Operators of Lake Tapps make largest trust water donation in state history

Water flows for struggling fish in the White River will be protected for decades now that the operators of Lake Tapps have agreed to make a massive water donation to a state ecology program.

The Cascade Water Alliance has agreed not to divert a total of 684,571 acre-feet of water from the river that it was entitled to take. The agreement, which supports the state Department of Ecology’s Trust Water Rights Program, is part of a larger agreement dating back to 2010.

“That’s a tremendous benefit for flows in the river for fish habitat,” said Dan Partridge, communications manager for the state program. “It’s the largest trust water donation in Washington state history.”

It would be enough water to fill a football field 130 miles deep, Partridge said.

Mike Gagliardo, Cascade’s director of planning, said it agreed to draw less water from the river each year to help fish while continuing to meet its obligations to lakefront residents and recreational users and, several years from now, to drinking water customers.

“We basically said, ‘We have a right to divert this water, but we’re not going to,’ ” Gagliardo said.

The permanent donation — and another temporary donation of 154,751 acre-feet — completes an agreement made five years ago between the state and the alliance. It guaranteed the donation of some water rights in the river after Cascade purchased the man-made reservoir in East Pierce County from Puget Sound Energy.

The temporary donation will be re-evaluated in 20 years, which is around the time Cascade could begin using Lake Tapps as a municipal water source. Gagliardo said the temporary status maintains the state’s ecological effort while providing Cascade with flexibility in case extraordinary circumstances require tapping more water from the river to maintain lake levels.

The White River, which suffers from fish-passage problems, is on a national endangered rivers list. Cascade’s donation will benefit about a 20-mile stretch that flows through the Muckleshoot Reservation.

“That’s the most important part of the river for fish habitat,” Gagliardo said.

Partridge said the tribe relies on that area to sustain fish hatcheries.

“It’s part of our obligation in water management in Washington state to ensure there are adequate flows to support fish habitat,” Partridge said. “This is a critical contribution to sustaining fish habitat on the White River for generations.”

Cascade Water Alliance — a consortium of King County cities and water and sewer districts — bought Lake Tapps from Puget Sound Energy in December 2009.

The change of ownership came five years after PSE closed its White River hydroelectric plant, which was powered by the lake. For 93 years, PSE diverted White River water into the lake via flumes, concrete pipes and canals. Lake water was then spilled through a powerhouse and returned to the river.

In 2010, Ecology and the alliance entered into a water-rights agreement. It outlined a multi-year project to develop a regional water supply system to meet the long-term municipal needs of several cities, including about 400,000 residents, in King County.

Cascade drains and fills the lake throughout the year, maintaining high levels during summer months for boating and other recreation.

About 1,500 houses — home to many of Lake Tapps’ nearly 12,000 residents — line the shores of the reservoir.

Gagliardo said the donations won’t affect recreation or the eventual water supply. He said the amount set aside is in excess of what’s needed to operate the lake.

Currently, the water-supply project gives Cascade the authority to take an average of 48 million gallons of lake water a day for public use, according to a Department of Ecology news release.

Partridge said the trust water donation and the larger water rights agreement were the result of strategic partnerships between Cascade, the Ecology department and the Puyallup and Muckleshoot tribes. All these parties will continue to work closely to promote further environmental stewardship, he said.

The community of Lake Tapps has been included in that partnership, Gagliardo said.

“We wanted to ensure we weren’t giving away too much water,” he said.