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Finding Water For Columbia River Fish In A Low Flow Year; Most Comes From Canada Storage Reservoirs
Posted on Friday, July 24, 2015 (PST)

Canadian storage reservoirs have provided the lion’s share of water releases for the Columbia River Basin, and in a timely fashion, during one of the driest years in decades throughout the region.


“It’s a message that folks should understand, that the Columbia River Treaty has provisions that provide for releases for the lowest-of-low streamflow conditions,” said Tony Norris, operations planner with the Bonneville Power Administration. “And this year, (releases) came out coincident with the needs of fish.”


An estimated total of 8.7 million acre feet is scheduled to be released through September, with about 5.7 million acre feet coming from Canada.


Even with U.S. reservoirs such as Hungry Horse and Lake Koocanusa in Montana drafting a maximum of 20 feet below full pool, under provisions of a salmon and steelhead biological opinion for the Columbia Basin for dry years, U.S. storage will provide just about 3.2 million acre feet. The maximum provided for under the BiOp in the driest of years from U.S. storage is about 4.1 million acre feet.


Norris explained that the total U.S. flow target was arguably reached, but a large portion of it flowed downstream in the spring rather than being released from storage later in the summer.


“Since we have a low streamflow year, the U.S. portion of that streamflow augmentation (from storage) is diminished to a significant degree,” Norris said. “There would normally be more U.S. storage released per the BiOp.”


“We cannot make a dry year a wet year from storage,” Norris said, adding however, that water managers can control and “shape” releases from storage.


This year, releases from Canadian storage to meet energy needs throughout the region were highly timely, totaling about 5.7 million acre feet of the total 8.7 million acre feet, with most of it coming in June and continuing into July.


“That’s a notable number,” Norris said, referring to the high proportion of water coming from Canada in relation to total storage releases.


About 3.2 million acre feet of the total releases are considered to be “Proportional Draft,” a provision of the Columbia River Treaty with Canada that is designed to “meet firm energy needs during low streamflow conditions,” Norris explained. “Fortunately, the release of water due to Proportional Draft occurred coincident with the needs of migrating salmon in the Columbia River.”


Proportional flows, under the treaty, are separate from “flow augmentation” obligations for fisheries that amounted to about 4.7 million acre feet this year — 3.2 million acre feet from U.S. and about 1.5 million acre feet from Canada. So the proportional flows from Canada under the treaty, and the timing of the flows, were significant.


“It’s pretty rare to see proportional flows in June,” Norris said. “It’s fortunate this year, extremely fortunate, that these releases occurred during juvenile salmon migration.”


Out of the total 8.7 million acre feet of storage releases, flows in June totaled 2.4 million acre feet while flows in July totaled 3 million acre feet. Aggregate storage releases are projected to drop sharply to 1.5 million acre feet in August and .5 million acre feet in September.


Those numbers include flow augmentation for the Upper Snake River Basin, which is not related

to Canadian proportional flows. Total augmentation flows for the Upper Snake River Basin are expected to amount to 427 thousand acre feet.


Norris and other water managers note that estimates for flow augmentation will likely be adjusted as releases continue through the summer.


Also see:


-- CBB, July 17, 2015, “Officials In Teleconference Detail Situation, Issues Associated With Basin’s ‘Snow Drought’



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