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.. Flood of Auaust 1933. The stonn of 2 and 3 August 1933 occurred over a 175 square mile area upstream from Franktown. Unofficial rainfall amounts varied from 3 to 9 inches and occurred over a 9-hour period between 6 p.m. on 2 August and 3 a.m. on 3 August. The most intense activtty of the stonn occurred between 9 p.m. and 10 p.m. Waters, in the then existing Castlewood Dam and Reservoir, reached the spillway crBst at about 11 p.m. The inflow was Bstimated at 35,000 cubic feet per second. Water overtopped the crest of the dam and the structure failed at about midnight. The sudden release of water caused a flood wave to move down the valley. The peak discharge is estimated to have ranged from 126,000 cubic feet per sBcond downstream from the dam to about 16,500 cubic feet per second near the South Platte River. The Cherry CreBk Flood Commission estimated the damages to be about $1,000,000; approximately $200,000 of this total occurred upstream from Denver. This flood cauSBd addttional economic effects in the Cherry Creek basin. Loss of the dam cut off water supplies to about 3,000 acres of land. The basin suffered a severe recession and many families moved from the area. , Flood of Auaust 1945. A large stonn mass moved into southeastern Colorado on 5 August 1945 and extended over the Cherry Creek basin. Unofficial rainfall amounts varied from 2 to 5 inches. Severe flooding occurred along ChBrry Creek in the Franktown - Parker area. The gaging station at Melvin recorded a peak discharge of 10,700 cubic feet per second. Total damages were estimated to be $200,000. Flood of June 1965. On 16 June 1965, a major storm centered over the Plum Creek and Cherry Creek basins. Rainfall amounts, reported by unofficial sources, ranged up to 10 inches. Most of the rainfall occurred wtthin a 3-hour period. Peak discharges along Cherry Creek were 1,000 cubic feet per second upstream from Franktown, 39,900 cubic feet per second near Melvin, and 58,000 cubic feet per second at Cherry Creek dame An estimated peak flow of 14,100 cubic feet per second discharged from Piney Creek, a right- bank tributary of Cherry Creek. During the evening and night of 16 June, the Cherry Creek reservoir impounded a flood which had a volume of 16,000 acre-feet. Of the 18 small dams constructed by the Soil Conservation Service in the upper Cherry Creek basin between Franktown and Parker, 3 were filled. Two of these were subsequently overtopped and sustained erosion damage. The remaining 15 structures were outside of the area of high intenstty rainfall and received only moderate runoff. The heavy runoff caused major flooding along the main stem of Cherry Creek from the vicinity of Franktown to the Cherry Creek reservoir. About 2,720 acres were flooded. Most of the bridges across Cherry Creek were etther damaged or destroyed. one life was lost during the flood on Cherry Creek. Flood damages totaled $1,306,000. 4.1.6 SAND CREEK BASIN . Flood Historv. Available data indicate that major flood events in the Sand Creek basin are caused by runoff from intense thunderstonn-type rainfall. Nine major floods have occurred in the Sand and Toll Gate Creek basins since 1896. No flood discharges are available for floods in 1896. 1912, 1917, 1921, 1933. and 1938. The other events are listed below. .. Colorado Flood Hydrology Manual 4.9 [PACT