USGS Water-Year Summary 2021
11047300 Arroyo Trabuco at San Juan Capistrano, CA
LOCATION - Lat 33°29'54", long 117°39'54" referenced to North American Datum of 1927, in SW 1/4 SE 1/4 sec.01, T.8 S., R.8 W., Orange County, CA, Hydrologic Unit 18070301, on left bank, 30 ft downstream from Del Obispo Street Bridge, in San Juan Capistrano.
DRAINAGE AREA - 54.1 mi².
PERIOD OF RECORD - October 1972 to September 1977, October 1983 to September 1989, October 1995 to current year.
WATER TEMPERATURE: Water years 1971-77, 1984.
SEDIMENT DATA: Water Years 1971-77, 1984-93.
GAGE - Water-stage recorder, crest-stage gage, and concrete control. Elevation of gage is 80 ft above NGVD of 1929, from topographic map.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 10,000 ft³/s, Feb. 23, 1998, gage height, 19.81 ft, from rating curve extended above 1,600 ft³/s; no flow at times in some years.