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4.0 FLOOD PLAIN MANAGEMENT APPLICATIONS The NFIP encourages State and local governments to adopt sound floodplain management programs. Therefore, each FIS provides I-percent annual chance flood elevations and delineations of the 1- and 0.2-percent annual chance floodplain boundaries and I-percent annual chance floodway to assist communities in developing floodplain management measures. This information is presented on the FIRM and in many components of the PIS report, including Flood Profiles and Ploodway Data Table. Users should reference the data presented in the FIS report as well as additional information that may be available at the local map repository before making flood elevation and/or floodplain boundary determinations. 4.1 Flood Boundaries To provide a national standard without regional discrimination, the I-percent annual chance flood has been adopted by FEMA as the base flood for floodplain management purposes. The 0.2-percent annual chance flood is employed to indicate additional areas of flood risk in the community. For each stream studied by detailed methods, the 1- and 0.2- percent annual chance floodplain boundaries have been delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic maps at scales of 1 :2,400, 1: 1 ,200, and 1 :6,000, with contour intervals of 2 and 4 feet (References 19, 20, 21, 23, 24, 25, 26, and 29). For the Big Thompson River near Loveland, the 1- and 0.2-percent annual chance floodplain boundaries have been delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic maps prepared in August 2004 at a scale of 1 :2,400 and with a contour interval of 2 feet. For Dry Creek - BTR, the 1- and 0.2-percent annual chance floodplain boundaries have been delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic maps prepared in August 2004 at a scale of 1 :2,400 and with a contour interval of 2 feet. The Ayres topography was supplemented by ground survey. For the Big Thompson River near Johnstown, the 1- and 0.2-percent annual chance floodplain boundaries have been delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic maps. For Dry Creek in Fort Collins, the 1- and 0.2-percent annual chance floodplain boundaries have been delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were interpolated using topographic maps at a scale of 1 :4,800, with 2-foot contour intervals. 40