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USGS Water-Year Summary 2024
11102300 Rio Hondo below Whittier Narrows Dam, CA
LOCATION - Lat 34°01'00", long 118°05'15" referenced to North American Datum of 1927, in sec.00, T.2 S., R.12 W., Los Angeles County, CA, Hydrologic Unit 18070105, in Paso de Bartolo Grant, on right levee, 0.2 mi upstream from Beverly Boulevard, 0.4 mi downstream from axis of Whittier Narrows Dam, and 1.0 mi northeast of Montebello.
DRAINAGE AREA - 124 mi².
SURFACE-WATER RECORDS
PERIOD OF RECORD - October 1966 to current year.
GAGE - Water-stage recorder and concrete-lined flood-control channel. Datum of gage is 177.06 ft above NAVD of 1988.
COOPERATION - Discharge records are were furnished by Los Angeles County Department of Public Works and include small secondary drainage area adjacent to the gage. Above 300 cfs USGS records are used but furnished values may be used if they compare well with USGS daily values. There has been no field verification of this data by the U.S. Geological Survey since the 2009 Water Year.
REMARKS - Flow regulated by Whittier Narrows Flood-Control Reservoir, capacity, 36,160 acre-ft. There are several small flood-control reservoirs (combined capacities, 1,700 acre-ft) and several small debris basins above Whittier Narrows Dam. Many diversions for domestic use and irrigation. Los Angeles County Department of Public Works diversion from San Gabriel River below Santa Fe Dam (11085000) to Rio Hondo during water year:
2014 - no diversion
2015 - no diversion
2016 - 801 acre-feet
2017 - 53,700 acre-feet
2018 - 6,480 acre-feet
2019 - 50,100 acre-feet
2020 - 34,500 acre-feet
2021 - 6,360 acre-feet
2022 - 17,700 acre-feet
2022 - 17,700 acre-feet
2023 - 96,100 acre-feet
See schematic diagram of San Gabriel River and Los Angeles River Basins available from the California Water Science Center.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 38,800 ft³/s, Jan. 25, 1969, gage height, 13.82 ft, from rating curve extended above 15,000 ft³/s, on basis of gate openings at dam at gage heights 12.32 and 13.82 ft; no flow at times in most years.
