FLOOD06011 - Laserfiche WebLink

Home Browse Search

. . . . 2 We reviewed the submitted data and the data used to prepare the effective FIRM for your community and determined that the proposed project meets the minimum floodplain management criteria of the NFIP. The submitted existing conditions HEC-RAS hydraulic computer model, dated January 11,2001, based on updated hydrologic watershed conditions, 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 submitted topographic work map entitled "McKay Lake Channel CLOMR 100-year Floodplain (figures 5 and 6)" and on the "McKay Lake Channel100-year Water Surface Profile (figure 4)," both prepared by Kiowa Engineering Corporation and dated December 26,2000, and the data listed below are received, a revision to the FIRM would be warranted. The proposed project conditions HEC-RAS model incorporates reduced peak flows based on the construction of McKay Lake Regional Detention Facility and channelization of McKay Lake Drainageway from just upstream to approximately 5,500 feet upstream ofI-25. The proposed relocated and channelized portion of McKay Lake Drainageway WIll contain the base flood from approximately 500 feet upstream to approximately 5,500 feet upstream ofI-25. As a result of the proposed project, the entire SFHA will be removed along the existing McKay Lake Drainageway. Upon completion of the project, your community may submit the data listed below and request that we make a final determination on revising the effective FIRM. . Our review of the proposed conditions HEC-RAS hydraulic model revealed that the 16-foot by 5-foot RCB at Bull Canal and the three 72-inch-diameter RCPs for the 1-25 crossings were not included in the model. Please include these structures in the as-built hydraulic model, or provide an explanation for why these culverts were not analyzed. . In May 1999, FEMA formalized a Cooperating Technical Partner (CTP) agreement with the Urban Drainage and Flood Control District (UDFCD) to coordinate flood hazard mapping efforts within UDFCD. The agreement will work in conjunction with UDFCD's Flood Hazard Area Delineation and Maintenance Eligibility Programs. Because your community is served by UDFCD, please submit an acknowledgement letter from UDFCD stating that they have been officially notified of this revision request. In addition, if this project is a part ofUDFCD's Maintenance Eligibility Program, the letter must state that the project has been completed in accordance with UDFCD's program requirements. Mr. Bill DeGroot, P.E., Chief, Floodplain Management Program, UDFCD, is the CTP Coordinator for the agreement and can be reached at (303) 455-6277 for further information regarding this requirement. . 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, Form I, entitled "Revision Requester and Community Official Form," must be included. (A copy of this form is enclosed.) . The detailed application and certification forms listed below may be required if as-built conditions differ from the preliminary plans. If required, please submit new forms (copies of which are enclosed) or annotated copies of the previously submitted forms showing the revised information. Form 3, entitled "Hydrologic Analysis Form" . Form 4, entitled "Riverine Hydraulic Analysis Form"