USGS Water-Year Summary 2024
12448000 CHEWUCH RIVER AT WINTHROP, WA
LOCATION - Lat 48°28'38", long 120°11'07" referenced to North American Datum of 1927, in SW 1/4 NW 1/4 sec.02, T.34 N., R.21 E., Okanogan County, WA, Hydrologic Unit 17020008, on right bank, 80 ft downstream from State Road 20 bridge crossing, at northwest end of Winthrop, WA, and at mile 0.2.
DRAINAGE AREA - 525 mi².
SURFACE-WATER RECORDS
PERIOD OF RECORD - 1912 to 1913, seasonal records only. October 1991 to current year. Prior to October 1991 published as "Chewack River at Winthrop, WA".
GAGE - Water-stage recorder. Datum of gage is 1,736.26 ft above NGVD of 1929 (Okanogan County Public Works benchmark). Prior to November 1991, nonrecording gage 10 ft upstream from bridge, and at datum 8.74 ft higher.
EXTREMES OUTSIDE PERIOD OF RECORD - Maximum discharge, 18,100 ft³/s May 29, 1948, determined by slope-area measurement of peak flow.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 8,910 ft³/s May 9, 2018, gage height, 10.64 ft; minimum discharge, 20 ft³/s Sept. 18 and 19, 2001, gage height, 2.24 ft.