Water Supply Conditions

Seattle's Water Supply
Section of the original 1930 Cedar River Pipeline on display at the SPU Operations Control Center – This photo was taken in 2022 by A. F. Chinn.

Below are current supply conditions for Seattle's regional water system.    

November 28, 2022

Last week, 4.35 inches and 4.42 inches of precipitation were recorded in our Cedar River and South Fork Tolt River watersheds, respectively.

Chester Morse Lake at the Overflow Dike was at elevation 1549.3 feet, about 0.8 feet lower than last week, and about 2.0 feet below its long-term average (based on the years 1990 to 2019).  Masonry Pool Reservoir at Masonry Dam was at elevation 1538.7 feet, about 3.3 feet higher than last week, and about 8.9 feet below its long-term average.  The South Fork Tolt Reservoir at the South Fork Tolt Dam was at elevation 1734.8 feet, about 1.0 feet higher than last week, and about 15.4 feet below its long-term average.  Water releases from reservoir storage are actively being managed for water supply, fish habitat and flood management objectives for both the Cedar and South Fork Tolt Rivers.

Water consumption for the previous seven days averaged approximately 101 million gallons per day (mgd).  That is less than the 102 mgd consumed during the same period last year, and less than the average of 103 mgd used during the same period over the years 2010-2019.

Based on current conditions and forecasts, Seattle anticipates the regional water system will have sufficient water supply for people and fish this fall.

As always, we continue to ask customers to use water wisely. For information about ways to save water, visit www.savingwater.org.

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