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All elevations are referenced to the National Geodetic Vertical Datum of 1929 (NGVD). Elevation reference marks used in this study are shown on the maps; the descriptions of the w~rks are presented in Elevation Reference ~~rks (Exhibit 3). 4.0 FLOOD PLAIN ~mNAGEME~~ APPLICATIONS The NFIP encourages State and local governments to adopt sound flood plain management programs. Therefore, each Flood Insurance Study pro- vides 100-year flood elevations and delineations of the 100- and 500- year flood plain boundaries and 100-year floodway to assist communities in developing flood plain management measures. 4.1 Flood Boundaries To provide a national standard without regio.ial discrimination, the 1 percent annual chance (lOO-year) flood has been adopted by F~m as the base flood for flood plain management purposes. The 0.2 percent annual chance (SOD-year) flood is employed to indicate additional areas of flood risk in the community. For each stream studied in detail, the 100- and SOO-year flood plain boundaries have been delineated using the flood elevations determined at each cross section. Between cross sections, the boundaries were inter- polated using topographic maps as detailed below. Flood plain boundaries for Fountain Creek and for Ji~~y Camp Creek below cross section X were determined using topographic maps at a scale of 1:4,800 with a contour interval of 5 feet (Reference 20). Some ~ross sections for Fountain Creek, particularly those in and around the City af Colorado Springs, were determined using topo- graphic ~aps at a scale of 1:6,000 with a contour interval of 5 feet (Reference 2l}. Flood plain tQundaries for Jiw~y Camp Creek above cross section X and its tributaries were deter~ined from topographic maps at a scale of 1:2,400, with a contour interval of 2 fe~t \rteference 14}. Flood plain boundaries for Sand Creek above t~e Colorado Springs corporate limit were determined using topo- g~aphic ~aps at a scale of 1:2,400, with a contour interval of 4 feet (Reference 15). Flood plain boundaries for Cottonwood Creek above Wood~an Road were determined using topographic maps at a scale of 1:2,400, with a contour interval of 2 feet (Reference 25). Flood plain ~u~daries for ~onument Creek below the U.S. Air Force Acade~y wer~ deterrtoined using topographic maps at a scale of 1:6,000, with a co~tocr i~terval of 5 feet (Reference 21). Flood plain bou~daries were determined for U?per Fountain Creek, Security Creek, Widefield Creek, a~d ~indmil: Gulch using topogra?hic 8aps at a scale of 1:2,400, with a contour interval of 2 feet. Flood plain boundaries ~~=e determined for Cottonwood Creek below Woodman Road, Xon~ment Creek above ~~e ~.S. Air Force Academy, Peterson Field Drainase, Kettle Creek, Pine Creek, Sand Creek East Fork, Sand 19