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XI-5 Channel Design; Sand Creek to Baseline Road. For planning and design of the South Platte River in Adams County (Sand Creek to Baseline Road) the following channel design criteria shall be used: e) Floodplain management programs prepared and adopted for the frequent floods with appropriate consideration of the potential for larger floods which are in excess of 100-year event. Design Parameter Bottom width Normal depth Ch anne 1 depth Manning n Side slope of banks Slope of river bed between drops Radius of curvature Degree of curvature Length of crossing 100-Year Event 300 feet 12.5 feet 14 feet 0.035 4:1 7 feet per mil e 10-Year Event 250 feet 8.1 feet 9 feet 0.035 4: 1 7 feet per mi 1 e REFERENCES - SECTION XI Adams County, Colorado, "Subdivision Regulations, Section 6." 400 to 1,500 feet 55 to 75 degrees 400 to 700 feet 400 to 1,500 feet 55 to 75 degrees 400 to 700 feet Denver Regional Council of Governments, "Urban Storm Drainage Criteria Man- u a 1, Vo 1 urnes I and II," March 1969. New Gravel Pits. Future gravel mining in the South Platte River corridor has been determined to have a long-term impact on the geomorphology, hydrau- lics, stability, meandering, water quality, and sediment characteristics of the South Platte River. Engineering criteria for the design and construc- t i on for new gravel pits wi 11 be developed separate ly duri ng the course of thi s study. Gingery Associates, Inc., "Flood Hazard Area Delineation, South Platte River, Adams County," September 1977. Merrick & Company, "South Platte River Hydrologic Study, Chatfield Dam to Sand Creek," May 1983. Simons, Li and Associates, "Design Guidelines and Criteria, Channels and Hydraul ic Structures on Sandy Soil," June 1981. Criteria for Non-Structural Methods. The following measures may be consid- ered in managing flood damages by other than structural means. Stevens, Michael A., "Final Report, Stream Stability Investigation, South Platte River, Chatfield Dam to Baseline Road," November 1983. a) Floodproofing of commercial and industrial structures. (Considered in both structural and non-structural methods.) U.S. Army Corps of Engineers, Hydrologic Engineering Center," HEC-2, Water Surface Profiles, Users Manual," September 1982. b) Early warning systems in conjunction with emergency plans. c) Flood insurance for flood prone properties. U.S. Department of Housing and Urban Development, Flood Insurance Adminis- tration, "Flood Insurance Study, Adams County, Colorado," August 1978. d) Reconstruction plans for land purchase and post-disaster plans.