USGS Water-Year Summary 2021
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.
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 (levels by City of San Francisco). Prior to Feb. 8, 1960, at site 0.65 mi upstream at different datum.
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, 634 ft³/s, Oct. 18, 2017, gage height, 6.58 ft; no flow for many days most years. Peak gage height, 6.74 ft, Oct. 18.
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.