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<br />
<br />Federal Emergency Management Agency
<br />Washington, D.C, 20472
<br />
<br />CERTIFIED MAIL
<br />RETURN RECEIPT REQUESTED
<br />
<br />IN REPLY REFER TO:
<br />Case No,: 95-08-227P
<br />
<br />The Honorable Marsha Osborn
<br />Chairperson, Summit County
<br />Board of Commissioners
<br />P,O, Box 68
<br />Breckenridge, Colorado 80424
<br />
<br />Community: Summit County, Colorado
<br />Community No,: 080290
<br />Panels Affected: 0119 C, 0182 C, and 0010
<br />Effective Date of
<br />This Revision: FE B 0 8 1996
<br />
<br />102-I-A-C
<br />
<br />Dear Ms, Osborn:
<br />
<br />This is in response to a request for a revision to the effective Flood Insurance Study (FIS) and National
<br />Flood Insurance Program (NFIP) map for your community, Specifically, this responds to a letter dated
<br />January 19, 1996, from Mr. Gray Pearson, p, E,. Pearson Engineering, Inc" regarding the effective FIS
<br />report, Flood Insurance Rate Map (FIRM), and Flood Boundary and Floodway Map (FBFM) for the
<br />unincorporated areas of Summit County, Colorado, With his letter, Mr. Pearson provided additional
<br />information to support his July 18, 1995, request for a Letter of Map Revision (LOMR), Mr, Pearson
<br />requested that the Federal Emergency Management Agency (FEMA) revise the effective FIRM and FBFM
<br />to incorporate the results of a hydraulic analysis of the Blue River based on more detailed topographic
<br />data from approximately 350 feet downstream of Swan Mountain Road to approximately 2,200 feet
<br />upstream of Swan Mountain Road,
<br />
<br />All data required to complete our review of this request were submitted with Mr, Pearson's letters dated
<br />July 18, September 21, and December 6, 1995, and January 2 and January 19, 1996, and with letters
<br />dated October 4 and December 8, 1995. from Mr. James C. y, Guo, Ph,D., P,E.. Storm Water
<br />Computer Software Library, Inc. Because this LOMR solely incorporates more detailed information, fees
<br />were not assessed for the review,
<br />
<br />We have completed our review of the submitted data and the flood data shown on the effective FIRM and
<br />FBFM, and have revised the FIRM and FBFM to modify the elevations and floodplain and floodway
<br />boundary delineations of a flood having a I-percent chance of being equaled or exceeded in any given year
<br />(base flood) along the Blue River from approximately 350 feet downstream of Swan Mountain Road to
<br />approximately 2,200 feet upstream of Swan Mountain Road,
<br />
<br />The revised Special Flood Hazard Area (SFHA), floodway boundary delineation, and base flood elevations
<br />(BFEs) are the result of a hydraulic analysis that incorporates more detailed topographic data, The SFHA
<br />width and BFEs increased and decreased, and the floodway width decreased along the revised reach, The
<br />maximum decrease in SFHA width, approximately ISO feet, occurs approximately 500 feet upstream of
<br />Swan Mountain Road. The revised hydraulic analysis shows a backwater area just upstream of Swan
<br />Mountain Road, A new SFHA, Zone AH, an area of shallow base flooding with average water-surface
<br />elevations between 1 foot and 3 feet, was added to the FIRM and FBFM because of this backwater area.
<br />The backwater area also causes the maximum increase in the SFHA width of approximately 400 feet.
<br />
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