With an expected increase in solar radiation and air
temperature in the lower Snake River basin, river and power operators at
Wednesday’s Technical Management Team meeting began to use what could be the
last available water from Dworshak Dam until September to cool water in August
in the Lower Granite Dam tailrace.
While other juvenile and adult salmon continue to pass lower
Snake River projects, a bi-product of keeping water temperatures cool at Lower
Granite Dam is that occasionally an endangered sockeye salmon shows up at the
dam, as occurred this week, according to Russ Keifer of Idaho Department of
Fish and Game.
While the trap and haul operation officially ended August 5,
Keifer said the Nez Perce Tribe and IDFG received an extension of their permit
from NOAA Fisheries to continue the operation, but it is more on an on-call
basis. Rather than have a transfer truck ready at all times, IDFG will keep the
fish on site overnight and transfer the fish the next morning.
Three sockeye salmon showed up Tuesday this week, Keifer
said. They were kept at the dam and hauled the next day to the Eagle Hatchery
near Boise, Idaho.
That brings the tally of sockeye hauled to the hatchery to
50 fish, he said. Nine more fish have been trapped in the Stanley Basin,
bringing the total to 59 trapped fish. “As long as we think this (trap and
haul) is productive, we’d like to continue to do so,” he concluded.
Through Thursday, 403 sockeye had passed Lower Granite Dam
about 30 miles from Lewiston, Idaho, but concerns continue that only a fraction
of the fish will make it on their own into the Sawtooth Basin.
“It’s too early to say how many have died” and we won’t know
that for a while, according to Paul Wagner of NOAA Fisheries.
The southern-most population of sockeye salmon in the world
swims 900 miles from the Pacific Ocean to a 6,500-foot elevation in central
Idaho’s mountains to spawn.
The average tailwater temperature at Lower Granite Dam on
Thursday was about 67 degrees Fahrenheit, but Steve Hall of the U.S. Army Corps
of Engineers in Walla Walla said water temperatures in the Snake River Basin
will likely rise due to two factors: higher outdoor temperatures and clear
skies, resulting in more solar radiation, are expected, and a three-day release
of warmer water from Idaho Power’s Hells Canyon Dam begins this weekend to
accommodate the local boating community.
The discharge of cold water from Dworshak Dam on the North
Fork of the Clearwater River has been at 5,600 cubic feet per second since last
week, Hall said, and with that amount of water the reservoir is on target to
reach an elevation of 1,535 feet by August 31.
However, with higher water temperatures expected this
weekend, fisheries managers worried about fish passage at Lower Granite Dam if
the temperature rose above 68 degrees.
“We probably have a couple of days we can pass 7.5 kcfs,”
Hall said, mindful of the reservoir’s elevation limit, “but there’s not much
beyond that. It depends a lot on inflows. If we have more thunderstorm
activity, we’ll have water to work with.” Inflow into the reservoir is
currently 0.5 kcfs and last week inflow was 0.7 kcfs.
The flow increase would need to be made by Thursday at
midnight, he said, if the water is to benefit fish at Lower Granite Dam by the
weekend. Water from Dworshak Dam takes up to 72 hours to arrive at Granite.
After a short caucus, fisheries managers at TMT decided to
increase Dworshak’s outflow to 7.5 kcfs beginning midnight Thursday, August 13,
for two full days, reducing outflows to a range of 5.4 kcfs to 5.6 kcfs
Saturday at midnight, and then to revisit the operation next week.
This may be the last pulse of water available this month from
Dworshak to keep the Lower Granite Dam tailwater within the temperature
parameter of 68 degrees set by a NOAA Fisheries biological opinion. The
required Dworshak reservoir elevation of 1,535 feet is to ensure there will be
enough cold water for salmon migrations in September and later.
As of August 13, the Fish Passage Center reports that 510,245
sockeye, most headed to Central Washington, had reached Bonneville Dam, but
counts have progressively diminished upstream, to 429,001 at The Dalles, and 277,979
at McNary Dam.
“This is the second highest sockeye run on record, said Dan Rawding,
Washington Department of Fish and Wildlife, at this week’s Northwest Power and
Conservation Council meeting in Missoula, Montana. “But, just 277,000 passed
McNary Dam.” That’s just a 54 percent conversion rate, but still 150 percent of
the 10-year average for sockeye passage by that date.
“However, we can’t account for 200,000 and that’s due to
water temperature,” he said, adding that sockeye are less tolerant to higher
temperatures than other adult salmon. “Fish are making it up the Wenatchee
River, but the jury’s still out for the Okanagan River.”
For Snake River sockeye, as of Thursday, August 13, 1027 were
counted at Ice Harbor Dam, 873 at Lower Monumental Dam, 558 at Little Goose
Dam, and just 403 at Lower Granite Dam. One known sockeye has naturally
migrated up the Salmon River to central Idaho.
When Idaho sockeye were listed in 1991 under the federal
Endangered Species Act, only four adult sockeye returned to the Sawtooth Basin.
The combined annual returns from 1991-99 was 23 fish, including two years when
no sockeye returned to Idaho.
Trapping and transporting sockeye is one of many safeguards
IDFG implemented to restore the Snake River sockeye population.
Another safeguard is IDFG’s captive breeding program, which
raises sockeye from egg to adult in a hatchery, foregoing the trip to the
ocean. The program ensures that regardless of how many adults return this summer,
the agency will still be able to ramp up its release of juveniles in the
At this week’s Council meeting, Ritchie Graves of NOAA
Fisheries, the federal agency that implements the Endangered Species Act for
salmon, said Northwest fishery managers coordinated their efforts well this
year in response to the extraordinary conditions and plan to issue a report
this fall. Graves said it is scientifically impossible to tell whether the 2015
conditions were an aberration or a harbinger of future summers, a new normal.
“Personally, I think we need to plan for events like this to
recur,” he said.
As for sturgeon, Tom Rien of the Oregon Department of Fish
and Wildlife told the Council at its two-day Missoula gathering that 134
“oversized” sturgeon – large fish of spawning age - have been found dead in the
Columbia. There are many possible causes for the die-off, he said, including
prolonged exposure to warm water and gorging on dead sockeye. Dead spring
Chinook salmon and steelhead also have been found in the Columbia, notably
downstream of Bonneville Dam, Rien said.
-- CBB, July 31, 2015, “First Snake River Sockeye Reaches
Sawtooth Basin; Fish Trapped At Lower Granite Taken to Hatchery,” http://www.cbbulletin.com/434645.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