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CHANGES ARE MADE IN DETERMINATIONS OF BASE FLOOD ELEVATIONS FOR THE UNINCORPORATED AREAS OF JEFFERSON COUNTY, COLORADO, UNDER THE NATIONAL FLOOD INSURANCE PROGRAM On August 5, 1986, the Federal Emergency Management Agency identified Special Flood Hazard Areas (SFHAs) in the unincorporated areas of Jefferson County, Colorado, through issuance of a Flood Insurance Rate Map (FIRM). The Mitigation Directorate 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 this community is appropriate. The modified Base Flood Elevations (BFEs) revise the FIRM for the community. 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 XIII of the Housing and Urban Development Act of 1968, Public Law 90-448), 42 U.S.C. 4001-4128, and 44 CFR Part 65. A hydraulic analysis was performed to incorporate updated topographic information along Lena Gulch from just upstream of Orion Street to just downstream of U.S. Highway 6 and has resulted in increases and decreases in SFHA width and increased and decreased BFEs for Lena Gulch. In the revised hydraulic analysis, floodwater breaks out from the main channel just upstream of E Street and flows northeast into the Lena Gulch Overflow Area. This area, which extends to approximately 1,600 feet downstream of U.S. Highway 6, has been designated Zone AH, an SFHA subject to shallow base flooding with depths between 1 foot and 3 feet and with BFEs determined. 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 (feet)* Modified BFE (feet)* Lena Gulch: Just upstream of Orion Street Approximately 1,400 feet downstream of U.S. Highway 6 Just downstream of U.S. Highway 6 5,814 5,886 5,924 5,814 5,884 5,925 Lena Gulch Overflow: Approximately 1,300 feet downstream of E Street 5,880 5,876 *National Geodetic Vertical Datum, rounded to nearest whole foot Under the above-mentioned Acts of 1968 and 1973, the Mitigation Directorate 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. Upon the second publication of notice of these changes in this newspaper, any person has 90 days in which he or she can request, through the Chief Executive Officer of the community, that the Mitigation Directorate reconsider the determination. Any request for reconsideration must be based on knowledge of changed conditions or new scientific or technical data. All interested parties are on notice that until the 90-day period elapses, the Mitigation Directorate's determination to modify the BFEs may itself be changed.