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FIRM-92060494Le- If 6� L�l 1`7 FILE COPY P.O. Box 478 Coppell, Texas 75019 fhe City With A Beautiful Future 214- 462 -0022 June 4, 1992 Mr. William R. Locke Chief, Risk Studies Division Federal Insurance Administration Federal Emergency management Agency 500 C Street, Southwest Washington, D.C. 20472 Re: Revisions to FIS /FIRM /City of Coppell Dear Mr. Locke: This letter serves as the City of Coppell's formal appeal of flood elevation determinations, according to Part 67 of Title 44 of the Code of Regulations (44CFR). We have completed our detailed review of the preliminary Flood Insurance Study (FIS) and the Flood Insurance Rate Map (FIRM), dated December 18, 1992. In addition, we have coordinated the review with affected consultant engineers who have previously prepared floodplain studies for certain subdivision developments adjacent to flood hazard areas. We are providing you with the best available documents and plans reflecting existing conditions to support our appeal. Please note that one of the City's mayor concerns is the incorrect floodplain line delineations which impact some properties that are in fact outside of the flood hazard areas. The floodplain work maps previously provided to FEMA, by Morrison Hydrology Engineering on behalf of the City, were partially inaccurate, since the base maps used were the 1985 City topo maps. Recognizing the fact that over the past seven (7) years we have experienced a tremendous amount of growth, the 1985 topo base maps used did not reflect the existing grading conditions. This matter hasp caused a great deal of concern and it is our intent to work with your staff to update the FIRM according to the best available data. It is important to note that the City of Coppell is presently in the process of developing a base map which will provide accurate information reflecting the City's corporate limits, street locations, topos, etc. It is our intent to provide FEMA with the City's most accurate street and topo maps on a scale of 1" = 1000' by September, 1992. The maps should address concerns of several property owners who believe their properties are incorrectly shown in flood hazard areas. Letter to Mr. William R. Locke June 4, 1992 Page 2 Enclosed please find the necessary supporting documents provided for areas along Cottonwood Branch, Denton Creek, Elm Fork of Trinity River and Grapevine Creek. The attached summary report provides a brief explanation of our concerns and information submitted, entitled "Revisions to FIRM /FIS - 1992 ", pages 1 thru 6 of 10. Also attached is the flood prone street index reflecting staff's comments in regard to the street and grid locations, see attached page 7 of 10. Also attached are copies of the revised pages of the FIS, dated 12- 18 -91, reflecting changes such as our current population estimates (19,250) and geographical size (13.5 sq. miles), etc. See Page 8 thru 10 of 10. We respectfully request your favorable consideration of our appeal and that the enclosed documents be carefully reviewed prior to finalization of flood elevation determinations. Our staffs have worked together on previous FIS /FIRM revisions and the continued coordination is greatly appreciated. If you have any questions and /or need any additional information please contact M. Shohre Daneshmand, P.E. or myself at (214) 393 -1016. Sincerely, 4nneth M. 'G 3. ivff n, P.E. d ,qty Enginee -- -__ KMG /MSD /bd cc: Alan D. Ratliff, City Manager William A. Anderson, P.E., Dan M. Dowdey Associates, Inc. +% M. Shohre Daneshmand, P.E., Civil Engineer Phil Deaton, P.E., Carter & Burgess Bill Wallace, P.E., Nathan D. Maier Robert Porter, P.E., Don Tipton Engineers Jean Hansen, P.E., Albert H. Halff Associates Kevin Kendrick, P.E., Unzicker, Schnurbusch Associates REVFIS REVISIONS TO FIRM %FIS - 1992 COTTONWOOD BRANCH IC - Oakbend Addition Attached please find a copy of the final plat for this subdivision to delineate correct street locations. There was no alterations made to the designated flood hazard area under this development. A copy of the report had been provided to FEMA for references only. (Plans prepared by Nathan D. Maier Consulting Engineers.) 2C - Shadow Woods Estates Attached is a copy of the final plat for this subdivision to delineate correct street locations. A floodplain study by Nathan D. Maier Consulting Engineers had been forwarded to FEMA for review. (See attachment 2C -A, letter from FEMA dated 10%1689.) 3C - Villages of Cottonwood Creek The floodplain and floodway delineations are incorrect, and appear to be a drafting error. A certified copy of the 'As-Built" grading plan for this subdivision prepared by Wier & Associates, Inc. is provided for your use in correcting this error. This subdivision was constructed in January, 1986. The correct floodplainjfloodway line is also delineated on a copy of the FIRM, noted as 3C. e4C - Parkway Blvd Extension West /Coppell High School Approximately 560 T.F. ( +) of Parkway Blvd. is extended west of Denton Tap Road to provide access to the Coppell High School (CHS). Also, a certified existing grading plans (record drawings) for the CHS, as prepared by SHW Group, Inc., dated June 9, 1988, is enclosed. Page 1 of 10 REVISIONS TO FIRM /FIS - 1992 DENTON CREEK D - City of Coppell's Corporate Limits in the Vicinity of S.H. 121 and Denton Creek: op- Attached annexation Ordinances #88410 & Ordinance #91504 fare provided in support limit line in the vicinity of S. H. 121 attached City limit map (scale 1" _ corporate limits in this area. 1D - Park Meadows Section I & II 88427 OW and disannexation of changes made to the City and Denton Creek. The 1200') reflects the correct Some of the streets currently shown on the FIRM are incorrect. Attached final plats, for Park Meadow Section I and Section II, are provided for correct delineation of certain streets, such as Clear Haven, etc. 2D - MacArthur Blvd Bridge Crossing Denton Creek Attached are "As -Built Plans" for the MacArthur Blvd. Bridge along with a letter from Mr. Phil Deaton, P.E., Carter & Burgess Inc., dated June 4, 1992, regarding "Vista Ridge Development" along with a grading plan for "Island Area Along MacArthur Blvd., Exhibit "A ". In his letter Mr. Deaton appeals that the island area along MacArthur Blvd. between the old Denton Creek and the new flood control channel is outside of the 100 -year flood hazard area. Reference is made to the split flow analysis that was prepared and submitted by Mr. Ron Morrison, P.E., Case #6 -89 -236, letter dated September 5, 1990. (See attached documents.) 10'3D - Lakes of Coppell /Villages of Coppell III & IV (Phases A & B) The floodplain line is delineated incorrectly in this area. The flood hazard area south of Deforest Lane is narrower than shown. The effective FIRM (dated 10- 16 -91) is more accurate than the preliminary FIRM under revision. Floodplain Study Report prepared by Don Tipton Engineers (Case #92- 06 -037R) has been submitted to FEMA for review. Attached final plats are submitted for correct delineation of streets. We request that if review is completed, the final LOMR be issued and the revision be shown on the City's revised FIRM. i 4D - Gibbs Station In response to FEMA's letter dated 3 -17 -92 and to support Mr. D.M. Dowdey's request, the attached certified existing grading plans prepared by D. M. Dowdey & Associates Inc. is provided. The FIRM dated 10 -16 -91 correctly shows this particular area. Please note that the base maps used by the City, in providing the previous floodplain delineations, were the 1985 topographical maps which was Page 2 of 10 prior to completion of Lakes of Coppell (Case #IA -RA -RS (102a) reclamation project. During the previous map revision, to keep the floodplain lines continueous, the old topo lines were used. However, the as -built grading plan certifies the area to be outside of the 100 -year flood hazard area, as intended. City supports this request. �5D - Lakes of Coppell /Lake Wood Estates As per attached letter from Mr. K. Kendrick, P.E. of Unzicker, Schnurbusch Associates, Inc., dated 4/28/92, the proposed floodplain line is incorrect, as fully explained under the previous item ( #4D), due to the City's use of old topo maps. The City supports this request. Attached also please find the certified existing grading plan, prepared by Unzicker, Schnurbusch Associates, Inc. '076D - Corporate City Limit Line/T.U. Electric Easement Attached is a copy of Annexation Ordinance #89430 as supporting document stating that this strip of land is within the corporate limits of the City of Coppell. Page 3 of 10 REVISIONS TO FIRM(FIS - 1992 ELM FORK OF THE TRINITY RIVER r 1EF- The Zone 'X' Area South of Belt line Road A portion of the area shown as Zone 'X' on the preliminary maps dated 12/18/91 should be shown as 100 -year floodplain. It should not be labeled a floodway because it is in an area of non effective flow. Please see the attached copy of existing grading plan prepared by A.H.H. & Associates and a copy of the marked -up FIRM. Page 4 of 10 REVISIONS TO FIRM /FIS - 1992 GRAPEVINE CREEK 1G - Grapevine Creek Channelization /Drop Structure Case #92- 06-006P Attached is additional information, including a letter from the City regarding channel maintenance. See letters from the City, dated 6 -4 -92 and 6 -2 -92, along with A.H.H.'s letter to the City, addressing said comments. City supports this request for issuance of the final letter of Map Revision, and actual map revision of the area under this appeal. �2G - Big Cedar Addition (Tributary G -1) Attached is an executed copy of the final plat for street location and delineation along Tributary G -1. Please note that Bethel School Road is no longer a public access road from the south. Also, see a status report letter from Mr. M. Goodwin, P.E. on Case #91- 06 -70R. If your review of this project is completed, please reflect the map revision on the City's FIRM as part of this request. *03G - Denton Tama Road Bridge /Case #88- 06-13R A floodplain study for widening of Denton Tap bridge had been submitted to FEMA in 1988. The FIS profile for the portion of Grapevine Creek Crossing Denton flap does not show the new bridge. Please make appropriate correction, (see attached letter from Ginn, Inc. to FEMA, dated 11- 20 -90). 4G - Creekview Estates /Case #88- 06 -37R The above referenced subdivision has been constructed. As per the attached letter from Mr. William Wallace, P.E. of N.D. Maier Consulting Engineers, Inc., the "As- Built" documents and plans are presently being prepared. The complete "As- Built" documents are to be submitted to FEMA in the next 30 - 60 days. See attached letter, dated 5 -29 -92 from Mr. Wallace, P.E., along partially completed as -built survey map. Attached you also will find a copy of the final plat for Creekview North showing the street location, prepared by Don Tipton Engineers, Inc. 5G - Corporate Limits of the City of Coppell Attached is a copy of Ordinance #88412 in support of correct City limit line in the southwest area of Grapevine Creek and Denton Tap Road. 016G - Carter Estates /Street Delineation Attached is a copy of the plat for Carter Estates showing the street locations. Please make revisions accordingly. Page 5 of 10 4OW7G - Northlake Woodlands #12 The above referenced floodplain study has been under the previous administration. Attached is plat prepared by Don Tipton Engineers. Please revisions to the FIRM. Page 6 of 10 submitted to FEMA a copy of the final make appropriate .USX P 0 -el r . a o zz a�o � CC .22JJyy� i` ME a c W `J NOX UM�t �! 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O J 0 LL COPPELL, TX FLOOD PRONE STREET INDEX NOTE TO USER This index provides a List of all streets shown on the Flood Insurance Rate Map (FIRM) that are partially or totally within Special Flood Hazard Areas (SFHAs). This index should not be used as an authoritative source for determining whether specific streets, properties, or buildings are within an SFHA. The appropriate FIRM panel must be consulted for these purposes. This index is intended to be used only as a guide for determining which FIRM panel displays the street in question and the relative location of the street on the FIRM panel. J- e�ls� KEY BAKER STREET . . . . . . . . . . . . . . . . . . . . . . 0005 (A2) Street Name . . . . . . . . . . . . . . Panel Number (Grid Location) • AIRLINE DRIVE . . . . . . . . . . . . . . . . . . . . . ALLEN ROAD . . . . . . . . . . . . . . . . . . . . . . . BELTLINE ROAD . . . . . . . . . . . . . . . . . . . . . . BETHEL ROAD . . . . . . . . . . . . . . . . . . . . . . . BETHEL SCHOOL ROAD . . . . . . . . . . . . . . . . . . . 0 BRE /NWOOD DRIVE . . . . . . . . . . . . . . . . . . . . . COPPELL ROAD . . . . . . . . . . . . . . . . . . . . . . DEFOREST ROAD . . . . . . . . . . . . . . . . . . . . . . • DENTON TAP ROAD . . . . . . . . . . . . . . . . . . . . . • FREEPORT PARKWAY . . . . . . . . . . . . . . . . . . . . S•.4•3aI ........... . LEDBETTER ROAD . . . . . . . . . . . . . . . . . . . . . LOCH AVENUE . . . . . . . . . . . . . . . . . . . . . . . • MACARTHUR BOULEVARD . . . . . . . . . . . . . . . . . . . MEADOW CREEK ROAD . . . . . . . . . . . . . . . . . . . . • MOORE ROAD . . . . . . . . . . . . . . . . . . . . . . . RIVER CHASE DRIVE . . . . . . . . . . . . . . . . . . . . ROYAL LANE . . . . . . . . . . . . . . . . . . . . . . . SANDY LAKE ROAD . . . . . . . . . . . . . . . . . . . . . • SOUTHWESTERN BOULEVARD . . . . . . . . . . . . . . . . . STATE ROAD . . . . . . . . . . . . . . . . . . . . . . . VILLAGE PARKWAY . . . . . . . . . . . . . . . . . . . . . 0010 (C5) 0010 (G2) 0010 kr��—� 0010 (CO 0010 (04) 0010 (G1) 0010 (65) 0010 (F1) 0010 (D3) 0010 (CS) 0010 (Cl) 0010 (H5) 0010 (CO 0010 (F1) 0010 (D4) 0010 (E3) 0010 (H3) 0010 (A3) 0010 (C2) 0010 (CO 0010 (B3) 0010 (G2) jLto e- S er�s C �'Ci 1 eS 4 10 6:-�j W; & k � tkA- l00 -y,/ f 100A �' a+,ea S . of40MON00 110 FLOOD INSURE STUD C E CITY OF COPPELL, TEXAS DALLAS AND DENTON COUNTIES PRELIMINARY DEC 18 1991 at 3e _... o to REVISED: MAN�C� z .Federal Emergency Management Agency ��yo 0 b COMMUNITY NUMBER - 480170 � a�D 0 Soo In 1980 Coppell had a population f 3,826 and in 198 , (population °F of eference 1). Coppell is a sparsely developed residen- tia mmunity of approximatel quare miles. The city is drained by the Elm Fork of Trinity River and its tributaries. The Elm Fork flows in a southern direction, while the tributaries flow in an eastern direction. The climate of the study area is warm, temperate, and humid. Summers are hot, and winters and short and mild. The mean relative humidity is 63 percent, and average temperature is 65.8 degrees Fahrenheit (0Fa. The record temperature extremes range from a maximum of 111 F in July 1954 to a minimum of -30F in January 1930. Coppell has terrain characteristic of the Black and Prairie. The topography is gently rolling to almost level with narrow streams being well incised. The soils in the area are mainly of the Houston Black, Haiden, and Austin series. The native vegetation consists of bunch and short grasses with scattered mesquite trees on the uplands and hardwood, mainly elm, hackberry, and pecan occurring along the streams. 2.3 Principal.Flood Problems Most of the floods producing storms that occur in Coppell are ex- perienced in the spring and fall. Most of the higher floods that have occurred in the general geographical region have resulted from prolonged or successive storms that produce heavy rainfall during this period; however, severe flooding can be produced by intense local thunderstorms at any time. i Coppell has experienced few flood problems in the past, due primarily to the fact that little development exists on the floodplains at this time. There are two USGS stream gages in the study area. The gage on the Elm Fork of Trinity River located at Sandy Lake Road was established in November 1943. The gage on Denton Creek located at Interstate Route 121 was established in October 1947 (Reference 2). Historical data for ungaged watersheds are dependent on local resident observations, news media records, published reports, and analysis of other nearby watersheds with gage data and similar characteristics. Significant flooding is known to have occurred within the vicinity in 1908, the early 1930s, 1942, 1947, 19492 1957) 19629 1963, 1964, 1965, 1969, 1973, 1974, 1976, and 1977; however, little specific data is available. Grapevine Creek and Cottonwood Branch undoubtedly experienced flooding during the periods listed above, but no details are avail- able. ow 1bf to t << T, 1 .r ale FIGURE 2: Potential Flood Height on Grapevine Creek This photograph shows future flood heights on Grapevine Creek at Moore Road. ILIk ?¢z c Y 3y k � � G• i -t f. . .z 7 to