Cascade Water Alliance outlines long-term regional water supply

January 3, 2012

By Warren Kagarise

Cascade Water Alliance leaders outlined a plan Dec. 30 to secure water for Issaquah and the region in the decades ahead.

The nonprofit organization purchases water from Seattle Public Utilities, but the water bought from the utility is due to start declining in 2024 as the Cascade Water Alliance switches to other sources. Then, in 2030, officials plan to start drawing water as needed from Lake Tapps in Pierce County.

The information is contained in the transmission and supply plan — a document outlining the water systems in alliance member jurisdictions and plans for the future. Residents can also weigh in, as the plan is open for public comment until Jan. 31.

The regional alliance includes the Sammamish Plateau Water and Sewer District, Issaquah and Bellevue, plus other Eastside and South King County cities and water districts. The agency serves about 400,000 residents and 22,000 businesses.

The members own, operate and maintain individual water distribution systems. The alliance operates the Bellevue-Issaquah Pipeline, a 24-inch transmission line in operation since 2006.

Get involved

Residents can comment on the Cascade Water Alliance’s long-term transmission and supply plan through Jan. 31. The public should direct comments and questions to Director of Planning Michael Gagliardo at 453-1503 or

Officials estimate the current system should be able to meet members’ water needs through 2023.

“In recent years, the downturn in housing and economic activity has affected demands for water throughout the Puget Sound region, and this effect is expected to persist for the next several years,” alliance Chairman Lloyd Warren said in a statement. “This is a change from past planning efforts when rapid growth was occurring.”

Officials considered more than 20 water supply options to meet long-term needs for alliance members. In 2024, the alliance plans to dip into the Green River supply from Tacoma Public Utilities. Water could start flowing northward from Lake Tapps to local residents in 2030.

“This, coupled with our conservation efforts, means the demand for water in Cascade’s service area is forecast to remain constant through 2020 at about 40 million gallons per day,” Warren said. “After that, the demand begins to rise again.”

In December 2010, the state Department of Ecology and the alliance sealed a deal for a Lake Tapps water-rights package.

The rights allow the alliance to store water in the Lake Tapps Reservoir, divert water from the White River into the lake to supply water for the water supply project and withdraw water from Lake Tapps for municipal water supply purposes. The project as proposed could take 50 years to develop.

Under the agreement, Cascade has the authority to use up to 48 million gallons of lake water per day for public use.

Warren Kagarise: 392-6434, ext. 234, or Comment at

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One Response to “Cascade Water Alliance outlines long-term regional water supply”

  1. Kitsap Connection » January 5, 2012 on January 5th, 2012 6:22 am

    […] Cascade Water Alliance outlines long-term regional water supply… Work begins to empty another Hanford tank […]

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