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Creek B~~ass, would convey floodwater only during the SOD-year flood. For the SOG-year flood, the water-surface elevation would be high enough on Monument Creek to produce a peak discharge of 2,410 cfs in Monument Creek Bypass. This overflow enters Monument Creek Tributary at cross section B and then flows back into ~onu- ment Creek approximately 1,100 feet downstream of cross section A (Reference 3). Peak discharge-drainage area relationships for the streams studied in detail in El Paso County are shown in Table 1. 3.2 Hydraulic Analyses Analyses of the hydraulic characteristics of flooding from the sources studied were carried out to provide estiw~tes of the eleva- tions of floods of the selected recurrence i,ltervals. Water-surface elevations were developed with the COE HEC-2 water- surface profile computer program (Reference 19). Flood profiles were drawn showing computed water-surface elevations for the 10-, 50-, 100-, and SOD-year recurrence intervals. Hydraulic analyses were not carried out to provide water-surface elevations for the 10- and 50-year recurrence intervals for Dry Creek and its tributaries. Cross sections for the backwater analyses of the streams studied in detail were obtained from aerial topographic mapping compiled between 1972 and 1983 (References 20, 21, 22, 23, 24, 25, and 26). Fountain ~reek cross sections were obtained from maps compiled by Bohannan and Huston, Inc., in 1972 (Reference 20), as well as from ae:ial topographic mapping compiled by Hogan and Olhausen, Inc., in 1975 (Reference 21). Cross sections for Jiw~y Camp Creek and its tributaries were co~piled from aerial photographs taken by the SCS in 1973 (~eference 22). Cross sections for Sand Creek were obtained from aerial topographic maps prepared by the SCS in 1972 (Reference 23), with cross sections of Sand Creek East Fork, Sand Creek Center Tributary, Sand Creek East Fork Subtributary, and portions of Sand Creek being obtained from aerial topographic ~aps compiled by Landmark Mapping in i981 (Reference 24). Cross sec- tions for Cottonwood Creek above Woodman Road were obtained from topographic ffiaps prepared by the COE in 1975 {Reference 25). Cross 3ections for ~onunent Creek below the U.S. Air Force Academy were ob~ained from topograpr.ic maps prepared by Sogan and 01hausen, Inc., in 1975 (Reference 21). Cross sections for Upper Fountain Creek, Security Creek, Widefield Creek, and Wind~ill Gulch were compiled from aerial topographic mapping prepared for the COE by v~, Inc., in 1976 (Reference 26). 17