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CHANGES ARE MADE IN DETERMINATIONS OF BASE FLOOD ELEVATIONS FOR TIIE CITY OF BOULDER AND UNINCORPORATED AREAS OF BOULDER COUNTY, COLORADO, UNDER THE NATIONAL FLOOD INSURANCE PROGRAM ' On June 2, 1995, the Department of Homeland Security's Federal Emergency Management Agency identified Special Flood Hazard Areas (SFHAs) in the City of Boulder and in unincorporated areas of Bo:ulder County, Colorado, through issuance of a Flood Insurance Rate Map (FIRM). The Mitigation Division has determined that modification of the elevations of the flood having a I-percent chance of being equaled or exceeded in any given year (base flood) for certain locations in these communities is appropriate. The modified Base Flood Elevations (BFEs) revise the FIRM for the communities. The changes are being made pursuant to Section 206 of the Flood Disaster Protection Act of 1973 (Public Law 93-234) and are in accordance with the National Flood Insurance Act of 1968, as amended (Title xm of the Housing and Urban Development Act of 1968, Public Law 90-448), 42 U.S.C. 4001-4128, and 44 CFRPart 65. A hydraulic analysis was performed on portions of Fourmile Canyon and Wonderland Creeks and has resulted in a revised delineation of the regulatory floodway, increases and decreases in SFHA width, and increased and decreased BFEs for Fourmile Canyon Creek, Wonderland Creek, Fourmile Canyon Creek (Left Bank Overflow), and Fourmile Canyon Creek (Right Bank Overflow). The table below indicates existing and modified BFEs for selected locations along the affected lengths of the flooding source(s) cited above. Location Existing BFE Modified BFE (feet) * (feet) * 5,668 5,657 5,425 5,429 5,344 5,331 5,373 5,382 None 5,173 Founnile Canyon Creek: Approximately 4,470 feet upstream of Broadway Street Approximately 910 feet downstream of 19th Street Wonderland Creek: Approximately 90 feet upstream of Kalima Avenue Just downstream of 26th Street Founnile Canyon Creek (Left Bank Overflow): Approximately 2,900 feet upstream of confluence with Boulder Creek Fourmile Canyon Creek (Right Bank Overflow): Approximately 1,880 feet upstream of confluence with Wonderland Creek None 5,497 *National Geodetic Vertical Datum, rounded to nearest whole foot Under the above-mentioned Acts of 1968 and 1973, the Mitigation Division must develop criteria for floodplain management. To participate in the National Flood Insurance Program (NFIP), the community must use the modified BFEs to administer the floodplain management measures of the NFIP. These modified BFEs will also be used to calculate the appropriate flood insurance premium rates for new buildings and their contents and for the second layer of insurance on existing buildings and contents.