Overview
- In the summer of 2024, HRWC staff, interns, and volunteers conducted an extensive survey of freshwater mussels in the Huron River: The Great 2024 Huron River Mussel Hunt. The project was linked to the planned removal of the Peninsular Paper Dam, a structure recently downgraded to "poor" condition by the State of Michigan.
- Freshwater mussels filter bacteria, provide habitat, and serve as critical water quality indicators. In Michigan, many of the state’s 43 mussel species are threatened due to pollution, invasive species like zebra mussels, and habitat disruptions caused by dams. Mussel Species in the Huron River: The Huron River hosts both common and conservation-sensitive mussel species, including the Eastern Elliptio and the Fatmucket, alongside endangered species, like the Snuffbox and Rayed Bean.
- Removing the Pen Dam could release sediment, potentially smothering downstream mussel populations. While relocation efforts are planned for endangered species, the stress and environmental changes pose short-term risks to these slow-moving organisms.
- Long-Term Habitat Restoration: Once the dam is removed, the river will return to a more natural state, benefiting mussel species over time. Natural sediment distribution and improved water flow will create better habitats for mussels and other aquatic species, like fish, that are vital to mussel reproduction.
- Removing the dam also provides broader community benefits. The dam’s removal will enhance the river’s health, improve fish migration, and create more recreational opportunities like kayaking and fishing. It is expected to boost local tourism and support the Ypsilanti community’s economic and environmental goals.
Transcription
David Fair: This is 89 one WEMU, and the riverscape in Ypsilanti is expected to change over the next few years. The old Peninsular Paper Dam is expected to be removed in fall of 2025 and restoration of natural river flow completed by fall of 2026. I'm David Fair, and welcome to this week's edition of Issues of the Environment. Over this past summer, the Huron River Watershed Council conducted an extensive survey of freshwater mussels in the Huron River to determine potential impacts when the dam is removed. What will become of the mussels once it is removed? Well, Dr. Paul Steen is an ecologist with the Huron River Watershed Council, and he's here to fill us in on what was found in the research. Dr. Steen, thank you for making time for us today!
Dr. Paul Steen: You're welcome! I'm happy to be here!
David Fair: Now, as I mentioned, over the summer, you and a host of volunteers conducted what was called the Great 2024 Huron River Mussel Hunt. What were you trying to learn?
Dr. Paul Steen: Well, we wanted to know what species of mussels are in the river, their abundance, where they are specifically, any hotspots that would be of particular concern to us.
David Fair: If I have the numbers correct, in the state of Michigan, there are some 43 different species of mussels. How many did you find?
Dr. Paul Steen: We found, regularly, five particular mussels, including one state endangered mussel called the wavy-rayed lampmussel. The others were common species. Yeah. All beautiful, let me tell you.
David Fair: Pardon my ignorance, but I'm going to ask you perhaps the most rudimentary of questions. What is the benefit to a healthy mussel population for our river system?
Dr. Paul Steen: Right. So, mussels are certainly unique animals. You don't even necessarily think of them as animals because they don't move or barely move. They're shelled creatures. They are filter feeders. That means they're taking in the debris that's floating down the river--the bacteria, the detritus. And they're breaking down those nutrients and putting it back into the soil of the bottom substrate of the river.
David Fair: Our Issues of the Environment conversation with Dr. Paul Steen continues on 89 one WEMU. Dr. Steen is an ecologist with the Huron River Watershed Council. Now, the state of Michigan recently downgraded the status of the Pen Dam to poor. That's in reference to the actual physical structure. When a dam is deteriorating, does it have ecological or environmental ramifications to the mussels, the fish and the wildlife dependent on the waters around it?
Dr. Paul Steen: No. In this case, the downgraded status is a safety issue for residents in and around the dam. So, it means that there is a potential catastrophic failure--release of the upstream water potential flooding downstream. So, I suppose, if the dam were to break in the near future and we had not done anything to protect the mussels at that point, certainly, they would be badly affected by this, as well as everyone living downstream of the dams.
David Fair: Prior to removal of the dam, how do you go about protecting the mussels?
Dr. Paul Steen: Right now, we're doing this survey, so that we can find out where they live. We want to relocate these mussels out of the immediate area downstream of the dam. There's a possibility, upon dam removal, that sediment will be released. Dams just are sediment blockers, so streams are transport systems. They move sediment nutrients downstream normally. But when you have a dam, it blocks all of that buildup of sediment--fine sediment, bad for mussels--behind the dam. So, by figuring out where they are and then going back and moving those prior to a dam removal, we're safeguarding the population. And that's what we're hoping to do next summer. We found out where the river mussels are. Now, we'll go back and move them to safer locations prior to dam removal.
David Fair: As mentioned, the dam is scheduled to be removed in fall of 2025. And when it is, as you mentioned, there will be that release of built-up sediment, and some of it contains harmful pollutants. How do we get to the point where the natural river flow is once again beneficial to the health of the mussels?
Dr. Paul Steen: We feel that, in this particular dam, that will happen very quickly. So, the engineers have shown, through their sediment studies in the upstream pond, that there isn't nearly as many harmful toxic sediments or heavy metals, as there are in other places around Michigan that have this issue. So, there'll be a little bit of sediment stabilization when the dam comes out. But we're pretty confident that not too much will get released downstream. So, anything can happen, of course. That's why we're taking precautions with the mussel population now. But for the most part, we think that within really, just within a month or so of dam removal, that the river should be flowing in its normal way.
David Fair: I probably don't need to tell you, but not everyone in the community is on board with removing the Pen Dam. The group called Friends of the Peninsular Park--they've pointed out that earlier studies found that contaminants are not only harmful for aquatic life but exceed human tolerances as well. That is in contrast to the sediment study the Watershed Council received from Limnotech. Where are the disparities coming from?
Dr. Paul Steen: You know, I'm not 100% sure. I don't know where they got their data. I know that it certainly is in contrast to what we have found. And I have been out there personally and seen the bottom. And most of it is is sand. It's sand that is not going to be holding these contaminants. So, immediately behind the dam, there is some thicker muck, but that gives way pretty quickly to sand and even gravel in some cases in this pond. And that generally is not bad for most aquatic life or human health.
David Fair: This is 89 one WEMU, and we're talking with Huron River Watershed Council ecologist Paul Steen on this week's Issues of the Environment. Much of the holdup in getting the dam removed to this point has been the high cost. Cost estimates put it at about $14 million, over $10 million of that allocated to environmental restoration and sediment cleanup. Now, in a city that's struggling with finances, why, as you just mentioned, is the dam removal, in your view, the best way to go for the environment?
Dr. Paul Steen: Well, one thing to know is that, to fix the dam and to restore it, estimates have it equal to if not more expensive to actually fix it. And the dam either has to be fixed or has to be removed. There's no choice to just do nothing because it does pose a potential human life hazard if that the status quo is just to be maintained. So, from a human health perspective, we need to take action. If we go with the maintenance method, then we're just setting ourselves up for more problems in the future. If we take the dam out, the problem is solved. You move forward for the rest of City of Ypsilanti's life of being there. The dam is gone, and it will no longer be hazard and also no longer a hazard to the biology living in what we want to be a free-living, free-flowing stream, where the fish and the mussels are able to move back and forth where there once was a barrier.
David Fair: Well, I'm very curious as to how the removal of the dam would change the land, space and community access to Peninsular Park and the surrounding area. So, if you don't mind or if you can, paint me a word picture. What does the Huron River through Ypsilanti look like a year after removal and perhaps a decade after removal?
Dr. Paul Steen: Yeah, I think it will be beautiful! What we have right now is this pretty stagnant water behind the dam full of algae, a lot of rather unsightly, oftentimes smelly conditions. So, with the dam gone, imagine a meandering river--free-flowing. Water is constantly moving forth. The width of the river is probably 150, 200 feet of flowing water. Initially, when the dam is watered, you'll have mudflats but vegetation will quickly grow into that. And so, we'll have wetland edges. The park there, Peninsular Park, will have a chance to expand. Right now, it's a pretty narrow strip of grass and trees and maybe one trail. We'll be able to put multiple trails through this new wetland area, so there'll be safer places for people to access the water. You would step off the shore and be in multiple feet of water. It will be a slow entry, like other places in the river that you see downstream. So, you can imagine what Riverside Park looks like or Frog Island Park with the river looks like there. That's what we anticipate that this new, freely flowing section will look like.
David Fair: Well, thank you for the time today and sharing the information on the study and the perspective on what the future holds, Paul! I appreciate it!
Dr. Paul Steen: Yeah, I'm happy to be here! Thank you for thinking of us!
David Fair: That is Dr. Paul Steen, Huron River Watershed Council ecologist and our guest on Issues of the Environment. For more information on the research, pay a visit to our website at wemu.org. Issues of the Environment is produced in partnership with the office of the Washtenaw County Water Resources Commissioner. You hear it every Wednesday. I'm David Fair, and this is your community NPR station, 89 one WEMU FM, Ypsilanti.
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