USGS Water-Year Summary 2021
11137900 Huasna River near Arroyo Grande, CA
LOCATION - Lat 35°04'40", long 120°22'15" referenced to North American Datum of 1927, San Luis Obispo County, CA, Hydrologic Unit 18060007, in Huasna Grant, on right bank, 300 ft downstream from mouth of Huasna Creek, and 12 mi southeast of Arroyo Grande.
DRAINAGE AREA - 103 mi².
PERIOD OF RECORD - June 1959 to September 1986, October 2003 to current year.
GAGE - Water-stage recorder and crest-stage gage. Elevation of gage is 640 ft above NGVD of 1929, from topographic map.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 21,000 ft³/s, Jan. 25, 1969, gage height, 15.90 ft, from rating curve extended above 1,300 ft³/s on basis of slope-area measurement of peak flow; no flow at times in some years.