USGS Water-Year Summary 2021
12031000 CHEHALIS RIVER AT PORTER, WA
LOCATION - Lat 46°56'22", long 123°18'47" referenced to North American Datum of 1927, in SW 1/4 SE 1/4 sec.21, T.17 N., R.5 W., Grays Harbor County, WA, Hydrologic Unit 17100103, at downstream end of left bank bridge pier, 30 ft downstream from Porter Creek, 0.1 mi west of Porter, and at mile 33.3.
DRAINAGE AREA - 1,294 mi².
- WDR-US-2013: 2007, 2008, 2009 Daily discharges and totals. WDR-WA-2008: 1983. WSP 1716: Drainage area. WSP 1932: 1954, 1956, 1960(M).
PERIOD OF RECORD - January 1952 to September 1972, water years 1973-75 (annual maximum), May 1975 to September 1985, October 1985 to September 1986 (monthly means only), October 1986 to current year. Daily routed values for October 1985 to September 1986 are available in the files of the U.S. Geological Survey.
GAGE - Water-stage recorder and crest-stage gage. Datum of gage is NAVD of 1988. Prior to May 10, 2018, water-stage recorder at present site at datum 23.64 ft above NGVD of 1929.
EXTREMES OUTSIDE PERIOD OF RECORD - Flood of Dec. 28, 1937, reached a stage of 24.7 ft, from levels by Grays Harbor County. Flood of December 1933 reached a stage of 23.13 ft, from river profile by Corps of Engineers.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 86,500 ft³/s, (revised), Dec. 5, 2007, gage height, 26.06 ft; minimum discharge, 164 ft³/s, Oct. 17, 1952, gage height, 2.25 ft.
PERIOD OF DAILY RECORD - TURBIDITY: December 2018 to current year.
INSTRUMENTATION - Turbidity sensor (Observator Analite NEP-5000) interfaced with a Data Collection Platform/Electronic Datalogger, with 15-minute logging interval, since December 2018. 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, 254 FNU, Dec. 21, 2019; minimum, 0.4 FNU, July 15, 2019.