USGS Water-Year Summary 2021
11044350 Sandia Creek near Fallbrook, CA
LOCATION - Lat 33°25'28", long 117°14'54" referenced to North American Datum of 1927, in SW 1/4 NE 1/4 sec.01, T.9 S., R.4 W., San Diego County, CA, Hydrologic Unit 18070302, on left bank, 0.8 mi upstream from mouth, 1.05 mi north of intersection of Sandia and Rock Mountain Roads, and 3.8 mi north of Fallbrook.
DRAINAGE AREA - 21.1 mi².
- WDR CA-91-1: 1990 (instantaneous maximum discharge).
PERIOD OF RECORD - October 1989 to current year.
GAGE - Water-stage recorder and crest-stage gage. Elevation of gage is 380 ft above NGVD of 1929, from topographic map. Prior to Sept. 30, 1993, at site 0.65 mi downstream at different datum.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 5,100 ft³/s, Jan. 16, 1993, gage height, 17.60 ft, site and datum then in use, from floodmarks (may have been affected by backwater from the Santa Margarita River); no flow for many days in summer of 1996.