USGS Water-Year Summary 2020
12061500 SKOKOMISH RIVER NEAR POTLATCH, WA
LOCATION - Lat 47°18'36", long 123°10'33" referenced to North American Datum of 1927, in SE 1/4 NW 1/4 sec.15, T.21 N., R.4 W., Mason County, WA, Hydrologic Unit 17110017, on upstream side of bridge on U.S. Highway 101, 3.7 mi downstream from confluence of North and South Forks, 4.7 mi southwest of Potlatch, and at mile 5.3.
DRAINAGE AREA - 227 mi². including 97.9 mi² (revised) upstream from Cushman Dam No. 2, which is noncontributing except during spillage.
- WSP 1716: 1950(M), 1956. WSP 1932: Drainage area. WDR WA-72: 1968(M), 1971(M). WDR WA-75: 1974, 2012.
PERIOD OF RECORD - July 1943 to current year. TURBIDITY: November 2011 to September 2012.
GAGE - Water-stage recorder. Datum of gage is 10.52 ft above NGVD of 1929. Prior to May 27, 1964, water-stage recorders or nonrecording gage at several sites about 0.6 mi upstream at different datums. Supplementary water-stage recorder on right bank at site 0.6 mi upstream at datum 16.47 ft above NGVD of 1929 used Nov. 16 to Dec. 10, 1964, June 11 to July 7, and Nov. 2-24, 1965.
EXTREMES OUTSIDE PERIOD OF RECORD - Flood of December 1933 reached an elevation of 30.8 ft above NGVD of 1929 at site on left bank 150 ft upstream from old highway bridge, discharge, 18,600 ft³/s.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 36,600 ft³/s, Nov. 23, 1990, gage height, 16.80 ft (floodmark), from rating curve extended above 14,000 ft³/s; maximum gage height, 18.16 ft, Dec. 3, 2007; minimum discharge, 99 ft³/s, Oct. 27, 28, Nov. 6-9, 1987.
PERIOD OF DAILY RECORD - TURBIDITY: November 2011 to September 2012 (discontinued).
INSTRUMENTATION - Turbidity sensor (FTS DTS-12) interfaced with a Data Collection Platform/Electronic Datalogger, with 15-minute recording interval, since November 2011. Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.
EXTREMES FOR PERIOD OF DAILY RECORD - TURBIDITY: Maximum, 576 FNU, Nov. 23, 2011; minimum, 0.0 FNU on several days in August and September 2012.