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USGS Water-Year Summary 2024
11097000 Big Tujunga Creek below Hansen Dam, CA
LOCATION - Lat 34°15'13", long 118°23'17" referenced to North American Datum of 1927, Los Angeles County, CA, Hydrologic Unit 18070105, in Mission San Fernando Grant, in city of Los Angeles, on left bank of concrete outlet channel, 0.1 mi upstream from Glen Oaks Boulevard, 0.5 mi downstream from Hansen Dam, and 3 mi southeast of San Fernando.
DRAINAGE AREA - 153 mi².
REVISIONS HISTORY - WDR CA-84-1: 1978 (instantaneous maximum discharge). WDR CA-01-1: 1992.
SURFACE-WATER RECORDS
PERIOD OF RECORD - May 1932 to February 1938, August 1940 to current year. Monthly discharge only for some periods, published in WSP 1315-B. Prior to October 1975, published as "Tujunga Creek below Hansen Dam."
GAGE - Water-stage recorder and concrete-lined flood-control channel. Datum of gage is 945.75 ft above NAVD of 1988. See WSP 1735 for history of changes prior to Oct. 1, 1953.
COOPERATION - Records of diversion provided by Los Angeles County Department of Public Works.
REMARKS - Flow regulated since July 1931 by Big Tujunga Flood-Control Reservoir, capacity, 5,690 acre-ft, and since September 1940 by Hansen Flood-Control Reservoir, capacity, 25,450 acre-ft. Several small diversions for domestic use and irrigation. Since about 1948, Los Angeles County Department of Public Works has diverted water 0.3 mi upstream from gage to spreading grounds. See schematic diagram of San Gabriel River and Los Angeles River Basins available from the California Water Science Center.
EXTREMES OUTSIDE PERIOD OF RECORD - Maximum discharge, 54,000 ft³/s, estimated, Mar. 2, 1938.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 15,200 ft³/s, Feb. 10, 1978, Mar. 2, 1983; maximum gage height, 7.64 ft, Mar. 2, 1983; no flow for many days in most years.
