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- Water-Year Summary reports summarize a year of hydrologic data in a printer-friendly format.
- For water years 2014 onward, choose a water year and parameter and an on-demand Water-Year Summary report will be generated.
- For water years 2006 through 2013, choose a water year and an Annual Water Data Report will be provided.
- For water years 2005 and earlier, Annual Water Data Reports may be available in digital format.
- Not all sites have reports available for every water year.
USGS Water-Year Summary 2024
11173575 Alameda Creek below Welch Creek, near Sunol, CA
LOCATION - Lat 37°32'26", long 121°51'19" referenced to North American Datum of 1927, Alameda County, CA, Hydrologic Unit 18050004, unsurveyed, in Valle de San Jose Grant, on left bank, 0.3 mi downstream from Welch Creek, 4.0 mi southeast of Sunol, at bridge to entrance at city of San Francisco Water Department Filtration Plant.
DRAINAGE AREA - 149 mi².
SURFACE-WATER RECORDS
PERIOD OF RECORD - October 1999 to current year.
GAGE - Water-stage recorder. Datum of gage is 302.73 ft above NAVD of 1988.
REMARKS - Flow regulated by Calaveras Reservoir, usable capacity, 96,800 acre-ft, 3.7 mi upstream from gage and by diversion dam on Alameda Creek, 5.5 mi upstream. Dead storage, 3,200 acre-ft. Flow is diverted out of basin from Calaveras Reservoir by city and county of San Francisco for domestic use. See schematic diagram of Alameda Creek Basin available from the California Water Science Center.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 5,750 ft³/s, Dec. 16, 2002, gage height, 19.07 ft, from rating curve extended above 2,610 ft³/s; maximum gage height, 20.11 ft, Jan. 10, 2017; no flow many days August and September 2002, Oct. 29 to Nov. 4, 2002, Aug. 8 to Sep. 30, 2004; Aug. 30 to Sept. 8, 2007, Sept. 5-10, 2008.
WATER-QUALITY RECORDS
PERIOD OF RECORD -
DISCRETE WATER-QUALITY DATA:
SEDIMENT DATA: Water years October 1999 to June 5, 2003, October 2006 to 2013 (storm season only).
CONTINUOUS WATER-QUALITY DATA:
WATER TEMPERATURE: Water years October 1999 to June 2003, October 2006 to current year.
SUSPENDED-SEDIMENT DISCHARGE: Water years October 1999 to May 2003, October 2006 to 2013 (storm season only).
REMARKS - Interruptions in record are due to malfunction of recording and/or sensing equipment.
Water temperature records for 2014-2016 water years rated excellent. The practice of assigning qualitative accuracy ratings to water-quality data was discontinued in WY2017.
