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B.C. reservoirs will help aid Northwest during drought

Thu., June 11, 2015

A robust snowpack in British Columbia will help ease drought conditions in the Northwest this summer.

Three B.C. reservoirs will release additional water into the Columbia River to help migrating salmon, power production, irrigation and barge navigation.

The water releases are part of a “dry year strategy” for the Columbia Basin, which also includes drafting reservoirs behind Grand Coulee and other U.S. storage dams starting in July.

“This is among the worst dry years,” said Steve Barton, the U.S. Army Corps of Engineers’ chief of the Columbia Basin’s water management division.

Flows on the Lower Columbia River are projected at about 71 percent of normal through August. But through strategic water releases, federal hydropower dams will operate under near-normal conditions, and dam operators said there will be water for salmon and steelhead migration.

Overall, “what you are describing is a pretty resilient system,” said Phil Rockefeller of Washington, chairman of the Northwest Power and Conservation Council, during a briefing Wednesday in Coeur d’Alene.

The council is made up of governor-appointed representatives from Washington, Idaho, Oregon and Montana. Council members plan for the Northwest’s energy needs, while mitigating for the environmental impacts of building dams on the Columbia and Snake rivers.

Low snowpack caused this year’s drought. Average amounts of precipitation fell across most of the Northwest, but warmer temperatures reduced snow accumulations in the mountains. At elevations of 5,000 feet or less, most snowpack melted in March.

“That water is already in the ocean,” said Tony Norris, a Bonneville Power Administration research analyst.

But British Columbia’s higher mountain ranges fared better, with near-normal snowpack to feed stream flows and fill up reservoirs later in spring. Canada will release about 1.5 million acre feet of water from storage dams this year to aid downstream flows. The releases come through provisions in the Columbia River Treaty and other water agreements between the two nations.

Lake Roosevelt, the reservoir behind Grand Coulee Dam, also will be drafted to increase downstream flows in the Columbia.

The reservoir will fill for the busy Fourth of July weekend, with water levels peaking about a week later. Then, Lake Roosevelt will be gradually drawn down, lowering about 12 feet by the end of August.

Reservoirs behind Libby and Hungry Horse dams in Montana and Idaho’s Dworshak Dam also be will drawn down to increase flows in the Columbia.

Fisheries managers are monitoring the pulse of young salmon and steelhead making their way downriver to the ocean. Based on tracking at the dams, the fish appear to be reaching the ocean on schedule, which bodes well for survival rates, said Ritchie Graves of NOAA Fisheries.

“We try to get the fish to the ocean on time and in as good a condition as possible,” he said.

Rockefeller asked federal water managers what would happen if the drought persists for another couple of years. Would they again be able to blunt the impact to the Columbia through reservoir releases, or would the situation worsen?

Many of the same actions would occur, though there’s no guarantee that Canada would be willing to release as much water in 2016, the managers said.

“Hopefully, it will be a little colder next winter, and some of that precipitation will fall as snow instead of rain,” said Norris, the BPA analyst.



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