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Cambridge1P/FP-CS 940419 Federal Emergency Management Agency Washington, D.C. 20~-72 APR 19 1994 CERTIFIED MAIL IN RI~PLY RI~FER TO: RETURN RECEIPT RI~QUI~STED Case No.l 96-06-050R The Honorable Tom Morton Co~mnmity= City of Coppell, Texas Mayor, City of Coppell Community No.l 480170 255 Parkway Boulevard Coppell, Texas 75019 104 Dear M~yor Morton~ This is in response to a letter dated February 4, 1994, from Mr. Allen J. Harts, P.E., Dan M. Dowdey and Associates, Inc., to the Federal F~nergency Management Agency (FENA) regarding the effective Flood Insurance Rate Map (FIRI~) for the City of Coppell, Texas. With his letter, Mr. Harts provided addltlonal information to support a November 22, 1993, request for a Conditional Letter of Hap Revision (CLOMR) from Mr. Kenneth M. Griffin, P.E., City Engineer, City of Coppell. Mr. Griffin requested that FEMA evaluate the effect that proposed fill between Cross Section 20980~ a distance of approximately 1,780 feet downstream of HacArthur Boulevard, and Cross Section 21665, a distance of approximately 2,540 feet downstream of MacArthur Boulevard along Denton Creek, would have on the effective FIRM. All data required by FEHA to evaluate this request were submitted by Mr. Griffin with his November 22 letter; by Mr. William A. Anderson, P.E., Dan M. Dowdey and Associates, Inc., with his transmittal dated January 12, 19961 and by Mr. Harts with his February 4 transmittal. All fees necessary to process this CLOHR (a total of $1,600) have been received. We have reviewed the data submitted and the flood data used to prepare the effective FIILM for the City of Coppell. The submitted existing conditions HEC-2 hydraulic computer model, dated February 1, 1994, based on updated topographic iuformatlon and additional cross sections, was used as the base conditions model in our review of the proposed conditions model for this CLOMR request. We believe that if the proposed project is constructed as shown on the topographic work map entitled "Floodplain Hap, STA. 199+30 - STA. 230+00, Cambridge Manor States," prepared by Dan N. Dowdey and Associates, Inc., dated November 11, 1993, and as described in the repor~ entitled "Flood Plain Reclamation, Denton Creek, City of Coppell, Dallas County, Texas, a revision to the FIRM would be warranted. The limits of fill as shown on the above plan are located in an ineffective flow area caused by backwater from Denton Creek. This area will be removed from the Special Flood Hazard Area (SFHA) after the fill has been placed and compacted. The updated topographic information, addition of new cross sections, and the proposed fill placement viii result in a decrease of the SFHA along the entire reach of study. Base (100-year) flood elevations (BFEs) are increasing by a m--imum of 0.06 foot. The increase in BFE is the result of a more detailed hydraulic analysis to reflect existing conditions. Upon completion of the project and receipt of the data listed below, we will make a final determination on revising the effective FIRM. ® Detailed application and certification forms, which were used in processing this request, must be used for requesting final revisions to the maps. Therefore, when the map revision request for the area covered by this letter is submitted, each of the forms listed below must be submitted. (Copies of the forms are enclosed.) Form 1, entitled "Revision Requester and Community Official Form" Form 2, entitled "Certification by Registered Professional Engineer and/or Land Surveyor" · Please note that the National Flood Insurance Program (NFIP) is non-taxpayer funded and its expenses are paid for by policyholders. Therefore, to minimize the financial burden on the policyholders while maintaining the NFIP as self-sustaining, FEMA has implemented a procedure to recover costs associated with reviewing and processing requests for modifications to published flood information and maps. Therefore, an initial fee of $225, which represents the minimum charges associated with a request of this type, must be submitted before we can process your revision request. Payment of this fee shall be made in the form of a check or money order made payable in U.S. funds to the National Flood Insurance Program, or by credit card payment. The payment is to be forwarded to the following address: Federal Emergency Management Agency Revisions Fee-Collection System Administrator P.O. Box 3173 Merrifield, Virginia 22116 · As-built plans, certified by a registered professional engineer, of all proposed project elements · Certification that all fill placed in the currently effective 100- year floodplain and below the proposed BFE is compacted to 95 percent of the maximum density obtainable with the Standard Proctor Test method issued by the American Society for Testing and Materials (ASTM Standard D-698) or an acceptable equivalent method for all areas to be removed from the 100-year floodplain This response to Mr. Griffin's request is based on minimum floodplain management criteria established under the NFIP. Your community is responsible for approving all proposed floodplain development, including this request, and for assuring that the necessary permits required by Federal or State law have been received. State and community officials, based on knowledge of local conditions and in the interest of human safety, may set higher standards for construction or may .limit development in floodplain areas. If the Sta~e of Texas or the City of Coppell has adopted more restrictive or comprehensive floodplain management criteria, those criteria take precedence over the minimum NFIP requirements. 3 Should you have any questions regarding this matter, please contact the Division Director, Mitigation Division of FEMA in Denton, Texas, at (817) 898-5127, or Mr. Alan Johnson of our staff in Washington, DC, either by telephone at (202) 646-3403 or by facsimile at (202) 646-3445. Sincerely,t. /~I :Michael K./~uckle~, P.E., Chief //i' ~Hazard Identification Branch z ~ Mitigatio~Directorate Enclosures cc: Mr. Kenneth M. Griffin, P.E. City Engineer City of Coppell Mr. William A. Anderson, P.E. Dan M. Dowdey and Associates, Inc.