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Water-Year Summary for Site 12181000

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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.
  • For water years 2006 through 2013, choose a water year and an Annual Water Data Report will be provided.
  • For water years 2005 and earlier, Annual Water Data Reports may be available in digital format.
  • Not all sites have reports available for every water year.
Available Parameters
00010 Temperature, water(Max.,Min.,Mean)  
00060 Discharge(Mean)  
00065 Gage height(Mean)  

Water year 2020: 2019-10-01 to 2020-09-30

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USGS Water-Year Summary 2020
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.
REVISIONS HISTORY - 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.
REMARKS - All diversions returned to river upstream from gage. Flow regulated by Ross Reservoir (station 12175000), Diablo Reservoir (station 12176500), and Gorge Reservoir (station 12177700) since 1960. U.S. Geological Survey satellite telemeter at station.
  • Water Years 2014 to 2017: No estimated daily discharges. Records good.
  • Water Years 2018 and 2019: No estimated discharges. Records good.
  • Water Year 2020: No estimated discharges. Records good except for Jan. 8 to Sept. 30, which are fair.
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.
INSTRUMENTATION - Water-temperature sensor with 15-minute logging interval, interfaced directly with a data collection platform for satellite telemetry.
  • Water Years 2014 and 2017: WATER TEMPERATURE records are good.
  • Water Years 2015, 2016, 2018, 2019: WATER TEMPERATURE records are excellent.
  • Water Year 2020: WATER TEMPERATURE records are excellent except for May 28 to July 17, which are good.
EXTREMES FOR PERIOD OF DAILY RECORD - WATER TEMPERATURE: Maximum, 16.3°C Aug. 27, 2015; minimum, 0.5°C (rounded), Dec. 27, 1996.