Black Rock reservoir cost exceeds benefits, report says

YAKIMA – The costs to build and operate a massive reservoir in central Washington’s Yakima River basin exceed the benefits more than previously thought, according to a draft environmental impact statement released Tuesday by the U.S. Bureau of Reclamation.

The report doesn’t immediately spell doom for Black Rock reservoir, which was studied along with two other storage proposals for improving water supplies in the drought-prone basin.

But the results are likely another strike against a proposal that has already drawn criticism for its high cost and potential threat to the nation’s most contaminated nuclear site.

State and federal officials have been researching additional water storage in the Yakima River basin – and the Columbia River basin, as well – in hopes of alleviating water rationing for irrigators during dry years, improving streamflows for threatened and endangered fish and providing water to meet demand from growing communities.

The draft EIS examined the potential for three proposals for the Yakima River basin: Black Rock, Wymer Dam and a third proposal that would include Wymer Dam and a pump exchange system in which water would be pumped from the mouth of the river upstream for irrigation.

Federal officials hadn’t previously conducted a cost-benefit analysis for Wymer Dam alone. The draft EIS released Tuesday put the benefits at 29 cents for every dollar spent to build and operate it. The Wymer Dam pump exchange proposal had a benefit of 7 cents for every dollar spent.

But the largest and most controversial of the proposals is Black Rock, in which water would be pumped from behind Priest Rapids Dam in the Columbia River to the Black Rock Valley, about 30 miles east of Yakima. The reservoir, corralled by a 600-foot-tall dam, would hold an estimated 1.6 million acre-feet of water and cost $6.7 billion to build and operate.

An acre-foot is the amount of water needed to cover an acre to a depth of one foot.

According to the report, Black Rock would return just 16 cents for every dollar spent to build and operate it, down from 28 cents in a study two years ago.

The cost-benefit analysis does not include regional economic benefits from Black Rock, but it does show that the reservoir is not a good benefit to the nation alone, said Kim McCartney, with the Bureau of Reclamation.

“The federal government on its own is not going to go forward with Black Rock – with any of these alternatives – based on the economics,” McCartney said. “It’s not a federally economically feasible project. But the state isn’t held to that standard, and there are other reasons to implement a project.” Those could include regional recreation or economic benefits and environmental benefits, McCartney said.

Earlier this year, the bureau released a report that showed the reservoir could seep so much it would significantly raise the water table at the neighboring Hanford Nuclear Reservation, increasing the risk of spreading radioactive and toxic contaminants to the Columbia River.

John Osborn, a board member of the Center for Environmental Law and Policy, called Black Rock a “nuclear time bomb” for the Columbia River and said the risk of catastrophic failure is too high. To spend billions of dollars to build it “would be pure folly,” he said.

Federal officials have also said the reservoir likely would only serve the the Yakima Valley, and not the larger Columbia Basin, where at least one aquifer is declining and irrigators and municipalities face water rationing during dry years as well.