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. The COE, Omaha District, supplied base mapping, hydrologic input, and information on Chatfield Dam for the study reach of the South Platte River. In addition, conferences were held with the COE, Omaha District, on October l6, 1974, November 27, 1974, and March 2l, 1975. Of particular significance to this study was a COE floodplain information study of the Denver Metropolitan Region, dated October 1968 (Reference 24) and a Floodplain Information report prepared by the COE, dated July 1971 (Reference 25). . The U.S. Geological Survey (USGS) was contacted to obtain historical flow data (References 26, 27, and 28). Maps of flood-prone areas prepared by the USGS, showing approximate floodplain boundary delineations at a scale of 1:24,000, were also reviewed (Reference 29). At a meeting on August 16, 1974, attended by representatives of UDFCD, FIA, and Gingery Associates, Inc., the study reaches were clearly explained with the methodology to be used in the study. An additional meeting was held on January 24, 1975, to further clarify the purpose of the study and methods used for floodplain delineation. UDFCD supplied contour maps at2-foot intervals for Big Dry Creek, Sand Creek, and Coal Creek along with an interim report entitled Malor Drainagewav Master Plan--Big Drv Creek (Reference 30). Numerous other agencies and individuals were contacted for background information, including the Colorado Water Conservation Board (CWCB), which provided published rainfall-runoff data (Reference 31); Colorado Highway Department; Union Pacific Railroad; and U.S. Soil Conservation Service (SCS). Private citizens of Watkins, Strasburg, Byers, and Deer Trail were interviewed regarding past floods, high-water marks, and flood damage. Prior to the restudy, a meeting was held in early April 1984 with the Arapahoe County Engineering Department and UDFCD to define study reaches; however, no reaches were identified at this meeting. The study reaches were selected at a meeting in late April 1984 attended by the study contractor and FEMA. .. An intermediate community coordination meeting for the restudy was held in July 1985 and attended by the County, the study contractor and the FEMA representative to explain the reaches studied and the methods used. << UDFCD provided copies of previous master plans and flood hazard delineation maps that covered some of the stream reaches being studied. The County provided up-to-date road maps and corporate boundary maps. FEMA authorized a countywide restudy for Arapahoe County in December 1985. 3