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Westhaven-FS121121 °- Federal Emergency Management Agency O\ \ ,, ` Washington, D.C. 20472 �i�tAND SEGJ4 November 21, 2012 CERTIFIED MAIL IN REPLY REFER TO: RETURN RECEIPT REQUESTED Case No.: 12-06-3818R The Honorable Karen Hunt Community Name: City of Coppell, TX Mayor,City of Coppell Community No.: 480170 P.O. Box 9478 Coppell, TX 75019 104 Dear Mayor Hunt: We are providing our comments with the enclosed Conditional Letter of Map Revision(CLOMR)on a proposed project within your community that,if constructed as proposed,could revise the effective Flood Insurance Study report and Flood Insurance Rate Map for your community. If you have any questions regarding the floodplain management regulations for your community,the National Flood Insurance Program(NFIP)in general,or technical questions regarding this CLOMR, please contact the Director, Mitigation Division of the Federal Emergency Management Agency(FEMA)Regional Office in Denton,Texas, at (940) 898-5127, or the FEMA Map Information eXchange(FMIX)toll free at 1-877-336-2627 (1-877-FEMA MAP). Additional information about the NFIP is available on our Web site at http://www.fema.gov/business/nfip. Sincerely, d?!"-A P Stuart W.Rooney, CFM, PMP, Program Specialist For: Luis Rodriguez, P.E., Chief Engineering Management Branch Engineering Management Branch Federal Insurance and Mitigation Administration Federal Insurance and Mitigation Administration List of Enclosures: Conditional Letter of Map Revision Comment Document cc: Ken Griffin,P.E Director of Engineering City of Coppell Mr. Kyle A. Dickey, P.E. Kimley-Horn and Associates, Inc. Page 1 of 5 Issue Date: November 21,2012 Case No.: 12-06-3818R CLOMR-APP �' Federal Emergency Management Agency � 4 Washington, D.C. 20472 4ND 0 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT COMMUNITY INFORMATION PROPOSED PROJECT DESCRIPTION BASIS OF CONDITIONAL REQUEST City of Coppell BRIDGE BASE MAP CHANGES Dallas County EXCAVATION FLOODWAY Texas FILL HYDRAULIC ANALYSIS COMMUNITY DETENTION BASIN NEW TOPOGRAPHIC DATA COMMUNITY NO.: 480170 Westhaven Residential Development APPROXIMATE LATITUDE AND LONGITUDE: 32.986,-97.007 IDENTIFIER SOURCE: PRECISION STREET MAPPING DATUM: NAD 83 AFFECTED MAP PANELS TYPE: FIRM* NO 48113C0135J DATE:August 23,2001 *FIRM-Flood Insurance Rate Map TYPE: FIRM* NO.: 48113C0155J DATE:August 23,2001 FLOODING SOURCE AND REACH DESCRIPTION Denton Creek—from approximately 4,500 feet downstream of Interstate 121 to just downstream of Interstate 121 PROPOSED PROJECT DESCRIPTION Flooding Source Proposed Project Location of Proposed Project Denton Creek Fill and Excavation Three proposed ponds and proposed fill placement will be located along the left overbank of the revised reach of Denton Creek New Detention Basins Three proposed ponds will be located adjacent to Denton Creek along the left overbank of the revised reach New Bridges The proposed pedestrain bridge and aerial sanitary sewer crossing are to be located approximately 1,700 feet and 3,200 downstream of Interstate 121,respectively SUMMARY OF IMPACTS TO FLOOD HAZARD DATA Flooding Source Effective Flooding Proposed Flooding Increases Decreases Flooding Source Name Zone AE Zone AE Yes Yes Zone X(shaded) Zone X(shaded) Yes Yes Floodway Floodway Yes Yes BFEs* BFEs Yes Yes *BFEs-Base(1-percent-annual-chance)Flood Elevations COMMENT This document provides the Federal Emergency Management Agency's(FEMA's)comment regarding a request for a CLOMR for the project described above. This document is not a final determination;it only provides our comment on the proposed project in relation to the flood hazard information shown on the effective National Flood Insurance Program(NFIP)map. We reviewed the submitted data and the data used to prepare the effective flood hazard information for your community and determined that the proposed project meets the minimum floodplain management criteria of the NFIP. Your community is responsible for approving all floodplain development and for ensuring that all permits required by Federal or State/Commonwealth law have been received. State/Commonwealth, county,and community officials,based on their knowledge of local conditions and in the interest of safety,may set higher standards for construction in the Special Flood Hazard Area(SFHA),the area subject to inundation by the base flood). If the State/Commonwealth,county,or community has adopted more restrictive or comprehensive floodplain management criteria,these criteria take precedence over the minimum NFIP criteria. This comment is based on the flood data presently available. If you have any questions about this document,please contact the FEMA Map Information eXchange(FMIX) toll free at 1-877-336-2627(1-877-FEMA MAP)or by letter addressed to the LOMC Clearinghouse,847 South Pickett Street,Alexandria,VA 22304-4605. Additional Information about the NFIP is available on the FEMA Web site at http://www.fema.gov/business/nfip. '-• A0 P7 Stuart W.Rooney,CFM,PMP,Program Specialist Engineering Management Branch Federal Insurance and Mitigation Administration 12-06-3818R 104 Page 2 of 5 Issue Date: November 21,2012 Case No.: 12-06-3818R CLOMR-APP Federal Emergency Management Agency �� Washington, D.C. 20472 BAND stc- CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION To determine the changes in flood hazards that will be caused by the proposed project,we compared the hydraulic modeling reflecting the proposed project (referred to as the proposed conditions model)to the hydraulic modeling used to prepare the Flood Insurance Study(FIS)(referred to as the effective model). If the effective model does not provide enough detail to evaluate the effects of the proposed project,an existing conditions model must be developed to provide this detail. This existing conditions model is then compared to the effective model and the proposed conditions model to differentiate the increases or decreases in flood hazards caused by more detailed modeling from the increases or decreases in flood hazards that will be caused by the proposed project. The table below shows the changes in the BFEs: BFE Comparison Table Flooding Source: Denton Creek BFE Change(feet) Location of maximum change Existing vs. Maximum increase 1.2 Just downstream of Interstate 121 Effective Maximum decrease 0.4 Approximately 4,500 feet downstream of Interstate 121 Proposed vs. Maximum increase None N/A Existing Maximum decrease 0.4 Just downstream of Interstate 121 Proposed vs. Maximum increase 0.8 Just downstream of Interstate 121 Effective Maximum decrease 0.4 Approximately 4,500 feet downstream of Interstate 121 NFIP regulations Subparagraph 60.3(b)(7)requires communities to ensure that the flood-carrying capacity within the altered or relocated portion of any watercourse is maintained. This provision is incorporated into your community's existing floodplain management ordinances;therefore,responsibility for maintenance of the altered or relocated watercourse,including any related appurtenances such as bridges,culverts,and other drainage structures,rests with your community. We may request that your community submit a description and schedule of maintenance activities necessary to ensure this requirement. This comment is based on the flood data presently available. If you have any questions about this document,please contact the FEMA Map Information eXchange(FMIX) toll free at 1-877-336-2627(1-877-FEMA MAP)or by letter addressed to the LOMC Clearinghouse,847 South Pickett Street,Alexandria,VA 22304-4605. Additional Information about the NFIP is available on the FEMA Web site at httpi/www.fema.gov/business/nfip. A,p7 Stuart W.Rooney,CFM,PMP,Program Specialist Engineering Management Branch Federal Insurance and Mitigation Administration 12-06-3818R 104 Page 3 of 5 Issue Date: November 21,2012 'Case No.: 12-06-3818R CLOMR-APP T _ Federal Emergency Management Agency ° ` Washington, D.C. 20472 t.I ND StiG�. 4- CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) DATA REQUIRED FOR FOLLOW-UP LOMR Upon completion of the project,your community must submit the data listed below and request that we make a final determination on revising the effective FIRM and FIS report. If the project is built as proposed and the data below are received,a revision to the FIRM and FIS report would be warranted. •Detailed application and certification forms 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,Form 1,entitled"Overview and Concurrence Form,"must be included. A copy of this form may be accessed at http://www.fema.gov/plan/prevent/fhm/dl_mt-2.shtm. •The detailed application and certification forms listed below may be required if as-built conditions differ from the proposed plans. If required,please submit new forms,which may be accessed at http://www.fema.gov/plan/prevent/fhm/dl_mt-2.shtm,or annotated copies of the previously submitted forms showing the revised information. Form 2,entitled"Riverine Hydrology and Hydraulics Form." Hydraulic analyses for as-built conditions of the base flood,the 10- percent,2-percent,and 0.2-percent-annual-chance floods,and the regulatory floodway,must be submitted with Form 2. Form 3,entitled"Riverine Structures Form." •A certified topographic work map showing the revised and effective floodplain and floodway boundaries.Please ensure that the revised information ties-in with the current effective information at the downstream and upstream ends of the revised reach. •An annotated copy of the FIRM,at the scale of the effective FIRM,that shows the revised floodplain and floodway boundary delineations shown on the submitted work map and how they tie-in to the floodplain and floodway boundary delineations shown on the current effective FIRM at the downstream and upstream ends of the revised reach. •As-built plans,certified by a registered Professional Engineer,of all proposed project elements. •A copy of the public notice distributed by your community stating its intent to revise the regulatory floodway,or a signed statement by your community that it has notified all affected property owners and affected adjacent jurisdictions. •Documentation of the individual legal notices sent to property owners who will be affected by any widening or shifting of the base floodplain and/or any BFE increases along Denton Creek. This comment is based on the flood data presently available. If you have any questions about this document,please contact the FEMA Map Information eXchange(FMIX) toll free at 1-877-336-2627(1-877-FEMA MAP)or by letter addressed to the LOMC Clearinghouse,847 South Pickett Street,Alexandria,VA 22304-4605. Additional Information about the NFIP is available on the FEMA Web site at http://www.fema.gov/business/nfip. et A.P7 Stuart W.Rooney,CFM,PMP,Program Specialist Engineering Management Branch Federal Insurance and Mitigation Administration 12-06-3818R 104 Page 4 of 5 Issue Date: November 21,2012 Case No.: 12-06-3818R CLOMR-APP OEQlT4F Federal Emergency Management Agency Washington, D.C. 20472 #t9ND StiG�4 CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) DATA REQUIRED FOR FOLLOW-UP LOMR(continued) •An officially adopted maintenance and operation plan for the proposed West Pond,Central Pond,and East Pond.This plan,which may be in the form of a written statement from the community Chief Executive Officer,an ordinance,or other legislation,must describe the nature of the maintenance activities,the frequency with which they will be performed,and the title of the local community official who will be responsible for ensuring that the maintenance activities are accomplished. • FEMA's fee schedule for reviewing and processing requests for conditional and final modifications to published flood information and maps may be accessed at http://www.fema.gov/plan/prevent/fhm/frm_fees.shtm. The fee at the time of the map revision submittal must be received before we can begin processing the request. Payment of this fee can be made through a check or money order,made payable in U.S.funds to the National Flood Insurance Program,or by credit card(Visa or MasterCard only). Please forward the payment,along with the revision application,to the following address: LOMC Clearinghouse 847 South Pickett Street Alexandria,Virginia 22304-4605 After receiving appropriate documentation to show that the project has been completed,FEMA will initiate a revision to the FIRM and FIS report. Because the flood hazard information(i.e.,base flood elevations,base flood depths,SFHAs,zone designations,and/or regulatory floodways)will change as a result of the project,a 90-day appeal period will be initiated for the revision,during which community officials and interested persons may appeal the revised flood hazard information based on scientific or technical data. This comment is based on the flood data presently available. If you have any questions about this document,please contact the FEMA Map Information exchange(FMIX)toll free at 1-877-336-2627(1-877-FEMA MAP)or by letter addressed to the LOMC Clearinghouse,847 South Pickett Street,Alexandria,VA 22304-4605. Additional Information about the NFIP is available on the FEMA Web site at http://www.fema.gov/business/nfip. Stuart W.Rooney,CFM,PMP,Program Specialist Engineering Management Branch Federal Insurance and Mitigation Administration 12-06-3818R 104 Page 5 of 5 Issue Date: November 21,2012 Case No.: 12-06-3818R CLOMR-APP N"' Federal Emergency Management Agency Washington, D.C. 20472 641VD SEC' CONDITIONAL LETTER OF MAP REVISION COMMENT DOCUMENT (CONTINUED) COMMUNITY INFORMATION (CONTINUED) COMMUNITY REMINDERS We have designated a Consultation Coordination Officer(CCO)to assist your community. The CCO will be the primary liaison between your community and FEMA. For information regarding your CCO,please contact: Mr.Frank Pagano Director,Mitigation Division Federal Emergency Management Agency,Region VI Federal Regional Center,Room 206 800 North Loop 288 Denton,TX 76209 (940)898-5127 A preliminary study is being conducted for Dallas County,Texas and Incorporated Areas. Preliminary copies of the revised FIRM and FIS report were submitted to your community for review on September 28,2010,and may become effective before the revision request following this CLOMR is submitted. Please ensure that the data submitted for the revision ties-in to the data effective at the time of the submittal. This comment is based on the flood data presently available. If you have any questions about this document,please contact the FEMA Map Information eXchange(FMIX) toll free at 1-877-336-2627(1-877-FEMA MAP)or by letter addressed to the LOMC Clearinghouse,847 South Pickett Street,Alexandria,VA 22304-4605. Additional Information about the NFIP is available on the FEMA Web site at http://www.fema.gov/business/nfip. -1A P7 Stuart W.Rooney,CFM,PMP,Program Specialist Engineering Management Branch Federal Insurance and Mitigation Administration 12-06-3818R 104