The Elwha River is free!
August 27, 2014 2:31 PM   Subscribe

With the last scheduled blast on the Glines Canyon Dam the Elwha River is flowing completely free for the first time in a century.

The Elwha River, located on the Olympic Peninsula in Washington State, was first dammed in 1913 by the Elwha Dam, with the Glines Canyon Dam following in 1927. While the dams originally powered multiple towns, paper mills, and a Navy yard, Thomas Aldwell (the civic leader behind the dams' construction) built the dams without fish ladders in violation of state law, and the hatchery he proposed as a solution never successfully produced fish. This limited fish runs to the lower 5 miles of the river, drastically reducing salmon and trout populations and cutting off an important resource for the Lower Elwha Klallam Tribe as well as wildlife upstream.

Over time power demands far outstripped dam generation and in 1978 the Elwha Dam failed a federal safety inspection. Safety concerns combined with tribal calls for river restoration and public concern over a dam in a national park (when Olympic National Park was formed it contained Glines Canyon Dam and its reservoir Lake Mills) resulted in the 1992 Elwha River Ecosystem and Fisheries Restoration Act and the 1994 Elwha Report which concluded that full removal of both dams stood the best chance for total restoration of the Elwha ecosystem.

It took nearly 20 years to plan the removal and secure the $325 million in funding required for the project (federal stimulus money played a role) and demolition began in September 2011. The price of the project is tied to its scope: it's the largest dam removal project in U.S. history in terms of height (Glines Canyon Dam was 210 feet tall) and more importantly sediment load. A total of 19 million cubic meters of sediment [PDF] was trapped in the reservoirs, most behind the upper Glines Canyon Dam. The trapped sediment caused serious problems with beach erosion at the river mouth and even required the Army Corps of Engineers to armor Ediz Hook, the spit that shelters Port Angeles' harbor. The loss of sediment input also changed the seafloor composition off the river mouth, altering the makeup of the benthic community.

Because of the large amount of sediment to be released and the desire to get the river back to its natural state as quickly as possible a dramatic reservoir draining like the Condit Dam removal would be too damaging to the lower river. A gradual demolition approach was adopted. Much less sediment was behind the Elwha Dam so its removal only took months, while the Glines Canyon Dam had to be demolished much more carefully. The process also slowed as it progressed because the dam was thicker at the bottom and demolition was frequently halted for two weeks at a time to prevent sediment release from interfering with fish runs. Armies of volunteers revegetated hundreds of acres of newly-exposed lakebed in hopes of preventing invasive species gaining a foothold and reducing erosion of some of the lake sediment.

Immediately after the Elwha Dam was removed fish began spawning above it for the first time in a century and biologists have relocated some spawning salmon upriver in hopes of jump-starting recovery. There have also been dramatic growth of beaches at the river mouth, indicating that over time the river may undo the erosion caused by the dams (you can see some of the growth in these timelapses). This new sediment transport means sediment levels will likely get high enough in times of stormy weather and high river flow to suffocate fish in the coming years, but the long-term impact of the project on fish runs is projected to be overwhelmingly positive.

Estimates range from 15-40 years for total recovery of the Elwha ecosystem. Teams of scientists from many federal agencies and universities are studying every aspect of the process, and it's being used as a model for other large dam removals.

More info:

The USGS keeps a list of Elwha publications. This report specifically has tons of background on every aspect of the project (that I stole for this post).

A slightly cheesy documentary by the local public TV station.

The Seattle Times coverage won an AAAS Science Journalism Award. Lynda Mapes in particular has continued to write articles and blog about the project. Her most recent article is here.
posted by edeezy (9 comments total)

This post was deleted for the following reason: Poster's Request -- frimble

Great post!
posted by the man of twists and turns at 2:32 PM on August 27, 2014

posted by No Robots at 2:35 PM on August 27, 2014

posted by hal9k at 2:54 PM on August 27, 2014 [3 favorites]

What they said!
posted by Melismata at 3:00 PM on August 27, 2014

That is one ballsy excavator operator. I hope they had some kind of escape plan if they started to go over.
posted by echo target at 3:23 PM on August 27, 2014 [1 favorite]

This is an awesome post!

I remember hearing about the proposed demolition of Elwha Dam back when I lived in the PNW in the early 90s; I think I had some friends who were working on it, but at the time I didn't really believe it would ever happen. Nice to see I was so wrong.
posted by suelac at 3:24 PM on August 27, 2014

I want to buy a raffle ticket to push the plunger on the explosion of the next dam to go. It ought to be an Acme brand wooden box with the handle on top, as seen in cartoons. Tickets should be 25 bucks a pop and the funds should go to river restoration. I've been fantasizing about this sort of fund/awareness raiser for years.
posted by ssr_of_V at 3:30 PM on August 27, 2014

This really is an incredible story. How often is environmental news actually inspirational? And for the Americans among us, how often do we get to see our own country lead the way? To put this in perspective, many sources say the Glines Canyon, Condit, and Elwha Dams are the first, second, and third biggest dams ever removed, not just in the U.S. but in the entire world. And we may yet overtake those removals with projects on the Klamath River.

In all, over 1,100 dams have been removed in the U.S. So far, we're responsible for more than half the world's dam removals — and hopefully that won't be the case for too much longer, as France and other countries follow our lead. Patagonia sponsored a documentary about dam removal that came out earlier this year. There's also another documentary specifically about the Elwha coming out next month.
posted by neal at 7:55 PM on August 27, 2014

In my neck of the world, the old Bloede's Dam on the Patapsco River is up for removal, and I'm a little sad, as it's an important piece of industrial history, but it's also of an age where the concept of a whole environment in which we're a part and not the peak was just completely alien, so I'll pause on my bike and take it in while I can, and cheer on the eels when it blows. We've achieved great things, we evolved apes, but wisdom is a better monument than structures.
posted by sonascope at 5:39 AM on August 28, 2014

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