U.S. Army Corps of Engineers begins the Annual Summer Refill of Lake Washington
#1
February 16, 2011 - 12:01pm
RodHilden
U.S. Army Corps of Engineers begins the Annual Summer Refill of Lake Washington
U.S. Army Corps of Engineers begins the annual summer
refill of Lake Washington
Seattle - The U.S. Army Corps of Engineers Seattle District began its annual practice of increasing the level of Lake Washington on Feb. 15. This is in preparation to meet the high water use in the summer months.
Each year, the refill process typically gets underway in mid-February, reaching full pool no later than June 1. However, each year has a different rate of fill and target elevations through the end of May based upon conditions at the time.
Water Managers target having a 21.95-foot pool mid-May. This target is necessary to provide water for fish, navigation, and salinity control throughout the summer and fall. As water use increases and Lake Washington inflows decrease, the lake begins to draft. Water use increases at the locks beginning in mid-April with the operation of the smolt flumes. As boat traffic increases, more lockings are required, which increases water use for lock operations and to control salinity concentrations within the ship canal and Lake Union. Managing water demands during the summer also includes keeping enough water in the lake to maintain the lake level above 20 feet in the fall as feasible.
The official lake level is measured at the Locks. Levels in Lake Washington may vary due to the natural gradient between the lake and the locks or wind that can push the lake levels up for short durations. Boat owners and other private and commercial maritime interests along Lake Washington shores and the Lake Washington Ship Canal should expect a gradual rise to approximately
21.95 feet by early to mid-May, targeting final refill of 22.0 feet by June
1. Depending on conditions, the lake may remain at full pool through June
and July. Owners who maintain their vessels in a boathouse, for instance, should closely monitor the rise in lake elevation.
More information on Lake Washington's status is available on the Corps'
Seattle District river basin Web site at http://www.nwd-wc.usace.army.mil/nws/hh/basins/lkwash.html