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" , Federal Emergency Management Agency Washington, D.C. 20472 ., RECEIVED AUG 2 6 1996 I L-Li CERTIFIED MAIL Colorado Water Conservation Board RETURN RECEIPT REQUESTED IN REPLY REFER TO: Case No.: 96-08-29IP 11~1 The Honorable Jan C. Schenck Mayor, City of Golden City Hall 911 Tenth Street Golden, Colorado 80401 Community: City of Golden, Colorado Community No,: 080090 Panel Affected: 0004 A Effective Date of This Revision: AU G 20 1996 102-I-A-C Dear Mayor Schenck: This responds to a request for a revision to the effective Flood Insurance Study (FIS) and National Flood Insurance Program (NFIP) map for your community. Specifically, this responds to a letter dated March I, 1996, from Mr. Edgar B. Jennings, P .E., P .L.S., regarding the effective FIS report and Flood Insurance Rate Map (FIRM) for the City of Golden, Colorado. Mr. Jennings requested that the Federal Emergency Management Agency (FEMA) revise the effective FIRM to incorporate the results of a hydraulic analysis based on more detailed topographic information along West Fork Kenneys Run and to show the effects of fill in the flOOdplain and channel modifications. This request follows up on a Conditional Letter of Map Revision, which was issued on December 6, 1994. All data required to complete our review of this request were submitted with Mr. Jennings' March I letter. We have completed oUr review of the submitted data and the flood data shown on the effective FIRM, and have revised the FIRM to modify the elevations, floodplain boundary delineations, and zone designations of the flood having a I-percent chance of being equaled or exceeded in any given year (base flood) along West Fork Kenneys Run from approximately I ,350 feet downstream of We1ch Ditch to Illinois Street. The base flood elevations (BPEs) and the width of the Special Flood Hazard Area (SFHA), the area inundated by the base flood, decreased along some portions of the revised reach and increased along others. The maximum decrease in BFE, approximately I foot, occurred approximately 850 feet downstream ofWe1ch Ditch. The maximum increase in BPE, approximately 0.7 foot, occurred approximately 500 feet downstream , of Welch Ditch. The maximum decrease in SFHA width, approximately 400 feet, occurred approximately 250 feet downstream of Lost Dutchman Lane. The maximum increase in SFHA width, approximately 700 feet, occurred approximately 250 feet downstream of Welch Ditch. All increases in BFE or SFHA width are contained on property owned by the community, The maximum increases in BFE and SFHA are the result of using more detailed topographic information and making corrections to the hydraulic analysis used to develop the effective FIRM and are not the result of fill or channel modifications. The fill and channel modifications resulted in a maximum increase in BFE of approximately 0.3 foot.