Laserfiche WebLink
<br />All elevations are referenced to the National Geodetic Vertical <br />Datum of 1929 (NGVD). Elevation reference marks in the vicinity of <br />Estes Park are shown on the maps; other elevation mark data can be <br />obtained from the Larimer County Planning Commission. <br /> <br />4.0 <br /> <br />FLOOD PLAIN MANAGEMENT APPLICATIONS <br /> <br />. <br /> <br />The National Flood Insurance Program (NFIP) encourages State and local <br />governments to adopt sound flood plain management programs. Therefore, <br />each Flood Insurance Study produces maps designed to assist communities <br />in developing flood plain management measures, <br /> <br />4.1 Flood Boundaries <br /> <br />To provide a national standard without regional discrimination, the <br />1 percent annual chance (lOO-year) flood has been adopted by FEMA <br />as the base flood for flood plain management purposes. The 0.2 <br />percent annual chance (SOO-year) flood is employed to indicate <br />additional areas of flood risk in the community. For each stream <br />studied in detail, the 100- and SOO-year flood plain boundaries <br />have been delineated using the flood elevations determined at each <br />cross section. Between cross sections, the boundaries were <br />interpolated using topographic maps at scales of 1:2,400, 1:1,200, <br />and 1:6,000, with contour intervals of 2 and 4 feet (References 19, <br />20, 21, 23, 24, 25, 26, and 29). <br /> <br />On the Little Thompson River, approximate flood boundaries were <br />delineated using aerial photographs at a scale of 1:12,000 <br />(Reference 27). Approximate flood boundaries for the Cache La <br />Poudre River were delineated from two COE Flood Plain Information <br />reports (References 6 and 28). <br /> <br />Approximate flood boundaries for Boxelder Creek and Cooper Slough <br />in the vicinity east of the City of Fort Collins were delineated <br />using topographic maps at a scale of 1:1,200 with a contour <br />interval of 2 feet (Reference 30). <br /> <br />The 100- and SOO-year flood plain boundaries are shown on the Flood <br />Boundary and Floodway Map (Exhibit 2), In cases where the 100- and <br />SOO-year flood plain boundaries are close together, only the 100- <br />year flood plain boundary has been shown, Small areas within the <br />flood plain boundaries may lie above the flood elevations but <br />cannot be shown due to limitations of the map scale and/or lack of <br />detailed topographic data. <br /> <br />For the streams studied by approximate methods, only the 100-year <br />flood plain boundary 1S shown. <br /> <br />Approximate laO-year flood plain boundaries in some portions of the <br />study area were taken directly from the Flood Hazard Boundary Map <br />(Reference 31). <br /> <br />21 <br />