Endangered Snake River sockeye salmon passage at Lower
Granite Dam on the lower Snake River has stalled, leaving 300 or more of the
salmon somewhere in the downstream pools.
Fisheries managers believe the fish (listed as endangered
under the federal Endangered Species Act) have stalled due to overheated water
in reservoirs and at the entrance to the Lower Granite and Little Goose dams’
This week water temperatures at the ladder entrances hovered
around 71 degrees.
While the managers generally agree that the warm water is
the cause for the dismal fish passage through the dams, they don’t agree how
best to cool the river and fish ladders, enticing sockeye salmon up through the
two dams, without also impacting migrating juvenile chinook salmon, listed as
threatened under the ESA.
As of July 21, 919 sockeye had passed Ice Harbor Dam on the
Snake River, 816 had passed Lower Monumental Dam, 495 made it past Little Goose
Dam, but just 321 had made it the distance to Lower Granite Dam, the most
upstream of the four lower Snake River dams, according to information released
by NOAA Fisheries Thursday.
This is just a fraction of the fish that have passed
“We’ve seen less than 10 percent of the fish (at Lower
Granite Dam) that passed Bonneville Dam. Ninety percent have disappeared,” said
Paul Wagner of NOAA Fisheries at Wednesday’s regional Technical Management Team
meeting. “From a record run to a bust.”
Last week the Idaho Department of Fish and Game asked NOAA
for an emergency action that would allow biologists to trap and transport adult
sockeye from Lower Granite Dam to the Sawtooth Valley in Idaho.
This week, according to Russ Kiefer of IDFG, Idaho promoted
an experimental operation that encompassed both Lower Granite and Little Goose
dams. The combined operation went into effect Thursday.
It includes: Operate Lower Granite Dam’s Unit 1 as the
priority turbine unit through the rest of the summer; spill the remainder of
the river in a uniform pattern. Trap and haul as many adult sockeye to Sawtooth
Valley and safety-net hatchery programs as is practicable.
All the fisheries managers agree with this operation, which
began a couple of weeks ago. Putting most of the water through Unit 1, the
closest turbine to the fish ladder, they believe, will provide flow and
slightly cooler water right next to the fish ladder and attract the fish to the
However, there was disagreement on the Little Goose
operation proposed by Idaho, which is to operate Units 1 and 2 from 4 am to 8
pm with no spill in two-day blocks beginning July 23 at 4 am, and to operate
spillways normally, which is to operate one turbine and spill the remainder,
from 8 pm to 4 am.
In a letter, NOAA Fisheries staff recommended this operation
at Little Goose Dam as a test “to assess whether more adult sockeye can be
encouraged to concentrate near the ladder entrance and increase the proportion
of these fish passing upstream over the dam over the next 1-2 weeks.”
“Given the relative importance of Endangered adult sockeye
salmon, (compared to likely effects on Threatened fall Chinook smolts), NMFS
believes that actions attempting to improve passage conditions – which, if
successful would provide additional adults for the trap and transport efforts
at Lower Granite Dam – are warranted,” the letter continued. “The operation of
two powerhouse units during the time of highest adult sockeye passage would
provide all the flow and the coolest water near the fishway entrances,
encouraging sockeye to congregate, and find the ladder entrances. This would
likely increase the probability that adults will successfully pass upstream
through the fishway and migrate on to Lower Granite Dam.”
TMT will meet Monday, July 27, to assess whether this
operation is working (see TMT’s agenda for July 27 at
http://www.nwd-wc.usace.army.mil/tmt/agendas/2015/0727_Agenda.html) and at
least weekly for as long as the operation occurs.
The Oregon Department of Fish and Wildlife opposed the
Little Goose operation and Thursday issued a warning that it was elevating the
issue to the Regional Implementation Oversight Group.
“Given Oregon and others earlier objection to this planned
operational change at Little Goose Dam and the solidification of a similarly
premised special operation that did not clearly demonstrate an association
between the operational changes at Lower Granite Dam and adult sockeye passage
over Lower Granite Dam, we feel it necessary to elevate this discussion to the
Regional Implementation Oversight Group process,” wrote Erick Van Dyke,
Oregon’s representative to TMT, in an email to TMT members.
Fisheries managers had met Monday to consider Idaho’s
proposal, but there was a lack of consensus. Oregon clearly opposed the
operation at Little Goose and Steve Haesecker of the U.S. Fish and Wildlife
Service worried juvenile chinook passage at Little Goose Dam would suffer.
Charles Morrill of the Washington Department of Fish and
Wildlife wondered if the lost fish are really still there below Lower Granite
and Little Goose dams, although he didn’t object to Idaho’s proposal.
However, Kiefer, clearly distressed by the lack of movement
by whatever sockeye are still in the river, made an impassioned plea to at
least try the operation and check its success after the weekend.
“Our idea is to change things up, and by changing to get the
sockeye to pass,” Kiefer said. “The more we delay (changing operations at
Little Goose), the more they die. There is a passage issue at Goose and time is
“Russ (Kiefer) makes a reasonable proposal. The sockeye are
on life support,” said Jim Litchfield, representing Montana at TMT. “On the
other hand, fall chinook are migrating. If I was to take risks, I’d side with
Another tool managers have to keep the Snake River cool at
Lower Granite Dam is releases of cool water from Dworshak Dam. Releases have
been at full powerhouse, about 9,500 cubic feet per second, since last week. In
an effort to conserve water in the Dworshak reservoir for August flows, Steve
Hall of the Army Corps of Engineers in Walla Walla suggested dropping flows to
7.5 kcfs while air temperatures are lower in Idaho, which they did Thursday at
midnight. Flows will be adjusted if conditions change.
If flows continue at full powerhouse through July, Hall
said, then average flows from Dworshak during August would be 6.1 kcfs. If
flows drop to 7.5 for just four days, August flows could be 6.4 kcfs.
To further complicate the task of keeping water cool in the
lower Snake River, Idaho Power will begin releasing 71 degree water beginning
the first of August from its Hells Canyon Dam. That will create a challenge to
meet the 68 degree required temperature in the Lower Granite Dam tailrace, Hall
said. The company is required to release a total of 243,000 acre feet of water
in early August to augment flows, regardless of the water temperature.
For background, see:
-- CBB, July 17, 2015, “Snake River Sockeye Trapped,
Transported At Lower Granite; ‘Fish Are Stressed And In Rough Condition,” http://www.cbbulletin.com/434539.aspx
-- CBB, July 10, 2015, “Lower Granite Tailwater Temps Go
Above 68 Degrees; Returning Snake River Sockeye Stalling Through System,” http://www.cbbulletin.com/434488.aspx
-- CBB, June 12, 2015, “NOAA Fisheries Releases Snake River
Sockeye Salmon Recovery Plan: 25 Years Of Actions At $101 Million” http://www.cbbulletin.com/434233.aspx