UNITED STATES DEPARTMENT OF THE INTERIOR BUREAU OF RECLAMATION Wilbur A. Dexheimer, Commissioner L. N. McClellan, Assistant Commissioner and Chief Engineer TECHNICAL RECORD OF DESIGN AND CONSTRUCTION O'SULLIVAN DAM Constructed 1947-1949 Columbia Basin Project Denver, Colorado 1954 Engl. Library TC 558 .07 08 458 General Information Dam O'SULLIVAN DAM Purpose: Irrigation and catchment basin for return flow and waste water from irri- Location: On lower Crab Creek, about 22 miles south and 12 miles east of Ephrata, Constructed: 1947-1949 Water supply: Lower Crab Creek at certain times of year fed completely by return flow and waste water from irrigated lands in drainage area. Drainage area: 4,000 square miles Maximum flood: 3,000 cubic feet per second (1943) Reservoir: Area: 32,000 acres Total storage: 675,000 acre-feet at elevation 1052.0 (spillway crest) Maximum water surface: El. 1055.0 Minimum water surface: El. 940.0 Type: Zoned rolled-earth fill Foundation: Basalt, varying from dense to crushed and sheared types Height: 160 feet above streambed, 225 feet above excavation at deepest point Crest elevation: 1061.0 Volume: 8, 770, 000 cubic yards Slopes: Upstream, 4 to 1 to elevation 960, 3 to 1 to elevation 1047.5, then 2-1/2 to 1 to elevation 1061 Downstream, 2 to 1 to elevation 930, 4 to 1 to elevation 960, then 2 to 1 to elevation 1061 Cutoff trench: 15-foot bottom width from elevation 1060 to elevation 1045; from elevation 1045 to elevation 1010 the trench was widened 1 foot for each foot the bottom of the trench was below elevation 1045 and from elevation 1010 down the width remained 50 feet; side slopes of trench 1-1/2 to 1 Spillway and Outlet Works Type of spillway: Overflow open channel, concrete crest width, 500 feet Maximum discharge: Spillway, 7,500 cubic feet per second at maximum water surface Outlets: 4- by 4-foot gate, 1, 150 cubic feet per second; 18inch gate, 67 cubic feet per second |