USGS Water-Year Summary 2020
12181000 SKAGIT RIVER AT MARBLEMOUNT, WA
LOCATION - Lat 48°32'02", long 121°25'43" referenced to North American Datum of 1927, in NE 1/4 SW 1/4 sec.07, T.35 N., R.11 E., Skagit County, WA, Hydrologic Unit 17110005, on right bank 0.5 mi north of Marblemount, 0.6 mi upstream from Cascade River, and at mile 78.7.
DRAINAGE AREA - 1,381 mi². of which 400 mi² are in Canada.
- WDR WA-76-1: Drainage area. WDR WA-90-1: 1983, 1976-87 (M).
PERIOD OF RECORD - September 1943 to July 1944, October 1946 to September 1951, and annual maximum, water years 1952-57. May 1976 to current year.
GAGE - Datum of gage is 305.1 ft above National Geodetic Vertical Datum of 1929 (river-profile survey) and 308.64 ft above North American Vertical Datum 1988 (Washington State Department of Transportation bench mark). To obtain stream water-surface elevations in NAVD 1988 add 308.64 feet to gage height values.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 64,800 ft³/s, Oct. 20, 2003, gage height, 14.11 ft, from rating curve extended above 30,000 ft³/s; minimum daily discharge, 1,190 ft³/s, Feb. 25, 1944.
PERIOD OF DAILY RECORD - WATER TEMPERATURE: March 1986 to current year.
INSTRUMENTATION - Water-temperature sensor with 15-minute logging interval, interfaced directly with a data collection platform for satellite telemetry.
EXTREMES FOR PERIOD OF DAILY RECORD - WATER TEMPERATURE: Maximum, 16.3°C Aug. 27, 2015; minimum, 0.5°C (rounded), Dec. 27, 1996.