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- Water-Year Summary reports summarize a year of hydrologic data in a printer-friendly format.
- For water years 2014 onward, choose a water year and parameter and an on-demand Water-Year Summary report will be generated.
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USGS Water-Year Summary 2025
13172454 Snake River blw Swan Falls Dam, ID
LOCATION - Lat 43°14'57.72", long 116°23'01.71" referenced to North American Datum of 1983, Ada County, ID, Hydrologic Unit 17050103, on right bank, 0.5 mi downstream from Swan Falls power plant, at river mi 457.2.
DRAINAGE AREA - 41,900 mi².
SURFACE-WATER RECORDS
PERIOD OF RECORD - October 2016 to current year.
GAGE - Water stage recorder and crest-stage gage. Datum of gage is National Geodetic Vertical Datum of 1929.
COOPERATION - Discharge records furnished by Idaho Power and reviewed by U.S. Geological Survey beginning October 2016.
REMARKS - Major regulation by American Falls Reservoir, 260.5 mi upstream. Diurnal fluctuation caused by hydroelectric plants upstream. Diversions above station for irrigation of about 2,590,000 acres, of which about 701,000 acres are irrigated by withdrawals from ground water (1966 determination).
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 35,200 ft³/s Feb. 11, 2017, gage height, 2297.32 ft; minimum daily, 4,260 ft³/s June 24, 2021.
