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<br />CHANGES ARE MADE IN DETERMINATIONS OF BASE FLOOD ELEVATIONS FOR THE CITY <br />OF BLACK HAWK, GILPIN COUNTY, COLORADO, UNDER THE NATIONAL FLOOD <br />INSURANCE PROGRAM <br /> <br />On October 16,1984, the Department of Homeland Security's Federal Emergency Management Agency <br />identified Special Flood Hazard Areas (SFHAs) in the City of Black Hawk, Gilpin County, Colorado, <br />through issuance of a Flood Insurance Rate Map (FIRM). The Mitigation Division has determined that <br />modification of the elevations of the flood having a I-percent chance of being equaled or exceeded in any <br />given year (base flood) for certain locations in this community is appropriate. The modified Base Flood <br />Elevations (BFEs) revise the FIRM for the community. <br /> <br />The changes are being made pursuant to Section 206 of the Flood Disaster Protection Act of 1973 (Public <br />Law 93-234) and are in accordance with the National Flood Insurance Act of 1968, as amended <br />(Title XIII of the Housing and Urban Development Act of 1968, Public Law 90-448), 42 U.S.C. <br />4001-4128, and 44 CFR Part 65. <br /> <br />A hydraulic analysis was performed to incorporate the effects of an updated hydrologic analysis and <br />updated topographic data for North Clear Creek from approximately 100 feet downstream to <br />approximately 6,500 feet upstream of Richman Street; for Chase Gulch from the confluence with North <br />Clear Creek to approximately 1,500 feet upstream; and for Gregory Gulch from the confluence with <br />North Clear Creek to approximately 2,200 feet upstream. This has resulted in increases and decreases in <br />SFHA width and increased and decreased BFEs for North Clear Creek, Gregory Gulch, and Chase Gulch. <br />The table below indicates existing and modified BFEs for selected locations along the affected lengths of <br />the flooding source(s) cited above. <br /> <br />Location <br /> <br />Existing BFE Modified BFE <br />(feet) * (feet) * <br />8,003 8,005 <br />None 8,202 <br />8,052 8,057 <br />8,150 8,153 <br /> <br />North Clear Creek: <br />Approximately 20 feet upstream of Richman Street <br />Approximately 2,510 feet upstream of Golden <br />Gilpin Gold Mill Bridge <br /> <br />Gregory Gulch: <br />Approximately 100 feet upstream of confluence with <br />North Clear Creek <br />Approximately 1,150 feet upstream of confluence with <br />North Clear Creek <br /> <br />Chase Gulch: <br />Approximately 250 feet upstream of confluence with <br />North Clear Creek <br />Approximately 1,450 feet upstream of confluence with <br />North Clear Creek <br /> <br />8,090 <br /> <br />8,089 <br /> <br />8,160 <br /> <br />8,161 <br /> <br />*National Geodetic Vertical Datum, rounded to nearest whole foot <br /> <br />Under the above-mentioned Acts of 1968 and 1973, the Mitigation Division must develop criteria for <br />floodplain management. To participate in the National Flood Insurance Program (NFIP), the community <br />must use the modified BFEs to administer the floodplain management measures of the NFIP. These <br />