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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.
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USGS Water-Year Summary 2024
11174000 San Antonio Creek near Sunol, CA
LOCATION - Lat 37°34'39", long 121°51'24" referenced to North American Datum of 1927, Alameda County, CA, Hydrologic Unit 18050004, in Valle de San Jose Grant, on right bank, 0.4 mi upstream from Calaveras Road Bridge, 0.85 mi upstream from mouth, and 2.2 mi southeast of town of Sunol.
DRAINAGE AREA - 37 mi².
SURFACE-WATER RECORDS
PERIOD OF RECORD - January 1912 to September 1930 (records furnished by Spring Valley Water Company), February 1960 to September 1965, and October 1999 to current year. Monthly discharge only for some periods, published in WSP 1315-B (published as "La Costa Creek near Sunol").
GAGE - Water-stage recorder and concrete control. Datum of gage is 271.56 ft above NGVD of 1929 and 274.23 ft above NAVD of 1988. Prior to Feb. 8, 1960, at site 0.65 mi upstream at different datum.
REMARKS - Flows regulated by Lake San Antonio located 0.6 mi upstream of gage beginning in October 1964. Reservoir filling completion date was February 1965. Flows can be released for emergency flood conditions, but purpose of the reservoir is for water supply. Total storage capacity, 50,500 acre-ft. See schematic diagram of Alameda Creek Basin available from the California Water Science Center.
EXTREMES OUTSIDE PERIOD OF RECORD - Flood of Dec. 23, 1955, 5,180 ft³/s (by slope-area measurement of peak flow).
EXTREMES FOR PERIOD OF RECORD - Maximum discharge prior to regulation for years with available instantaneous maximum (1921-30 and 1960-63), 1,970 ft³/s, Jan. 31, 1963, gage height, 7.16 ft.
Maximum discharge for period after regulation, 900 ft³/s, Jan. 16, 2023, gage height, 6.16 ft; no flow for many days most years. Peak gage height, 6.74 ft, Oct. 18, 2017.
WATER-QUALITY RECORDS
PERIOD OF RECORD -
DISCRETE WATER-QUALITY DATA:
SEDIMENT DATA: Water years January 2000 to April 2001.
CONTINUOUS WATER-QUALITY DATA:
WATER TEMPERATURE: Water years October 2008 to current year.
INSTRUMENTATION - Water-quality monitor since Oct. 1, 2008.
REMARKS - Interruptions in record are due to malfunction of recording and/or sensing equipment. The practice of assigning qualitative accuracy ratings to water-quality data was discontinued in WY2017.
