USGS Water-Year Summary 2024

11092450 Los Angeles River at Sepulveda Dam, CA

LOCATION - Lat 34°09'42", long 118°27'57" referenced to North American Datum of 1927, in sec.00, T.1 N., R.15 W., Los Angeles County, CA, Hydrologic Unit 18070105, in Mission de San Fernando Grant, on right bank of outlet channel, 0.6 mi downstream from Sepulveda Dam, 200 ft upstream from Sepulveda Boulevard in city of Los Angeles, and 1.8 mi southwest of Van Nuys.

DRAINAGE AREA - 158 mi².

SURFACE-WATER RECORDS

PERIOD OF RECORD - January 1929 to February 1938, May 1938 to September 1979, October 2002 to current year. See WSP 1315-B and 1735 for history of records prior to September 1950.

GAGE - Water-stage recorder and concrete-lined flood-control channel. Datum of gage is 655.13 ft above NAVD of 1988. See WSP 1735 for history of changes prior to Aug. 29, 1953.

REMARKS - Flow regulated since December 1941 by Sepulveda Flood-Control Reservoir, capacity, 17,400 acre-ft. Some diversion above station. At times, the city of Los Angeles discharges imported Owens River water into the Los Angeles River from upstream distributing reservoirs. Since 1998, most of the base flow at this station represents releases of treated effluent from the city of Los Angeles Donald C. Tillman Water Reclamation Plant, located upstream of Sepulveda Dam. Such releases are discharged to the river approximately 300 ft downstream of Sepulveda Dam. See schematic diagram of San Gabriel River and Los Angeles River Basins available from the California Water Science Center.

EXTREMES OUTSIDE PERIOD OF RECORD - Flood of Mar. 2, 1938, 12,000 ft³/s, estimated.

EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 19,600 ft³/s, Mar. 20, 2011, gage height, 14.79 ft; no flow on Sept. 19, 20, 1930.