“The remains of the Glines Canyon Dam are located 13 river miles from the Strait of Juan de Fuca, the passage from the Pacific Ocean to Puget Sound. Eight miles downstream, the Elwha dam — built a century ago without accommodation for fish passage and long reviled by Native Americans and fishermen — is already gone, demolished in 2011 and 2012.
With the river now flowing freely, the legendary salmon runs — blocked for a century — have begun a tentative return to the Elwha’s 70 miles of salmon habitat, much of it in Olympic National Park. It is the dream of restorationists to bring back these extraordinary fish to the Elwha, most of which remains pristine, shaded by the gargantuan old-growth firs and cedars and primeval ferns for which the Olympic Mountains are famous.
The demolition of these two dams has become an evolving scientific experiment, one that entails the restoration of an entire watershed, from salmon to alders to otters. The two dams had starved the lower reaches of the watershed of sediment, and the lakes that formed behind them were filled with unnaturally warm water. Lake Mills and Lake Aldwell also elevated water temperatures downstream, and marine nutrients failed to cycle into the ecosystem, affecting species throughout the food chain, from black bear, eagles, and osprey at the top, to frogs and flies.”
Read more: Yale Environment 360