USGS Water-Year Summary for Site 12178000

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	Available Parameters
	00010 Temperature, water(Max.,Min.,Mean)
	00060 Discharge(Mean)
	00065 Gage height(Mean)

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Water year 2023: 2022-10-01 to 2023-09-30

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USGS Water-Year Summary 2023

12178000 SKAGIT RIVER AT NEWHALEM, WA

LOCATION - Lat 48°40'19", long 121°14'42" referenced to North American Datum of 1927, in SW 1/4 SE 1/4 sec.21, T.37 N., R.12 E., Whatcom County, WA, Hydrologic Unit 17110005, Ross Lake National Recreation Area, on right bank 0.4 mi upstream from Newhalem Creek, 0.5 mi downstream from City of Seattle power plant at Newhalem, 10.8 mi upstream from Bacon Creek, and at mile 93.7.

DRAINAGE AREA - 1,175 mi². of which 400 mi² are in Canada.

REVISIONS HISTORY - WSP 512: 1909-14. WSP 1012: 1929. WSP 1316: 1914(M). WSP 1932: Drainage area.

SURFACE-WATER RECORDS

PERIOD OF RECORD - October 1908 to May 1914, October 1920 to current year. June 1914 to September 1920 (monthly discharge only), in State Water-Supply Bulletin 6. Published as "near Marblemount" 1908-14, 1920-31.

GAGE - Water-stage recorder. Datum of gage is 400 ft. above Seattle City lights As-built datum. Add 406.20 ft. to convert gage datum to NAVD88, from SCL datum conversion survey of 2018. Prior to May 24, 1914, non-recording gages at site 0.5 mi upstream at datum 91 ft. higher. Nov. 15, 1920, to June 4, 1923, non-recording gage at site about 500 ft. upstream at same datum.

REMARKS - Water is diverted 2.9 mi upstream from station and is returned to river at City of Seattle powerplant 0.5 mi upstream from station. Flow regulated by Gorge powerplant since August 1924 and by Ross Reservoir (station 12175000) since March 1940, Diablo Reservoir (station 12176500) since October 1929, and Gorge Reservoir (station 12177700) since June 1960, having a combined total capacity of 1,533,000 acre-ft. U.S. Geological Survey satellite telemeter at station. Chemical analyses October 1973 to September 1974.

EXTREMES OUTSIDE PERIOD OF RECORD - Flood of 1815 reached a stage of approximately 20.5 ft, discharge about 115,000 ft³/s. Records for other floods, prior to establishment of station, are given in WSP 1527.

EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 63,500 ft³/s, Nov. 29, 1909, gage height, 22.0 ft, from flood mark, site and datum then in use; minimum daily discharge, 136 ft³/s, Aug. 24, 1930.

WATER-QUALITY RECORDS

PERIOD OF DAILY RECORD - WATER TEMPERATURE: January 1999 to current year.

INSTRUMENTATION - A Xylem waterlog H-377 analog water-temperature sensor with a 5-minute logging interval, interfaced with a data collection platform for satellite telemetry.

REMARKS - U.S. Geological Survey satellite telemeter at station.

EXTREMES FOR PERIOD OF DAILY RECORD - WATER TEMPERATURE: Maximum recorded, 15.4°C, Aug. 29, 2015; minimum, 2.2°C, Feb. 21, 2002 and Feb. 22, 2019.