KAY COUNTY, OKLAHOMA. Federal Emergency Management Agency AND INCORPORATED AREAS

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1 KAY COUNTY, OKLAHOMA AND INCORPORATED AREAS Notice: This preliminary FIS report includes only revised Flood Profiles. See Notice to Flood Insurance Users page for additional details. Community Name Community Number BLACKWELL, CITY OF BRAMAN, TOWN OF KAW CITY, CITY OF KAY COUNTY (UNINCORPORATED AREAS) KILDARE, CITY OF NEWKIRK, CITY OF PONCA CITY, CITY OF TONKAWA, CITY OF Kay County PRELIMINARY: APRIL 5, 2012 Federal Emergency Management Agency FLOOD INSURANCE STUDY NUMBER 40071CV000B

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 (FIS) may not contain all data available within the repository. It is advisable to contact the community repository for any additional data. Part or all of this FIS may be revised and republished at any time. In addition, part of this FIS may be revised by the Letter of Map Revision process, which does not involve republication or redistribution of the FIS. It is, therefore, the responsibility of the user to consult with community officials and to check the community repository to obtain the most current FIS components. This FIS report was revised on. Users should refer to Section 10.0, Revisions Description, for further information. Section 10.0 is intended to present the most up-to-date information for specific portions of this FIS report. Therefore, users of this FIS report should be aware that the information presented in Section 10.0 supersedes information in Sections 1.0 through 9.0 of this FIS report. Initial Countywide FIS Effective Date: September 25, 2009 Revised Countywide FIS Date: TBD This Preliminary FIS report does not include unrevised Flood Profiles. These unrevised Flood Profiles will appear in the final FIS report. i

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 APPLICATIONS FLOOD INSURANCE RATE MAP OTHER STUDIES LOCATION OF DATA BIBLIOGRAPHY AND REFERENCES REVISIONS DESCRIPTIONS First Revision (<Insert Revision Date>) 42 ii

4 TABLE OF CONTENTS contiued FIGURES Page Figure 1 - Floodway Schematic 38 TABLES Table 1 - Streams Studied by Detailed Methods 3 Table 2 - Summary of Discharges 9 Table 3 - Summary of Roughness Coefficients 15 Table 4 - Floodway Data Table 19 Table 5 - Community Map History 40 EXHIBITS Exhibit 1 - Flood Profiles Arkansas River Bois d Arc Creek Chikaskia River Salt Fork Arkansas River Tributary 1 Tributary 2 Tributary B Tributary C Tributary D Tributary D Right Tributary 1 Tributary E Tributary G Tributary G Left Tributary 1 Tributary H Tributary H Left Tributary 1 Panels 01P-05P Panels 06P-10P Panel 11P Panel 12P Panels 13P-14P Panels 15P-16P Panels 17P-18P Panels 19P-21P Panels 22P-24P Panel 25P Panels 26P-27P Panel 28P Panel 29P Panels 30P-31P Panel 32P iii

5 TABLE OF CONTENTS - contiued EXHIBITS - continued Exhibit 1 - Flood Profiles - continued Tributary I Tributary I Left Tributary 1 Tributary K Tributary L Tributary M Tributary N Tributary O Tributary O Tributary Tributary P Tributary Q Tributary Q Left Tributary 1 Tributary Q Left Tributary 2 Tributary Q Right Tributary 1 Tributary R Tributary S Tributary W Panel 33P Panel 34P Panel 35P Panel 36P Panels 37P-40P Panel 41P Panels 42P-43P Panel 44P Panels 45P-46P Panels 47P-48P Panel 49P Panel 50P Panel 51P Panel 52P Panel 53P Panels 54P-55P Exhibit 2 - (Published Separately): Flood Insurance Rate Map Index Flood Insurance Rate Map iv

6 1.0 INTRODUCTION FLOOD INSURANCE STUDY KAY COUNTY, OKLAHOMA AND INCORPORATED AREAS 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 Kay County, including the Cities of Blackwell, Kaw City, Kildare, Newkirk, Ponca City, and Tonkawa; the Town of Braman; and the unincorporated areas of Kay County (referred to collectively herein as Kay 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 The hydrologic and hydraulic analyses covering all significant flooding sources in the Cities of Blackwell and Tonkawa were performed by Hydro Tech Engineers, Inc. for the Federal Insurance Administration (FIA) under Contract No. H This work was completed in July The hydrologic and hydraulic analyses for the Arkansas River and Tributary W were prepared by the Tulsa District of the USACE for FEMA, under Inter-Agency Agreement No. EMW-86-E-2226, Project Order No. 13, during the preparation of the FIS for the City of Ponca City, Oklahoma. This work was completed in May The hydrologic and hydraulic analyses for the Salt Fork Arkansas River were taken from the FIS for the City of Tonkawa, Oklahoma. The hydrologic and hydraulic analyses for the Chikaskia River were taken from the Flood Plain Information Report for the Chikaskia River, City of Blackwell, Oklahoma. The hydrologic and hydraulic analyses for this study were performed by Watershed Concepts, for FEMA, under Contract No. EMT-2002-CO This study was completed in July Also incorporated in this study are the hydrologic and hydraulic analyses performed by Meshek & Associates, Inc. for the City of Ponca City Stormwater Master Plan (Reference 1).The studied streams include Arkansas River Tributaries B, C, D, E, G, H, I, and W and Bois d Arc Creek Tributaries L, M, N, S, O, and O Tributary. 1

7 1.3 COORDINATION The initial Consultation Coordination Officer (CCO) meeting was held on July 25, 2006, and attended by representatives of FEMA; Kay County; the Cities of Blackwell, Newkirk, and Ponca City; Meshek & Associates, Inc.; and the study contractor. The results of the study were reviewed at the final CCO meeting held on January 23, 2008, and attended by representatives of the community, FEMA, and the study contractor. All problems raised at that meeting have been addressed in this study. The history of the Flood Insurance Studies' coordination activities for the individual communities before the first countywide are presented below. The FIA identified the area for detailed study of the Chikaskia River, Tributary 1 and Tributary 2 in a May 1977 meeting attended by the City Manager, City Engineer, and various other city officials of Blackwell, personnel of Hydro Tech Engineers, Inc., and Coordination Consultation Officers of the FIA, Department of Housing and Urban Development (HUD). The U.S. Coast Guard and Geodetic Survey and the Oklahoma Department of Transportation provided information on elevation reference marks. The Northern Oklahoma Council of Governments had no flood information to contribute at this time. The U.S. Army Corps of Engineers provided copies of their 1976 Floodplain Information Study (Reference 2) and their hydrologic and hydraulic analyses information for the Chikaskia River. Information was also solicited from other appropriate Federal, State, and Local agencies; however, those agencies had no new or relevant flood information to contribute for study purposes at this time. A final coordination meeting was held in Blackwell on March 20, 1979, to formally present the results of the study, answer questions, and receive comments. The FIA identified the area for detailed study in the City of Tonkawa in a May 1977 meeting attended by the City Manager, personnel of Hydro Tech Engineers, Inc., and Coordination Consultation Officers of the FIA, Department of HUD. The U.S. Coast Guard and Geodetic Survey and the Oklahoma Department of Transportation provided information on elevation reference marks. The U.S. Geological Survey provided flood gage information and high water marks. The Northern Oklahoma Council of Governments had no flood information to contribute at this time. Information was also solicited from other appropriate Federal, State, and Local agencies; however, those agencies had no new or relevant flood information to contribute for study purposes at this time. A final coordination meeting was held in Blackwell on March 13, 1980, to formally present the results of the study, answer questions, and receive comments. In August and November 1976, preliminary meetings were held with representatives of the U.S. Department of the Army, Corps of Engineers (COE), to obtain information on the Arkansas River below Kaw Dam to be used in determining the approximate flood boundaries of the Arkansas River. The USGS supplied topographic data, which served as part of the input for the hydraulic analysis and assisted in the delineation of a portion of the floodplain boundaries. On April 2, 1986, an initial CCO meeting was held with representatives of FEMA, Ponca City, and the COE (the study contractor) to determine the streams to be studied by detailed methods. On November 9, 1987, Kay County was notified by FEMA of the initiation of a Flood Insurance Study for the county. 2

8 On March 22, 1989, a final CCO Meeting was held with representatives from FEMA and the county to review the results of this study. 2.0 AREA STUDIED 2.1 SCOPE OF STUDY This FIS report covers the geographic area of Kay County, Oklahoma, including the incorporated communities listed in Section 1.1. The limits of detailed study in Kay County were determined by FEMA with community and study contractor consultation. The areas studied by detailed methods were selected with priority given to all known flood hazard areas and areas of projected development and proposed construction through May 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 and Watershed VI Alliance. "Streams Studied by Detailed Methods" are presented in Table 1. Table 1: Streams Studied by Detailed Methods Flooding Source Study Type Reach Length (miles) Arkansas River Redelineation Study Area From approximately 2.0 miles downstream of US Route 40 to approximately 0.2 mile downstream of Kaw Dam Bois d Arc Creek Redelineation 6.4 From E0240 Road to Hubbard Road Chikaskia River Redelineation 1.4 Salt Fork Arkansas River Redelineation 2.9 Tributary 1 Redelineation 1.7 Tributary 2 Redelineation 1.3 Tributary B Detailed 1.1 Tributary C Detailed 2.2 Tributary D Detailed 4.2 Tributary D Right Tributary 1 Detailed 0.5 Tributary E Detailed 1.5 From approximately 3.1 miles downstream of the confluence of Tributary 1 to approximately 1.0 mile upstream of the confluence of Tributary 2 From US Route 77 to approximately 0.7 mile upstream of US Route 77 From confluence with Chikaskia River to approximately 0.3 mile upstream of 9 th Street From confluence with Chikaskia River to approximately 0.1 mile upstream of 13 th Street From confluence with Tributary C to Hartfort Avenue From confluence with Tributary D to approximately 0.1 mile upstream of Havenwood Road From confluence with Arkansas River to Prospect Avenue From confluence with Tributary D to approximately 0.2 mile upstream of Bradley Avenue From confluence with Tributary D to approximately 0.1 mile upstream of Donahoe Drive

9 Flooding Source Table 1. Streams Studied by Detailed Methods (cont.) Tributary G Detailed 0.8 Tributary G Left Tributary 1 Tributary H Detailed 1.2 Tributary H Left Tributary 1 Tributary I Detailed 1.3 Tributary I Left Tributary 1 Tributary K Detailed 0.7 Tributary L Detailed 1.1 Tributary M Detailed 4.4 Tributary N Detailed 0.6 Tributary O Detailed 1.3 Tributary O Tributary Detailed 0.7 Tributary P Detailed 2.0 Tributary Q Detailed 1.6 Tributary Q Left Tributary 1 Tributary Q Left Tributary 2 Tributary Q Right Tributary 1 Tributary R Detailed 0.1 Tributary S Detailed 1.6 Tributary W Detailed 5.3 Study Type Reach Length (miles) Study Area From confluence with Tributary E to Overbrook Avenue Detailed 0.2 From confluence with Tributary G to Virginia Avenue From confluence with Arkansas River to approximately 0.2 mile upstream of South Avenue From confluence with Tributary H to Detailed 0.2 approximately 0.1 mile upstream of Madison Avenue From confluence with Arkansas River to Fourth Street From confluence with Tributary I to Detailed 0.1 approximately 0.1 mile upstream of the confluence with Tributary I From confluence with Bois d Arc Creek to approximately 0.2 mile upstream of Flormable Street From confluence with Bois d Arc Creek to Waverly Street From confluence with Bois d Arc Creek to Prospect Avenue From confluence with Tributary M to Prospect Avenue From confluence with Tributary M to approximately 1,200 feet upstream of Ash Street From confluence with Tributary O to approximately 0.7 mile upstream of the confluence with Tributary O From confluence with Tributary M to approximately 0.3 mile upstream of E0200 Road From confluence with Bois d Arc Creek to Union Street From confluence with Tributary Q to Detailed 0.2 approximately 0.2 mile upstream of confluence with Tributary Q Detailed 0.1 From confluence with Tributary Q to Union Street From confluence with Tributary Q to Detailed 0.3 approximately 0.3 mile upstream of confluence with Tributary Q From confluence with Tributary M to approximately 0.1 mile upstream of the confluence with Tributary M From confluence with Bois d Arc Creek to Waverly Street From confluence with Arkansas River to Hubbard Road 4

10 2.2 COMMUNITY DESCRIPTION Kay County is located in the north central portion of Oklahoma. It is bordered by the unincorporated areas of Sumner and Cowley Counties, Kansas, to the north; the unincorporated areas of Osage County to the east; the unincorporated areas of Noble County to the south; and the unincorporated areas of Grant County to the west. The economy of the area relies heavily on the petroleum industry and agriculture. The county includes portions of the watersheds of the Arkansas River, Bois d Arc Creek, and their tributaries. The Arkansas River flows southeast out of Colorado to the Mississippi River; its floodplains consist of deep, sandy soils. The uplands are largely devoted to agricultural uses, and dense brush and trees are concentrated near stream channels. Bois d Arc Creek originates to the north of the community and runs in a southern direction. The upland area is generally level to moderately sloping, with deep loamy soils and clayey subsoils. The region is characterized by a moist, subhumid climate, with approximately 75 percent of the normal annual precipitation occurring between April and October; much of the rainfall occurs in the form of thunderstorms. May is normally the wettest month of the year and January is the driest. Rapid changes in weather are commonly accompanied by distinct fluctuations of temperature, humidity and wind. There are also marked seasonal changes in temperature. 2.3 PRINCIPAL FLOOD PROBLEMS Low-lying areas of Kay County are subject to periodic flooding caused by overflow of the Arkansas River. A major flood occurred along the Arkansas River in July Gaging station records maintained from 1922 to 1975 at Arkansas City, Kansas, approximately 25 miles upstream of Ponca City, and from 1923 to 1975 at Ralston, approximately 35 miles downstream of Ponca City, indicate that this flood had a frequency of approximately 10% annual chance flood. Floods have been recorded in Blackwell beginning in Since that time, major floods have occurred in June 1942 and October The storm in 1923 was the largest recorded and had an estimated discharge of 100,000 cubic feet per second (cfs) and produced a stage height of 34 feet. The storms of 1942 and 1973 had discharges of 85,000 CFS and 63,500 CFS respectively and produced gage heights of 33.3 feet and feet respectively (Reference 2). Much of the flooding within and near Northeast, East, and Southeast Blackwell is caused by the Chikaskia River. Therefore, the flood may be caused by a locally intense thunderstorm in the upper reaches, or a combination of both of the above types of events. In western parts of the city, the flooding would result primarily from locally intense thunderstorms combined with the effects of backwater from the Chikaskia River. Both Tributary 1 and Tributary 2 have short reaches that contain adverse streambed slopes which would cause ponded waters after the floodwaters have receded. An additional problem is that some of the culverts and most of the bridges are undersized for the 10% annual chance floods and can produce backwater conditions. In addition, floatable material, such as lumber crates, wood building materials, trees, and empty storage tanks, may be carried away by floodwaters, causing serious damage to downstream structures and clogging bridge openings. This creates a more hazardous flooding problem. The hazards are especially severe on the two tributaries where in some cases very small bridges and several small culverts may be plugged by even small 5

11 floating debris. Because of the extent of flooding during a major flood, several thoroughfares are submerged. The affected transportation facilities in the flood plain include portions of U.S. Highway 177, Oklahoma Highway 11, the Atchison, Topeka, and Santa Fe Railway, the St. Louis-San Francisco Railway, and various county roads and various city streets and alleys. Low-lying areas of Ponca City are subject to periodic flooding caused by overflow of Bois d Arc Creek and the Arkansas River. Flooding caused by the Arkansas River in July 1951 gaging station record ( ) on the Arkansas River at Arkansas City, Kansas, 25 miles upstream from Ponca City indicate this flood to have had a frequency of approximately 10% annual chance. The City of Tonkawa is drained by the Salt Fork of the Arkansas River along the southwestern edge of the city, with some major tributaries extending into the developed area of the city. The flood of record on the Salt Fork occurred in October 1973, when water flowed past the city at 97,300 CFS, and reached an elevation of at a flood gage on the east side of the Main Street Bridge. The banks of the Salt Fork rise sharply, almost 40 feet, to the plateau holding almost all the developed area of the city, so the Salt Fork itself is not the major concern for flooding within the city. The major problems are caused by the rather flat terrain inside the city and the inability of the inadequate drainage facilities to effectively move the runoff during periods of heavy rainfall. Even rains of less than two inches have been observed causing flooding of Grand Avenue. There is very little underground storm sewer system, the culverts under the streets usually amount to little more than low water crossings, and the open channels have very little capacity with some of the streets themselves serving as drainage channels. Flooding is also caused by backwater from road and railroad fills and undersized bridges. 2.4 FLOOD PROTECTION MEASURES Most of the flood problems in Ponca City are caused by the Arkansas River, however, all floods except major floods, should be controlled by Kaw Dam. The ephemeral streams B, C, D, E, G, H, I, L, and M are concrete lined with concise channels. In addition, Tributaries C, D, and I have detention ponds designed to reduce flooding downstream. Tributaries in the community have recreational park areas in the floodplains and streets that follow the general path of the tributaries. Dams have been constructed by the USACE and Soil Conservation Service (SCS) on the Salt Fork upstream of Tonkawa. The effect of the dams on the flow of the river was reflected in the flows used for calculations. The National Weather Service, a division of the National Oceanic and Atmospheric Administration (NOAA), issues flash flood watches and warnings for the Kay County area as part of its responsibility for furnishing severe local storm watches and warnings over Oklahoma. A specific flood forecast and warning service is provided for the Salt Fork at Tonkawa, Oklahoma. Severe weather, flash flood warnings, and flood forecasts, with general weather forecasts, are distributed by NOAA Weather Wire Service. This service links, by teletype, the National Weather Service offices with outlets to the news media and other private or government agencies in the area where a primary wire service has been established. 6

12 3.0 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 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. The flood-frequency discharge values for the Arkansas River were determined from outflowfrequency curves depicting existing sediment conditions and the current lake regulation plan. The lower end of the curve was developed by routing period-of-record inflows through Kaw Lake, using the SUPER computer program (Reference 3). The upper end of the modified frequency curve was established by routing the antecedent flood through the lake and plotting the peak outflow at the same frequency as the peak inflow plotted on the inflowfrequency curve. A best fit curve was then drawn using the data points that were established by the above procedure. The flood-frequency discharge values for Tributary W were determined using regional relationships of basin characteristics versus discharge frequency (Reference 4). Discharge frequency was defined using regional relationships of basin characteristics versus the hydrologic analysis (Reference 5). For the Arkansas River, a continuous peak discharge was routed upstream with no attempt to account for minor distortions of the flood hydrograph due to ponding. The hydrologic analyses for the Salt Fork Arkansas River were taken from the Flood Insurance Study for the City of Tonkawa (Reference 6). Flood-frequency discharge values for the Salt Fork Arkansas River were developed using log-pearson Type III distribution (Reference 7). The hydrologic analyses for the Chikaskia River were taken from the USACE Floodplain Information Report for the Chikaskia River (Reference 2). Flood-frequency discharge values for the Chikaskia River were determined through a Log- Pearson Type III analysis performed at the City of Blackwell. This analysis was based on stream gage information from 1938 to 1975 and also incorporated data concerning past floods of significance. The flood-frequency discharge values for Arkansas River Tributaries B, C, D, E, G, H, I, W, Bois d Arc Creek Tributaries L, M, N, S, O, and O Tributary were performed using the COE HEC-HMS rainfall runoff computer model (Reference 8). 7

13 Peak discharge-drainage area relationships for the streams studied are shown in Table 2, Summary of Discharges. 8

14 Table 2: Summary of Discharges Drainage Area Peak Discharges (Cubic Feet per Second) Flooding Source and Location (Square Miles) 10-percent 2-percent 1-percent 0.2-percent ARKANSAS RIVER At Kaw Lake 46,350 0,000 66,000 81, ,000 BOIS D ARC CREEK At U.S. Route 60 * 7,716 15,400 19,000 30,200 At confluence of Bois d Arc Creek Tributary M * 7,100 14,800 17,600 28,400 At Hartford Avenue * 6,130 12,100 14,900 23,700 CHIKASKIA RIVER At Cross Section A 1,859 * * 140,000 * SALT FORK ARKANSAS RIVER At Tonkawa 4,520 39,835 75,400 93, ,851 TRIBUTARY 1 Confluence with Chikaskia River ,030 1,810 2,280 3,270 A.T. & S.F. Railway ,175 1,442 2,115 Cross Section W ,285 TRIBUTARY 2 A.T. & S.F. Railway ,380 1,685 2,450 Dewey Street ,155 * Data not available 9

15 Table 2: Summary of Discharges (cont.) Drainage Area Peak Discharges (Cubic Feet per Second) Flooding Source and Location (Square Miles) 10-percent 2-percent 1-percent 0.2-percent TRIBUTARY B At Hartford Avenue At confluence with Tributary C ,172 TRIBUTARY C At Hartford Avenue ,221 1,373 1,786 At confluence with Tributary D ,336 1,918 2,122 2,643 TRIBUTARY D At Prospect Avenue At Hartford Avenue ,398 2,228 2,395 2,827 At confluence with Arkansas River ,960 6,964 7,915 9,918 TRIBUTARY D RIGHT TRIBUTARY 1 At Bradley Avenue ,052 At confluence with Tributary D ,195 TRIBUTARY E At Virginia Avenue ,114 1,334 1,857 At Elmwood Avenue ,816 2,319 2,541 3,358 At confluence with Tributary D ,195 2,911 3,294 4,137 TRIBUTARY G At 5 th Street ,010 1,183 At confluence with Tributary E ,356 1,486 1,776 TRIBUTARY G LEFT TRIBUTARY 1 At confluence with Tributary G

16 Table 2: Summary of Discharges (cont.) Drainage Area Peak Discharges (Cubic Feet per Second) Flooding Source and Location (Square Miles) 10-percent 2-percent 1-percent 0.2-percent TRIBUTARY H At 12 th Street ,076 At confluence with Arkansas River TRIBUTARY H LEFT TRIBUTARY 1 At confluence with Tributary H TRIBUTARY I At 7 th Street ,145 1,443 1,983 At confluence with Arkansas River ,215 1,414 1,807 TRIBUTARY I LEFT TRIBUTARY 1 At confluence with Tributary I TRIBUTARY K At Flormable Street At confluence with Bois d Arc Creek TRIBUTARY L At Waverly Avenue At confluence with Tributary K TRIBUTARY M At Prospect Avenue At Hartford Avenue ,087 At Ash Street ,202 1,659 1,843 2,197 At confluence with Bois d Arc Creek ,030 3,004 3,440 4,511 TRIBUTARY N At confluence with Tributary M

17 Table 2: Summary of Discharges (cont.) Drainage Area Peak Discharges (Cubic Feet per Second) Flooding Source and Location (Square Miles) 10-percent 2-percent 1-percent 0.2-percent TRIBUTARY O At Ash Street At confluence with Tributary M TRIBUTARY O TRIBUTARY At confluence with Tributary O TRIBUTARY P At Industrial Road ,081 At confluence with Tributary M ,343 TRIBUTARY Q At Union Street ,077 1,344 At confluence of Tributary Q Right Tributary ,318 2,350 2,911 3,711 At confluence with Bois d Arc Creek TRIBUTARY Q LEFT TRIBUTARY 1 At confluence with Tributary Q TRIBUTARY Q LEFT TRIBUTARY 2 At confluence with Tributary Q TRIBUTARY Q RIGHT TRIBUTARY 1 At confluence with Tributary Q TRIBUTARY R At confluence with Tributary M

18 Table 2: Summary of Discharges (cont.) Drainage Area Peak Discharges (Cubic Feet per Second) Flooding Source and Location (Square Miles) 10-percent 2-percent 1-percent 0.2-percent TRIBUTARY S At Waverly Street Approximately 3,600 feet above confluence with Arkansas River ,040 1,354 TRIBUTARY W At Lake Road ,330 3,160 4,510 8,520 13

19 3.2 HYDRAULIC 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. Users should be aware that flood elevations shown on the Flood Insurance Rate Map (FIRM) represent rounded whole-foot elevations and may not exactly reflect the elevations shown on the Flood Profiles or in the Floodway Data tables in the FIS report. Flood elevations shown on the FIRM are primarily intended for flood insurance rating purposes. For construction and/or floodplain management purposes, users are cautioned to use the flood elevation data presented in this FIS in conjunction with the data shown on the FIRM. The hydraulic analyses of the Chikaskia River consisted of checking and verifying the USACE HEC-2 computer runs from the 1976 Flood Plain Information Study. The hydraulic properties for the floodway were then determined using the updated COE HEC-2, Water- Surface Profiles computer program (Reference 9). The starting profile elevations for the two tributaries were then assumed to be the same elevation as that of the Chikaskia River at the point of confluence with each tributary and the Chikaskia flood plain. The floodways for Tributary 1 and Tributary 2 were determined using their natural 1% annual chance flood event profiles unaffected by the backwater of the Chikaskia and with the standard criterion of a one (1) foot rise in water-surface elevation above the base flood. Cross sections for streams studied in detail were surveyed at close intervals at bridges and culverts in order to determine the significant backwater effects of these structures in developed areas. All bridges and culverts were surveyed to obtain elevation data and structural geometry. Roughness coefficients were determined at each cross section and each structure by field inspection and are shown in Table 3: Summary of Roughness Coefficients. Cross-section data for the streams studied by detailed methods in Ponca City, except the Arkansas River, were marked on aerial photographs following field inspection of the streams. Cross sections were located at uniform intervals along the streams except near highway and railroad fills, bridges, and culverts, where they were closely spaced in order to compute the backwater effects above these structures. Cross section geometry was obtained by use of the aerial photographs and digital plotter. Cross sections for the Arkansas River were determined using photogrammetric surveys, on-site visual surveys, and high water marks. Locations of selected cross sections used in the hydraulic analyses are shown on the Flood Profiles (Exhibit 1). For stream segments for which a floodway was computed (Section 4.2), selected cross-section locations are also shown on the FIRM. Water-surface elevations of floods of the selected recurrence intervals for the streams studied by detailed methods, except the Arkansas River, were computed using the USGS step-backwater computer program (Reference 10). Water-surface elevations for the Arkansas River were computed using the COE HEC-2 step-backwater computer program (Reference 9). Flood profiles were drawn showing the computed water-surface elevations for floods of the selected recurrence intervals. The hydraulic analyses of the Arkansas River Tributaries B, C, D, E, G, H, I, W, Bois d Arc Creek Tributaries L, M, N, S, O, and O Tributary were performed using the COE HEC-RAS computer step backwater program (Reference 11). Roughness coefficients (Manning s n ) used for the hydraulic computations for the streams studied by detailed methods were estimated on the basis of field inspection and are shown in Table 3: Summary of Roughness Coefficients. 14

20 Routing of flood hydrographs through areas of major ponding was accomplished by using a reservoir routing technique. This program computes the cross section properties and routes a predetermined discharge with resultant water-surface elevations at each cross section from the downstream limit to the upstream limit of the stream. The elevations were computed using the cross section properties and balancing the energy and mass conservation equations. Cross section data for the streams in the study area of City of Tonkawa were obtained by field survey. All bridges and culverts were field surveyed to obtain elevation data and structural geometry. Cross sections were located at close intervals upstream and downstream of bridges and culverts in order to compute significant backwater effects of these structures. The locations of selected cross sections used in the hydraulic analyses are shown on the Flood Profiles. For streams for which a floodway is computed (Section 4.2), selected cross section locations are also shown on the FIRM. Channel roughness factors (Manning's "n" values) used in the hydraulic computations were chosen by engineering judgment after field reconnaissance of the watershed. Table 3, "Manning's "n" Values," shows the channel and over bank "n" values for the streams studied by detailed methods. Table 3: Summary of Roughness Coefficients Roughness Coefficients Flooding Source Channel Overbanks Arkansas River Arkansas River Tributary B Arkansas River Tributary C Arkansas River Tributary D Arkansas River Tributary D Right Tributary Arkansas River Tributary D Right Tributary 1 Right Tributary Arkansas River Tributary E Arkansas River Tributary G Arkansas River Tributary G Left Tributary Arkansas River Tributary H Arkansas River Tributary H Left Tributary Arkansas River Tributary I Arkansas River Tributary I Left Tributary Bois d Arc Creek Bois d Arc Creek Tributary K Bois d Arc Creek Tributary L Bois d Arc Creek Tributary M Bois d Arc Creek Tributary N Bois d Arc Creek Tributary O

21 Roughness Coefficients Flooding Source Channel Overbanks Bois d Arc Creek Tributary O Tributary Bois d Arc Creek Tributary P Bois d Arc Creek Tributary Q Bois d Arc Creek Tributary Q Left Tributary Bois d Arc Creek Tributary Q Left Tributary Bois d Arc Creek Tributary Q Right Tributary Bois d Arc Creek Tributary R Bois d Arc Creek Tributary S Chikaskia River * Salt Fork Arkansas River * Tributary * Tributary * Tributary W * Data Not Available Locations of selected cross sections used in the hydraulic analyses are shown on the Flood Profiles (Exhibit 1). For stream segments for which a floodway was computed (Section 4.2), selected cross section locations are also shown on the FIRM (Exhibit 2). The hydraulic analyses for this study were based on unobstructed flow. The flood elevations shown on the Flood Profiles (Exhibit 1) are thus considered valid only if hydraulic structures remain unobstructed, operate properly, and do not fail. 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, 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 NAVD. 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 Kay County is feet. For additional information regarding conversion between the NGVD and NAVD, visit the National Geodetic Survey website at Hwww.ngs.noaa.govH, or contact the National Geodetic Survey at the following address: 16

22 Vertical Network Branch, N/CG13 National Geodetic Survey, NOAA Silver Spring Metro Center 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. To obtain current elevation, description, and/or location information for benchmarks shown on this map, please contact the Information Services Branch of the NGS at (301) , or visit their web site at Hwww.ngs.noaa.govH. 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. Between cross sections, the boundaries were interpolated using a digital elevation model (DEM) created from three datasets: USGS DEM in Grid ASCII format, both 10 meters and 30 meters, at a data creation scale of 1:24,000 and 2 foot contours and spot elevations. The 2 foot contours and spot elevations were utilized inside the City of Ponca City, while the USGS DEM dataset was used in the remainder of the study area (Reference 12, 13, and 14). 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 detailed topographic data. 17

23 For the streams studied by approximate methods, only the 1-percent-annual-chance floodplain boundary is shown on the FIRM. 4.2 S 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 floodways in this study are presented to local agencies as minimum standards that can be adopted directly or that can be used as a basis for additional floodway studies. 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. Floodway widths were computed at cross sections. Between cross sections, the floodway boundaries were interpolated. The results of the floodway computations are tabulated for selected cross sections (see Table 4). In cases where the floodway and 1-percent-annual-chance floodplain boundaries are either close together or collinear, only the floodway boundary is shown. 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. 18

24 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH2 (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY (FEET NAVD) BASE FLOOD WATER-SURFACE ELEVATION WITHOUT (FEET NAVD) WITH (FEET NAVD) INCREASE Arkansas River A , B 2,851 1,185 18, C 5,776 1,712 17, D 8,358 1,125 17, E 10, , F 13,918 1,065 18, G 15,391 1,029 16, H 17, , I 18, , J 19, , K 22,577 1,223 17, L 24,895 1,282 19, M 28,903 1,848 20, N 32,741 1,719 20, O 35,846 1,245 13, P 39,193 1,178 12, Q 42, , R 46, , S 50, , T 52, , U 54, , V 57,394 1,044 12, W 59, , Feet above limit of detailed study (limit of detailed study is locate approximately 2.0 miles downstream of U.S. Route 60) 2 This width extends beyond county boundary. TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA ARKANSAS RIVER

25 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Bois d Arc Creek A 600 1,425 6, B 2,500 1,100 6, C 6,300 1,785 7, D 6,880 2,500 8, E 8,540 2,300 5, F 9,700 3,000 7, G 9,900 2,600 14, H 13,200 1,700 5, I 14,800 2,000 8, J 15,400 2,000 8, K 17, , L 19,400 1,507 9, M 20,800 1,654 9, N 21,700 1,300 4, O 23,700 1,478 6, P 25,400 1,190 4, Q 27,600 1,694 10, R 28,800 1,800 7, S 29,100 1,800 9, T 30,900 1,500 7, U 33,500 1,304 6, V 35,200 1,200 4, W 3,660 1,200 6, X 39,300 1,300 4, Y 42,300 1,400 6, Feet above County Road TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA BOIS D ARC CREEK

26 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Bois d Arc Creek (continued) Z 43,400 1,200 3, AA 44,800 1,700 5, AB 46,600 1,100 5, AC 48,200 1,346 5, AD 50,700 1,209 5, AE 52,700 1,350 5, Feet above County Road TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA BOIS D ARC CREEK

27 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Chikaskia River A ,644 74, , B ,406 62, , , , C ,205 45, , , , D ,487 68, , , , E ,687 67, , , , F ,914 36, , , , G ,853 52, , , , H ,809 64, , , , Miles above confluence with the Salt Fork Arkansas River TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA CHIKASKIA RIVER

28 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Salt Fork Arkansas River A , , B , , C ,720 40, Miles above confluence with the Arkansas River 2 This width extends beyond county boundary TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA SALT FORK ARKANSAS RIVER

29 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary B A B C 1, D 3, E 3, F 3, , , , G 4, , , , H 5, , , , I 5, , , , Feet above confluence with Tributary C TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY B

30 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary C A , B 1, C 2, D 2, E 3, F 3, G 4, H 5, , , , I 6, , , J 6, , , , K 7, , , , L 8, , , , M 9, , , , N 9, , , , O 10, , , , P 11, , , , Q 12, , , , Feet above confluence with Tributary D TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY C

31 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary D A 6, B 7, , C 7, , D 8, E 8, F 9, G 9, H 10, I 11, J 14, K 14, L 16, , , , , M 17, , , , N 18, , , , O 19, , , , P 20, , , , Q 21, , , , R 21, , , , S 22, , , , Feet above confluence with Arkansas River TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY D

32 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary E A B 1, C 2, D 2, E 4, F 6, G 7, H 7,818 * * * * * 1 Feet above confluence with Tributary D * Not determined TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY E

33 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary G A 1, B 2, C 2, D 3, E 4, Feet above confluence with Tributary E TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY G

34 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary H A 3, B 4, C 4, D 5, E 6, F 6, Feet above confluence with Arkansas River TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY H

35 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary I A 2, , B 2, , C 2, , D 2, E 4, F 5, G 5, Feet above confluence with Arkansas River TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY I

36 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary L A 3, B 4, C 4, D 5, E 5, F 6, Feet above confluence with Bois d Arc Creek TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY L

37 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary M A 3, B 4, , C 4, D 5, E 6, F 6, G 7, H 7, I 8, J 8, K 9, L 10, M 11, N 11, O 12, P 12, Q 13, R 13, S 13, , , , T 14, , , , U 14, , , , V 15, , , , W 16, , , , X 17, , , , Y 17, , , , Feet above confluence with Bois d Arc Creek TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY M

38 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary M (continued) Z 18, , , , AA 19, , , , AB 20, , , , , AC 20, , , , , AD 21, , , , , AE 22, , , , AF 23, , , , AG 24, , , , Feet above confluence with Bois d Arc Creek TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY M

39 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY BASE FLOOD WATER SURFACE ELEVATION WITHOUT WITH INCREASE Tributary N A 763 1,016 6, , , , B 1, , , , C 2,191 * * * 1, ,041.1 * * D 2,738 * * * 1, ,042.0 * * 1 Feet above confluence with Tributary M * Not determined TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY N

40 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY (FEET NAVD) BASE FLOOD WATER-SURFACE ELEVATION WITHOUT (FEET NAVD) WITH (FEET NAVD) INCREASE Tributary O A B C 1, D 1, E 2, F 2, G 3, H 3, I 3, J 4, , , , K 4, , , , L 5, , , , M 6, , , , N 6, , , , Feet above confluence with Tributary M TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY O

41 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY (FEET NAVD) BASE FLOOD WATER-SURFACE ELEVATION WITHOUT (FEET NAVD) WITH (FEET NAVD) INCREASE Tributary O Tributary A B 1, C 1, D 2, , , , E 2, , , , Feet above confluence with Tributary O TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY O TRIBUTARY

42 FLOODING SOURCE CROSS SECTION DISTANCE 1 WIDTH (FEET) SECTION AREA (SQUARE FEET) MEAN VELOCITY (FEET PER SECOND) REGULATORY (FEET NAVD) BASE FLOOD WATER-SURFACE ELEVATION WITHOUT (FEET NAVD) WITH (FEET NAVD) Tributary W A 10, B 10, C 11, D 11, E 12, F 12, G 13, H 14, I 14, J 15, INCREASE 1 Feet above confluence with Arkansas River 2 Elevation computed without consideration of backwater effects from the Arkansas River TABLE 4 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS DATA TRIBUTARY W

43 Figure 1: Floodway Schematic 5.0 INSURANCE APPLICATION 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. 38

44 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- and 0.2-percent-annual-chance floodplains, floodways, and the locations of selected cross sections used in the hydraulic analyses and floodway computations. The countywide FIRM presents flooding information for the entire geographic area of Kay 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 5, Community Map History. 7.0 OTHER STUDIES 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 FEMA Region VI, Federal Insurance and Mitigation Division, 800 North Loop 288, Denton, Texas

45 COMMUNITY NAME INITIAL IDENTIFICATION FLOOD HAZARD BOUNDARY MAP REVISIONS DATE FIRM EFFECTIVE DATE FIRM REVISIONS DATE Blackwell, City of February 1, 1974 April 9, 1976 May 1, 1980 May 19, 1997 September 25, 2009 Braman, Town of September 25, September 25, Kaw City, City of September 25, September 25, Kay County March 5, 1990 (Unincorporated Areas) --- March 5, 1990 May 19,1997 September 25, 2009 Kildare, City of September 25, September 25, Newkirk, City of April 30, August 5, 1985 September 25, 2009 Ponca City, City of February 1, 1974 December 24, 1976 July 2, 1980 November 18, 1988 September 25, 2009 Tonkawa, City of November 23, 1973 February 20, 1976 February 4, 1981 September 25, 2009 TABLE 5 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS COMMUNITY MAP HISTORY

46 9.0 BIBLIOGRAPHY AND REFERENCES 1. Meshek & Associates, City of Ponca City, Oklahoma Arkansas River Tributaries Stormwater Master Plan. Sand Springs, Oklahoma, October U.S. Department of the Army, Corps of Engineers, Tulsa District, Flood Plain Information: Chikaskia River, Blackwell, Oklahoma, June U.S. Army Corps of Engineers, Southwest Division, Regulation, Simulation, and Analysis for Multi- Purpose Reservoirs Systems, SUPER Computer Program, Dallas, Texas, March U.S. Department of the Interior, Geological Survey, Water Resources Investigation 52-73, Flood Characteristics of Oklahoma Streams by Vernon B. Sauer, Oklahoma City, Oklahoma, U.S. Department of the Interior, Geological Survey, Water Resources Investigation 23-74, An Approach to Estimating Flood Frequency for Urban Areas in Oklahoma by Vernon B. Sauer, Oklahoma City, Oklahoma, Federal Emergency Management Agency, Federal Insurance Administration, Flood Insurance Study, City of Tonkawa, Kay County, Oklahoma, Washington, D.C., February 4, Water Resources Council, Guidelines for Determining Flood Flow Frequency, Bulletin 17, Washington, D.C., February 4, U.S. Department of the Army, Corps of Engineers, Hydrologic Engineering Center, HEC Hydrologic Modeling System, Version 2.2.2, May 28, U.S. Army Corps of Engineers, Hydrologic Engineering Center, HEC-2 Water Surface Profiles, Generalized Computer Program, Davis, California, April U.S. Department of the Interior, Geological Survey, Open-File Report, Computer Application for Step-Backwater and Floodway Analysis, by James O. Sherman, Washington, D.C., U.S. Department of the Army, Corps of Engineers, Hydrologic Engineering Center, HEC-RAS River Analysis System, Version 3.1.1, May City of Ponca City, Digital Elevation Data for the City of Sapulpa, U.S. Department of the Interior, Geological Survey, 10 Meter Digital Elevation Models. 14. Qlinks Media Group, GeoCommunity, GIS Data Depot, Copyright

47 10.0 REVISIONS DESCRIPTIONS This section has been added to provide information regarding significant revisions made since the original FIS report and FIRM were printed. Future revisions may be made that do not result in the republishing of the FIS report. All users are advised to contact the Community Map Repository to obtain the most up-to-date flood hazard data First Revision (Revised <insert effective date>) a. Acknowledgements The hydrologic and hydraulic analyses for this restudy of the Arkansas River were performed by Meshek & Associates, PLC., for the City of Ponca City (Meshek & Associates). This work was completed in June of This analysis, submitted in support of Letter of Map Revision (LOMR) case number P, is now being incorporated through this Physical Map Revision. b. Coordination c. Scope A final Consultation Coordination Officer s (CCO) meeting was held on <insert CCO meeting date>, to review the results of this revision. Base map information shown on the FIRM was derived from 2004 aerial imagery provided by the Ponca City Engineering Department, produced at a 1-foot resolution, and from the 2010 National Agriculture Imagery Program (NAIP), produced at a 1-meter resolution. The projection used in the preparation of this map was NAD 1983 State Plane Oklahoma North FIPS 3501 Feet, and the horizontal datum used is the North American Datum 1983 (NAD83). This revision includes revised detailed analyses and mapping for the Arkansas River, as well as revised backwater analyses for several tributaries of the Arkansas River. As part of this revision, updated analyses were included for the following flooding sources: Stream Arkansas River Tributary H Limits of Revised Study From approximately 2.0 miles downstream of US Route 60 to just downstream of Kaw Dam. From the confluence with Arkansas River to approximately 500 feet upstream of Scott Avenue. 42

48 Stream Tributary I Tributary W Limits of Revised Study From the confluence with Arkansas River to approximately 1,325 feet downstream of 7 th Street. From the confluence with Arkansas River to La Cann Drive. This revision also incorporates the LOMR determinations outlined below. Case Number Community Project Identifier Effective Date P City of Ponca City Tributary M Flood Profile Correction P City of Ponca City Hartford Avenue Street Improvements October 19, 2010 July 19, 2011 d. Hydrologic and Hydraulic Analyses This restudy to the Arkansas River modifies the existing backwater model, incorporates newer topographic data, and revises the existing hydrology using more recent high release rates from Kaw Dam. This revised study also incorporates updated structural data along the Arkansas River. The hydrology for this study was produced using SUPER, a computer program developed by the Southwest Division of the US Army Corps of Engineers. SUPER is a computer program that simulates the regulation of a multi-purpose system of reservoirs over a long period of daily hydrologic record (USACE, 1982). The basic inputs include (1) uncontrolled area daily accumulated local flows at every reservoir and control point in the modeled area, (2) a basin description file that describes reservoir characteristics, control point flood flow constraints, water supply requirements, low flow requirements and hydropower requirements. The basic outputs include simulated daily reservoir elevations, reservoir releases and control point flows. The Arkansas River Basin SUPER model includes 24 reservoirs and 50 control points. The prepared daily hydrologic input covers the calendar year period The hydraulic analysis was performed using HEC-RAS (USACE, 2003). Cross Sections were laid out according to the changes in topography and at locations of the existing lettered cross sections. The digital terrain model was supplied by the City of Ponca City. The terrain data was created in 2004 and consisted of 2 foot contour mapping (City of Ponca City). 43

49 As-built plans from the Oklahoma Department of Transportation (ODOT) were used to code in the two bridges along the Arkansas River. The Highway 60 plans were identified as ODOT project number (04)(06) and the county road bridge was ODOT project number 20589(04). The detailed information from the two roadway plans at the bridges was used to modify the channel bottom throughout the Arkansas River reach. Changes to the Summary of Discharges, Manning s n Values, and Floodway Data tables have been incorporated into this FIS report. 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 county. For the streams studied in detail, the 1- and 0.2-percent-annual-chance-floodplain boundaries have been delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic data with a contour interval of 2 feet (City of Ponca City). The 1- and 0.2-percent-annual-chance floodplain boundaries are shown on the FIRM (Exhibit 2). 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 detailed topographic data. e. Other Studies A PMR for Osage County, Oklahoma and incorporated areas is in progress as of the date of this revision. The purpose of the Osage County PMR is to incorporate the updated analysis to the Arkansas River. 44

50 f. Bibliography and References City of Ponca City, Oklahoma. (February 2004). Digital Topography, Contour Interval of 2 feet. Meshek & Associates, PLC., Arkansas River Flood Study, Tulsa, Oklahoma, June U.S. Army Corps of Engineers, Southwest Division, Regulation, Simulation, and Analysis for Multi-Purpose Reservoirs Systems, SUPER Computer Program, Dallas, Texas, March U.S. Army Corps of Engineers, Hydraulic Engineering Center, HEC-RAS River Analysis System, Version 3.1.1, May

51 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS FLOOD PROFILES ARKANSAS RIVER STREAM DISTANCE IN FEET ABOVE LIMIT OF DETAILED STUDY 01P LIMIT OF DETAILED STUDY US RTE 60 & STATE RTE 11 CONFLUENCE OF TRIBUTARY I CONFLUENCE OF TRIBUTARY H E LEGEND 0.2% ANNUAL CHANCE FLOOD 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD STREAM BED A B C D CROSS SECTION LOCATION LIMIT OF DETAILED STUDY IS APPROXIMATELY 2.0 MILES DOWNSTREAM OF US RTE 60 ELEVATION IN FEET

52 SOUTH AVE FLOOD PROFILES ARKANSAS RIVER ELEVATION IN FEET F G H I J K LIMIT OF DETAILED STUDY IS APPROXIMATELY 2.0 MILES DOWNSTREAM OF US RTE 60 STREAM DISTANCE IN FEET ABOVE LIMIT OF DETAILED STUDY L LEGEND 0.2% ANNUAL CHANCE FLOOD 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD STREAM BED CROSS SECTION LOCATION FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK 02P AND INCORPORATED AREAS

53 FLOOD PROFILES ARKANSAS RIVER ELEVATION IN FEET M N O LEGEND 0.2% ANNUAL CHANCE FLOOD 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD LIMIT OF DETAILED STUDY IS APPROXIMATELY 2.0 MILES DOWNSTREAM OF US RTE 60 STREAM DISTANCE IN FEET ABOVE LIMIT OF DETAILED STUDY STREAM BED CROSS SECTION LOCATION FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK 03P AND INCORPORATED AREAS

54 FLOOD PROFILES ARKANSAS RIVER ELEVATION IN FEET P Q R LIMIT OF DETAILED STUDY IS APPROXIMATELY 2.0 MILES DOWNSTREAM OF US RTE 60 STREAM DISTANCE IN FEET ABOVE LIMIT OF DETAILED STUDY S LEGEND 0.2% ANNUAL CHANCE FLOOD 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD STREAM BED CROSS SECTION LOCATION FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK 04P AND INCORPORATED AREAS

55 KAW DAM LIMIT OF DETAILED STUDY FLOOD PROFILES ARKANSAS RIVER ELEVATION IN FEET T U V W LIMIT OF DETAILED STUDY IS APPROXIMATELY 2.0 MILES DOWNSTREAM OF US RTE 60 STREAM DISTANCE IN FEET ABOVE LIMIT OF DETAILED STUDY LEGEND 0.2% ANNUAL CHANCE FLOOD 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD STREAM BED CROSS SECTION LOCATION FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS 05P

56

57 % ANNUAL CHANCE BACKWATER EFFECTS FROM ARKANSAS RIVER THE 0.2, 2 AND 10% ANNUAL CHANCE PROFILES ARE TOO CLOSE TO THE 1% ANNUAL CHANCE FLOOD TO BE SHOWN SEPERATELY CONFLUENCE WITH ARKANSAS RIVER GRAVEL RD GRAVEL RD EDWARDS AVE HWY 77 SCOTT AVE TH ST ALLEY 11TH ST FLOOD PROFILES TRIBUTARY H ELEVATION IN FEET A B C STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH ARKANSAS RIVER D LEGEND 0.2% ANNUAL CHANCE FLOOD 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD STREAM BED CROSS SECTION LOCATION FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS 30P

58 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS FLOOD PROFILES TRIBUTARY I % ANNUAL CHANCE BACKWATER EFFECTS FROM THE ARKANSAS RIVER F G D C A B E STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH ARKANSAS RIVER 33P CONFLUENCE WITH ARKANSAS RIVER PLEASANT VIEW ROAD HIGHWAY 77 7TH ST 6TH ST 4TH ST LIMIT OF DETAILED STUDY LEGEND 0.2% ANNUAL CHANCE FLOOD 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD STREAM BED CROSS SECTION LOCATION ELEVATION IN FEET

59 % ANNUAL CHANCE BACKWATER EFFECTS FROM BOIS D'ARC CREEK FLORMABLE ST PEDESTRIAN BRIDGE IRVING ST HIGHLAND AVE NEW FARM RD FLOOD PROFILES TRIBUTARY M ELEVATION IN FEET LEGEND 0.2% ANNUAL CHANCE FLOOD 930 A B C ,000 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000 5,500 6,000 6,500 7,000 STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH BOIS D'ARC CREEK D E F 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD STREAM BED CROSS SECTION LOCATION FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK 37P AND INCORPORATED AREAS

60

61

62 RAILROAD 5TH ST WINDSOR RD LIMIT OF DETAILED STUDY FLOOD PROFILES TRIBUTARY M ELEVATION IN FEET (NAVD 88) AB AC AD AE AF AG STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH BOIS D'ARC CREEK LEGEND 0.2% ANNUAL CHANCE FLOOD 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD STREAM BED CROSS SECTION LOCATION FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK 40P AND INCORPORATED AREAS

63 FEDERAL EMERGENCY MANAGEMENT AGENCY KAY COUNTY, OK AND INCORPORATED AREAS FLOOD PROFILES TRIBUTARY O K L A B C E F G H I J STREAM DISTANCE IN FEET ABOVE CONFLUENCE WITH TRIBUTARY M 42P LIBERTY AVE RAILROAD CONFLUENCE OF TRIBUTARY 0 TRIBUTARY HARTFORD AVE ASH ST LEGEND 0.2% ANNUAL CHANCE FLOOD 1% ANNUAL CHANCE FLOOD 2% ANNUAL CHANCE FLOOD 10% ANNUAL CHANCE FLOOD D STREAM BED CROSS SECTION LOCATION ELEVATION IN FEET

64