Condit Dam Removal Condit Dam Removal - Access Washington

Condit Dam Hydroelectric Project
Final Supplemental EIS
Dam Breaching and Removal
Sedimentation or scour of downstream riparian habitat from dam removal and woody debris
removal is likely to remove or kill much of the vegetation. The new deposits of sediment
along the river edge will be colonized by riparian vegetation. The end result will be a similar
amount of riparian area, but there will be some temporal loss.
Sediment will probably cover and kill any existing Columbia River tiger beetle larvae
occupying sandy beach habitat along the White Salmon River. The amount of available
sandy beach habitat in the lower reach of the river should increase significantly after dam
breaching and Columbia River tiger beetle populations, if they exist in the project area,
should recover quickly to a higher than pre-project levels due to the increase in available
habitat. This increase should be long-term, but will decrease over time as sandy sediments
are transported from the lower reach of the river and into the Bonneville pool.
Post-Removal Management
No new impacts are expected.
4.5.3 Mitigation Measures
• PacifiCorp has provided a revegetation plan designed to encourage development
of natural habitats.
• PacifiCorp will contribute $25,000 (1999 dollars) for habitat enhancement.
4.5.4 Significant Unavoidable Adverse Impacts
There will be no significant unavoidable adverse impacts.
4.5-2