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I. Project description. The project was authorized for construction by the'Flood Control Act of 1968, substantially in accordance vi th the recommendations of the Chief of Engineers in Senate Document Number 81, Ninetieth Congress. The project would consist of construction of a lake on Bear Creek for the purposes of flood control, general recreation and fish and wildlife enhancement. The dam would be a rolled earthfill structure wi th a mul tiple- level outlet works. It would be located on Bear Creek about 2 1/2 miles downstream from Morrison, Colorado just below the Turkey Creek confluence. The valley closure would consist of two parts, a main embankment 143.1 feet high with a 4,100 foot crest, and a supplementary embankment to the south 33.1 feet high with a 2,100 foot crest. The right abutment of the main embankment and the left abutment of the supplementary embankment would tie in to Mt. Carbon, an alluvial deposit rising some 225 feet above the right bank of Bear Creak. The lake created by the embankments would contain a sediment/multiple- purpose pool of 2,400 acre-feet capacity with a surface area of 130 acres. Total shore line distance of this pool would be about 2.5 miles. The flood control pool of 26,000 acre-feet capacity would cover 620 acres. The reservoir would be equipped with a grassed earthen and rock cut ungated emergency spillway having a 500 foot crest width. Features of the authorized project are shown on the inclosed plates No. 1 and 2. The project is presently in the preconstruction planning stage. The current benefit-cost ratio for the project is 2.7 to 1 based on a 3.25 percent interest rate. II. Environmental settiOK without the project. Bear Creek, a left bank tributary of the South Platte River, empties into the South Platte River near Sheridan, Colorado. The creek drains a total of 261 square miles. About 90 percent of its basin is located in the Rocky Mountain range west of Denver; the remaining 10 percent of the basin is composed of high plains and rolling foothills. Bear Creek basin shares its boundary with the Clear Creek basin to the north and west, the North Fork of the South Platte River basin to the south and west, and numerous small tributary basins near the mouth. The basin is approximately 36 miles long and has a maximum width of about 13, miles. See plate No.1. Streamflow originates near Summit Lake on the Mount Evans plateau. As the stream flows eastward through the Arapahoe National Forest, it picks up contributions from numerous small tributaries. At Morrison the creek breaks out of the confinement of the canyon and flows through the foothills region. About two miles downstream from Morrison, Bear Creek is joined by the 52 square mile Turkey Creek drainage, the only major tributary in the' Bear Creek basin.