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USGS Water-Year Summary 2024
09429490 COLORADO RIVER ABOVE IMPERIAL DAM, AZ-CA
LOCATION - Lat 32°53'05.77", long 114°28'05.20" referenced to North American Datum of 1983, in sec.09, T.15 S., R.24 E., Imperial County, CA, Hydrologic Unit 15030104, Gila and Salt River meridian. Imperial Dam is 5 mi upstream from Laguna Dam, 15 mi northeast of Yuma, AZ, 90 mi downstream from Palo Verde Dam, and 147 mi downstream from Parker Dam.
DRAINAGE AREA - 188,500 mi² of which 4,000 mi² probably is noncontributing. In Great Divide basin in southern Wyoming.
SURFACE-WATER RECORDS
PERIOD OF RECORD - 1903-34 (yearly discharge only, published in WSP 1313), July 1934 to current year (monthly discharge only Oct. 1942 to Sept. 1979). Prior to Oct. 1942 published as "near Picacho, Ca." Oct. 1942 to Sept. 1971 published as "at Imperial Dam" (monthly discharge shown as "flow reaching Imperial Dam," listed as supplement to "flow passing Imperial Dam").
GAGE - None. This record is synthesized from records of several other stations (see REMARKS). July 13, 1934, to Sept. 30, 1942, water-stage recorder at site 14.5 mi upstream at datum 167.38 ft above sea level.
COOPERATION - Imperial Irrigation District and contents of Senator Wash Reservoir furnished by Bureau of Reclamation.
REMARKS - Record is as good as those making up the summation record, which are rated fair to good.
Records show flow of Colorado River reaching Imperial Dam, and are based on combined daily total flow of Colorado River below Imperial Dam (sta 09429500), All-American Canal near Imperial Dam (sta 09523000), Gila Gravity Main Canal at Imperial Dam (sta 09522500), and diversions to Mittry Lake (sta 09522400). Records for 1903-34 and for Oct. 1942 to Sept. 1960 were computed as combined flow of Colorado River at Yuma (sta 09521000) and the canals diverting at Imperial and Laguna Dams, less the flow of Gila River near Dome (sta 09520500); for some of these periods drainage and waste return flows and channel losses between the gaging stations and Imperial Dam were considered, and for other periods they were neglected. Records for Oct. 1960 to Sept. 1979 are based on combined monthly total flow of same stations on which daily flows are currently based. Records for July 1934 to Sept. 1942 show daily discharge of Colorado River at gaging station near Picacho, CA, water withdrawals, and diversions for irrigation, municipal, and industrial uses, and return flows from irrigated areas. Additional regulation, beginning Jan. 31, 1966, to equalize supplies for downstream water users, is provided by pumped storage in reservoir on Senator Wash, about 2 mi upstream from Imperial Dam.
EXTREMES FOR PERIOD OF RECORD - 1934 to current year: Maximum discharge of 40,800 ft³/s on Sept. 5, 1939; minimum discharge of 538 ft³/s on Aug. 3, 1934; minimum daily since regulation of Hoover Dam began, 1,450 ft³/s on Feb. 17, 1935.
WATER-QUALITY RECORDS
PERIOD OF RECORD - Aug. 1969 to Sept. 1992, Aug. 1996 to current year.
PERIOD OF DAILY RECORD - SPECIFIC CONDUCTANCE: Oct. 1969 to Sept. 2000.
WATER TEMPERATURE: Oct. 1974 to Sept. 2000.
INSTRUMENTATION - Streamflow not gaged by USGS.
REMARKS - Water samples collected below trash racks at All-American Canal headworks at west end of Imperial Dam.
