Haven’t heard much about breaching the Lower Snake River dams lately. Here are facts you might want to share.
- If 16 million salmon returned to the Columbia River before Euro Americans reduced the populations by overharvest, dams, and other loss or destruction of habitats, the number of returning salmon was reduced 97 percent to 428,816 by 1939, the first full count at Bonneville Dam.
- Breaching the dams will provide no additional spawning habitat for spring/summer chinook, steelhead, coho or sockeye. Historically, flows were too low and too hot for spawning by salmon. The Lower Snake River was a migration corridor to spawning areas far upstream in the river or tributaries.
- Because of efforts by the Army Corps of Engineers to improve dam passage and operations, research has shown adult salmon survive past each dam at over 99 percent and juvenile salmon at over 98 percent.
- The highest counts of salmon have occurred from 2000 through 2024 with the Lower Snake River dams in place.
- Current spill operations required by the harvest management agencies and federal judge cause 40 percent to 60 percent mortality through the hydropower systems compared to 2 percent mortality to juvenile salmon collected and transported past downstream dams and reservoirs.
