas Red Arkansas Red Arkansas Red Red White Arkansas Arkansas Arkansas Red White Arkansas Red Arkansas Arkansas White 110 Mile Creek Chariton River Little Platte River Hickman Br. Salt Creek Sac River Little Chariton River Tomahawk Creek Thompson River Big Blue River S. Br. Middle Creek Hickman Br. Salt Creek Saline River Blue River Cardwell Br. Salt Creek Arkansas-White-Red Region Deep Fork River Bayou Bodcau White River Strawberry River Big Hill Creek Big Pine Creek Birch Creek Ouachita River Petit Jean River Boggy Creek Mountain Fork White River Candy Creek North Canadian River Cedar Creek Jackfort Creek Black River South Canadian River South Sulphur River Little Caney River Grand River James River 322 213 9.7 1,160 1a47 24 1,079 9,556 11 16 1, q1?45 8.4 105 656 1,186 78 3?66 1,105 500 2,273 754 6,036 43 7,600 119 275 898 7,409 476 505 246 153 26.2 23.7 23.9 26.0 19.7 25.0 26.4 22.6 14.5 25.9 25.2 20.2 26.1 26.0 28.5 35.3 24.3 26.4 25.4 31.3 29.0 21.5 21.8 27.6 32.5 15.2 29.-3 12.4 25.4 31.3 16.0 4.8 30.9 26.2 25.5 27.2 25.2 21.1 20.2 22.7 18.9 23.0 24.8 20.1 8.1 22.6 21.9 10.8 24.5 22.?24.9 33.6 22.4 23.5 23.6 29.3 26.0 19.6 18.2 20.8 29.4 1ý.0 27 5 4.1 22.6 29.3 13.8 3.0 29.2 21.1 22.7 25.3 186,000 188,000 185,000 50,500 470,000 79,000 26,800 342,400 798,000 56,000 53,500 252,000 58,000 58,400 1i44,000 168,?00 480,000 57,000 47, 500 86,ooo 91,000 418,000 258,000 405,000 569,000 765, 000 67, 500 371,000 208,000 24O0,oo 432,000 582,000 194,40o 169,000 250,000 133,000

TABLE B.1 ( )Drainage Basin Average PMF Peak in Stream Area (in inches) Discharge (sq.mi.) Prec. Runoff _(cfs) _Project State River Bas Lu--1 DeGray Denison DeQueen Dierks Douglas El Dorado Elk City Eufaula Fall River Ferrells Bridge Fort Gibson Fort Supply Gillham Great Salt Plains Greers Ferry Heyburn Hugo Hulah John Martin John Redmond Kaw Keystone Lake Kemp Lukfata Marion Millwood Narrows Neodesha Nimrod Norfolk Oologah Optima Pat Mayse Pine Creek Robert S. Kerr Sand Shidler Skiatook rable Rock Ark.Okla.Ark.Ark.Kans.Kans.Kans.Okla.Kans.Tex.Okla.Okla.Ark.Okla.Ark.Okla.Okla.Okla.Colo.Kans.Okla.Okla.Tex.Okla.Kans.Ark.Ark.Kans, Ark.Ark.Okla.Okla.Tex.Okla.Okla.Okla.Okla.Okla.No.Red Red Red Red Arkansas Arkansas Arkansas Arkansas Arkansas Red Arkansas Arkansas Red Arkansas Red Arkansas Red Arkansas Arkansas Arkansas Arkansas Arkansas Red Red Arkansas Red Red Arkansas Arkansas White Arkansas Arkansas Red Red Arkansas Arkansas Arkansas Arkansas White Caddo River Red River Rolling Fork Saline River Little Walnut Creek Walnut River Elk River Canadian River Fall River Cypress Creek Grand River Wolf Creek Cossatot River Salt Fk. Arkansas River Little Red River Polecat Creek Kiamichi River Caney River Arkansas River Grand River Arkansas River Arkansas River Wichita River Glover Greek Cottonwood River Little River Little Missouri River Verdigris River Fourche La Fave River North Fork White River Verdigris River North Canadian hiver Sanders Creek Little River Arkansas River Sand Creek Salt Creek Hominy Creek White River 453 33,783 169 113 238 234 634 8,405 556 880 9,477 1,494 271 3,200 1, !i46 123 1,709 732 18,130 3,015 7,250 22,351 2,056 291 200 4,104 23?1,100 68o 1,765 4,339 2,341 175 635 64,386 137 99 354 4,020 28.4 12.9 35. 5 36.2 26.7 23.0 15.9 27.1 31.1 15.2 20. 5 34.6 i6ý?17.9 26.3 27.1 16. 5 7.4 16.2 14.5 12.9 23.7 34.6 24.8 25.0 18.7 20.2 15.7 17.8 13.8 31.8 32.8 10.0 31.3 27.3 18.3 26.0 6.5 32. 5 33.2 22.9 22.8 20.3 10.9 23.0 28.1 12.6 15.7 31.5 9.3 17.5 24.2 25.8 13.5 2.0;56 9.9 6.7 19.2 31.5 2J..9 25.3 23.0 16.6 17.2 12.8 13.9 9.0 29.4 29.8 5.8 28.3 24.0 23.8 15.4 397,000 1,830,000 254,000 202,000 156,000 196,000 319,000 700,000 442,000 367,000 865,000 547,000 355,000 412,000 630,000 151,000 339,000 239,000 630,000 038,000 774,000 1,035,000 566,000 349,0o0 160,000 442,o00 194,000 287,000 228,000 372,000 451,000 386,000 150,000 523,000 1,884,000 154,000 104,100 147,800 657,000

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

TABLE B.1 ( )Project State River Basin Stream Drainage Area (so.mi.)Basin Average (in inches)Prec. Runoff PMF Peak Discharge (cfs)North Fork Pecan Bayou Proctor Roanoke Rockland Sam Rayburn San Angelo Somerville South Fork Stillhouse Hollow Tennessee Colony Town Bluff Waco Lake Whitney Abiquiu Alamogordo Cochita Jemez Canyon Los Esteros Two Rivers Alamo McMicken Whitlow Ranch Painted Rock Little Dell Mathews Canyon Pine Canyon Tex.Tex.Tex.Tex.Tex.Tex.Tex.Tex.Tex.Tex.Tex.Tex.Tex.Tex.Brazos Colorado Brazos Trinity Neches Neches Colorado Brazos Brazos Brazos Trinity Necnes Braazos Brazos N. Fk. San Gabriel River Pecan Bayou Leon River Denton Creek Neches River Angelina River North Concho River Yogua Creek S. Fk. San Gabriel River Lampasas River Trinity River Neches River Bosque River Brazos River Rio Grande Region Rio Grande Pecos River Rio Grande Jemez Canyon Peccs River Rio Hondo Lower Colorado RegLon Bill Williams River Aqua Fria River Queen Creek Gila River 246 316 1,265 604 3,557 3,449 1, 511 1,006 123 1,318 12,687 7, 573 i, 670 17,656 3,159 3,917 4,065 1,034 2,434 1,027 4,770 247 143 50,600 31.7 30.7 27.*0 28.9 21.0 23.7 21.2 22.0 32.6 27 *7 18.9 2?. 7 25.7 2 5. 7 26.6 23.8 21.4;>',. I 20.6 13.1 13.6 27.*4 22.5 20.4 15.7 20.6 7.7 N.N.N.N.N.N.Me M.M.M.M.M.Rio Rio Rio Rio Rio Rio Grande Grande Grande Grande Grande Grande 4.6 9.2 12.2 8.2 1.9 1.9 3.7 4.7 265,800 236,200 459,200 313,600 150, 00 395,600 (14,-00 415,700 145,300 686,400 575,600 326,000 622,900 700,000 130,000 277,000 320,000 220,000 352,000 282,400 580,000 52,000 230,000 620,000 23,000 35,000 38,000 99,500 39,500 Ariz.Ariz.Ariz.Ariz.Utah Nev.Nev.Colorado Colorado Colorado Colorado 12.0 3.5 3,3 11 .5 9.7 7.7 2.8 6.1 6.0 8.6 7.4 8.2 6.6 Jordon (Great)Great Basin Great Basin Great Basin Region Dell Creek Mathews Canyon Pine Canyon 36 34 4ý5 Applegate Blue River Oreg. Rogue Oreg. Columbia Columbia-North Pacific Region Applegate River S. Fk. McKenzie River 223 88 28.9 22.7 TABLE B.1 ( )Project State River Basin Stream Drainage Area (sa.mi.)Basin Average (in inches)Prec. Runoff PMF Peak Discharge (cfs)C)Bonneville Cascadia Chief Joseph Cottage Grove Cougar Detroit Dorena Dworshak Elk Creek Fall Creek Fern Ridge Foster Green Peter Gate Creek Hills Creek Holley Howard A. Hanson Ice Harbor JOhn Day Libby Little Goose Lookout Point Lost Fork Lower Granite Lower Monumental Lucky Peak McNary Mud Mountain Ririe The Dalles Wynoochee Zintel Bear Big Dry Creek Black Butte Brea Oreg.Oreg.Wash.Oreg.Oreg.Oreg.Oreg.Ida.Oreg.Oreg.Oreg.Oreg.Oreg.Oreg.Oreg.Oreg.Wash.Wash.Oreg.Mont.Wash.Oreg.Oreg.Wash.Wash.Ida, Oreg.Wash.Ida.Oreg.Wash.Wash.Cal.Cal.Cal.Cal.Columbia Columbia Columbia Columbia Columbia Columbia Columbia Columbia Rogue Columbia Columbia Columbia Columbia Columbia (2 olum bia Columbia Green Columbia Columbia Columbia Columbia Columbia Rogue Columbia Columbia Columbia Columbia Puyallup Columbia Columbia Chechalis Columbia San Joaquin San Joaquin Sacramento Santa Ana Columbia River 240,000 South Santiam River 179 Columbia River 75,000 Coast Fk. Willamette River 104 S. Fk. McKenzie River 208 North Santiam River 438 Row River 2hc N. Fk. Clearwater River 2,440O Elk Creek 132 Willamette River 184 Long Tom River 252 South Santiam River 4c!4 Middle Santiam River 277 Gate Ck. McKenzie River 50 Middle Fk. Willamette River 38q Gala.pooia River 105 Green River Snake River 109,000 Columbia River 226,000 Kootenai River 9,070 Snake River 3.03.900 MiddJe F

k. Wilamette

?iver 9ga Lost Fk. Howie River 6L Snake River Snake River 1.08,500 Boise River 2,650 Columbia River 21.4,000 White River '400 Willow Ck. Snake River 620 Columbia River 237,000 Wynoochee River 4i Zintel Canyon Snake River 1Q 22,1 42,2 29.0 29.7 34.2 36.0 34.6 70.5 32.6 33.8 20.3 40 .8 41.1 33.0 35.8 26. 8 13.a 21.1 3r:.5 14.6-40.8 22.7 14.7 14.0 32. 5 23.0 33.9 2i.1 69.9 7.8 13.6 13.8 12,3 6.6 2,720,000 115,000 1,550,000 45,000 98,000 203,000 131,600 280,000 63,500 100,000 4,8,600 260,000 160,0oo 37,000 197,000 59,000 164,000 954,000 2,650,000 282,000 850,000 360,000 169,OOC 850,000 850,000 123,000 2,610,000 386,000 4?, 000 2,660,000 52, 500 40, '500 California Region Bear Creek Big Dry Creek Stony Creek Brea Creek 72 91.741 23 I 3.b 19.0 19.7 10. LL 30,400 17,000 254,000 37,000 K-

TABLE B.1 ( )Project State River Basin Stream Drainage Basin Average PMF Peak Area (in inches) Discharge (sq.mi.) Prec. Runoff (cfs)Buchanan Burns-Butler Valley Carbon Canyon Cherry Valley Comanche Coyote Valley Dry Creek Farmington Folsom Fullerton Hansen Hidden Lake Isabella Knights Valley Lakeport Lopez Mariposa Martis Creek Marysville Mojave River New Bullards Bar New Exchequer New Hogan New Melones Oroville Owens Pine Flat Prado San Antonio Santa Fe Sepulveda Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.Cal.San Joaquin San Joaquin Mad Santa Ana San Joaquin San Joaquin Russian Russian San Joaquin Sacramento Santa Ana Los Angeles San Joaquin San Joaquin Russian Sacramento Los Angeles San Joaquin Truckee Sacramento Mojave Sacramento San Joaquin San Joaquin San Joaquin Sacramento San Joaquin San Joaquin Santa Ana Santa Ana San.Gabriel Los Angeles Chowchilla River Burns Creek Mad River Santa Ana River Cherry Creek Mokelumne River East Fk. Russian River Dry Creek Little John Creek American River Fullerton .Creek Tujunga Wash Fresno River Kern River Franz-Maacama Creek Scotts Creek Pacoima Creek Mariposa Creek Martis Creek Yuba River Mojave River North Yuba River Merced River Calaveras River Stanislaus River Feather River Owens Creek Kings River Santa Ana River San Antonio Creek San Gabriel River Los Angeles River 235 74 352 19 117 618 105 82 212 1,875 5.0 147 234 2,073 59 52 34 108 39 1,324 215 489 1,031 362 897 2,600 26 1, 542 2,233 27 236 152 26.0 20.1 17.4 10.6 35.2 10.4 10.3 24.3 23.1 25.0 19.9 22.9 21.3 15.6 11.3 10.9 21.2 17.5 9.0 6.8 9.8 29.9 18.4 27.1 6-5 31.6 28.9 30.9 24.0 20.8 18.6 13.0 26.5 12.7 38.9 27.0 40.4 30.4 38.9 25.7 27.1 15.9 18.3 25.8 16.3 23.3 22.8 14.4 9.2 28.5 14.4 26.3 13.0 13.0 35.5 15.0 127,000 26,800 137,000 56,000 60,000 261,000 57,000 4-5,000 56, 000 615,000 16,000 130,000 114,000 235,000 44,300 36,100 32,000 43,000 12,400 460,000 186,000 226,000 396,000 132,000 355,000 720,000 11,400 437,000 700,000 60,000 194,000 220,000 I -- ----

TABLE B.] ( )Project State River Basin StreamBasin Average PMF Peak Area (in inches) Discharge (sq.mi.) Prec. Runoff (cfs)Lf1 Success Terminus Tuolumne Whittier Narrows Cal.Cal, Cal.Cal.San San San San Joaquin Joaquin Joaquin Gabriel Tule River Kaweah River Tuolumne River San Gabriel River 38-560 1,533 551+32.5 40.1 25.1 17.4 12.6 24.8 20.?13.7 200,000 290,000 602,000 305,000

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 T A B L E S ....................................: 1.59-59 FIGURES Figure C.1 -Probable Maximum Surge Estimates, Gulf Coast .... .............

C.2 -Probable Maximum Surge Estimates, Atlantic Coast ..........

TABLES Table C. 1 -Probable Maximum Surge Data ...... ....................

C. 2 -Probable Maximum Hurricane, Surge, and Water Level -Port Isabel ..C. 3 -Probable Maximum Hurricane, Surge, and Water Level -Freeport ....C. 4 -Probable Maximum Hurricane, Surge, and Water Level -Eugene Island .C. 5 -Probable Maximum Hurricane, Surge, and Water Level.- Isle Dernieres C. 6 -Probable Maximum Hurricane, Surge, and Water Level -Biloxi C. 7 -Probable Maximum Hurricane, Surge, and Water Level -Santarosa Island .C. 8 -Probable Maximum Hurricane, Surge, and Water Level -Pitts Creek ...C. 9 -Probable Maximum Hurricane, Surge, and Water Level -Naples .......C.10 -Probable Maximum Hurricane, Surge, and Water Level -Miami .....C.1l- Probable Maximum Hurricane, Surge, and Water Level -Jacksonville

...C.12 -Probable Maximum Hurricane, Surge, and Water Level -JeckyUl Island...C.1 3 -Probable Maximum Hurricane, Surge, and Water Level -Folly Island ...C.14 -Probable Maximum Hurricane, Surge, and Water Level -Raleigh Bay ...C.I 5 -Probable Maximum Hurricane, Surge, and Water Level -Ocean City ...C.1 6 -Probable Maximum Hurricane, Surge, and Water Level -Atlantic City ..C.17 -Probable Maximum Hurricane, Surge, and Water Level -Long Island ...C. 18 -Probable Maximum Hurricane, Surge, and Water Level -Watch Hill Point C.19 -Probable Maximum Hurricane, Surge, and Water Level -- Hampton Beach C.20 -Probable Maximum Hurricane, Surge, and Water Level -Great Spruce Island C.21 -Ocean Bed Profiles ................................1.59-57........1.59-58 1.59-59 1.59-60 1.59-61 1 .59-62 1 .59-63 1.59-64 1.59-65 1.59-66 1.59-67 1.59-68 1.59-69 1.59-70 1.59-71 1.59-72 1.59-73 1.59-74 1.59-75 1.59-76 1.59-77 1.59-78 1.59-79 1.59-53

C.1 INTRODUCTION

C.3.1 Methods Used This appendix presents timesaving methods of esti-mating the maximum stillwater level of the probable maximum surge (PMS) from hurricanes at open-coast sites on the Atlantic Ocean and Gulf of Mexico. Use of the methods herein will reduce both the time necessary for applicants to prepare license applications and the NRC staff's review effort.The procedures are based on PMS values determined by applicants for licenses that have been reviewed and accepted by the NRC staff and by the staff and its consultants.

The information in this appendix was developed from a study made by Nunn, Snyder, and Associates, through a contract with NRC (Ref. 1).The PMS data are shown in Tables C.A through C.21 and on maps of the Atlantic and Gulf Coasts (Figures C.A and C.2). Suggestions for interpolating between these values are included.Limitations on the use of these generalized methods of estimating PMS are identified in Section C.4. These limitations should be considered in detail in assessing the applicability of the methods at specific sites.Applicants for licenses for nuclear facilities at sites on 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 application of the methods in this appendix will in many cases be accepted by the NRC staff with no further verification.

C.2 SCOPE The data and procedures in this appendix apply only to open-coast areas of the Gulf of Mexico and the Atlantic Ocean.Future studies are planned to determine the applica-bility of similar generalized methods and to develop such methods, if feasible, for other areas. These studies, to be included in similar appendices, are anticipated for the Great Lakes and the Pacific Coast, including Hawaii and Alaska.C.3 PROBABLE MAXIMUM SURGE LEVELS FROM HURRICANES

The data presented in this appendix consist of all determinations of hurricane-induced PMS peak levels at open-coast locations computed by the NRC staff or their consultants, or by applicants and accepted by the staff.The data are shown in Tables C.A through C.21 and on Figures C.A and C.2. All represent stillwater levels for open-coast conditions.

All PMS determinations in Table C.A were made by NRC consultants for this study (Ref. 1), except Pass Christian, Crystal River, St. Lucie, Brunswick, Chesa-peake Bay Entrance, Forked River-Oyster Creek, Mill-stone, Pilgrim, and Seabrook.The computations by the consultants were made using the NRC surge computer program, which is adopted from References

2 and 3. Probable maximum hurricane data were taken from Reference

4. Ocean bottom topography for the computations was obtained from the most detailed available Nautical Charts pub-lished by the National Ocean Survey, NOAA. The traverse line used for the probable maximum hurricane surge estimate was drawn from the selected coastal point to the edge of the continental shelf or to an ocean depth of 600 feet MLW, and was one hurricane radius to the right of the storm track. It was oriented perpendicular to the ocean bed contours near shore. The ocean bed profile along the traverse line was determined by roughly averaging the topography of cross sections perpendicular to the traverse line and extending a maximum of 5 nautical miles to either side. The 10-mile wide cross sections were narrowed uniformly to zero at the selected site starting 10 nautical miles from shore. It was assumed that the peak of the PMS coincided with the 10% exceedance high spring tide 1 plus initial rise.2 In each case the maximum water level resulted from use of the high translation speed for the hurricane in combination with the large radius to maximum wind, as 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.Lucie, Chesapeake Bay Mouth, and Seabrook are shown in Table C.21.The water levels resulting from these computations are open-coast stillwater levels upon which waves and wave runup should be superimposed.

C.3.2 Use of Data in Estimating PMS Estimates of the PMS stillwater level at open coast sites other than those shown in Tables C.1 through C.21 and on Figures CA and C.2 may be obtained as follows: 1. Using topographic maps or maps showing sound-ings, such as the Nautical Charts, determine an ocean bed profile to a depth of 600 ft MLW, using the methods'The 10% exceedance high spring tide is the predicted maximum monthly astronomical tide exceeded by 10% of the predicted maximum monthly astronomical tides over a 21-year period.2 Initial rise talso called forerunner or sea level anomaly) is an anomalous departure of the tide level from the predicted astronomical tide.1.59-55 outlined above. Compare this profile with the profiles of the locations shown in Tables C.2 through C.21. With 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 interpolated from the wind setup data for these loca-tions.2. Pressure setup may be interpolated between loca-tions on either side of the site.3. Initial rise, as shown in Table C1, may be interpolated between locations on either side of the site.4. The 10% exceedance high spring tide may be computed from predicted tide levels in Reference

5; it may be obtained from the Coastal Engineering Research Center, U.S. Army Corps of Engineers, Ft. Belvoir, Va.;or it may be interpolated, using the tide relations in Reference

5.5. An estimate of the PMS open-coast stillwater level at the desired site will be the sum of the values from Steps 1 through 4, above.C.3.3 Wind-Wave Effects Coincident wave heights and wave runup should be computed and superimposed on the PMS stillwater level obtained by the foregoing procedures.

Acceptable methods are given in Reference

2.C.4 LIMITATIONS

1. The NRC staff will continue to accept for review detailed PMS analyses that result in less conservative estimates.

In addition, previously reviewed and approved detailed PMS analyses at specific sites will continue to be acceptable even though the data and procedures in this appendix result in more conservative estimates.

2. The PMS estimates obtained as outlined in Section C.3.2 are maximum stillwater levels. Coincident wind-wave effects should be added.3. The PMS estimates obtained from the methods in Section C.3.2 are valid only for open-coast sites, i.e., at the point at which the surge makes initial landfall.

If the site of interest has appreciably different offshore bathy-metry, or if the coastal geometry differs or is complex, such as for sites on an estuary, adjacent to an inlet, inshore of barrier islands, etc., detailed studies of the effect of such local conditions should be made. Refer-ence 2 provides guidance on such studies.APPENDIX C REFERENCES

.1. Nunn, Snyder, and Associates, "Probable Maximum Flood and Hurricane Surge Estimates," unpublished report to NRC, June 13, 1975 (available in the public document room).2. U.S. Army Coastal Engineering Research Center,"Shore Protection Manual," 1973.3. B.R. Bodine, "Storm Surge on the Open Coast: Fundamental and Simplified Prediction," Technical Memorandum No. 35, U.S. Army Coastal Engineering Research Center, 1971.4. U.S. Weather Bureau (now U.S. Weather Service, NOAA), "Meteorological Characteristics of the Probable Maximum Hurricane, Atlantic and Gulf Coasts of the United States," Hurricane Research Interim Report, HUR 7-97 and HUR 7-97A, 1968.5. U.S. Department of Commerce, NOAA, "Tide Tables," annual publications.

1.59-56

840 830 820 810 800 790 780 360 350 340 330 330 320 310 310 LOUISIANA-4 Z290 U300 0 FLORIDA 29 Wry > l 280270 280 270 _ 260 260 43 250 250 240 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 C-,.PORT ISABEL FREEPORT EUGENE ISLAND ISLE DERNIERES PASS CHRISTIAN (a)BILOXI SANTAROSA

ISLAND PITTS CREEK CRYSTAL RIVER (a)NAPLES MIAMI STr. LUCIE(a)JACKSONVILLE

JEKYLL ISLAND FOLLY ISLAND BRUNSWICK RALEIGH CHESAPEAKE

BAY ENTRANCE (a)OCEAN CITY ATLANTIC CITY FORKED RIVER -OYSTER CREEK LONG ISLAND MILLSTONE WATCH HILL POINT PILGRIM HAMPTON BEACH SEABROOK(a)

GREAT SPRUCE ISLAND 86 152 192 165 160 183 205 248 100 90 108 150 135 110 146 166 166 115 148 30 00 30 00 00 00 00 00 00 00 00 00 00 0.23 0.20 2.00 0.62 3.40 0.09 8.84 2.31 0.17 0.17 0.10 0.10 2.60 0.19 0.12 0.49 0.55 20.00 1.75 11.20 0.18 9.23 0.79 0.94 0.20 4.00 2.17 0.30 1.94 5.50 30.00 11.90 30.00 0.48 24.30 31.40 15.70 2.01 2.58 15.60 12.00 11.10 24.0 44.1 30.4 50.1 11.9 69.4 45.6 2.2 30.0 39.6 32.8 69.2 20.9 107.0 85.8 2.7 55.0 64.3 47.0 33.10 55.5 60.0 45.3 44.0 70.9 90.0 58.5 77.0 78.0 45.0 132.0 127.0 145.0 3.9 18.7 62.5 72.6 57.6 10.07 15.99 29.74 18.61 28.87 27.77 9.12 24.67 26.55 18.47 2.51 8.25 16.46 20.63 17.15 12.94 8.84 3.57 2.89 3.29 3.29 2.88 2.98 3.25 2.31 2.65 2.90 3.90 3.80 3.23 3.34 3.23 2.20 3.09 2.50 2.40 2.00 2. 00 0.80 1. 50 1.50 1.20 0.60 1. 00 0.90 0.98 1.30 1.20 I. 00 1. 00 1 -00 1.10 1.14 1.10 1.80 2.90 2.40 1.90 1.20 2.50 1.80 4.20 4.30 3.60 3.60 3.70 6.20 7.50 6.80 5.80 5.20 3.50 5.10 5.80 2.70 8.00 3.56 8.80 17.94 24.18 37.44 25.80 33.75 34.76 15.67 32.38 34.10 25.97 10.91 16.73 27.20 32.67 28.18 21.94 18.13 21.90 23. 17 24.80 21.78 20.16 19.17 22.19 19.6 19.01 19.53.30.51 1.75 12.0 25.4 35.2 62.0 00 0.12 0.26 3.67 17.8 45.0 59.0 00 0.20 0.85 5.00 23.1 58.4 70.0 17.30(b) (b)14.30 2.83 15.32 2.57 00 0.09 0.18 00 0.07 0.14 00 0.22 0.31 00 0.04 0.08 1.35 4.8 27.2 68.4 0.64 1.6 34.3 84.0 18.08(b)8.73 12.41 10.01 4.25 4.79 9.73 (b) 1.00 2.46 0.97 2.20 1.00 2.42 0.96 0.71 2.0 0.20 1.1 7.2 6.3 40.0 44.0 178.0 2.23 0.83 11.70 2.28 0.86 11.60 1.82 0.56 18.40 a. See Table C.H for ocean bed profile.b. Combined wind and pressure setup.a. 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

ZONE C AT LOCATION 260 04' DEGREE NORTH SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW MODERATF HIGH_(ST) (MT) (.)_3ENTRAL PRESSURE INDEX P 0 INCHES 26.42 26.42 26.42ýPER IPHERAL PRESSURE Pn INCAES 31.30 31.30 31.30 RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 20 20 20 rRANSIATION

SPEED Fv (FORWARD SPEED) KNOTS 1 4 11 28 WIAXMUM WIND SPEED V M.P.H. 147 151 161 INITIAL DISTANCE-NAUT.

MI, i/FROM 20 MPH WIND 398 374 318 6T SHORE TO MAX. WIND 0 OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)0 0 0.2 9.0_ 0.5 20.5 1.0 35.0_ 1.5 43.0 2.0 51.0_ 3.0 58.5-5.0 69.0 10 95.5 15 116 20 138_ 30 171 40 266 44 600 50 1,850 LATITUDE 26° 05'DEGREE AT TRAVERSE MID-POINT

FROM SHORE TO 600-FOOT DEPTH C 0 E F F I CI E N T S BOTfIOF FhICTION FACTOR 0.0030 WIND STRESS CORRECTION

FACTOR 1.10 WATER LEVEL DATA (AT OPEN CCAST SHORELINE)

PMH (CNPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES 14ULe Maximum wind speed is assumed Lto be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-/Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph-isovels is approxi-mately double the initial distance.PMH SPEED OF TPANSLATION

COMPONENTS

ST MT nIT F E E T WIND SETUP 10.07 PRESSURE SETUP 3.57 INITIAL WATER LEV. 2.50 kSTRONONICAL

1.80 FIDE LEVEL rOTAL-SURGE

STILL WATER LEV. 17.9.4 FEET NLW 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" TEXAS 22' : 'PRAVERSE-AZIMUTH

152 DEGREEt LENGTH 70.9 NAUTICAL MILES PROBABLE MAXIMUM HURRICANE

INDEX CHARACTERISTICS

ZONE C AT LOCATION 280 56' DEGHEE NORI'H I SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW MODERATF HIGH S(ST) (?Tr) I MENTRAL PRESSURE INDEX 26.69 P INCHES 26.69 26.69 26.69 0 PERIPHERAL

PRESSURE P INCHES 31.25 31.25 31.25 RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 26.0 26.0 26.0 rRANS1ATION

SPEED F (FORWARD SPEED) KNOTS I 4 11 28.0 AIMUM WIND SPEED V M.P.H. 139 143 153 x INITIAL DISTANCE-NAUT.MI.Y

FROM 20 MPH WIND 491 458 390 AT SHORE TO MAX. WIND I U)&OCEAN BED PROFILE TRAVERSE WATER DISTANCE DErTH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)0 0 1.0 30 2.0 32_ 3.0 37 4.0 40_ 5.0 47 10.0 66 1 15.0 78 20.0 9o 30.0 114_ 40°.0 132_ 50.0 168 6o.o0 240 70.0 570 70.9 600 LATITUDE 28' 26'DEGREE AT TRAVERSE MID-POINT

FROM SHORE TO 600-FOOT DEPTH PMH OCPIPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BO'nUfM FRICTION FACTOR 0.0030 WIND STRESS CORRECTION

FACTOR 1.10 W A T E h L EV E L D A T A (AT OPEN CCAST SHORELINE)

Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-/Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.PMH SPEED OF TRANSLATION

COMPONENTS

ST I MT I HT F E E T WIND SETUP 15.99 PRESSURE SETUP 2.89 INITIAL WATER LEV. 2.40 kSTRONOMICAL

2.90 rIDE LEVEL TOTAL-SURGE

STILL WATER LEV. 24.18 FEET MLW

TABLE C4 SUM MARY-PERTINENT

PROBABLE MAXIMUE hUHRICANE (FMH), STORM SURGE COMPUTATIONAL

DATA AND RESULTANT

WATER LEVEL LOCATION EUGENE LAT. 290 20' LONG. 91 ISLAND, LOUISIANA 1 :0 t 21 'rTRAVERSE-AZIMUJTHl9

2 30 DEG~REE, LENGTH 90 NAUTICAL MILES PROBABLE MAXIMUM HURRICANE

INDEX CHARACTEIISTICS

ZONE B AT LOCATION 290 20' DEGREE NORTH SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW MODERATF HIGH 2 (ST) (nT) (HT)MENMAL PRESSURE INDEX P INCHES 26.87 26.87 26.87 PERIPHERAL

PRESSURE P INCHES 31.24 31.24 31.24 RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 29.0 29.0 29.0 rRANSLATION

SPEED Fv (FORWARD SPEED) KNOTS 4 11 28.0 MAXIMUM WIND SPEED V M.P.H. 141 144 153 INITIAL DfSTANCE-NAUT.

MI.i_FROM 20 MPH WIND 534 484 412 4T SHORE TO MAX. WIND .OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BEL40W SHORE MLW (NAUT.MI.) (FErT)-0.0 0 -1.0 5 --2.0 10 -3.0 12 --5.0 15 --10.0 15 --15.0 18 --20.0 20 --30.0 50 --40 60 --50 140 --6o 200 --70 260 -80 320 --90 600 -IATITUDE 28 04 DEGREE AT TRAVERSE MID-POINT

FROM SHORE (ro 600-FOOT DEPTH PMH CCNPUTATIONAL

COEFFICIENT

AND LEVEL (SURGE) ESTIMATES BOIOM FilICTION

FACTOR 0.0030 WIND STRESS CORRECTION

FACTOR 1.10 WATER LEVEL DATA (AT OPEN CCAST SHORELINE)

PMH SPEED OF TRANSLATION

COMPONENTS

ST M MT HTI F E E' T WIND SETUP 29.74 PRESSURE SETUP 3.29 INITIAL WATER LEV. 2.00 ASTRONOMICAL

2.40 TIDE LEVEL TAL-SURGE STILL WATER LEV. 37.44 FEET MLW I Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.-~-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 DERNIERES, LOUISIANA PROBABLE MAXIMUM HURRICANE

INDEX CHARACTEIISTICS

ZONE B AT LOCATION 290 03' DEGREE NORTH SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW I4ODERATF

HIGH_(ST) (rT) )JENTRAL PRESSURE INDEX P INCHES 26.88 26.88 26.88 PER IPHERAL PRESSURE P INCHES 31.25 31.25 31.25 n _ a _RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 29 29 29 rRANSLATION

SPEED F (FORWARD SPEED) KNOTS 4 11 28 MAXIMUM WIND SPEED V M.P.H. 140 144 153 INITIAL DISTANCE-NAUT.MI.1!

FROM 20 MPH WIND 528 487 394ýT SHORE TO MAX. WIND I _OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)0 0-0.2 6.0 0.5 9.0 1.0 13.0 1.5 17.5 2.0 22.5 3.0 26.e 5.0 32.0 7.0 34.0 7.5 28.0-8.0 25.5-8.5 25.0 9.0 28.5.9.5 34.0 1 10.0 42.5-15.0 62.0-20.0 56.0 30.0 97.9-40.0 152.0 50.0 243-58.5 600-60.o 688 LATITUDE 0 28°3 4.4 DEGREE AT TRAVERSE MID-POINT

FROM SHORE rO 600-FOOT DEPTH DEGREE, LENGIH 58.5 NAUTICAL MILES PMH OCXPUTATIONAL

COBYFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S B(yJ']fj .FhICTION FACTOR 0.0030 WIND STRESS

FACTOR 1.10 WATER LEVEL DATA (AT OPEN CCAST SHORELINE)

Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.y Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.PMH SPEED OF TANSIATIOI

COMPONENTS

ST MT I HT F E E T WIND SETUP 18.61 PRESSURE SETUP 3.29 INITIAL WATER LEV. 2.00 kSTRONONICAL

1.90 rIDE LEVEL TOTAL-SURGE

STILL WATER LEV. 25.aO FEET MLW 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

ZONE B AT LOCATION 300 24' DEGREE NORTH SPEED OF THRANS TION PARAMETER

DESIGNATIONS

SLOW MODERATF HIGHl ST)'n (n) (HT)CENTRAL PRESSURE INDEX P INCHES 26.9 26.9 26.9 0 PER IPHERAL PRESSURE P INCHES 31.23 31.23 31.23 n__RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 30 30 30 TRANSLATION

SPEED Fv (FORWARD SPEED) KNOTS 4 11 28 MAXIMUM WIND SPEED V M.P.H. 139 143 153 x INITIAL DISTANCE-NAUT.MI.i/

FROM 20 MPH WIND 525 498 396&T SHORE TO MAX, WIND OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NALT.MI.) (FEET)o 0 0.2 3.0 -_ 0.5 2.0_ 1.0 6.5_ 1.5 9.0" 2.0 9.0 -_ 3.0 9.5 -_ 5.0 12.0_ 9.0 9.5_ 9.5 11.0 10.0 14.0-10.5 18.5_ 11.0 17.5 -_ 11.5 23.0 j 12.0 29.0_ 13 34.5__ 15 41.5 20. 45.0-25 47.0_ 30 50.0 40 65.0 L 50 99.0 60 164 -S70 203 L '78 600o LATITUDE 290 5'*DEfGREE AT TRAVERSE MID-POINT

FROM SHORE rO 600-FOOT DEPTH PMH OCCPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I 9 N T S BOT'1OYM FHICTION FACTOR 0.0030 WIND STRESS CORRECTION

FACTOR 1.10 WATER LEVEL DATA (AT OPEN CCAST SHORELINE)

PMH SPOED OF TRANSLATION

COMPONENTS

ST I MT IHT F E E T WIND SETUP 27.77 RESSURE SETUP 2.98 INITIAL WATER LEV. 1.50 TNOMICAL 2.50 rAL-SURGE STILL WATER LU. 34.76 BET MLW Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-/Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.

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 ISLAND, ALABAMA DEGXREEs LENGTH 44.7 NAUTICAL MILES PROBABLE MAXIMUM HURRICANE

INDEX CHARACTERISTICS

ZONE B AT LOCATION 300 24' DEGREE NORTH SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW ,ODERATF HIGH_ (ST) (MT) (HT)CTL PRESSURE INDEX P INCHES 26.88 26.88 26.88 0 PERIPHERAL

PRESSURE P INCHES 31.20 31.20 31.20 n RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 29 29 29 TRANSLATION

SPEED F (FORWARD SPEED) KNOTS 4 ii 28 MAXIMUM WIND SPEED" V M.P.H. 140 144 153 INITIAL DISTANCE-NAUT.MI.I.i FROM 20 MPH WIND 528 487 394 IT SHORE TO MAX. WIND I I vi OCEAN BED PROFILE TRAVERSE WATER DISTANCE DERPH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)0 0 0.2 22 0.5 52 1.0 66 1.5 66"2.0 66 3.0 73 5.0 76 10 88 15 120 20 182 30 377 40 510 45 600 50 756 LATITUDE ; 30°1.3'DEGREE AT TRAVERSE AID-POINT

FROM SHORE iv 600-FOOT DEPTH PMH CNhPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BO'i0JM

FilICTION

FACTOR 0.0030 WIND STRESS CORRECTiON

FACTOR 1.10 WATEh LEVEL DATA (AT OPEN CCAST SHORELINE)

Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximumwind.-Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.PMH SPEED OF TRANSLATION

COMPO1ENTS

ST I MT I I-l'F E E T WIND SETUP 9.12 PRESSURE SETUP 3.25 INITIAL WATER LEV. 1.50 ASTRONOMICAL

1.80 TIDE LEVEL TOTAL-SURGE

STILL WATER LEV. 15.67 FEET MLW

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'FLORIDA PROBABLE MAXIMUM HURRICANE

INDEX CHARACTEIISTICS

ZONE A AT LOCATION 300 01' DEGREE NORTH 53' : TRAVERSE-AZIMUTH

205 t SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW IODERATF HIGH (ST) (MT) .HT ENTRAL PRESSURE INDEX P INCHES 26.79 26.79 26.79 ERIPHERAL

PRESSURE P INCHES 30.22 30.22 30.22ýEDUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 26 26 26 FRANSIATION

SPEEDý_ (FORWARD SPEED) KNOTS 1 4 11 21 MAXIMUM WIND SPEED V M.P.H. 138 142 146 INITIAL DISTANCE-NRUT.MI.li FROM 20 MPH WIND 354 322 278 TT SHORE _O MAX. WIND OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)DEGREEi LENGTH 110 NAUTICAL MILES PMH CDNPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BOT'ION FlICTION FACTOR 0.0030 WIND STRESS CORRECTION

FACTOR 1.10 WA T ER LEVEL DATA (AT OPE12 CCAST SHOFELINE)

/1 0 0.2 0.5 1.0 1.5 2.0 3.0 5.0 10 15 20 30 40 50 6o 70 80 9o 100 110 120 130 132 140 0 1.0 2.0 3.0 4.0 5.0 6.5 9.0 22.0 31.0 41.0 62.0 78.0 81.0 84.0 101.0 117.0 144.0 180.0 210.0 280.0 543.0 6oo.0 846 Note: Maximum wind speed is.assumed to be on the traverse that is to right of storm track a distance equal to.the radius to maximum wind.-/Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.PMH SPEED OF TPANSLATION

COMPONENTS

ST I MT H Ti'F E E T WIND SETUP 24.67 PRESSURE SETUP 2.31 INITIAL WATER LEV. 1.20 ASTRONOMICAL

4.20 TIDE LEVEL TOTAL-SURGE

STILL WATER LEV. 32.38 FEET M LW____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 FLORIDA LAT. 26001.4' LONG. 81"46.2':

TRAVERSE-AZIMUTH

2413 DELREE, LENGTH 145 NAUTICAL MILES PROBABLE MAXIMUM HURRICANE

INDEX CHARACTERISTICS

ZONE A AT LOCATION 260 01' DEGREE NORTH SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW IMODERATF

HIGH_(ST) (ni) (HT)CENTRAL PRESSURE INDEX P INCHES 26.24 26.24 26.24 PER IPHERAL PRESSURE P INCHES 31.30 31.30 31.30 n RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 15 1 I TRANSLATION

SPEED F (FORWARD SPEED) KNOTS 4 17 MAXIMUM WIND SPEED V M.P.H. 150 1LL 158 INITIAL DISTANCE-NAUT.

MI.i/FROM 20 MPH WIND 292 270 256 AT SHORE TO MAX. WIND Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-I OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)0-0,.5 +/-8.0-1.0-!.55 3.0 27.0 5.0 150 41.0 151 48.20 4) 90.0 50 108-60 144 70 165 80 186 90 210 100 228 110 249 120 252 130 432 140 452-145 600 150 1,200 LATITUDE 0 250 35'DEGREE AT TRAVERSE MID-POINT

FROM SHORE TO 600-FOOT DEPTH PMH CCNPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BO'ITUr FHICTION FACTOR 0.r1030 WIND STRESS CORRECTION

FACTOR 1.10 WATEh LEVEL DATA (AT OPEN CCAST SHORELINE)

PMH SPEED OF TRANSLATION

COMPONENTS

ST I MT I HT F E E T WIND SETUP 13.49 15.87 18.47 PRESSURE SETUP 3.29 2.87 2.90 INITIAL WATER LEV. 1.00 1.00 1.00 ASTRONOMICAL

3.60 3.60 3.60 TIDE LEVEL AOTKL-SURGE

STILL WATER LEV. 21.38 23.35 25.97 FEE MLW .. I II _I-Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-matelv double the initial distance.

TABLE C.10 SU MMARY-PERTINENT

PROBABLE MAXIMU. hiUaRICANE (PMH), STORM SURGE COMPUTATIONAL

DATA AND RESULTANT

WATER LEVEL LOCATION MIAMI FLORIDA LAT. 25047.2' LONG. 80"07.8' ; TRAVERSE-AZIMUTH

100 DBYGREEj LEN.GTH 3.9 NAUTICAL MILES PROBABLE MA.XIMUM HURRICANE

INDEX CHARACTEISTICS

ZONE 1 AT LOCATION 250 47.2' DEXGREE NORTH OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)0 0 0.2 12 0.5 16 1.5 25 2.0 47_ 3.0 266 3.9 600 5.0 822 LATITUDE 0 25I46-.DEGREE AT TRAVERSE MID-POINT

FROM SHORE To 600-FOOT DEPTH PMH OCMPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BOi7IFO FiRICTION

FACIOR 0.0025 WIND STRESS CORRECTION

FACTOR 1.10 WATER LEVEL DATA (AT OPEN CCAST SHORnELINE)

PMH SPEED OF TRANSLATION

COMPONENTS

ST T MT i HI'F E E T WIND SETUP 2.06 2.37 2.51 PRESSURE SETUP 3.97 3.82 3.90 INITIAL WATER 0.90 0.90 0.90 ASTRONOMICAL

3.60 3.60 3.60 FIDE

____AOTAL-SURGE

STILL WATER LER .10.53 10.68 10.91 FEET MLW I Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.

TABLE C.11 PROBAWLE NAXIMUI h.HURRICANE (FMH), STORM SURGE COMPUTATIONAL

FATA AND RESULTANT

WATER LEVEL LOCATION JACKSONVILLELAT.

300 21' LONG. 81 FLORIDA PROBABLE MAXIMUM HURRICANE

INDEX CHARACTERISTICS

ZONE 2 AT LOCATION 300 21' DEGREE NORTH 24.3: TRAVERSE-AZIMUTH

90 DECREEt LENGTH 62.5 NAUTICAL MILES SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW MODERATF HIGH_(ST) (T HT CENTRAL PRESSURE INDEX P INCHES 26.67 26.67 26.67 PERIPHERAL

PRESSURE Pn INCHES 31.21 31.21 31.21 RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 38 38 38 TRANSIATION

SPEED I F (FORWARD SPEED) KNOTS 1, 4 11 22 MIMUM WIND SPEED V M.P.H. 138 142 149 INITIAL DISTANCE-NAUT.MI.]_

FROM 20 MPH WIND 407 372 334 NT SHORE TO MAX. WIND I OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)0 0 0.2 20 0.5 25 1.0 32 1.5 37 2.0 43 3.0 55 5.0 59 10.0 66 12.0 66 14.0 72 15.0 73 20.0 80 30.0 100 40.0 117 50.0 131-6o.o 270-62.5 6oo 70.0 948 LATITUDE 30' 21 DEGREE AT TRAVERSE MID-POINT

FROM SHORE TO 600-FOOT DEPTH PMH CCXNPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C.1 E N T S BO)'Ir0N FkICTION FACTOR 0.0025 WIND STRESS CORRECTION

FACTOR 1.10 WATER LEVEL DATA (AT OPEN CCAST SHORELINE)

PMH SPEED OF TRANSLATION

COMPONENTS

ST I MT M.HT F E E T WIND SETUP 16.46 PRESSURE SETUP 3.23 INITIAL WATER LEV. 1.30 ASTRONONICAL

6.20 TIDE LEVEL tOTAL-SURGE

STILL WATER LEV. 27.20 FEET MLW Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.l/ Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.II

TABLE C.12 SUMMARY-PERTINENT

PROBABLE MAXIMUk hURRICANE (FMH), STORM SURGE COMPUTATIONAL

rATA AND RESULTANT

WATER LEVEL LOCATION JEKYLL LAT. 310 ISLAND, GEORGIA 05' LONG. 81" 24.5': TRAVERSE-AZIMUTH

108 DEGREE, LENGTH 72.6 NAUTICAL MILES PROBABLE MAXIMUM HURRICANE

INDEX CHARACTENISTICS

ZONE .2 AT LOCATION 310 05' DEGREE NORTH! SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW IIODERATF

HIGH (ST) (NT) (21L JENTRAL PRESSURE INDEX P INCHES 26.72 26.72 26.72 PER IPHERAL PRESSURE Pn INCHES 31.19 31.19 31.].9 RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 40 40 40 rRANSLATION

SPEED F (FORWARD SPEED) KNOTS I 4 11 23 VJ MAXIMUM WIND SPEED V M.P.H. 135 141 147 INITIAL DISTANCE-NAUT.MI.i/

FROM 20 MPH WIND 400 380 336&T SHORE TO MAX. WIND 0n PMH CCD]PUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BOIU'ON FilICTION

FACTOR G.C025 WIND STRESS CORRECTION

FACTOR 1.10 WA T Ei LEVEL DATA (AT OPEN CCAST SHORELINE)

PMH SPEED OF TRANSLATION

COMPONENTS

ST I MT I H, F E E T'WIND SE'7UP 20.63 PRESSURE SETUP 3.34 INITIAL WATER LEV. 1.20 ASTRONOMICAL

7.50 TIDE LEVEL TOTAL-SURGE

STILL WATER LEV. 32.6.7 FEET MLW Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.

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 SOUTH CAROLINA PROBABLE MAXIMUM HURRICANE

INDEX CHARACTE1ISTICS

ZONE 2 AT LOCATION 320 39' DEGREE NORTH SPEED OF THANSLATION

PARAMETER

DESIGNATIONS

SLOW HODERATF HIGH (ST) (MT) (HT)CENTRAL PRESSURE INDEX P INCHES 26.81 26.81 26.81 0 PERIPHERAL

PRESSURE P INCHES 31.13 31.13 31.13 n RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 40 40 40 TRANSLATION

SPEED F, (FORWARD SPEED) KNOTS 4 13 29 MAXIMUM WIND SPEED V M.P.H. 1134 139 14 X INITIAL DISTANCE-NAUT.MI

.,/FROM 20 MPH WIND 400 364 311 fT SHORE TO MAX. WIND Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-- Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.OCEAN BED PROFILE I TRAVERSE WATER DISTANCE DEPTH FROM BFELOW SHORE MLW (NAUT.MI.) (FEET)0 0 0.2 10.5_ 0.5 12.0 -1.0 14.0 __ 1.5 16.5 2.0 18.0 __ 3.0 29.5_ 5.0 39.0 10.0 46.0 S1;. 0 56.0 o_ 20.0 65.0_ 30.0 85.0_ 40.0 138.0 __ 50.0 227.0 __ 57.6 600.0_ 60.0 1,800.0 LATITUDE ; 320 25'DEGREE AT TRAVERSE MID-POINT

FROM SHORE TO 600-FOOT DEPTH I DEGREEt LENGTH 57.6 NAUTICAL MILES PMH OCHPUTATIONAL

COEFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BO1FI)FM FRICTION FACTOR 0.0025 WIND STRESS CORRECTION

FACTOR 1.10 WA TER LEVEL DATA (AT OPEN CCAST SHORELINE)

PMH SPEED OF TRANSLATIO]

COMPONENTS

ST I MT H'F E E T WIND SETUP 17.15 PRESSURE SETUP 3.23 INITIAL WATER LEV. 1.00 ASTRONOMICAL

6.80 TIDE LEVEL TOTAL-SURGE

STILL WATER LEV. 28.18 FEET MLW I I

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 NORTH CAROLINA DECXREi LENG'i'H 35.2 NAUTICAL MILES PROBABLE MAXIMUM HURRICANE

INDEX CHARACTrEISTICS

ZONE 3 AT LOCATION 340 54' DEGREE NORTH r 1 I SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW MODERATF HIGH ,(ST) (wT) (HT)"ENTRAL PRESSURE INDEX P INCHES 26.89 26.89 26.89 PERIPHERAL

PRESSURE P INCHES 31.00 31.00 31.00 RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 35 35 35 tRANSlATION

SPEED v (FORWARD SPEED) KNOTS 5 17 38 FLAXfl4JM

WIND SPEED V M.P.H. 130 137 149 INITIAL DISTANCE-NAUT.MI.1/

FROM 20 MPH WIND 385 346 280 6T SHORE TO MAX. WIND tJn r'J OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.lI.) (FEET)0 0 0.2 16 0.5 28 1.0 40 1.5 46 2.0 54 3.0 64 5.0 72 10.0 92 15.0 112 20.0 124 30.0 264 35.2 6oo 40.0 900 LATITUDE # 34'41.A DEGREE AT TRAVERSE MID-POINT

FROM SHORE TO 600-FOOT DEPTH I PMH OCXPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SbRGE) ESTIMATES C 0 E F F I C I E N T S BOT'XOM FhIlCTION

FACTOR 0.0025 WIND STRESS CORRECTION

FACTOR 1.10 WATEh LEV E'L DATA (AT OPEN CLAST

PMH SPEED OF TRANSLATION

COMPONENTS

ST HI I HT F E E T WIND SETUP 8.84 PRESSURE SETUP 3.09 INITIAL WATER LEV. 1.00 ASTRONONICAL

5.20 TIDE LEVEL TOTAL-SURGE

STILL WATER LEV. 18.13 FEET MLW I Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-/Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.

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 MARYLAND DEREEt LENGTH 59 NAUTICAL MILES PROBABLE MAXIMUM HURRICANE

INDEX CHARACTERISTICS

ZONE 4 AT LOCATION 380 20' DEGREE NORTH SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW MODERATF HIGH__(ST) (NT) (.Tf CENTRAL PRESSURE INDEX P INCHES 27.05 27.05 27.05 PERIPHERAL

PRESSURE P INCHES 30.77 30.77 30.77 RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 38 38 38 TRANSLATION

SPEED F (FORWARD SPEED) KNOTS 1 10 26 48 MAXIMUM WIND SPEED V M.P.H. 124 133 146 INITIAL DISTANCE-NAUT.

MI,.ýJ FROM 20 MPH WIND 350 293 251 6T SHORE TO MAX. WIND I OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.MI.j (FEET)0 0 0.2 17 0.5 32 1.0 29_ 1.5 35 2.0 45 30 38_ 0 56_ 5.0 61 6 71 7 56 8 6o 9 58 10 59 11 65 12 64 13 70 14 62-18 103-20 90-2 ~ 114-146 840 LATITUDE;

38o14, DEGREE AT TRAVERSE MID-POINT

FROM SHORE To 600-FOOT DEPTH PMH CCINPUTATIONAL

COEFFICIEN'

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BQ'I1ON FRICTION FACTOR 0.0025 WIND STRESS COiRRECTION

FACTOR 1.10 WA TER LEVEL DATA (AT OPEN CCAST SHORELINE)

PMH SPEED CF TRANSLATION

COMPONENTS

ST I MI HT F E E T WIND SETUP 14.30 PRESSURE SETUP 2.83 INITIAL WATER LEV. 1.14 ASTRONOMICAL

5.10 TIDE LEVEL TOTAL-SURGE

STILL WATER LEV. 23.37 IEET NLW Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.1/Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.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 CITY, NEW JERSEY 25 : TRAVERSE-AZIMUTH

146 DEGREEt LENGTH 70 NAUTICAL MILES PROBABLE MAXIMUM HURRICANE

INDEX CHARACTERISTICS

ZONE 4 AT LOCATION 390 21' DEGREE NORTH S OF TRANSLATION

PARAMETER

DESIGNATIONS

5 SLOW IHODERATF

HIGH_, (ST) (MT) (HT)CENTRAL PRESSURE INDEX P INCHES 27.12 PERIPHERAL

PRESSURE P INCHES 30.70 n _____ 0.70__ ____RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 40 TRANSLATION

SPEED Fv (FORWARD SPEED) KNOTS MAXIMUM WIND SPEED V M.P.H. 142 x X INITIAL DISTANCE-NAUT.

MI.Ii FROM420 MPH WIND AT SHORE TO MAX. WIND OCEAN BED PROFILU TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)K 0 0.2 10,_ 2.0-5.0_ 10.0 20.0-30.0_ 40.0-50.0 6o.o_ 65.0_ 70.0 0 10.0 15.0 _22.0 _38.0 _50.0 _72.0 _90.0 -120.0 _138.0 _162.0 210.0 -258.0 _600.0 PMH CCMPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T SFhICTION FACTOR 0.002r5 WIND STRESS CORRECTION

FACTOR 1.10 WATER Lh V EL DATA (AT OPEN CCAST SHOPELINE)

PMH SPEED OF TRANSLATION

COMPONENTS

ST F I mlE MT I__ E E T WIND SETUP 15.32 PRESSURE SETUP 2.57 INITIAL WATER LEV. 1.10 ASTRONOMICAL

5.80 TIDE LEVEL TOTAL-SURGE

STILL WATER LEV. 24.80 EET MLW Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.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

ZONE 4 AT LOCATION 4.1 00' DEGREE NOBTH-SPEED OF TRANSIATION

PARAMETER

DESIGNATIONS

SLOW HODERATF HIGH_ (ST) (MT) (HT()CENTRAL PRESSURE INDEX P INCHES 27.26 27.26 27.26 0 _PERIPHERAL

PRESSURE P INCHES 30.56 30.56 30.56 R US TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 48 48 48 TRANSLATION

SPEED (FORWARD SPEED) KNOTS 15 34 51 IMUM WIND SPEED V M.P.H. 115 126 136 INITIAL DISTANCE-NAUT.NI.i/

FROM 20 MPH WIND 346 293 259 AT SHORE TO MAX. WIND I I LA LI'OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)0 0 0.2 22_ 0.5 38-1.0 43_ 1.5 53_ 2.0 67-3.0 82-5.0 102-10.0 132-15.0 145_ 20.0 170-30.0 212 40.0 240 50.0 260 60.0 302 68.4 6o0 7 70.0 870 LATITUDE 0 400 27 DEGREE AT TRAVERSE MID-POINT

FROM SHORE To 600-FOOT DEPTH PMH ccNPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BO1J3'ON FriICTION

FACTOR 0.0029 WIND STRESS CORRECTiON

FACTOH 1.10 WAT Eh LE V E L DATA (AT OPEN CCAST SHORELINE)

PMH SPEED OF TRANSLATION

COMPONENTS

ST T MI I HT F E E T WIND SETUP 8.73 PRESSURE SETUP 2.46 INITIAL WATER LEV. 0.97 ASTRONOMICAL

8.00 TIDE LEVEL OTAL-SURGE

STILL WATER LEV. 20.16 VEE MLW _ I I Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-/Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance..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 POINT, RHODE ISLAND 50 ; TRAVERSE-AZIMUTH

166 0~'PROBABLE MAXIMUM HURRICANE

INDEX CHARACTrISTICS

ZONE 4 AT LOCATION 410 19' DEGREE NORTH SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW MODERATF HIGH_ (ST) (MT) (HT)CENTRAL PRESSURE INDEX P INCHES 27.29 27.29 27.29 PERIPHERAL

PRESSURE Pn INCHES 30.54 30.54 30.54 RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 49 49 49 TRANSLATION

SPEED F (FORWARD SPEED) KNOTS 15 35 51 MAXIMUM WIND SPEED V M.P.H. 113 126 134 INITIAL DISTANCE-NAUT.MI.i

/FROM 20 MPH WIND 348 284 255 AT SHORE TO MAX. WIND Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind./ Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW (NAUT.MI.) (FEET)o 0 0.2 28 0.5 40 1.0 77_ 1.5 98 2.0 119-3.0 117 4.0 114-5.0 128 6.0 114 7.0 113 8.0 117-9.0 118 10.0 93 11.0 70 12.0 65_ 13.0 51 14.0 56 15.0 77?20.0 131-0. g 00 222.0 240 --70 28g 90.0 1.488 LATITUDE 4 40° 38 DE)REE AT TRAVERSE MID-POINT

FROM SHORE TO 600-FOOT DEPTH DECREEs LENGTH 84 NAUTICAL MILES PMH CCNPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BO'T¶ON FRICTION FACTOR 0.0025 WIND STRESS CORRECTION

FACTOR 1.10 WATE h LEVEL DATA (AT OPEN CCAST SHORELINE)

PMH SPEED OF THANSLATION

COMP014ENTS

ST J MT i HT F E E T WIND SETUP 10.01 PRESSURE SETUP 2.42 INITIAL WATER LEV. 0.96 kSTRONOMICAL, 8.80 r IDE LEVEL rOTAL-SURGE

STILL WATER LEV. 22.1.9 F'EET MLW I__________

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'BEACH, NEW HAMPSHIRE PROBABLE MAXIMUM HURRICANE

INDEX CHARACTERISTICS

ZONE 4 AT LOCATION 420 57' DEGREE NORTH SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW 1-ODERATF

HIGH_(ST) (NT) (HT)METRAL PRESSURE INDEX P INCHES 27.44 27.44 27.44 PERIPHERAL

PRESSURE P INCHES 30.42 30.42 30.42 RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 57 57 57[RANSIATION

SPEED F (FORWARD SPEED) KNOTS 17 37 52 WAXIMUM WIND SPEED V M.P.H. 107 118 127 INITIAL DISTAoCE-HAUT.MI.1/

FROM 20 MPH WIND 353 290 262 kT SHORE TO MAX. WIND 47.1'; TRAVERSE-AZIMUTH

115 OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BELOW SHORE MLW INAUT.M1.) (FFM)-0 0 0.2 8-0.5 40-. 1.0 64-1.5 82'- 2.0 100-3.0 105-5.0 156-10.0 258-15.0 336-20.0 266-25.0 210-30.0 322-35.0 433-40.o 6o0 LATITUDE 420 48'DEGREE AT TRAVERSE MID-POINT

FROM SHORE 600-FOOT DEPTH D@CREE, LENGTH 40 NAUTICAL MILES PMH OCNPUTATIONAL

COEFFICIENT

AND WATER LEVEL (SURGE) ESTIMATES C 0 E F F I C I E N T S BO7'OI- FRICTION FACTOR 0.0025 WIND STRESS CORRECTION

FACTOR 1.10 WATE h LE V EL DATA (Ar OPEN CCAST SHORELINE)

PMH SPEED OF TRANSIATION

COMPONENTS

ST I MT HI, F E E T WIND SETUP 4.25 PRESSURE SETUP 2.23 INITIAL WATER LEV. 0.83 ASTRONOMICAL

11.70 TIDE LEVEL TOTAL-SURGE

STILL WATER LEV. 19.01 FEET MLW Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.-Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.

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 SPRUCE ISLAND, MAINE 30'; TRAVERSE-AZIMUTH

148 DEGREEs LFNGTH 178.6 NAUTICAL MILES PROBABLE MAXIMUM HUHRICANE

INDEX CHARACTERISTICS

ZONE 4 AT LOCATION 440 3' DEGREE NORTH SPEED OF TRANSLATION

PARAMETER

DESIGNATIONS

SLOW HODERATF HIGH (ST) (nT) (HT)CENTRAL PRESSURE INDEX P INCHES 27.61 27.61 27.61 PERIPHERAL

PRESSURE P INCHES 30.25 30.25 30.25 RADIUS TO MAXIMUM WIND LARGE RADIUS NAUT. MI. 64 64 64 TRANSLATION

SPEED F (FORWARD SPEED) KNOTS 19 39 53 MAXIMUM WIND SPEED V M.P.H. 102 114 122 INITIAL DISTANCE-NAUT.

• MI._ /FROM 20 MPH WIND 352 288 262 AT SHORE TO MAX. WIND I Note: Maximum wind speed is assumed to be on the traverse that is to right of storm track a distance equal to the radius to maximum wind.1/-/Initial distance is distance along traverse from shoreline to maximum wind when leading 20 mph isovel intersects shoreline.

Storm diameter between 20 mph isovels is approxi-mately double the initial distance.OCEAN BED PROFILE TRAVERSE WATER DISTANCE DEPTH FROM BFLOW SHORE MLW (NAUT.MI.) (FFET)0 0 0.2 50 0.5 96 1.0 95 1.5 125 2.0 125 3.0 165 4.o 247-5.0 188 10.0 233_ 15.0 438 20.0 570 30.0 271 40.0 511-50.0 443_ 6o.0 374 110 0~0.0 100.0 25-110.01-120.0 34O -I-180.0 1,620 LATITUDE $43 17.8-DEGREE AT TRAVERSE MID-POINT

FROM SHORE o 600-FOOT DEPTH PMH CCMPUTATIONAL

COEFFICIENT

ANL WATER LEVEL (SURGE) ESTIMATES C 0 E F F -C I E N T S BOTIOM 1i FICTION FACTOR 0.0025 WIND STRESS CORRECTION

FACTOR 1.10 W A T E R L E V E L DA T A (Ar OPEN CCAST SHORELINE)

PMH SPEED OF TRANSLATION

COMPONENTS

ST I MT HT F E E T WIND SETUP 9.73 PRESSURE SETUP 1.82 INITIAL WATER LEV. 0.56 STRONONICAL

18.40 IDE LEVEL

STILL WATER LEV. 30.51 EET MLW

TABLE C.21 OCEAN BED PROFILES PASS CHRISTIAN CRYSTAL RIVER CHESAPEAKE

BAY MOUTH ST. LUCIE SEABROOK Nautical Miles from Shore Depth, ft, MLW Nautical Miles from Shore Depth, ft, RLW Nautical Miles from Shore Depth, ft, HLW Nautical Nautical Miles from Depth, Miles from Depth, Shore ft, ffLW Shore ft, MLW-4 1 2 5 10 15 20 30 40 50 60 70 77 3 9 12 13 35 36 40 52 90 160 335 600 0.55 2.31 6.25 8.33 31.4 100 113 127 3 10 14 9 50 180 300 600 0.1 10 16 18.7 10 90 390 600 5 10 30 50 55 62 44 56 102 178 240 600 0.5 4 10 25 44 20 120 250 250 600

UNITED STATES NUCLEAR REGULATORY

COMMISSION

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COMMISSION