USGS Water-Year Summary 2020
11176500 Arroyo Valle near Livermore, CA
LOCATION - Lat 37°37'24", long 121°45'28" referenced to North American Datum of 1927, Alameda County, CA, Hydrologic Unit 18050004, in Valle de San Jose Grant, on right bank, 900 ft downstream from highway bridge, 1.1 mi upstream from Dry Creek, 1.3 mi downstream from Del Valle Dam, 4.1 mi south of Livermore, and 6.9 mi southeast of Pleasanton.
DRAINAGE AREA - 147 mi².
PERIOD OF RECORD - January 1912 to September 1930, October 1957 to current year. Monthly discharge only for some periods, published in WSP 1315-B. Published as "Arroyo del Valle near Livermore," 1912-29.
GAGE - Water-stage recorder and concrete control. Elevation of gage is 510.44 ft above NGVD of 1929. Prior to November 1914, at site 900 ft upstream at different datum. Nov. 1, 1914, to Sept. 30, 1930, at site 300 ft upstream at different datum.
EXTREMES OUTSIDE PERIOD OF RECORD - Flood of Dec. 23, 1955, reached a stage of 13.9 ft, from floodmarks, discharge, 18,200 ft³/s, on basis of contracted-opening and slope-area measurement of peak flow.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 12,200 ft³/s, Apr. 2, 1958, gage height, 10.91 ft; no flow at times.
Maximum discharge since construction of Del Valle Dam in 1968, 2,980 ft³/s, Feb. 4, 1998, gage height, 9.17 ft.
PERIOD OF RECORD
DISCRETE WATER-QUALITY DATA:
CHEMICAL ANALYSES: Water years 1953 (partial-record station), October 1958 to July 1966.
CONTINUOUS WATER-QUALITY DATA:
WATER TEMPERATURE: Water years October 1959 to September 1961, October 1962 to December 1978, October 2011 to current year.
SEDIMENT DATA: Water years October 1962 to September 1967.
INSTRUMENTATION - Temperature recorder October 1963 to December 1978. Water-quality monitor since October 13, 2011.