Condit Dam Removal Condit Dam Removal - Access Washington

Condit Dam Hydroelectric Project
Final Supplemental EIS
The deposition of granular material in the in-lieu site and development of a stable channel
may eventually provide a habitat similar to that which naturally occurred at the mouth of the
White Salmon River before the creation of the Bonneville pool. It is likely that the majority
of the production of fall-run Chinook salmon before the construction of Condit Dam
occurred in the lower 2.6 miles of the river and particularly in the low gradient reach near the
mouth of the river. Juveniles produced in this stretch are limited to the habitat available
below falls such as the one at RM 2.6 because they cannot ascend over any but the most
minor falls.
The banks of the channel created by the river down-cutting through sediments deposited at
the in-lieu site also may e deep and have a very steep angle, well above the stable angle of
repose. Bank sloughs can have lethal consequences for fish, as described above in the
upstream sediment management section. The situation may be prevented if the dam is
breached at a time when the Bonneville pool is at the low end of the range of pool depths.
4.3.3 Cumulative Impacts
The notable potential cumulative impacts from removal of the Condit Dam relate to
management of the fish and fisheries in the river. The new fish stocks that will occur above
the current dam site would undoubtedly attract fishermen. A definite potential exists for the
fishermen to adversely affect resident trout populations while pursuing anadromous fish.
This would be both an indirect and a cumulative impact, since fishermen currently catch
resident trout in the reservoir and the river system above it. The impacts are manageable by
WDFW fishing regulation modifications and enforcement. Therefore, there is no need to
consider the effects to be either significant or unavoidable.
The other potential adverse cumulative effect could result from supplemental hatchery
actions that might be used to help the anadromous fish stocks to become established after the
dam is removed. If fish stocks are brought in from elsewhere to get a start or supplement the
establishment, there are risks of causing unintended adverse impacts on other stocks, such as
interactions with residual steelhead, or introgression that might reduce their fitness, or
outright competition. Specific measures can be taken to minimize or avoid such impacts
(Nielsen 2005). Therefore, these effects also are avoidable or manageable to a level that
would probably be insignificant. All such actions would be managed by the state and federal
resource agencies responsible for the fish.
There would also be long-term cumulative beneficial impacts, since there are regional efforts
to recover populations of anadromous salmonids. The regional efforts would be furthered by
the removal of Condit Dam.
4.3.4 Mitigation Measures
Pre-Dam Removal Activities
Haul Roads, Staging Areas, and Disposal Sites
• To reduce the delivery of fine sediments to the White River stream channel, areas
where soil has been disturbed will be revegetated in accordance with the plan for
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