DECATUR COUNTY, GEORGIA AND INCORPORATED AREAS

Transcription

1 DECATUR COUNTY, GEORGIA AND INCORPORATED AREAS Community Name Community Number ATTAPULGUS, CITY OF BAINBRIDGE, CITY OF BRINSON, TOWN OF CLIMAX, CITY OF DECATUR COUNTY (UNINCORPORATED AREAS) Decatur County EFFECTIVE SEPTEMBER 25, 2009 Federal Emergency Management Agency FLOOD INSURANCE STUDY NUMBER 13087CV000A

2 NOTICE TO FLOOD INSURANCE STUDY USERS Communities participating in the National Flood Insurance Program have established repositories of flood hazard data for floodplain management and flood insurance purposes. This Flood Insurance Study may not contain all data available within the repository. It is advisable to contact the community repository for any additional data. This preliminary revised Flood Insurance Study contains profiles presented at a reduced scale to minimize reproduction costs. All profiles will be included and printed at full scale in the final published report. Part or all of this Flood Insurance Study may be revised and republished at any time. In addition, part of this Flood Insurance Study may be revised by the Letter of Map Revision process, which does not involve republication or redistribution of the Flood Insurance Study. It is, therefore, the responsibility of the user to consult with community officials and to check the community repository to obtain the most current Flood Insurance Study components. Initial Countywide FIS Effective Date: September 25, 2009

3 TABLE OF CONTENTS Page 1.0 INTRODUCTION Purpose of Study Authority and Acknowledgments Coordination AREA STUDIED Scope of Study Community Description Principal Flood Problems Flood Protection Measures ENGINEERING METHODS Hydrologic Analyses Hydraulic Analyses Vertical Datum FLOODPLAIN MANAGEMENT APPLICATIONS Floodplain Boundaries Floodways INSURANCE APPLICATION FLOOD INSURANCE RATE MAP OTHER STUDIES LOCATION OF DATA BIBLIOGRAPHY AND REFERENCES FIGURES Figure 1. Floodway Schematic TABLES Table 1: Streams Studied by Detailed Methods... 2 Table 2: Summary of Discharges... 5 Table 3: Summary of Elevations... 6 Table 4: Floodway Data Table 5: Community Map History i

4 TABLE OF CONTENTS (Cont d) EXHIBITS Exhibit 1 Flood Profiles Big Slough Tributary Panel 01P-02P Flint River Panels 03P Exhibit 2 Flood Insurance Rate Map Index (Published Separately) Flood Insurance Rate Maps (Published Separately) ii

5 FLOOD INSURANCE STUDY DECATUR COUNTY, GEORGIA AND INCORPORATED AREAS 1.0 INTRODUCTION 1.1 Purpose of Study This Flood Insurance Study (FIS) revises and updates information on the existence and severity of flood hazards in the geographic area of Decatur County, including the City of Attapulgus, the City of Bainbridge, the Town of Brinson, the City of Climax, and the unincorporated areas of Decatur County (referred to collectively herein as Decatur County), and aids in the administration of the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of This study has developed flood-risk data for various areas of the community that will be used to establish actuarial flood insurance rates and to assist the community in its efforts to promote sound floodplain management. Minimum floodplain management requirements for participation in the National Flood Insurance Program (NFIP) are set forth in the Code of Federal Regulations at 44 CFR, In some States or communities, floodplain management criteria or regulations may exist that are more restrictive or comprehensive than the minimum Federal requirements. In such cases, the more restrictive criteria take precedence, and the State (or other jurisdictional agency) will be able to explain them. 1.2 Authority and Acknowledgments The sources of authority for this FIS report are the National Flood Insurance Act of 1968 and the Flood Disaster Protection Act of For this countywide FIS, new hydrologic and hydraulic analyses were prepared by Watershed Concepts for the Georgia Department of Natural Resources (DNR), under Contract No This study was completed in August The histories of the individual communities before the first countywide study are presented below. City of Bainbridge The hydrologic and hydraulic analyses for this study were performed by the U.S. Geological Survey (USGS) (the Study Contractor) for the Federal Emergency Management Agency (FEMA), under Inter-Agency Agreement No. EMW-85-E-1823, Project Order No. 16. That study was completed in February 1986 (Reference 1). 1.3 Coordination An initial Consultation Coordination Officer s (CCO) meeting is held with representatives of the communities, FEMA, and the study contractors to explain the nature and purpose of the FIS and to identify the streams to be studied by detailed methods. A final CCO meeting is held with representatives of the communities, FEMA, and the study contractors to review the results of the study. 1

6 For this countywide FIS, the initial CCO meeting was held on January 25, 2007, and a final CCO meeting was held on October 23, The meetings were attended by representatives of the communities, the Georgia Department of Natural Resources (GADNR), FEMA, and the study contractor. All problems raised at the meeting have been addressed. The history of the coordination activities for the individual communities before the first countywide meeting is presented below. City of Bainbridge 2.0 AREA STUDIED On May 12, 1986, the results of the Flood Insurance Study were reviewed and accepted at a final coordination meeting attended by representatives of the Study Contractor, FEMA, and the community. 2.1 Scope of Study This FIS report covers the geographic area of Decatur County, Georgia, including the incorporated communities listed in Section 1.1. No new detailed studies have been performed as part of this countywide study. Streams previously studied by detailed methods are presented in Table 1. Table 1: Streams Studied by Detailed Methods Flooding Source Reach Length (miles) Big Slough Tributary 2.3 Flint River 6.3 Study Area From a point approximately 1,450 feet downstream of Thomasville Road to a point approximately 440 feet downstream of Lake Douglas Road. From a point approximately 2.4 miles downstream of U.S. Route 27 to a point approximately 2.9 miles upstream of Calhoun Street. Approximate analyses were used to study those areas having a low development potential or minimal flood hazards. The scope and methods of study were proposed to, and agreed upon, by FEMA, the GADNR, Decatur County, and the study contractor. 2.2 Community Description Decatur County covers approximately square miles and is located in the southwestern corner of the State of Georgia (Reference 3). The county is bounded on the north by Miller County, Georgia, Mitchell County, Georgia, and Baker County, Georgia, on the east by Grady County, Georgia, on the south by Gadsden County, Florida, and on the west by Seminole County, Georgia. The 2000 population of Decatur County was reported to be 28,240 (Reference 2). 2

7 City of Bainbridge The City of Bainbridge is located on the Flint River in Central Decatur County in the southwest corner of Georgia. It is surrounded by the unincorporated areas of Decatur County. Primary east-west traffic in Bainbridge is served by U.S. Route 84 and northsouth access is provided by U.S. Route 27. Railroad service is provided by the Seaboard Coast Line Railroad. The 2000 population of Bainbridge was reported to be 11,722 (Reference 2). The principal river system in the area is the Flint River, which runs in a southwesterly direction through the community before discharging into Lake Seminole. Bainbridge is surrounded by gently rolling hills and has a subtropical climate typified by long, hot summers and mild winters. Mean annual temperatures of 53 degrees Fahrenheit in winter and 81degrees Fahrenheit in summer are typical of the region. 2.3 Principal Flood Problems Flooding problems in the City of Bainbridge are primarily due to the overflow of the Flint River. The largest known flood in Bainbridge since 1893 occurred on January 24, The maximum elevation of this flood was 99 feet National Geodetic Vertical Datum of 1929 (NGVD) and had a peak discharge of 101,000 cubic feet per second (cfs). Flow of the Flint River is influenced by backwater from Lake Seminole, which is controlled by the Jim Woodruff Dam, about 29 miles downstream of Bainbridge. It is apparent from gaging station records on the Flint River at Bainbridge that floods for higher peak flows are not influenced by Lake Seminole elevations. The 100-yaer flood does not overtop any of the bridges in Bainbridge. 2.4 Flood Protection Measures Presently, the City of Bainbridge requires that structures built in the floodplain have a minimum lowest floor elevation of 101 feet, referenced to the National Geodetic Vertical Datum of ENGINEERING METHODS For the flooding sources studied by detailed methods in the community, standard hydrologic and hydraulic study methods were used to determine the flood-hazard data required for this study. Flood events of a magnitude that is expected to be equaled or exceeded once on the average during any 10-, 50-, 100-, or 500-year period (recurrence interval) have been selected as having special significance for floodplain management and for flood insurance rates. These events, commonly termed the 10-, 50-, 100-, and 500-year floods, have a 10-, 2-, 1-, and 0.2-percent chance, respectively, of being equaled or exceeded during any year. Although the recurrence interval represents the long-term, average period between floods of a specific magnitude, rare floods could occur at short intervals or even within the same year. The risk of experiencing a rare flood increases when periods greater than 1 year are considered. For example, the risk of having a flood that equals or exceeds the 1-percent-annual-chance flood in any 50-year period is approximately 40 percent (4 in 10); for any 90-year period, the risk increases to approximately 60 percent (6 in 10). The analyses reported herein reflect flooding 3

8 potentials based on conditions existing in the community at the time of completion of this study. Maps and flood elevations will be amended periodically to reflect future changes. 3.1 Hydrologic Analyses Hydrologic analyses were carried out to establish peak discharge-frequency relationships for each flooding source studied by detailed methods affecting the community. Pre-countywide Analyses A log-pearson Type III analysis of annual peak discharges at the U.S. Geological Survey (USGS) stream-gaging station No estimated a 100-year peak discharge of 97,500 cfs. Techniques used to arrive at this estimation are described in the U.S. Water Resources Council Bulletin No. 17B (Reference 4). The elevation-discharge relationship at the gaging station has been updated due to new elevation-discharge measurements made during the 1970s. The 100-year flood discharge of 97,500 cfs would occur at an elevation of 94.8 feet NGVD based on the current elevation-discharge relationship. Drainage areas along Big Slough Tributary were delineated and measured on U.S. Geological Survey (USGS) quadrangle maps at a scale of 1:24000 (Reference 5). The USGS report titled "Flood Frequency Analysis for Small Natural Streams in Georgia" (Reference 6), prepared for the Georgia Department of Transportation, was used to compute the peak discharge-frequency relationships for rural conditions. The rural values were then adjusted for urbanization using the USGS report titled "An Approach to Estimating Flood Frequency for Urban Areas in Oklahoma" (Reference 7). Peak discharge-drainage area relationships for selected recurrence intervals for streams studied by detailed methods are shown in Table 2, Summary of Discharges. Countywide Analyses Hydrologic analyses were carried out to establish peak discharge-frequency relationships for each flooding source studied by approximate methods affecting the county. Discharges for Zone A studies were developed using Region 3 regression equations for rural areas in Georgia (Reference 8) contained in the USGS report. Drainage areas along streams were determined using a flow accumulation grid developed from the USGS 10 meter digital elevation models and corrected National Hydrography Dataset (NHD) stream coverage. Flow points along stream centerlines were calculated using the regression equations in conjunction with accumulated area for every 10 percent increase in flow along a particular stream. 4

9 Table 2: Summary of Discharges Flooding Source and Location Drainage Area Peak Discharges (Cubic Feet per Second) (Square miles) 10-percent 2-percent 1-percent 0.2-percent BIG SLOUGH TRIBUTARY At Georgia Highway ,110 1,730 2,050 2,820 Above Lake Douglas ,200 1,420 2,000 FLINT RIVER Approximately 2.4 miles downstream of U.S. 7,570 * * 97,500 * Route 27 at USGS gage No *Data Not Available 5

10 TABLE 3 Summary of Elevations FLOODING SOURCE AND LOCATION PEAK ELEVATIONS (FEET NAVD88) 1-Percent Annual Chance LAKE SEMINOLE Hydraulic Analyses Pre-Countywide Analyses Analyses of the hydraulic characteristics of flooding from the sources studied were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. Cross-section data, bridge geometry, and elevations were determined through field surveys. Additional cross sections were developed to better define the watersurface profiles along the study reach using USGS topographic maps (Reference 5). Locations of selected cross sections used in the hydraulic analyses are shown on the Flood Profiles. Channel roughness factors (Manning's "n") used in the hydraulic computations were estimated from field observation of the floodplain areas. Roughness values used were for the channel, and to for the overbank areas. Water-surface elevations for the 100-year flood were computed using WSPRO, a step-backwater computer program developed by the USGS for the Federal Highway Administration (Reference 9). The starting water-surface elevation for the Flint River was determined for the USGS gaging station No and then transferred to the first downstream cross section using slope-conveyance studies. Profiles of the 10-, 50-, 100-, and 500-year floods on Big Slough Tributary were computed using the HEC-2 step-backwater computer model (Reference 10) and are shown on Flood Profile Panels 02P and 03P. Starting water-surface elevations were computed using the slope-area method. The cross- section data and bridge geometry used in the model were obtained from contour maps and field surveys. A channel roughness factor (Manning's "n") of 0.04 was used in the model, except for the lakes, where a factor of 0.02 was used with the assumption that no flow occurs below the normal water surface of the lakes. Overbank roughness factors ranged from 0.12 to Higher roughness values were used to define non-effective flow areas near the edge of the floodplain. A field inspection of the channel and floodplain along the stream was made to verify the model parameters. The hydraulic analyses were based on an assumption that flood flows are unobstructed. Topographic work maps of the study area, at a scale of 1:12000, were provided by the COE, Mobile District (Reference 11). The work maps are based on USGS 6

11 quadrangle maps with a contour interval of 10 feet (Reference 5), and all elevations are referenced to the National Geodetic Vertical Datum of Flood profiles were drawn showing the computed water-surface elevations for floods of the selected recurrence intervals. In cases where the 50- and 100-year flood elevations are close together, due to limitations of the profile scale, only the 100-year profile has been shown. The hydraulic analyses for this study are based only on the effects of unobstructed flow. The flood elevations shown on the profiles are thus considered valid only if hydraulic structures remain unobstructed, operate properly, and do not fail. Countywide Analyses Analyses of the hydraulic characteristics of flooding from the sources studied by approximate methods were carried out to provide estimates of the elevations of floods of the selected recurrence intervals. For this county study, water-surface profiles were computed using USACE HEC-RAS version computer program (Reference 12). Water surface profiles were produced for the 1-percent-annual-chance storms for approximate studes. The approximate study methodology used Watershed Information SystEm (WISE) (Reference 13) as a preprocessor to HEC-RAS. Tools within WISE allow verification of cross-section data. The WISE program was used to generate the input data file for HEC- RAS. Then HEC-RAS was used to determine the flood elevation at each cross-section of the modeled stream. No floodway was calculated for streams studied by approximate methods. Floodplains were mapped to include backwater effects that govern each flooding source near its downstream extent. Floodplains were reviewed for accuracy and adjusted as necessary. 3.3 Vertical Datum All FIS reports and FIRMs are referenced to a specific vertical datum. The vertical datum provides a starting point against which flood, ground, and structure elevations can be referenced and compared. Until recently, the standard vertical datum used for newly created or revised FIS reports and FIRMs was the National Geodetic Vertical Datum of 1929 (NGVD). With the completion of the North American Vertical Datum of 1988 (NAVD), many FIS reports and FIRMs are now prepared using NAVD as the referenced vertical datum. Flood elevations shown in this FIS report and on the FIRM are referenced to the NAVD88. These flood elevations must be compared to structure and ground elevations referenced to the same vertical datum. Some of the data used in this revision were taken from the prior effective FIS reports and FIRMs and adjusted to NAVD88. The datum conversion factor from NGVD29 to NAVD88 in Decatur County is negative feet. 7

12 For information regarding conversion between the NGVD and NAVD, visit the National Geodetic Survey website at or contact the National Geodetic Survey at the following address: NGS Information Services NOAA, N/NGS12 National Geodetic Survey SSMC-3, # East-West Highway Silver Spring, Maryland (301) Temporary vertical monuments are often established during the preparation of a flood hazard analysis for the purpose of establishing local vertical control. Although these monuments are not shown on the FIRM, they may be found in the Technical Support Data Notebook associated with the FIS report and FIRM for this community. Interested individuals may contact FEMA to access these data. 4.0 FLOODPLAIN MANAGEMENT APPLICATIONS The NFIP encourages state and local governments to adopt sound floodplain management programs. To assist in this endeavor, each FIS report provides 1-percent-annual-chance floodplain data, which may include a combination of the following: 10-, 2-, 1-, and 0.2-percent-annual-chance flood elevations; delineations of the 1- and 0.2-percent-annual-chance floodplains; and a 1-percent-annual-chance floodway. This information is presented on the FIRM and in many components of the FIS report, including Flood Profiles, Floodway Data tables, and Summary of Stillwater Elevation tables. Users should reference the data presented in the FIS report as well as additional information that may be available at the local community map repository before making flood elevation and/or floodplain boundary determinations. 4.1 Floodplain Boundaries To provide a national standard without regional discrimination, the 1-percent-annual-chance flood has been adopted by FEMA as the base flood for floodplain management purposes. The 0.2-percent-annual-chance flood is employed to indicate additional areas of flood risk in the community. For each stream studied by detailed methods, the 1- and 0.2-percent-annual-chance floodplain boundaries have been delineated using the flood elevations determined at each cross section. For each stream studied by approximate methods, the 1-percent-annual-chance floodplain boundaries have been delineated by interpolation using 10-foot topographic mapping developed from USGS DEM data. The 1- and 0.2-percent-annual-chance floodplain boundaries are shown on the FIRM. On this map, the 1-percent-annual-chance floodplain boundary corresponds to the boundary of the areas of special flood hazards (Zones A and AE), and the 0.2-percent-annual-chance floodplain boundary corresponds to the boundary of areas of moderate flood hazards. In cases where the 1- and 0.2-percent-annual-chance floodplain boundaries are close together, only the 1-percent-annual-chance floodplain boundary has been shown. Small areas within the floodplain boundaries may lie above the flood elevations, but cannot be shown due to limitations of the map scale and/or lack of 8

13 detailed topographic data. For the streams studied by approximate methods, only the 1-percent-annual-chance floodplain boundary is shown on the FIRM. 4.2 Floodways Due to the scope of the first effective Flood Insurance Study for the community of Bainbridge, a floodway was not determined for certain flooding sources. The first revision to this community s effective Flood Insurance Study incorporated the results of the floodway analysis for Big Slough Tributary in that revision. Encroachment on floodplains, such as structures and fill, reduces flood-carrying capacity, increases flood heights and velocities, and increases flood hazards in areas beyond the encroachment itself. One aspect of floodplain management involves balancing the economic gain from floodplain development against the resulting increase in flood hazard. For purposes of the NFIP, a floodway is used as a tool to assist local communities in this aspect of floodplain management. Under this concept, the area of the 1-percent-annual-chance floodplain is divided into a floodway and a floodway fringe. The floodway is the channel of a stream, plus any adjacent floodplain areas, that must be kept free of encroachment so that the base flood can be carried without substantial increases in flood heights. Minimum Federal standards limit such increases to 1 foot, provided that hazardous velocities are not produced. The area between the floodway and 1-percent-annual-chance floodplain boundaries is termed the floodway fringe. The floodway fringe encompasses the portion of the floodplain that could be completely obstructed without increasing the water-surface elevation (WSEL) of the base flood more than 1 foot at any point. Typical relationships between the floodway and the floodway fringe and their significance to floodplain development are shown in Figure 1. The floodways presented in this study were computed for certain stream segments on the basis of equal conveyance reduction from each side of the floodplain. The results of these computations were tabulated at selected cross sections for each segment for which a floodway was computed and are present in Table 3, Floodway Data. Along streams where floodways have not been computed, the community must ensure that the cumulative effect of development in the floodplain will not cause more than a 1.0-foot increase in the base flood elevations at any point within the county. 9

14 5.0 INSURANCE APPLICATION Figure 1. Floodway Schematic For flood insurance rating purposes, flood insurance zone designations are assigned to a community based on the results of the engineering analyses. These zones are as follows: Zone A Zone A is the flood insurance rate zone that corresponds to the 1-percent-annual-chance floodplains that are determined in the FIS report by approximate methods. Because detailed hydraulic analyses are not performed for such areas, no base (1-percent-annual-chance) flood elevations (BFEs) or depths are shown within this zone. Zone AE Zone AE is the flood insurance rate zone that corresponds to the 1-percent-annual-chance floodplains that are determined in the FIS report by detailed methods. Whole-foot BFEs derived from the detailed hydraulic analyses are shown at selected intervals within this zone. Zone X Zone X is the flood insurance rate zone that corresponds to areas outside the 0.2-percent-annual-chance floodplain, areas within the 0.2-percent-annual-chance floodplain, areas of 1-percent-annual-chance flooding where average depths are less than 1 foot, areas of 1-percent-annual-chance flooding where the contributing drainage area is less than 1 square mile (sq. mi.), and areas protected from the base flood by levees. No BFEs or depths are shown within this zone. 10

15 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) FLOODWAY SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY (FEET NAVD 88) BASE FLOOD WATER-SURFACE ELEVATION WITHOUT FLOODWAY (FEET NAVD 88) WITH FLOODWAY (FEET NAVD 88) INCREASE (FEET) BIG SLOUGH TRIBUTARY A 15, , B 17,350 1,200 10, C 20,430 1,151 7, D 22,130 2, , E 24,100 2,795 38, Feet above mouth. 2 This width extends beyond corporate limits. TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY DECATUR COUTY, GA AND INCORPORATED AREAS FLOODWAY DATA BIG SLOUGH TRIBUTARY 11

16 6.0 FLOOD INSURANCE RATE MAP The FIRM is designed for flood insurance and floodplain management applications. For flood insurance applications, the map designates flood insurance rate zones as described in Section 5.0 and, in the 1-percent-annual-chance floodplains that were studied by detailed methods, shows selected whole-foot BFEs or average depths. Insurance agents use zones and BFEs in conjunction with information on structures and their contents to assign premium rates for flood insurance policies. For floodplain management applications, the map shows by tints, screens, and symbols, the 1- percent-annual-chance floodplains and the locations of selected cross sections used in the hydraulic analyses. The countywide FIRM presents flooding information for the entire geographic area of Decatur County. Previously, FIRMs were prepared for each incorporated community and the unincorporated areas of the County identified as flood-prone. This countywide FIRM also includes flood-hazard information that was presented separately on Flood Boundary and Floodway Maps (FBFMs), where applicable. Historical data relating to the maps prepared for each community are presented in Table 3, Community Map History. 7.0 OTHER STUDIES A Flood Insurance Study has previously been prepared for the City of Bainbridge (Reference 1). This FIS report either supersedes or is compatible with all previous studies published on streams studied in this report and should be considered authoritative for the purposes of the NFIP. 8.0 LOCATION OF DATA Information concerning the pertinent data used in the preparation of this study can be obtained by contacting Federal Insurance and Mitigation Division, FEMA Region IV, Koger-Center Rutgers Building, 3003 Chamblee Tucker Road, Atlanta, GA Future revisions may be made that do not result in the republishing of the Flood Insurance Study report. To ensure that any user is aware of all revisions, it is advisable to contact the map repository of flood hazard data located in the community. 12

17 COMMUNITY NAME INITIAL IDENTIFICATION FLOOD HAZARD BOUNDARY MAP REVISIONS DATE FIRM EFFECTIVE DATE FIRM REVISIONS DATE Decatur County (Unincorporated Areas) June 30, 1978 None August 1, 1986 May, 19, 1997 Attapulgus, City of None None None None Bainbridge, City of May 24, 1974 February 13, 1976 October 26, 1979 April 3, 1987 June 5, 1989 Brinson, Town of July 18, 1975 None July 18, 1975 None Climax, City of None None None None TABLE 5 FEDERAL EMERGENCY MANAGEMENT AGENCY DECATUR COUNTY, GA AND INCORPORATED AREAS COMMUNITY MAP HISTORY 13

18 9.0 BIBLIOGRAPHY AND REFERENCES 1. Federal Emergency Management Agency, Flood Insurance Study, City of Bainbridge, Decatur County, Georgia, Washington, D.C., June 5, U. S. Department of Commerce, Bureau of the Census. Population Finder. [Online] Available: 3. Decatur Couty, Georgia. County Profile. [Online] Available: 4. U. S. Department of the Interior, Geological Survey, Interagency Advisory Committee on Water Data, Office of Water Data Coordination, Hydrology Subcommittee, Bulletin No. 17B, Guidelines for Determining Flood Flow Frequency. September 1981, revised March U. S. Department of the Interior, Geological Survey. 7.5-Minute Series Topographic Maps, Scale 1:24,000, Contour Interval 10 Feet: City of Bainbridge, Georgia, U. S. Department of the Interior, Geological Survey, Flood Frequency Analysis for Small Natural Streams in Georgia, U. S. Department of the Interior, Geological Survey, An approach to Estimating Flood Frequency for Urban Areas in Oklahoma, V. B. Sauer, July U. S. Geological Survey, Preliminary Flood-Frequency Relations for Small Streams in Georgia, Harold G. Golden, April U. S. Geological Survey, and the Federal Highway Administration, Office of Research and Development, Bridge Waterways Analysis Model/Research Report, Shearman, J. O., Kirby, W. H., Schneider, V. R., and Flippo, H. N., U. S. Army Corps of Engineers, Hydrologic Engineering Center, HEC-2 Water-Surface Profiles, Computer Program 723-X6-L202A, Davis, California, April U. S. Department of the Interior, Geological Survey, Limited Map Maintenance Program Work Map, City of Bainbridge, Georgia, Scale 1:12000, Contour Interval 10 Feet: Bainbridge, Georgia, undated. 12. U. S. Army Corps of Engineers, Hydrologic Engineering Center, HEC-RAS River Analysis System User s Manual, Version 3.1.2, April Watershed Concepts, a Division of HSMM/AECOM, Watershed Information System Version 3.1.1, Greensboro, NC, July

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