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Blackberry Farm-CS250613LOMC Clearinghouse, 3601 Eisenhower Avenue, Suite 500, Alexandria, VA 22304-6426 / PH: 1-877-FEMA MAP Compass, under contract with the Federal Emergency Management Agency, is a Production and Technical Services provider for the National Flood Insurance Program June 13, 2025 Jim O'Brien, P.E. O'Brien Engineering, Inc. 17300 Dallas Parkway, Suite 1000 Dallas, TX 75248 IN REPLY REFER TO: Case No.: 25-06-1267P Communities: Cities of Carrollton and Coppell, Texas Community Nos.: 480167, 480170 316-AD Dear Jim O'Brien: This is regarding your request received March 19, 2025, that the Department of Homeland Security’s Federal Emergency Management Agency (FEMA) issue a revision to the Flood Insurance Rate Map (FIRM) for Dallas County, Texas, and Incorporated Areas. Pertinent information about the request is listed below. Identifier:Blackberry Farms Flooding Sources:Elm Fork of Trinity River, Denton Creek FIRM Panels Affected:48113C0155K, 48113C0155K The data required to complete our review, which must be submitted within 90 days of the date of this letter, are listed on the attached summary. If we do not receive the required data within 90 days, we will suspend our processing of your request. Any data submitted after 90 days will be treated as an original submittal and will be subject to all submittal/payment procedures, including the flat review and processing fee for requests of this type established by the current fee schedule. A copy of the fee schedule is available for your information on the FEMA website at https://www.fema.gov/flood-maps/change-your-flood-zone/status/flood-map- related-fees. FEMA receives a very large volume of requests and cannot maintain inactive requests for an indefinite period of time. Therefore, we are unable to grant extensions for the submission of required data for revision requests. If a requester is informed by letter that additional data are required to complete our review of a request, the data must be submitted within 90 days of the date of the letter. Any fees already paid will be forfeited if the requested data are not received within 90 days. Page 2 of 2 316-AD Case No.: 25-06-1267PThis is regarding your request received March 19, 2025, that the Department of Homeland Security’s Federal Emergency Manageme If you have general questions about your request, FEMA policy, or the National Flood Insurance Program, please contact the FEMA Mapping and Insurance eXchange (FMIX), toll free, at 1-877-FEMA MAP (1-877-336-2627). If you have specific questions concerning your request, please contact your case reviewer, Alberto Bravo, E.I.T., CFM, by e-mail at alberto.bravo@aecom.com or by telephone at (972) 729-5862, or the Revisions Coordinator for your State, Sushban Shrestha, P.E., CFM, at sushban.shrestha@aecom.com or at (682) 316-7670. Sincerely, Benjamin Kaiser, P.E., CFM Revisions Manager Compass PTS JV Attachments: Summary of Additional Data Legal Notice Templates cc:Michael Garza Director of Engineering and Public Works City of Coppell Matt Brennan Civil Engineering Manager City of Carrollton LOMC Clearinghouse, 3601 Eisenhower Avenue, Suite 500, Alexandria, VA 22304-6426 / PH: 1-877-FEMA MAP Compass, under contract with the Federal Emergency Management Agency, is a Production and Technical Services provider for the National Flood Insurance Program Summary of Additional Data Required to Support a Letter of Map Revision (LOMR) Case No.: 25-06-1267P Requester: Jim O'Brien, P.E. Communities: Cities of Carrollton and Coppell, Texas Community Nos.: 480167, 480170 The issues listed below must be addressed before we can continue the review of your request. 1.Our review revealed that the City of Carrollton is affected by this revision. Please submit a copy of MT-2 Form 1, entitled “Overview and Concurrence Form,” that has been signed by an official of City of Carrollton, preferably the Floodplain Administrator. The MT-2 instructions are available for your information on the FEMA website at https://www.fema.gov/flood-maps/change-your-flood- zone/paper-application-forms/mt-2. Acceptable documentation includes a current corporate limits map provided by the community along with an annexation agreement, if applicable 2.Our review revealed that effective LOMR Case No. 21-06-1452P is located in the same vicinity as your submittal. Please obtain the model from LOMR Case No. 21-06-1452P from the FEMA Engineering Library and use this model as a base for your revised model. Please do not truncate the model. To request information from the FEMA Engineering Library, visit the website https://www.fema.gov/sites/default/files/documents/fema_flood-insurance-study-data-request- form.pdf and following the directions. Please note that the copy of the effective model that you receive from the Engineering Library is considered to be the duplicate effective model. 3.Our review revealed that a duplicate effective hydraulic model for Denton Creek was not included in the submittal. Please request the effective model from the FEMA Engineering Library by visiting the website https://www.fema.gov/sites/default/files/documents/fema_flood-insurance-study-data- request-form.pdf and following the directions. The copy of the effective model that you receive from the Engineering Library is considered to be the duplicate effective model. If this model is an executable HEC-RAS model, then please use it as a base for your revised model. Only modify the effective model within your revised area and do not truncate the model. If the effective model is not executable, then please truncate your revised model to only include cross sections within your revised area. The effective known water surface elevations (WSELs) at the location of your downstream cross section should be used as the downstream boundary condition and the upstream cross section in your revised model should be at the upstream end of your revised area where vertical tie-in to the effective 1-percent-annual-chance (base) flood elevation (BFE) of within 0.5 foot, or within 0.0 feet if practical, is achieved. 4.Our review revealed discrepancies between the natural WSELs of the base flood calculated in the Post-Project conditions HEC-RAS multiple-profile hydraulic model and the natural base flood WSELs calculated in the Post-Project conditions HEC-RAS floodway hydraulic model. Please revise the above-referenced hydraulic models so that the natural base flood WSELs match in the multiple- profile and floodway models and submit digital copies of the input and output files for these model 5.The HEC-RAS output shows negative surcharge at Cross-Section 93141 of 0.08 feet. Please revise the floodway analysis to eliminate all surcharges less than 0.00 feet or explain why this is not necessary. Page 2 of 2 316-AD Case No.: 25-06-1267PThis is regarding your request received March 19, 2025, that the Department of Homeland Security’s Federal Emergency Manageme 6.Please submit a copy of the newspaper notice distributed by the Cities of Carrollton and Coppell stating their intent to revise the flood hazard information (i.e., revise or establish base flood elevations, the base flood floodplain and regulatory floodway) along Elm Fork of Trinity River and Denton Creek. The notification must be published in a printed newspaper and not in a digital only publication. Alternatively, please submit documentation that individual legal notices were sent to all the property owners affected by any changes in the flood hazard information. Documentation of legal notice may take the form of a signed copy of the letter sent and either a mailing list or certified mailing receipts. Individual notices that are not sent on community letterhead must also include certification from the community that all affected property owners have been notified of the floodway revision. The newspaper notice or the individual legal notices must include the extent of revision and contact information for any interested parties and must also mention the community’s intent to revise the regulatory floodway.Please submit a draft copy of the notification for verification of content, prior to publication or distribution. One of the attached templates may be used to prepare the draft notification. If you choose newspaper notification, please coordinate with the community’s Floodplain Administrator to ensure that the notification can be done through newspaper notice because the community’s preference may be to deliver the notifications via individual legal notices. Under the NFIP, it is the community’s responsibility to coordinate and inform their local constituents about the flood hazard changes so the delivery method should be the community’s choice. Please upload the required data using the Online LOMC website at https://hazards.fema.gov/femaportal/onlinelomc/signin. For identification purposes, please include the case number referenced above on all correspondence. .