A case in point is the Elwha River on the Olympic Peninsula in Washington, where two hydroelectric dams built early in the last century exacted huge environmental costs but were no longer important as power generators. Salmon runs that once reached about 400,000 fish a year dropped to fewer than 3,000. A year after the Elwha Dam was removed, Chinook salmon returned to the river in numbers not seen in decades, with three-quarters of them observed spawning upstream of the former dam site. Today, the river runs free from its headwaters in Olympic National Park to the Strait of Juan de Fuca, and a terrible wrong imposed on the salmon-dependent Lower Elwha Klallam tribe has been righted.

President Obama should learn from that example. Most urgently, he should turn his attention to the Snake River in eastern Washington, where four dams along its lower reaches provide marginal (and replaceable) electricity generation that is outweighed by the opportunities for the revival of endangered salmon populations, plus the jobs and communities a healthy salmon fishery would support. Those deadbeat dams should be taken down and added to the list of dams in the process of being removed along the White Salmon River in Washington, the Penobscot in Maine and the Klamath in southern Oregon.

I’ve been working to take down dams for most of my life. The idea, once considered crazy, is gaining momentum. We should seize it and push for the removal of the many dams with high costs and low or zero value. The environmental impacts are too enormous.