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Elwha Dam Removal Update, February 2014: What Remains of the Dams?

Posted in Emerging Policy, Endangered/Threatened Species, Geeky Science Stuff, Natural Resources and Environment

It has been a while since my last dam removal update, and there is a lot to report. At the one year mark (September 2012), the lower dam had already been removed. Since that time, the area surrounding the dam has continued to be re-vegetated and the difference between September 2011 and September 2013 is dramatic:

 The work on the Glines Canyon Dam proceeds as well, but at a slower pace. Last spring, excess sediment clogged the water treatment plant that was installed to provide an alternate source of water to Port Angeles during the removal of the dams. That led to a stoppage of work on the removal of Glines Canyon Dam that lasted through summer and into fall while the treatment plant was repaired and as the strategy to remove the remaining portion of the dam was altered.

Over the summer, Glines Canyon Dam looked like this:

Removal of Glines Canyon continued in October, where a series of blasts reduced the remaining portion of the dam:

Then, in-water work was stopped during November and December for salmon protection reasons.

The contractor resumed removal activities the past few weeks. Two blasts, one in late January, and one last week, resulted in the dam almost disappearing:

More pictures and a video of the January 27 blast are available at John Gussman’s website.

After this weekend’s rain, the Glines Canyon Dam area looks almost like a free-flowing river, although I’d anticipate that a significant amount of debris is under that high water:

All of the above images are courtesy of  the National Park Service and Erdman Video Systems. More imagery is available on Erdman Video System’s great website. If you have time and a decent internet connection, it is worth looking at some of the imagery there–we’re lucky that technology is able to capture and archive the changes in the river.

It will be interesting to watch the remaining sediments and stretch of river above the dam react to these latest blasts. If you watch the slideshow for Lower Lake Mills starting in late January, you can watch the river cut downward into the remaining lake bottom sediments as more and more of Glines Canyon Dam is removed. Originally, the plan was to have the river meander back and forth in these sediments to wash them out as Glines Canyon Dam was taken down in segments, but it looks like we’ll end up with a bit of a canyon through the sediments, which I understand was a decision made in response to the water treatment plant issues the project experienced last spring.

Finally, I was out near the river mouth itself about a month ago, and the change there is absolutely mind-boggling. That river mouth used to be mostly cobble to boulders, with very little fine-grained sediment. Now, it is a fairly large delta consisting of sand to silt sized sediment–a totally different place.

This dam removal has been a massive undertaking. I’m impressed by how the project has proceeded, it appears to have been remarkably well-managed by the National Park Service so far. The habitat that is being made accessible to anadromous species is significant, as is the new in-water habitat that will come from the dam removals. I’m excited to watch this project continue to evolve.