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Hydroelectric Dams and the Decline of Chinook Salmon in the Columbia River Basin

The decline of chinook salmon runs into the mouth of the Columbia River in recent decades is thought to be partly attributable to the construction of hydroelectric dams. The purpose of this article is to estimate the magnitude of losses in chinook salmon runs caused by hydroelectric dams, using regression analysis. Such estimates are not only of historical interest but also can potentially affect the extent of efforts to mitigate salmon losses from hydropower operations. Congress has mandated the Northwest Power Planning Council to consider the magnitude of run losses caused by hydroelectric operations in determining the extent of mitigation efforts.