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percent of the basin is in the mountains with the remainder draining the foothills and high plains r~gion (Reference 1). The basin below Bear Creek Dam lis rapidly approaching a full devel- opment condition with the exception of the Bear Valley Park and areas near South Kipling Street. The lower basin is characterized by dense mobile home parks with the remainder of the basin generally in single family residences. There are some commercial areas located along South Federal Boulevard, and outside of Sheridan's corporate limits along South Sheridan and South Wadsworth Boulevards, most notably the Bear Valley S~opping Center near the intersection of West Hampden Avenue and South Wadsworth Boulevard. Bear Creek, in its lower reach~s, has been altered in the past by channel modifications, such ;as straightening and enlargement. The channel averages approximately 80 feet wide and slopes are 5.3 feet per 1,000 feet. Upstream from South Wadsworth Boulevard, the stream is generally in its natural state and averages approxi- mately 80 feet wide, with sloPes approximately 7.2 feet per 1,000 feet. 2.3 principal Flood Problems Historic flooding in Sheridan has usually been caused by intense rainstorms in summer. However, high flows have also occurred from snowmelt runoff combined with rain. Large floods in the Bear Creek :basin occurred in July 1933 with a discharge of 3,000 cubic feet per second (cfs) at Sheridan, in August 1934 (1,300 cfs) , in [September 1938 (2,810 cfs) , in August 1957 (2,560 cfs) , in Ju~y 1965. (2,900 cfs), and in May 1969 (8,150 cfs). Floods' of'wbich little information is .available occurred in May 1876, June 1894, and july 1896. The peak discharge for the 1896 flood was estimat~d to be 8,600 cfs at the Morrison gage, approximately 2 miles upstream of the study reach. High, sustained flows through the st4dy reach on May 9, 1957, caused severe bank erosion and damage ito a bridge under construction at South Wadsworth Avenue as w~ll as to residential lots abutting the stream. Minor flooding ocqurred in the study reach on July 23 and 24, 1965; 25 families were ievacuated, 15 basements and a tourist court were flooded, and severa~ bridges were damaged. Heavy rains from May 4 through 8, 1969, wi~h a total storm rainfall of 11.27 inches at Morrison, caused the 'greatest flood of record in the study reach. Many people were ievacuated from houses and trailers near Bear Creek from South Lowell Boulevard to the mouth. Many homes sustained basement and first floor damage. The areas subject to flooding ~long the South Platte River are largely commercial and industr~al developments on the right bank. In 1965, the South Platte Riv~r did flood large areas within Sheridan. This was estimated ,by the U.S. :Geological Survey to be approximately a 500-year flood. 4