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Water-Year Summary for Site 12147900

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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
62614 Elevation, lake/res, NGVD29(Obs.)  

Water year 2020: 2020-10-01 to 2021-09-30

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USGS Water-Year Summary 2020
LOCATION - Lat 47°41'38", long 121°41'16" referenced to North American Datum of 1927, in NW 1/4 SW 1/4 sec.32, T.26 N., R.9 E., King County, WA, Hydrologic Unit 17110010, on top and near the center of the dam, 11.4 mi northeast of Carnation, and at mile 8.4.
DRAINAGE AREA - 18.8 mi².
PERIOD OF RECORD - October 1991 to current year.
GAGE - Water-stage recorder. Datum of gage is NGVD of 1929 (Seattle Public Utilites benchmark).
COOPERATION - Capacity table furnished by Seattle Public Utilites.
REMARKS - Reservoir is formed by earthfill dam, with a concrete bell-mouth spillway, completed in 1962. Water used for municipal water supply by Seattle Water Department. Usable capacity, 15,600 acre-ft between elevations 1,749 ft (minimum pool) and 1,765 ft (maximum normal pool). Top of dam is at 1,775 ft with top of spillway at 1,757 ft. Flood control between elevations 1,749 and 1,757 ft. Figures given represent total contents at 2400 hours. U.S. Geological Survey satellite telemeter at station.
EXTREMES FOR PERIOD OF RECORD - Maximum contents, 59,511 acre-ft, May 20, 21, 2008, elevation, 1,766.54 ft; minimum contents observed, 16,280 acre-ft, Oct. 12, 2003, elevation, 1,711.77 ft.