USGS Water-Year Summary 2021
11176400 Arroyo Valle below Lang Canyon, near Livermore, CA
LOCATION - Lat 37°33'41", long 121°40'58" referenced to North American Datum of 1927, in NE 1/4 NE 1/4 sec.30, T.4 S., R.3 E., Alameda County, CA, Hydrologic Unit 18050004, Mt. Diablo meridian, on left bank, 100 ft upstream from small left-bank tributary, 1.2 mi downstream from Lang Canyon, and 9.5 mi southeast of Livermore.
DRAINAGE AREA - 130 mi².
PERIOD OF RECORD - October 1963 to current year. Prior to October 1974, published as "above Lang Canyon, near Livermore."
WATER TEMPERATURE: Water years 1974-79.
SEDIMENT DATA: Water years 1974-79.
GAGE - Water-stage recorder. Concrete control since June 19, 1975. Datum of gage is 749.09 ft above NAVD of 1988. Prior to June 19, 1975, at site 1.4 mi upstream at different datum.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 8,790 ft³/s, Feb. 17, 1986, gage height, 7.36 ft, from rating curve extended above 1,000 ft³/s, on basis of slope-area measurements at gage heights 4.13, 5.40, and 7.36 ft; no flow at times in most years.