Think Out Loud

In Washington, fish populations improve after dam removal in Elwha River

By Elizabeth Castillo (OPB)
Aug. 5, 2022 3:29 p.m.

Broadcast: Friday, Aug. 5

When this photo was taken, about 3 million cubic yards of sediment had been flushed down the Elwha River since dam removal began in 2011. That’s only 16 percent of what’s expected to move downstream over five years.

When this photo was taken in 2020, about 3 million cubic yards of sediment had been flushed down the Elwha River since dam removal began in 2011. That’s only 16% of what’s expected to move downstream over five years.

Katie Campbell/KCTS9


About a decade has passed since two dams were removed in the Elwha River. The health of the river has improved and dwindling populations of salmon are recovering. Mike McHenry is a fish habitat manager with the Lower Elwha Klallam Tribe. He shares more details on how the fish are doing and how their habitat has changed.

The following transcript was created by a computer and edited by a volunteer:

Dave Miller: It has been 10 years since the first of two century-old dams on the Elwha River, on Washington’s Olympic Peninsula, was breached. It was the largest dam removal project in U.S. history. The dams were taken down in large part to help salmon and steelhead. So how are those fish doing? Mike McHenry joins us now. He is a fish habitat manager and biologist with the Lower Elwha Klallam Tribe. Can you remind us first why these dams were good candidates for removal?

Mike McHenry: The dams in the Elwha and on the Olympic Peninsula have had a long history. The first dam was built at river mile five in 1910 and it was built basically to provide power to the city of Port Angeles, which was getting ready to capitalize on its wealth of forest resources. It was going to [provide] power to build the city and then to build mills for the timber harvests that were coming. The lower dam was built without fish passage facilities in direct conflict with state law at that time, which basically said that you can’t do anything to impede fish passage. But that law has never been enforced in Washington state. The second dam was built in 1925. The Glines Canyon Dam was built at river mile 13, also without fish passage facilities. It was built within what later became the boundaries of Olympic National Park. Fast forward to the 1970s, dams in the United States are managed by Federal Energy Regulatory Commission work. Those dams now require licenses to operate. When the owners of those two facilities went to work to license the dams, an organized opposition to the relicensing of those dams occurred, led up by the Lower Elwha Klallam Tribe, who I work for, Olympic National Park, and environmental groups.

Miller: Fast forwarding a bit: Eventually there was political momentum and push back, but the momentum won for the dam removal. It took decades and decades for it to actually happen. Were you there for some of the dramatic moments of the breaching of the dams?

McHenry: Yes, I’ve been here for 30 years. I was here when the Elwha Act passed Congress and was signed by President Bush Sr. That act basically directed the Department of the Interior to assess the best way to restore the river. They concluded through a lengthy environmental impact statement process that removing the dams, letting the river transport the sediment naturally and restoring the fish runs to their historic habitats was the best way to do that. That act passed in 1994 and there was significant opposition locally and in the congressional delegation. Things got held up for almost 20 years after the act passed.

Miller: What was going through your mind when it finally happened, when these two dams were finally breached?

McHenry: It was pretty surreal because I was in on the planning process for fish recovery and revegetation and basically went through three different versions of the fish restoration plan during that time. The day that we found out that the project was going through was pretty surreal, I almost couldn’t believe it.

Miller: I remember people saying things like, “the fish will come back. This is going to happen quickly and once they have a way to go, they will find out where they need to go.” How quickly has that happened?

McHenry: The big deal on Elwha was, the sheer amount of sediment stored behind the two reservoirs. We had upwards of 20 million cubic yards of sand, gravel, and silt. We knew that during the removal process, at peak sediment load, that was gonna be pretty hard on the fish populations. And indeed, we have seen a lag in recovery of about five years until the riverbed stabilized and basically came into equilibrium with its sediment load.

Miller: Why is that? What is the effect that sediment and the sediment load has on fish?


McHenry: So at peak sediment, we had very high turbidity, enough to be lethal to fish that were rearing in the river.

Miller: Turbidity, meaning stuff moving through the water?

McHenry: Yes, at peak sediment transport there was so much material suspended in the water that it would basically clog up their gills. We had a lag in recovery until about 2018. Since then we’ve seen some pretty dramatic responses in the fish population. On Elwha we have four phases of recovery. The first was stock preservation, which was basically getting through the peak sediment period. We used hatcheries to do that. We’re now in the recolonization phase where the various stocks of fish are accessing their historic habitats and starting to reoccupy those places.

Miller: So what are the numbers like right now?

McHenry: It varies. Salmon populations are notoriously variable, which makes monitoring them difficult. But we’re seeing positive responses in the coho salmon population. Last fall we had 6,000 returning adults and those were a mix of natural and hatchery-produced fish. The chinook population has varied from 2,000-7,000 returning adults. The steelhead numbers are building, and we’re seeing more and more wild fish, approximately 2,500 fish last year.

Miller: Is your hope that going forward there could be sustainable runs on this river that don’t require hatcheries, or will there always need to be hatchery additions?

McHenry: That’s the goal in our fish recovery plan is to basically convert this population that was completely propped up by hatchery production when the dams were in, to a rewilded population that has wild returns naturally producing, and greatly dialed back, if not eliminated, hatchery production. That’s definitely my hope.

Miller: As you’ve been talking about, the numbers have been bouncing around, but as of about four or five years ago they’ve really been on the rebound. What has this return of these hugely important fish meant for members of the Tribe that you’ve worked with for 30 years?

McHenry: The tribal members are very excited. They’re very proud of their role in the project and freeing this river. They’re very excited to regain access to some of their cultural sites that were inundated in the reservoirs. They’re anticipating greatly being able to go back and fish and get their hands on the resource that sustains them historically.

Miller: Has anything surprised you about this process of post dam breaching reconstitution of habitat?

McHenry: It’s really been amazing to watch. What you do when you dam a river is a pretty egregious act. You starve it of the building blocks it needs to create and maintain habitat. It’s pretty simple with rivers: They need water, they need a sediment supply that [includes] everything from boulders to fine sediment, and they need trees. In the Pacific Northwest we need big trees because the wood is an elemental habitat-forming feature. [We’ve seen] the river, almost overnight, go from sediment-starved to being sediment-oversupplied for a couple of years and then coming into balance with its sediment supply. It rebuilt habitats that were lost, including the estuary habitat because of sediment starvation from the dams that have become very eroded, it lost historic estuary areas. The beach was coarse and steep and now, following dam removal, we have a 120-acre estuary that’s absolutely beautiful and thriving with life. The floodplain, which was also sediment-starved, got a mantle deposit of fine sediment [and now] natural vegetation is flourishing. It’s been really fulfilling.

Miller: You noted that the dream and the plan is for members of the Lower Elwha Klallam Tribe to finally be able to fish again. What’s the expected timeline for that?

McHenry: The Tribe and co-managers of the state of Washington, the Tribes of fishery resources, have agreed to a moratorium on fishing that has been in place now for a decade. The moratorium is now to the point where it’s being evaluated annually in the spring. There is the likelihood within the next couple of years that a subsistence-type fishery could be implemented for returning coho salmon. I don’t think we’re ready to fish on our listed stocks, which are steelhead and chinook salmon – they need to continue to rebuild. But the coho population appears to be rebounding very quickly.

Miller: Meanwhile, an even bigger dam removal project is moving forward in upper Northern California, four dams on the Klamath River. What are you most interested in in terms of the post-removal process there?

McHenry: The Klamath steps into the spotlight and becomes the largest dam removal project in this country. I think in contrast to Elwha, which was really a large sediment management project, because there was so much sediment, there’s less on the Klamath. What the Klamath offers is a lot more habitat. The Elwha opened up something like 100 miles of habitat and the Klamath opens several hundred miles of habitat. I’m really interested to see what happens. I know the folks from Klamath have come up to Elwha and we’ve sort of exchanged notes. They have their own monitoring plan for that system. I think it’s going to be really exciting to see what unfolds there.

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