The 1963-64 Lake Mead Survey

The 1963-64 Lake Mead survey was run to compute the reservoir capacity. Results of the geodetic and hydrographic surveys and sediment sampling equipment are described. The geodetic survey showed Hoover Dam subsided an average of 118 mm since 1935. Sonic sounding, photogrammetry, and crosssectional profiling methods were used to run the hydrographic survey. Reservoir area and capacity tables were generated using an electronic computer. The present lake capacity is 29,755,000 acre-ft and the reservoir surface area is 162,700 acres at elevation 1229 ft. 2,720,000 acre-ft of sediments accumulated in the lake since 1935. A unit weight of 60 Ib/cu ft was determined representative of the deposited sediments. Samples were collected from the major basins with a piston core sampler. A gamma probe was used to measure in situ wet bulk densities. Special sampling with a drill rig was conducted in Pierce Basin representing the sediment accumulation in the delta area. The reservoir trap efficiency is judged to be 100%