DU Podcast Transcript: Ep. 23 – Elevated Great Lakes Levels in 2019

Host Dr. Mike Brasher talks with Kali Rush, regional biologist in DU’s Ann Arbor, Michigan office about elevated lake levels and how the high levels in 2019 impact waterfowl habitat

© Michael Furtman

Clay Baird: Welcome to the Ducks Unlimited podcast, the only podcast about all things waterfowl. From planning insights to science-based discussions about ducks, geese and issues affecting waterfowl and wetlands conservation in North America, we bring the resource to you. The DU podcast with your host, Dr. Mike Brasher.

Mike Brasher: We're fortunate today to have joining us, Kali Rush, a biologist with Ducks Unlimited out of the Great Lakes and Atlantic region. Kali is going to be speaking with us about elevated Great Lakes water levels that were experienced this year, and we're going to talk a little bit about the potential implications of that and help folks develop an understanding of what that might mean short term and long term. So Kali, thanks for joining us. Welcome to the podcast.

Kali Rush: Thank you.

Mike Brasher: How long have you been with Ducks Unlimited?

Kali Rush: I started at the end of April, 2019, so I've just hit five months.

Mike Brasher: Are you from the Midwest?

Kali Rush: I am. I'm actually from Michigan, so I have the opportunity to come back to my home state. I'm actually only about just under an hour from my parents and where I grew up. So the state of Michigan means a lot to me, and it's really cool to come back and be able to do great conservation work from where I'm from.

Mike Brasher: Kali, tell us a little bit about, maybe even describing a mental image of the wetlands that are most common throughout the Great Lakes system.

Kali Rush: Yeah, I'd be happy to talk about that. So to begin to orient everybody, the Great Lakes region is going to consist of Minnesota, Wisconsin, Michigan, Ohio, Indiana, Illinois, Pennsylvania and New York, just in the States. Then we also have provinces along the northern shores of Lake Superior and Lake Huron, and also along Lake Ontario and Lake Erie, so it's really by national waters that we're talking about. To understand what these coastal wetlands are, I'm going to take us back in time a little bit to describe how our system was formed here in the Great Lakes region. So historically, this part of the United States was covered in glaciers. About 10,000 years ago, those glaciers started receding out of the Great Lakes area, which eventually formed what's now the Great Lakes basin and the Great Lakes themselves. So when the glaciers receded, they left behind what's called drumlins and moraines. So drumlins are big hills or ridges, and then moraines are going to be like gravel hills of deposits from those glaciers moving and receding north. So after those glaciers receded, it left Michigan and much of the Great Lakes region with depressions throughout the area, and in these lowlands is where water would fill up and create these wetlands. So when we talk about coastal wetlands along the shore of the Great Lakes, we're looking for these areas that have some slope to them and there's a gradual decline in between water and lands. This doesn't happen everywhere along the coastline, but over the entire Great Lakes, we have about 11,000 miles of shoreline. These coastal wetlands are really found in the southern parts of the Great Lakes basin. So in the Northern part, it's very rocky, steep cliffs, and there's not much room for a wetland to form. But in these more southern areas where there's lowlands, these coastal wetlands are going to be emergent vegetation. So if people are familiar with grasses, and sedges, and rushes and cattails, it's going to be right at that juxtaposition of the land and the water along our coastlines.

Mike Brasher: Yeah, I've spend a little bit of time in Ohio in an earlier time in my career, and so I'm familiar with some of the wetlands there around Lake Erie in Northern Ohio and maybe even into Michigan and Southern Ontario. Are there particular lakes, which of the particular Great Lakes are these coastal wetlands most abundant, most dense? Can you can point to that?

Kali Rush: Yeah, so that's kind of a difficult question to say where the most are. I would say that most of our wetlands are going to be along Lake Erie, Lake Ontario. There's also a lot of wetlands in the Lake Michigan and Lake Huron, that combination of the lakes, especially when you get down into Saginaw Bay. So if you're looking at Michigan, and in between your index finger and the thumb is called Saginaw Bay, and there are a lot of coastal wetland systems within that area of Lake Huron. So these wetlands are found all along the shoreline, and rather than think about it by lake, it really just depends on what that part of the shoreline looks like. For example, a wetland isn't going to be able to form in an area that's always disturbed or if there's a hardened shoreline such as sea walls, or if it's just rocky cliffs. But if there's water that is sort of protected behind a barrier where it can us settle out and it doesn't have as much wave action, that's when sediment will start to deposit and coastal wetlands will begin to form.

Mike Brasher: Okay. Okay, very good. That's interesting. I enjoyed my time up there in the Great Lakes region. It was certainly a different system. The fluctuation of the water levels is something that was certainly talked about quite often and I never really fully appreciated all of that. I was looking at an article not too long ago where I think it might've even been on the DU website or the DU magazine, where the concern at that time was low water levels in the Great Lakes. So earlier this year, earlier in 2019, we began to see and you guys experienced record high water levels, and so naturally, these fluctuating water levels within the Great Lakes systems is to be expected. But describe a little bit about what happened this year with respect to the high water levels. Was it a single year event or does it take multiple years for these cycles to go through completion?

Kali Rush: Yeah, so I'll start there with describing the water fluctuations and their typical duration. So it's normal for the Great Lakes water levels to rise and fall among years, decades, centuries, and so that is a normal process. It might be relatively high for a few years and then relatively low for a few years, and it's naturally going to fluctuate. That's what wetlands require to establish themselves, is that fluctuation of water so that the plants can grow. What's different about this year is, really goes back maybe to 2012 or 2013 when the lake levels were extremely low and everybody was very worried we're missing water, the water is very low, which can impact a multitude of other things. However, what we're seeing is a rapid change in how frequently this water is fluctuating. So in the past, or historically it may be every 10 years or every 12 years, but in the past six or seven years, it's happened very rapidly, which is a very big concern because it's hard to predict the future when there's so many rapid changes. We can't know if it's going to be high or if its going to be low. So what contributed to that this year, of course, was our a lot of precipitation this spring, but there was also a change in evaporation. So there's a lot of very smart people looking into exactly what drives the water level fluctuation, and it's not as simple as pinning it down to just the precipitation, but there's a lot of different factors in there that led to the Great Lakes water levels beating records this year.

Mike Brasher: Hm, interesting. So the evapotranspiration that you referenced, that is, my thinking is that for evapotranspiration to have an effect on rising water levels, we're talking about a decline or a decrease in evapotranspiration levels, right?

Kali Rush: Yeah, so what happened here is that we were getting more precipitation and then the evaporation went down. So if you're having more precipitation, more water entering that system and less water leaving through evaporation, then the water is going to climb.

Mike Brasher: Yeah, and the evapotranspiration would be a function of cloud cover, right? The lack of increasing cloud cover, lack of sunlight fueling that evaporation, right?

Kali Rush: Yes, so there's a lot of different functions going on there, and it's very difficult to predict this evaporation or the precipitation because our weather systems react much differently when they're over the lakes, over the Great Lakes, than they are over land. So it takes different sort of weather monitoring systems that we don't necessarily have in place out in the middle of the lake to accurately calculate the evapotranspiration or evaporation.

Mike Brasher: Okay, with that as the background, let's talk about where we are now. I have a friend who has a cabin on Lake St. Clair and he kept us up to date on the lake levels as they were getting close to the bottom floor of his cabin. He actually had water covering his yard this summer and we were joking about how he was going to be able to catch fish out of his backyard before very long. It got pretty close to that, but then the last we checked in with him, I think the water levels had began to recede. So where are water levels now on the Great Lakes?

Kali Rush: So water levels are still high. They have gone down a little bit, but overall, they are above the average. So every single Great Lake is above their hundred year average by about 80 centimeters in all of them except for Lake Superior, which is just about 35 centimeters above average.

Mike Brasher: At this point, are there any expectations or any predictions that folks can make with confidence on what lake levels might might do from here?

Kali Rush: We don't know. Traditionally, the levels would be decreasing in the fall, and so hopefully they can follow that same trajectory and start to decline. But you really never know with this system and with things are changing, nothing would be surprising at this point. But it is predicted that for the fall, typically water will decline, the water levels.

Mike Brasher: Yeah, and in terms of water levels next year, you just have to wait and see what the precipitation, snowfall, those types of events will bring to those watersheds, right?

Kali Rush: Exactly.

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Mike Brasher: So let's talk now about an article that you wrote referencing the sustained high water levels or the high water levels within the Great Lakes, and you spoke a little bit in this article on that. I think we'll probably be able to link to this podcast somehow, about the potential implications of high water levels to coastal wetlands, and of course, let's also talk about implications for ducks. Folks that are familiar with that area know that the Great Lakes region is important not only for breeding waterfowl, but also for waterfowl during the non-breeding season. So there's a whole range of topics I'm sure that we could discuss here with potential implications. But from a general perspective, what's the biggest concern with high lake levels as it would affect wetlands important to waterfowl?

Kali Rush: Yeah, so referring to that article, so this I co-wrote with Chris Sebastian, our communications in the Great Lakes/Atlantic regional office. We were really interested in looking at not only the effects on the habitat themselves, but what's sort of the repercussion and the down the line effects would be. So for this year, we're looking at high water levels and how that can affect people, the habitat and waterfowl. So as far as habitat goes, when that water level rises, it will drown out some of the emergent vegetation. So as it gets deeper, the vegetational die that required the shallower waters, and so the wetland naturally would start to recede back. However, with the water level so high, if there is anything behind those wetlands that they don't have the ability to just keep pushing back, then we're going to be losing net wetlands.

Kali Rush: So what that means is that there'll be less habitat on the landscape, and these coastal wetlands are very critical for migrating birds. Breeding populations of birds will be affected, so some of the mallards and other birds that are nesting on these coastal landscapes, they have a lot of other options to move further inward. Breeding pairs like smaller wetlands anyways, so they want to be able to bond on these small ponds rather than these larger coastal wetland complexes. But again, back to these migrating habitat, a lot of waterfowl, as they're moving north or south, requires stopover sites. So they need a place to rest and they need a place to eat, and these coastal wetlands often serve as those stopover sites for waterfowl.

Mike Brasher: Kali, sorry to interrupt you there, but I'm guessing given the high water levels that have been experienced over the past few years, you've probably already seen some shifts in those coastal marsh vegetation communities, right?

Kali Rush: Yes, we have. So we have lost those emergent marshes into more open water habitat. So as that water has risen, it has kind of killed off the emergent vegetation and with nowhere else for it to start to form, then it's just wide open and we're losing ... we have seen a loss of that habitat.

Mike Brasher: Yeah, and just to be clear, when you say with the loss of areas or lack of areas for new wetlands to form, you're really talking about an inland migration. That's the way that I've spoken about it most often during my time on the Gulf Coast, is naturally, as you mentioned, these wetlands historically would just migrate inland as water levels increased. But the hardened structures, as you've referenced, prevent that from happening, right?

Kali Rush: Correct.

Mike Brasher: So one of the things that happens, based on my remembrance of things in Ohio, is it creates a situation if water levels are sustained for a period of time, the once emergent vegetation has converted to the open water, and there is, in some cases, a desire to construct impoundments in those areas, right? That creates a bit of a tension because it's creating these artificial structures, but in many respects, or in some cases, that becomes the only way to ensure the management of very productive wetlands. Do you still see some of that occurring?

Kali Rush: Yes. Yes, so we do still manage these large wetland complexes with impoundments, especially in these high developed areas that we want to ensure that what we're trying to do inside the marsh isn't effecting private land on the outside. So like you mentioned, your friend in Lake St. Clair, his cabin was probably low enough that the water rose so high and it tried to move back along the shoreline, but eventually, it hit his house and it couldn't move any further. That's when we have this flooding happened. So for these impounded wetlands, it's helpful to protect that and it gives us a way to manage these coastal wetlands. In that case, we can also have these marsh habitats, whether the Great Lakes are high or low, because we are purposefully managing the wetlands by having the impounded structure surrounding that.

Mike Brasher: And I imagine that when you make those decisions about whether or where to move forward with an impounded wetland, or creating a wetland of that nature, you want to achieve the right balance. We don't want to harden the entire coastline, right? We want to achieve an appropriate balance between ensuring those managed habitats, while also providing some of those, where they exist, where it's possible, making sure that we retain those areas where wetlands can migrate inland and back naturally. Is that correct?

Kali Rush: Correct, yes.

Mike Brasher: Any expectations? I think it's probably difficult for you to make any predictions about what these changes or what these high water levels will mean on any given year, but from a waterfowl use standpoint, or folks whether they be hunters or anyone else that enjoys observing waterfowl resource, are there any things that they would need to be aware of, or anything that they might expect to change their experience to the field this year?

Kali Rush: Yeah, so in regards to that, like you said, it's hard to give any certainty here, but if water levels remain high, there's going to be ... the birds will be using the landscape in a different way that they have in the past. So you may not be able to go to your favorite spot anymore and have birds coming in on the coast, but it could still work out for you. So that really just depends on where you're at, and it's hard to say with any certainty what somebody would see at any given point along the Great Lakes.

Mike Brasher: So the important message is the landscape is not static, it's always changing. The birds are going to exploit that changing landscape the best way that they can, right?

Kali Rush: Precisely. These landscapes are very dynamic and from year to year, the amount of acres of coastal wetlands always changes because of that natural fluctuation and water.

Mike Brasher: Kali, I think that probably sums up most of the points that we wanted to touch on today. I think that's some interesting information on a topic that most people probably don't hear much about. Obviously, the people in the Great Lakes region are acutely aware of the fluctuating water levels, and I hope we've today tried to paint a picture of helping people understand the implications of those water levels. As water levels decline, the next time they go through that declining cycle, I think we can probably expect that vegetation, emergent vegetation, hopefully to reemerge in those shallower areas. Yeah, the cycle will continue, and in the meantime, we and you guys in the Great Lakes region will continue to do the things that are best given those situations. So we thank you for that and we thank you for joining us on the podcast today, and we look forward to catching up with you sometime in the future.

Kali Rush: Yeah, thanks Mike. I had a really nice time talking about Great Lakes cycles, and thanks for pointing out that someday, they will go down again and it's that natural fluctuation, it's going to keep going. We just really need to keep an eye out in the future to be more acutely aware of how things are changing and what the future outlook is going to be.

Mike Brasher: Thanks, Kali.

Kali Rush: Yep. Thank you.

Clay Baird: Thank you for listening to this episode of the DU podcast. Be sure to rate, review and subscribe to the show and visit www.ducks.org/dupodcast for resources based on today's topics, as well as access to more episodes. Opinions expressed by guests do not necessarily reflect those of Ducks Unlimited. Until next time, stay tuned to the ducks.