Un-Damming the Elwha
A river in Washington dammed for almost 100 years will soon be set free. As Ashley Ahearn from Earthfix reports, scientists are taking measurements of the Elwha River’s ecosystem so they can have a baseline snapshot of the river’s health.
GELLERMAN: It’s Living on Earth, I'm Bruce Gellerman. In a few weeks, workers will start dismantling the Elwha and Glines Canyon dams in Washington State. The effort is the largest dam removal project in the world. The Elwha River has been dammed for nearly a century, generating electricity for the region, but it prevented salmon from making their legendary annual runs.
As engineers prepare to take down the two hydropower dams, scientists are hurrying to collect baseline data, so they can compare the Elwha River now and when it’s dam-free. Ashley Ahearn prepared two reports about the un-damming of the river. This week, we have her first.
[SOUND OF GURGLING WATER]
AHEARN: In a side channel of the Elwha, nestled between the two dams, there’s a scientist walking around in hip waders sporting a backpack that would make the Ghostbusters jealous.
[SOUNDS: BEEPING, WADING, SPLASHING]
MORLEY: That’s actually a modified car battery on the back of that. They’re electrofishing and it’s a way of temporarily stunning fish, and fish, such as salmonids that have swim bladders, will then float to the top.
AHEARN: Sarah Morley is crouched by the river, surrounded by buckets, bottles and nets. She’s one of a team of scientists from the National Oceanic and Atmospheric Administration that’s trying to record the food web of this river.
Basically, they’re trying to figure out who’s living here, who’s eating whom and how that might change once the dams are removed. Morley reaches into one of her buckets where several rainbow trout are recovering from their run-in with the Ghostbuster backpack.
MORLEY: So we’re going to do something called “gastric lavage” which is a non-lethal way of collecting their stomach contents - kind of like when you go to the hospital room and they make you throw up if they think you’ve ingested something toxic.
AHEARN: Morley grabs a fish and squirts water on its snout until it opens its mouth. Then in goes the syringe, and more water is used to flush out the brown, gunky contents of the rainbow trout’s belly.
MORLEY: Sometimes moving the needle in and out helps pull it out a little bit. So this is what was in the belly. This looks pretty digested - lots of small pieces.
[FLOWING WATER SOUNDS]
AHEARN: While Morley and her team are trying to map out what’s going on at the bottom of the food chain in this river, another team from NOAA is trying to figure out how the river itself is going to physically change once the dams come out.
And this is where the story gets personal. It’s my first time in hip waders, clambering over some pretty big slimy rocks in about 3 feet of water. I’m off to catch up with the other team of scientists when, before I know it, I’m on my back in the Elwha, I’m soaking wet, and so is my equipment.
George Pess leads NOAA’s restoration monitoring team on the Elwha. He explains that I didn’t slip simply because I’m a klutz (although that’s a big part of it). It’s about the rocks, which he and his team are measuring in this section of river.
[SPLASHING SOUNDS: “47…42”]
AHEARN: Most of the rocks here below the dams are the size of softballs to basketballs and larger.
PESS: It’s definitely a sediment-starved river. So what that means simply is that all the smaller material eventually kind of goes away with nothing coming upstream.
AHEARN: Rivers are like conveyor belts. They move massive amounts of sediment. When the dams went in that sediment flow was blocked. Now there’s about 23 Empire State Building’s worth of smaller-grained material built up above the dams, with mostly big slippery rocks left below. And that’s not just a problem for clumsy journalists.
PESS: So when the salmon spawns, what it does is the female will turn to its side and actually move its tail and project the water down, and actually dig, basically, a nest. Now if you have really large material, it’s going to be really hard for a smaller fish to actually dig through that, you know, almost like a sheet of concrete.
AHEARN: Once the dams come out, water will flush the sediment down the lower river and into the Strait of Juan de Fuca. Scientists predict some wildlife mortality initially, but big picture, that sediment will eventually rejuvenate the estuary and restore critical spawning habitat for salmon. Turns out the sediment in a river is almost as important as the water.
[SOUND OF WATER]
AHEARN: There are no salmon above the dams anymore, but every year steelhead and chinook, coho, pink and chum salmon bump their noses at the base of the lower dam, as if they know what they’re missing out on.
Population numbers of these fish have steadily declined since the dams went in, but Pess says, things will turn around once the dams are out.
PESS: I think what you’ll see is a rapid rate of change with these species in terms of going from, let’s say, hundreds to perhaps thousands and even tens of thousands in some cases, for some within, you know, several decades. It may not be a quick turn around in the sense of somebody’s life, but it’s a quick turn around for ecological recovery.
AHEARN: The question is: are people willing to wait for the fish to come back naturally? The Lower Elwha Klallam tribe has built a new hatchery to boost stocks of steelhead, coho and other salmon in the next few years. George Pess and his team will continue monitoring the Elwha ecosystem through the dam removal process, which starts September 15th.
[SOUND OF GURGLING WATER]
AHEARN: I’m Ashley Ahearn on the Elwha River.
GELLERMAN: Our story about the Elwha comes to us from EarthFix. It’s a public media project that explores the environment of the Pacific Northwest. Next week, Ashley Ahearn continues her series on the historic Elwha River dam removal project and efforts to restore fish there.
WARD: Ultimately, I think we’re looking for thousands of adults coming back to the hatchery: chum salmon, coho, steelhead, and producing upwards of a million and a half or two million fish to be released.
GELLERMAN: Not so fast, there’s controversy along the river. Some people don’t want fish hatcheries there at all. Tune in next week for part two of “Un-damming the Elwha.”
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