Current Water Supply Conditions and Outlook
July 29, 2014
Our overall water supply situation and outlook is good.
Last week, 1.78 inches and 2.46 inches of precipitation were recorded in our Cedar and South Fork Tolt River watersheds, respectively.
Chester Morse Lake at the Overflow Dike is at elevation 1558.9 feet, about 0.9 feet lower than last week, and about 3.5 feet above its long term average (based on the years 1989 to 2005). Masonry Pool Reservoir at Masonry Dam is at elevation 1558.8 feet, about 0.7 feet lower than last week, and about 4.9 feet above its long term average. The South Fork Tolt Reservoir at the South Fork Tolt Dam is at elevation 1752.9 feet, about 1.1 feet lower than last week, and about 3.0 feet below its long term average. Water releases from reservoir storage are actively being managed for water supply and fish habitat management objectives for both the Cedar and South Fork Tolt Rivers.
Water consumption for the previous seven days averaged approximately 151 mgd. That is less than the 180 mgd consumed during the same period last year, and less than the average of 193 mgd used during the same period over the years 1999-2008.
This year’s migration of adult sockeye salmon through the Ballard Locks facilities is drawing to a close. Based upon the counts of upstream migrating fish so far, the Washington Department of Fish and Wildlife projects that this year’s sockeye return will be well below the pre-season forecast. After passing through the ship canal, these fish move into the deep, cool waters of Lake Washington where they undergo final maturation prior to migrating into the Cedar River and other areas to spawn during the fall. Significant numbers of sockeye typically start to enter the Cedar River in early to mid-September. Most of these fish spawn from mid-September through mid-December.
The emergence of young coho salmon (fry) from their redds is complete in the Cedar and South Fork Tolt rivers. After emerging, young coho usually rear for one year in freshwater prior to migrating to sea. The emergence of young steelhead is nearly complete in the Tolt basin. These young fish typically rear for two years in freshwater before migrating to sea.
Adult summer-run steelhead are returning to the Tolt River basin. Most of these fish will move into the upper reaches of the South Fork Tolt where they hold through the summer and fall, then spawn during the following winter and spring.
View Current Water Supply Graphs (pdf)