WHILE THE LONG-TERM future of Lake Tapps remains uncertain, an agreement between the lake’s owner, the Federal Energy Regulatory Commission (FERC) and the US Army Corps (USACE) assures the lake will be full this summer.

The deal also buys time for an alliance of Eastside and South County cities, looking to Lake Tapps as a drinking water source, to continue negotiating to purchase the lake’s water rights from Puget Sound Energy (PSE) a Bellevue, Washington, US-based utility.

PSE applied to stop the hydro plant’s operations at Lake Tapps in January, because FERC’s licensing requirements and provision of fish passage made the hydro project uneconomical. The agreement allows PSE to continue operation of its river diversion dam, despite the utility’s rejection of its federal operating license.

USACE will pay PSE to operate and maintain the diversion dam and other parts of the hydro project so that the Corps can continue to meet its responsibility to save threatened fish species. The long-term strategy for keeping water in Lake Tapps involves using the reservoir as a drinking water source for growing suburban cities in King County.

The Cascade Water Alliance, which includes eight water agencies, is negotiating to buy Puget’s water rights to Lake Tapps. The alliance includes Bellevue, Redmond, Issaquah, Tukwila, Sammamish Plateau Water and Sewer District, Covington Water District and the Skyway Water and Sewer District. The group plans to build a US$200M treatment plant and a pipe system, worth around US$200M, to bring Lake Tapps water north.