March 7, 2002
Diana Cross
(208) 378-5020
Kathryn Puckett
(509) 575-5848 ext. 205
TDD: 1-800-735-2900

Keechelus Safety of Dams Work Scheduled to Start in April

The Bureau of Reclamation announced today that the Modification Report for Keechelus Safety of Dams has cleared the Office of Management and Budget and been transmitted to Congress. Following Congressional approval and the obtaining of the necessary permits from the State and the Corps of Engineers, construction is scheduled to begin in April 2002.

The two-year work period will last from about April or May (or as soon after as weather conditions permit) through about the middle of November each year. Reclamation plans to operate Keechelus Dam and Reservoir to store and supply water for downstream uses during both upcoming construction years. Site cleanup and borrow area restoration will occur in 2004. Water deliveries will continue and limited protection against floods will be provided during construction.

The first year of work will consist of preparing the site and building the downstream drain. Favorable conditions may allow additional work. Operation of Keechelus Reservoir and the other Yakima Project reservoirs is not expected to change significantly during the first year of construction.

In the second year of construction, sections of the dam’s earthen embankment will be removed and replaced and the outlet works will be modified. Changes to normal flow releases may be needed during certain phases of the work. Any such changes will be coordinated with the operation of the other basin reservoirs.

If precipitation in the second construction year is average or above average, less water than usual will be stored in the reservoir so that the water level will be low enough to permit construction by August. However, Reclamation expects that water demands should be fully met under this scenario.

If next year is a dry water year, construction could be more easily accommodated but the possibility of water supply shortages may increase. Yakima Project carryover storage is expected to be lower than normal after the second construction year.

Following discovery of internal erosion within Keechelus Dam in 1998, the structure was determined to be unstable and Reclamation began the process to request modification of the dam under Safety of Dams legislation. In the interim, Reclamation reduced the amount of water stored in Keechelus Reservoir by about 11 percent and implemented an intensive monitoring program.

Keechelus Lake is one of five Yakima basin storage reservoirs for the Yakima Project that provide water to the Kittitas and Yakima Valleys. Safety of Dams legislation requires that the irrigation water users on the Yakima Project repay 15 percent of the total project cost for the modifications. Total project cost is estimated at $32 million.

Located at the headwaters of the Yakima River near Snoqualmie Summit, Keechelus Dam is an earthfill structure completed in 1917. It has a structural height of 128 feet with an active capacity of 157,700 acre-feet at a full pool elevation of 2517 feet.