USGS Water-Year Summary for Site 12148000

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	Available Parameters
	00010 Temperature, water(Max.,Min.,Mean)
	00020 Temperature, air(Min.,Mean,Max.)
	00060 Discharge(Mean)
	00065 Gage height(Mean)
	63680 Turbidity, Form Neph(Max.,Med.,Min.)

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Water year 2024: 2024-10-01 to 2025-09-30

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USGS Water-Year Summary 2024

12148000 SOUTH FORK TOLT RIVER NEAR CARNATION, WA

LOCATION - Lat 47°41'22", long 121°42'44" referenced to North American Datum of 1927, in SW 1/4 SW 1/4 sec.31, T.26 N., R.9 E., King County, WA, Hydrologic Unit 17110010, on left bank 0.1 mi upstream from private road bridge, 1.6 mi downstream from South Fork Tolt Reservoir, 9.8 mi northeast of Carnation, and at mile 6.8.

DRAINAGE AREA - 19.7 mi².

REVISIONS HISTORY - 2016 (M), 2017 (M).

SURFACE-WATER RECORDS

PERIOD OF RECORD - October 1952 to December 1963, June 1969 to current year.

GAGE - Water-stage recorder. Datum of gage is 1,261.72 ft above NAVD of 1988 (USGS survey, Aug. 4, 2022).

REMARKS - Regulation by South Fork Tolt Reservoir since September 1963. Seattle Public Utilities diverts streamflow upstream from the station. U.S. Geological Survey satellite telemeter at station. The City of Seattle Water Department diverted an average daily discharge as follows:

Water Year	Discharge (cfs)	Water Year	Discharge (cfs)	Water Year	Discharge (cfs)	Water Year	Discharge (cfs)
2014	77	2015	72	2016	66	2017	71
2018	74	2019	63	2020	66	2021	75

EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 6,500 ft³/s, Dec. 15, 1959, gage height, 7.45 ft, from rating curve extended above 2,700 ft³/s; maximum gage height, 7.62 ft, Nov. 20, 1958, backwater from debris; minimum daily discharge, 12.5 ft³/s, Aug. 23, 1958.

WATER-QUALITY RECORDS

PERIOD OF DAILY RECORD - WATER TEMPERATURE: October 1994 to current year. TURBIDITY: December 2019 to current year.

INSTRUMENTATION - Temperature recorder with 15-min. logging interval, since October 1994. DTS-12 turbidity sensor with a 15-minute logging interval, since December 2019. 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.

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

EXTREMES FOR PERIOD OF DAILY RECORD - WATER TEMPERATURE: Maximum recorded, 17.9°C , July 18, 2015; minimum, 0.7°C , Dec. 23, 2022. TURBIDITY: Maximum recorded, 245 FNU, Feb. 22, 2021; minimum, 0.1 FNU, July 26 and Aug. 1, 2020.