Impoundment dams block off a river, disturb its flow, and kill fish populations by ruining their migration patterns. These dams should be removed and replaced with run-of-river dams that divert a portion of a river--not block off the whole thing--to flow through turbines and generate hydroelectricity, and then return the water to the river. This is important for restoring natural ecosystems and biodiversity that has been destroyed by impoundment dams and fish hatcheries.



