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USGS Water-Year Summary 2024
11160500 San Lorenzo River at Big Trees, CA
LOCATION - Lat 37°02'40", long 122°04'17" referenced to North American Datum of 1927, Santa Cruz County, CA, Hydrologic Unit 18060015, in Zayante Grant, on right bank, 12 ft upstream from bridge on Henry Cowell State Park Road, 200 ft upstream from Shingle Mill Creek, 0.25 mi south of town of Felton, 0.3 mi downstream from Zayante Creek, 0.9 mi northwest of Big Trees Station on Southern Pacific Railroad, and 5.3 mi northwest of Santa Cruz.
DRAINAGE AREA - 106 mi².
REVISIONS HISTORY - WSP 1315-B: 1938 (maximum discharge). WSP 1715: Drainage area.
SURFACE-WATER RECORDS
PERIOD OF RECORD - October 1936 to current year. Monthly discharge only for some periods, published in WSP 1315-B.
CHEMICAL DATA: Water years 1906-07, 1952-67, 1969-70, 1973-75, 1977, 1980-81.
WATER TEMPERATURE: Water years 1965-82, daily.
SEDIMENT DISCHARGE: Water years 1973-82, daily; 1986, 1990-93, monthly.
GAGE - Water-stage recorder and crest-stage gage. Datum of gage is 230.06 ft above NAVD of 1988. Prior to Oct. 6, 1972, at site 1.3 mi downstream at different datum.
REMARKS - Low flow partially regulated by Loch Lomond Reservoir since 1961, capacity, 8,820 acre-ft, and by an inflatable fiber dam located 500 ft upstream from gage. Many small diversions upstream from station for domestic supply.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 30,400 ft³/s, Dec. 23, 1955, gage height, 22.55 ft, site and datum then in use, from rating curve extended above 11,000 ft³/s, on basis of slope-area measurement of peak flow, maximum gage height, 28.85 ft, Jan. 5, 1982; minimum daily discharge, 5.6 ft³/s, July 27, 28, 1977.
