The Washington State Department of Ecology (DOE) on Wednesday officially granted the Cascade Water Alliance its water rights package which will allow Cascade to eventually use Lake Tapps for municipal drinking water.

The rights allow Cascade store water in the Lake Tapps Reservoir, divert water from the White River into Lake Tapps to supply water for the water supply project, and withdraw water from Lake Tapps for municipal water supply purposes. It also guarantees summer recreation levels for Lake Tapps and ensures flows in the White River that will support habitat and salmon runs while improving the river’s water quality.

The approval assures Cascade the first new municipal water supply in the region in decades. The documents were officially presented to Cascade at its December board meeting.

As currently proposed, the project will take 50 years to fully develop and gives Cascade the authority to take an average of 48 million gallons of lake water a day for public use.

In 1980, DOE adopted a rule that closed the White River to new water-right allocations, so Cascade had to demonstrate that that the water right package would significantly benefit the environment and the public. Additionally, Cascade needed to demonstrate that the water right would provide a new regional water supply; protect and maintain Lake Tapps; increase the minimum instream flows in the White River to improve water quality and enhance salmon habitat; and place conservation restrictions on streamside and adjacent lands in the White River watershed to support salmon and other wildlife.

Cascade worked with the tribes, Lake Tapps community, Pierce County, nearby cities and other agencies to develop the necessary mitigation strategies and agreements to ensure White River flows and lake levels are protected and enhanced.

Lake Tapps Reservoir, originally created in 1911, is located in Pierce County.

Cascade Water Alliance is a non-profit corporation, comprised of the cities of Bellevue, Redmond, Kirkland, Issaquah, Tukwila, the Covington Water District and the Sammamish Plateau and Skyway Water and Sewer Districts.