Report Title: Fluvial sediment in Double Creek subwatershed No. 5, Washington County, Oklahoma
Most precipitation falling on subwatershed No. 5 does not flow through the reservoir. During this study approximately three-fourths (47,000 acre-feet) of the precipitation was lost by evaporation and transpiration; a small amount is lost by deep subsurface percolation.
Fifty-nine percent of the total sediment load was discharged from the reservoir during four major outflow periods representing 34 percent of the outflow days. The highest percentage of runoff and sediment yield occurs from March through June. Fifty-three percent of the water discharged and 63 percent of the sediment yield occurred during this 4-month period. The average annual yield of fluvial sediment from watershed No. 5 was 607 tons per square mile, or 0.95 ton per acre.
A total of 21,370 tons of fluvial sediment was transported into reservoir No. 5 and a total of 19,930 tons was deposited. Seventy-eight percent of the total fluvial sediment was deposited during the first 9.2 years, or 63 percent of time of reservoir operation. The computed trap efficiency of reservoir No. 5 was 93 percent.