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USGS Water-Year Summary 2024
09421000 Lake Mead At Hoover Dam, AZ-NV
LOCATION - Lat 36°00'58", long 114°44'13" referenced to North American Datum of 1927, Clark County, NV, Hydrologic Unit 15010005, in center of Hoover Dam on Colorado River.
DRAINAGE AREA - 171,700 mi². including 3,959 mi² in Great Divide basin in southern Wyoming, which is noncontributing (previously considered part of the Missouri River basin).
REVISIONS HISTORY - WSP 899: 1935-39.
SURFACE-WATER RECORDS
PERIOD OF RECORD - Contents: Feb. 1935 to current year. Diversions (monthly totals only): to Boulder City area, since Oct. 1935; to Henderson and Las Vegas areas, since Apr. 1942; combined diversions since Oct. 1968. Prior to 1946 published as "at Boulder Dam."
GAGE - Water-stage recorder read once daily at midnight, with supplementary water-stage indicator. Datum of gage is 0.00 ft to Local Powerhouse datum.
COOPERATION - Records of gage height and contents furnished by Bureau of Reclamation. Records of diversions from Lake Mead furnished by Bureau of Reclamation and Colorado River Commission of Nevada.
REMARKS - Reservoir is formed by concrete arch-gravity dam; storage began Feb. 1, 1935; dam completed Mar. 1, 1936. Total capacity (based on 2001 bathymetric survey and 2009 light detection and ranging survey by the Bureau of Reclamation; capacity table put into use Jan. 1, 2012), 30,167,000 acre-ft, consisting of the following: Dead storage, 2,547,000 acre-ft below gage height 895.0 ft--gate sills in outlet towers; usable contents, 27,620,000 acre-ft (maximum water surface). Reservoir is used to store water for flood control, irrigation, municipal water supply, power development, and recreation. Figures given herein represent usable contents.
DIVERSIONS FROM LAKE MEAD: Diversions to Boulder City area at dam; diversions to Henderson and Las Vegas areas from intakes 6 mi upstream. Diversions measured by Venturi meters. Water used for municipal and industrial purposes.
EXTREMES FOR PERIOD OF RECORD - Maximum contents, 27,790,000 acre-ft, Jul. 29, 30, 1941 (on basis of original bathymetry), gage height, 1,220.45 ft; maximum gage height, 1,225.85 ft, Jul. 24, 1983 (equivalent to 26,868,000 acre-ft on basis of resurveyed bathymetry of 1963-64); minimum contents (since 1940), 9,577,000 acre-ft, Jun. 26, 2015, gage height, 1,074.71 ft.
