Proposed Snake River dam removals would break new ground

In terms of the size of the project, that is. Dam removals have become fairly common in the U.S., but not like this.

The surgical removal of the four dams would rapidly and dramatically change the river. Federal agency reports estimate that breaching would take about two years, but up to seven years could pass before the river flushes out the built-up sediment behind the dams and finds a balance between sediment flow and water. Water levels would drop, with dams no longer keeping them artificially high. Connective streams would re-emerge. Salmon numbers may improve, and, eventually, the three hatchery operations run by the Nez Perce might be pared down.

Dam removal doesn’t guarantee a full recovery, though, given the turbulent ocean conditions and degraded freshwater quality. Habitat elsewhere is also involved — other bodies in a larger community are experiencing their own pains. Still, last year the National Oceanic and Atmospheric Administration agreed that breaching is necessary for salmon recovery, the first time a federal agency has come to such a conclusion and an important sign of support. - High Country News