Switches will be flipped today on the Elwha River, as generators at two notorious hydroelectric dams — the Elwha and the Glines Canyon — are turned off. It’s a significant first-step in a process that will continue this summer, prepping the dams for their impending destruction.
Now, the pieces have finally fallen into place. This September, the first chunks of concrete will come out, kicking off the largest dam removal in U.S. history, and an equally colossal ecological experiment. “The dam removal on the Elwha is a science Olympics of sorts, a chance to watch natural processes in play as the river and its surroundings undergo ecological changes on a scale not seen before,” reported the Seattle Times last year. How salmon will recolonize the river, and how the river will respond to a massive release of sediment from the dams’ reservoirs, are among the project’s great unknowns.
Here’s a quick by-the-numbers look at the historic project:
390,000 Number of salmon and other sea-run fish that annually returned to the Elwha to spawn before the dams went up
3,000 Number of salmon and other sea-run fish that annually spawn in the Elwha today
5 River miles sea-run fish have access to on the Elwha with the dams in place
70 Miles of habitat sea-run fish will have access to on the Elwha and its tributaries once the dams come down
~ 24 million Cubic yards of sediment sitting in the dams’ reservoirs, “enough to fill a football stadium two miles high,” according to the AP
400,000 Plants expected to be planted to restore habitat where the reservoirs were
$27 million Value of contract to remove the dams
3 Years it’s expected to take to remove the dams
Cally Carswell is HCN‘s assistant editor
Photo courtesy National Park Service
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