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
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
“We cannot make a dry year a wet year from storage,” Norris
said, adding however, that water managers can control and “shape” releases from
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
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.
-- CBB, July 17, 2015, “Officials In Teleconference Detail
Situation, Issues Associated With Basin’s ‘Snow Drought’ http://www.cbbulletin.com/434538.aspx