Removing the White
Salmon’s 98-Year Old Condit Dam Marks the Return of Free
Flowing Waters for Protected Fish
Fall 2011
First Elwha, now
Condit. This October the region moved forward with a
plan to restore the White Salmon watershed to its
natural state by removing Condit Dam on the White Salmon
River, a tributary that flows through south-central
Washington and into the Columbia Gorge National Scenic
Area near Hood River, Oregon. The removal of Condit Dam
is one of the largest dam breaching projects in the
country, second only to the removal of the Elwha River
dams on the Olympic Peninsula of Washington State.
For nearly a
century now, Condit Dam has harnessed the energy of the
White Salmon River. It originally powered the Crown
Columbia Paper Company but more recently supplied
electricity to 7,000 local homes. The Northwestern
Electric Company completed its construction of the
125-foot structure in 1913, limiting the once vibrant
runs of salmon and steelhead to a three-mile stretch of
downstream habitat and preventing them from reaching
their historic habitat above the dam. Today, the runs
have declined so significantly that Tule fall Chinook
salmon, steelhead, and bull trout are protected under
the Endangered Species Act.
In 1996,
PacifiCorp—the owner and operator of the dam—was
directed by NOAA Fisheries to provide adequate fish
passage for threatened salmon and steelhead as part of
the Federal Energy Regulatory Commission (FERC)
relicensing process. This required extensive
modifications to the existing facility and the company
found it most cost effective to pursue decommissioning
and removal. Working with state and federal agencies,
the Yakama Nation, local governments, and several
environmental groups, PacifiCorp signed a settlement
agreement in 1999 to remove the dam and restore the
river to its free flowing state. Upon completion, 33
miles of habitat will be reopened to migrating Chinook
and steelhead.
On Oct. 26, crews
opened a tunnel at the base of the dam, releasing 10,000
cubic-feet-per-second of water into the Columbia River
downstream and draining the 92-acre reservoir in
approximately six hours. The event sent roughly 1.8
million cubic yards of sediment down the White Salmon
River. The sediment flow is expected to disperse in the
lower White Salmon and Columbia rivers behind Bonneville
Dam, and provide additional gravel for aquatic species
like steelhead and fall Chinook salmon. Water will flow
through the breached dam until next summer when crews
will finish dismantling the structure and by this time
next year Condit Dam will be a distant artifact.
As part of ongoing
monitoring efforts to evaluate the biological effects of
the dam's removal, scientists will evaluate fish passage
conditions for all adult fish migrating upstream. These
evaluations will occur over the course of
decommissioning and until the channels have stabilized.
Crews will correct all barriers to fish passage unless
the passage barrier is part of the natural geography of
the riverbed. Monitoring efforts will also assess
turbidity, total suspended solids, and pH levels in both
the White Salmon River and the Columbia River.
Through the Whole
Watershed Restoration Initiative, the NOAA Restoration
Center and Ecotrust are funding the Yakama Nation to
perform riparian plantings on three acres of the former
Condit Dam reservoir. The funding will also support the
Yakama Nation's efforts to reduce the spread of invasive
vegetation and it will contribute significantly to the
natural revegetation process at the historic site. This
active partnership will jump-start efforts to restore
habitat along the river and bring salmon, steelhead and
bull trout home, giving credence to the river's
namesake.
You can view the
breaching event via a webcast at: www.
pacificorp.com/es/hydro/hl/condit.html
To learn more
about the Condit Dam removal please see PacifiCorp's
website: http
://www.pacificorp.com/es/hydro/hl/condit.html
Photographs
Home page: Workers
survey the canyon of silt revealed when the 92-acre
reservoir was drained; photo by Scott Carlton, NMFS
This page, top
right: Aerial
view of Condit Dam prior to breaching; photo courtesy of
PacifiCorp
Below: Many
items came into view as the water drained; from early
dam construction materials to these tree stumps; photo
by Scott Carlton, NMFS