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Water-Year Summary for Site USGS 11456000

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Available Parameters
00060 Discharge(Mean)  

Water year 2023: 2022-10-01 to 2023-09-30
 
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USGS Water-Year Summary 2023
11456000 Napa River near St. Helena, CA
LOCATION - Lat 38°30'41", long 122°27'17" referenced to North American Datum of 1927, Napa County, CA, Hydrologic Unit 18050002, in Carne Humana Grant, on right bank, downstream side of Pope Street Bridge, and 0.9 mi northeast of Saint Helena.
DRAINAGE AREA - 78.8 mi².
REVISIONS HISTORY - WSP 1929: Drainage area. WDR CA-78-2: 1977 (instantaneous maximum discharge).
SURFACE-WATER RECORDS
PERIOD OF RECORD - October 1929 to September 1932, October 1939 to June 1995 (daily). July 1995 to May 2000 (stage only). June 2000 to current year. Monthly discharge only for some periods, published in WSP 1315-B. WATER TEMPERATURE: Water years 1958-79. SEDIMENT DATA: Water years 1961-62.
GAGE - Water-stage recorder and crest stage gage. Datum of gage is 193.21 ft above NGVD of 1929. Oct. 1, 2004, to Sept. 30, 2005, at datum 2.00 ft higher. Oct. 1, 1929, to Sept. 30, 2004, at site 2.2 miles downstream at datum 25.09 ft lower. Prior to Nov. 22, 1958, at datum 3.00 ft higher. Nov. 22, 1958, to July 22, 1976, at datum 2.00 ft higher.
REMARKS - Some regulation by Kimball Creek Reservoir, capacity, 344 acre-ft, since 1939, and Bell Canyon Reservoir, capacity, 2,530 acre-ft, since 1959. Small diversions upstream from station for irrigation of about 1,500 acres.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 18,300 ft³/s, Dec. 31, 2005, gage height, 23.61 ft, on basis of slope-area measurement of peak flow; no flow many days most years.