Over time people have caused extensive damage to rivers by scouring their banks with logs, channelizing them through towns and cutting them up with dams. In the last 50 years, scientists have discovered removing dams can vastly improve conditions in rivers. But not all dams can come down. Sometimes they are our greatest protection against invasive species.
For the first time, scientists believe it may be possible to have it both ways—allow fish to move throughout rivers and still block pests.
Credits for this episode:
Hosts: Dan Wanschura and Morgan Springer
Reporter/Producer: Taylor Wizner
Editor: Morgan Springer
Consulting Editor: Peter Payette
Music: Max Dragoo, Marlin Ledin
Logo: Erin O'Malley
Transcript
MORGAN SPRINGER, CO-HOST: From Interlochen Public Radio this is [Un]Natural Selection. A series about people tinkering with the natural world. We ask the question, are we helping the environment or hurting it? I’m Morgan Springer.
DAN WANSCHURA, CO-HOST: And I’m Dan Wanschura. Episode six. Damned If We Do. Damned If We Don’t.
TAYLOR WIZNER, BYLINE: Yep. This is a story about dams.
SPRINGER: That’s reporter Taylor Wizner.
WANSCHURA: Taylor, what do you have for us today?
WIZNER: Well by sheer luck, the dams we built happened to save a lot of our rivers from a bit of a catastrophe. But, of course, there are twists. And that’s where we’re going today.
SPRINGER: Ok, so many questions. So let’s get into it.
WIZNER: We’re going to start with just a little bit of history.
Back when European settlers first came, they built dams to divert water for drinking and irrigation. It was also really beneficial for things like electric power and flood control, but now we use them much less.
MARC GADEN: Many of those dams have long outlived their purpose and are just there, deteriorating.
WIZNER: That’s Marc Gaden. He handles communications for the Great Lakes Fishery Commission. Basically Marc says there’s only three solutions. You repair a dam. You replace it. Or you take it out.
And there’s this whole group of conservationists who are really in favor of taking out dams. They've found that dams actually hurt the river ecosystem. Dams carve up the river and block fish movement between their habitat and other parts of the river system.
GADEN: And if they've been denied access, what happens is the whole ecosystem of that river changes.
WIZNER: That’s already happened in the Great Lakes. Grayling and Atlantic salmon disappeared from its waters in the last 150 years because of dams, as well as overfishing and habitat loss. And today Lake Sturgeon populations are just one percent of their historical abundance, largely because of dams.
But river biologists say it may be possible to bring some of those fish back by taking out the dams.
WIZNER: I’m sitting beside a creek with writer Mike Delp. We’re at his fishing cabin outside of Traverse City, Michigan. This creek feeds into the Boardman-Ottaway River. A couple miles upstream, there used to be a big dam.
Mike fishes here almost every day in the summer.
MIKE DELP: I go back a long way with the Boardman. This particular section I know really really well. I know it well enough to fish in as dark as it gets around here.
WIZNER: Mike says since the dam was taken out, he’s noticed a larger number of brook trout — something he likes to catch and release.
DELP: The Middle Boardman and the Upper Boardman, it’s improved, there’s no question.
WIZNER: The dam that came out, it was one of four on the Boardman-Ottaway River. For a century, they created hydropower. Then, in the early 2000s, the power company stopped using them for electricity, so the city decided to remove them. The project organizers say it was the biggest dam removal project ever in the Great Lakes Basin.
To Mike, on the river, it looked like a success. But the landscape had changed dramatically. Where there had once been small lakes by the dams, it was now a wasteland. Some people in the community had a harder time accepting it. One day two ecologists overheard a couple talking.
BRETT FESSEL: They were remarking on how awful it looked that it was this barren landscape of tree stumps and black muck. And it’s just, ‘how could anybody do such a thing to a beautiful river?’
WIZNER: That’s Brett Fessel. He works with the Grand Traverse Bands of Ottawa and Chippewa Indians.
FESSEL: We both sat there listening and I badly, dearly, wanted to ask them, ‘Ok, park that perspective for right now and return to this very place next year.’
WIZNER: By then it had all greened up and Brett noticed animal activity he’d never seen there before.
FESSEL: You used to hear the drone of turbines and the fall of water, a very human-created condition. And now you go and you hear the water but you also hear the birds. You hear everything there. The wind, it’s not drowned out by this piece of infrastructure.
WIZNER: Only a few years in, the river ecology is stronger. One example is the temperature of the river has dropped seven degrees. Lakes heat up a river. So when you take out a dam, and the lake goes away, the river gets colder.
FESSEL: That simple shift in temperature has contributed to an expansion of range and also abundance of brook trout in the system. So that’s a signal to us that yeah this is going in a good direction.
SPRINGER: I’m just imagining this place. It sounds so beautiful and relaxing. And I really like that everything we imagined, it seems like it’s happening.
WANSCHURA: Yeah, this seems like a really good argument for dam removal and river restoration.
WIZNER: Yeah, our dream scenario, if only we didn’t have this other horrible problem to think about.
WANSCHURA: What’s that about?
WIZNER: Well there’s a segment of Great Lakes scientists who think most dams shouldn’t come out. Like Pete Hrodey, who works for the U.S. Fish and Wildlife Service.
PETE HRODEY: I certainly didn’t go to school thinking that I’d be advocating for keeping some dams in on the landscape.
WIZNER: But he does feel that way now because when dams were built they were protecting us against something we didn’t think about before: invasive species. Things like Asian Carp on the Mississippi River and certain types of mussels. In the Great Lakes region, the big threat is sea lamprey.
WANSCHURA: Oh yeah, I know about those. They’re like vampires really. They latch on to the fish and suck out its insides.
SPRINGER: Yuck.
WIZNER: Yeah they’re extremely harmful to Great Lakes fish. There’s a really stark example. Let’s head over to the Manistique River. It’s in Michigan’s Upper Peninsula. There’s a dam that blocks the Manistique River from entering Lake Michigan. But several years ago, it began to leak. At those leakage points, sea lampreys started swimming through the dam and entering the other side of the river. A single sea lamprey has about 100,000 eggs in its lifetime. And those eggs quickly become thousands of lampreys that are eating machines. Within a few years, the population doubled and then tripled.
SPRINGER: Sounds like a nightmare.
WIZNER: Oh, it is. Just one sea lamprey will destroy forty pounds of fish. And if the sea lampreys aren’t killed they can add up to hundreds of millions of dollars of damage to fisheries in the Great Lakes. On the Manistique alone, the federal government has spent $8 million treating the river over the last 20 years. The chemical they use, lampricide, kills larval sea lampreys. That’s millions of dollars spent because a dam wasn’t strong enough.
And at its core, that’s why Pete Hrodey wants dams to stay, for now. His job is to study technology that block or repel sea lamprey so that something like the Manistique doesn’t happen again. And what he’s found is, nothing blocks sea lamprey as well as a dam.
HRODEY: It's not even close, you know, a physical barrier that's well built and well placed and well operated and designed is still kind of the best thing that we have.
WIZNER: He says if we’d never put in dams, sea lampreys would have likely decimated all Great Lakes fish by now. So when communities and conservation groups started asking how they could get rid of their dams, Fish and Wildlife people like Pete Hrodey pushed back hard. That stopped a bunch of dam removals, including more than 20 in Michigan.
Fisheries officials across the country have blocked dam removal projects too. Dams in Iowa, Kentucky and Wyoming stopped non-native fish from moving further upstream.
WANSCHURA: So it sounds like there are two opposing problems here. Remove the dam and river ecosystems could flourish. But if you don’t keep the dam, invasives get through. Is there a way to tackle both of these things?
WIZNER: Well a lot of places have addressed the problem with a fish ladder. That’s where some fish can jump up a series of steps and basically hop over a dam. But that really only works for a handful of species, says Brett Fessel, that river biologist.
BRETT FESSEL: In the Great Lakes there aren’t mountains that need to be ascended by fish. So they didn’t evolve with the capacity to jump.
WIZNER: So the fish that can’t jump they can’t climb the ladder.
FESSEL: That’s the notion behind this is to have a system in place that could allow for those native species to ascend this river under their own volition.
WIZNER: They may be developing that system in Traverse City, Michigan. On the same river where we started, the Boardman-Ottaway, there’s actually one dam left. It partially upholds Boardman Lake, where there are homes, sailing lessons and a city park. It also blocks sea lampreys.
But it means the river isn’t fully restored. Even though the native brook trout are happier, most Boardman fish don’t have access to Lake Michigan, and Lake Michigan fish don’t have access to the Boardman.
A group of scientists is developing an idea called FishPass. Basically, they would keep a dam in place to catch all the fish but there would be a system on the side that would sort the fish. Dan Zielinski is the project manager. He says they might sort the fish using some pretty high tech methods.
ZIELINSKI: Image recognition. So being able to take a video or a photo of a fish, readily identify it, and then have that trigger like a gate that opens or closes to allow that fish to pass.
SPRINGER: That makes me think of facial recognition software. Ugh.
WIZNER: Yeah, I guess the age of surveillance applies to fish too. Yeah, so then the fish they want would move through the river into Lake Michigan, while leaving behind the fish they don’t want.
SPRINGER: Huh. Is this really the answer to our problems?
WANSCHURA: Yeah, it sounds experimental. How realistic is this project?
WIZNER: I guess that’s to be decided. Figuring out a system to selectively pass all the fish you want has already stumped researchers for years. That’s why scientists are so excited about FishPass because nothing of this scale has been attempted anywhere else.
FishPass would take research that’s happening in laboratories all around the world. Things like image recognition tech, or devices that repel certain fish, and then it would test them all together in an actual river, the Boardman.
ZIELINSKI: We’re now able to put those tools all in succession, or have fish be able to go through them repeatedly, so that yeah each one may only be 50% or 60% effective, but if you’re successful at parsing out 50% of your undesirable fish at 20 different steps, the amount of undesirable fish you have at the end is very very low to nill. And you would have never been able to get to that step through a single individual tool.
WIZNER: Because of that, a lot of places are watching the project and hoping they could apply it to their rivers.
SPRINGER: Yeah I mean it’s really cool that they could combine all these things and potentially have that success. Kind of scary too because of the facial recognition software or whatever they call it. But I wonder about this whole business of sorting fish. It makes me think, are we overstepping?
WIZNER: Yeah, it’s a part of the controversy with the project. Basically, to artificially pass fish in a river, you’re sort of playing God. Letting the fish you want in, expelling what you don’t want. And those choices have consequences. In the beginning, FishPass was only going to let native fish through. But then some people were unhappy about that restriction and so project leaders amended that to “desirable fish.” They're still figuring out what “desirable” means. But the choice still frustrated a different group of people, people like Mike Delp, who want the river restored closest to its original state—meaning native fish.
MIKE DELP: If you’re concerned about its natural being, why would you put a species of fish in there that doesn’t belong there?
WIZNER: The fighting’s really happening over two non-native fish, steelhead and salmon—large sportfish. Mike worries the steelhead will push the native brook trout out of their habitat.
DELP: There’s a lot of data that suggests those large fish—steelhead—get into smaller habitat, skinnier water way upstream, when they spawn, and that’s prime brook trout water up there.
WIZNER: But it’s complicated. The river already has an abundance of non-native brown trout. And the non-native sport fisheries are popular and an established part of the recreational economy.
To address this conflict, a whole group of stakeholders are meeting and trying to decide which fish to let through. They’ll play out the different scenarios of what could happen if they let “x” fish in, or not, or “y” fish in, or not. It likely won’t please everybody, but in these types of negotiations they can typically find a solution most people can accept.
Put a dam in. Take a dam out. Put a FishPass in? Brett Fessel, the guy who was part of restoring the Boardman-Ottaway, he says because of invasive threats, like sea lamprey, it’s unlikely people will ever be able to just leave the rivers be and stop managing them. But he thinks that’s ok, because at least in Traverse City, the community’s mindset about the river is changing.
BRETT FESSEL: I have seen a kind of change of an attitude in a way of the way people look at and consider the river with that kinship mind you know where it’s not just a thing that we use. It’s more a part of us. And that’s still manifesting.
WIZNER: That attention—Brett says it will bring more focus to what makes the rivers thrive. And that’s the end goal.
