Mike Davis figures that he has been keeping company with the Mississippi River for about 70 years. “When I was a little kid,” says Davis, “Dad would take me along on various expeditions to fish or just explore, occasionally Lake Pepin but mainly the area around Wabasha and Kellogg. He had an outboard motor, and we’d rent a boat, sometimes put up a tent and camp for the night.” Later, when he was 14 years old, his dad bought some property on an island in West Newton, in Pool 5, that came with an old cabin that is still in the family.
These days, anyone who pays attention to conservation issues in the Upper Mississippi likely knows the name Mike Davis. In 2020 he was honored by the National Rivers Hall of Fame for his outstanding efforts over 30 years with the Minnesota DNR focused on sustainability issues related to fisheries, water level management, floodplain restoration, and—in particular—freshwater mussels. He hasn’t followed the common trajectory of natural resource specialists who start out working outdoors then increasingly find themselves indoors at a desk. As he approaches retirement, he’s still regularly diving to collect, reintroduce, or survey for mussels. If the river is open, he’s likely as not to be in it. “Last year we surveyed the entirety of Pool 5 for mussels, repeating a survey that was done in 2006,” he says. “We’re analyzing comparison data now, looking for trends in abundance and locations.”
Davis has been a key player in the effort to save the federally endangered Higgins Eye Mussel from extinction: installing propagation cages that produced juvenile Higgins Eye mussels in a river setting, establishing a state-of-the-art propagation facility in Lake City, and pioneering techniques that made possible the restocking of millions of young juveniles and sub-adult Higgins Eye Mussels into the river. The good news is that the intensive work by Davis and his colleagues (funded almost entirely by interagency agreements with the Corps of Engineers) seems to be paying off. “We’re seeing great evidence now that the species is making a comeback in the Upper Mississippi,” says Davis. “And we’re going to take credit for it whether it had anything to do with us or not,” he adds with a laugh. “Without spending a lot of money on analysis, we can’t say whether it was what we did that made the difference. But we can say that we propagated and released juveniles in the river and now we’re seeing natural reproduction starting to occur and Higgins Eye showing up in places we never went near with our release sites. So it’s pretty cool.”
To look at his contributions, you’d think he was a career conservationist, and certainly 30 years constitutes a career. But prior to working for the DNR, at various times Davis made his living as a commercial fisherman, a motorcycle mechanic, and dairy farmer. He’s viewed the river of his youth from many different angles, and has gained perspective not only from his own personal experiences as an avid hunter and outdoorsman, but also by an understanding of environmental history and decades of interactions with other river managers and researchers who, like him, focused on large floodplain rivers. If you care about the Mississippi, he’s someone you hate to see retire.
For his part, he says he’s just glad to have been among the many people who have spent career time thinking about this river and its inhabitants.
Natural River Behavior
“What’s natural now” says Davis, “is different from what it was for thousands of years.” One characteristic of large-floodplain rivers here in the midsection of the continent, he notes, is their tendency to meander. Old river maps convey their snake-like undulations through time, the collective effects of which are still evident in present-day landforms. “You can see how their valleys have been sculpted by channel migration,” says Davis, “which is something you don’t find as much with rivers in mountainous terrain with steep gradients.”
Then there’s the flood pulse. “Floods can occur here at different times of the year, most typically in April/May, sometimes into June if we get a lot of rain,” he notes. “If you go back prior to humans manipulating the flows in the river, water would run out of the main channel of the river during floods and into backwater areas, which in low water season would just be a bunch of little shallow lakes. They would refill and the floodplain woods would be flooded. Then, when the volume of water in the river dropped, the flows would reverse and come back out of those areas, bringing with them all sorts of nutrients and larval fish from spawning that had taken place in the backwaters. All that would gradually re-enter the channel. This would favor the channel-dwelling fish in a lot of instances but others would live in the backwater lakes that were deeper. Occasionally the shallower lakes would trap fish and then they’d dry out and the birds would have a feast on the dying fish—you know, nature can be pretty brutal in that regard.”
What goes up never comes down
“But that doesn’t happen anymore on the Mississippi,” says Davis. “We’ve truncated that flood pulse. You still get seasonal high water, but it’s moderated—or affected— by the impoundments and the regulation of the dams. At some point the gates are opened and the river runs through the dams pretty much wide open. But they close the gates on the dam as the water drops, so water flows almost continuously from the channel into the backwater areas, at least for some distance, before it returns to go through the dams.” For life in the backwaters, he notes, flooding has become a year-round condition. “Water goes up but it never goes down below a certain level, with a couple of experimental exceptions. That has meant pretty significant shifts in the ecosystem.”
He also points to the channel-forming role of floods—both erosion and filling of channels—that historically created new habitat. “Some of that still goes on, but it’s been altered by structures built in the Mississippi River for navigation: the rip-rapping of shorelines, armoring of the banks, a lot of wing dikes built to concentrate the flow into the main channel.
“To me, if you think about all the plants and animals, fish, everything that lives and has lived in the rivers, you need to consider that they have—I like the language used by John Nestler, who’s with the Corps of Engineers—they have an evolutionary training set. This evolutionary training set developed over millennia in response to those flood pulses and the drought cycles that, under natural conditions, dry up the backwaters and cause seed banks to germinate, bringing about both replenishing renewal and destruction. It’s like prairie fires and forest fires that renew and recreate habitats. You have the plants and animals that have evolved to be opportunists and take advantage of those things to colonize new areas, while others are better adapted to stability, so their abundances fluctuate. We’ve altered all that so it’s favoring a different bunch of plants and animals than it once did. We’ve never had a normal cycle since the dams were put in.”
Davis was born too late to see the river before the lock and dam system was built in the 1930s and 40s. “Instead of building boats that conform to what the river can provide, does provide, we went down that rabbit hole of rebuilding the river to fit the boats we wanted to use. And we’re still paying huge amounts of cash outlays to maintain all that every year. It’s highly subsidized. But on the other hand, if you were to maintain the economy we have by having to move all that material around some other way, that would have huge environmental consequences too. Maybe that’s where we need to rethink what we’re even doing with the things we produce here. Instead of importing fertilizer and exporting corn and soybeans, maybe there’s another way. But we’re not seeing it because all the incentives are the opposite of that. So, if you’re a romantic idealist and want to see pristine nature, good luck. I would love to see it, but what we can best do is to do less harm, and that’s a good place to start.”
A good place to start
One potential point of influence that Davis has advocated for is management of water levels to better mimic the evolved conditions that animals and plants respond to in positive ways. Another is the strategic removal of infrastructure to restore more natural function where feasible. Both can bring benefits.
The same inherent trait that the lock and dam system has constrained—the dynamic nature of rivers—can bring swift positive returns for native plants and wildlife when conservation measures are tried. “It can be almost immediate,” says Davis. “They’re finding that out with dam removals all over the country. As more and more old dams are being removed, fish migrations occur almost instantly. And if you remove a levee to allow the river in and out of its floodplain you get huge responses from that. I mean, it doesn’t take long. All that stuff is just sitting in the wings waiting to happen. So the resilience concept is really valid.”
“Of the 143 native fish species in the Upper Mississippi River System, at least 34 species are migratory” (Upper Mississippi River—Illinois Waterway Navigation Study)
He points to an intentional drawdown done in Pool 5 for conservation management purposes in 2005 and 2006. “Prior to the drawdown, the backwaters were algae-choked, turbid, filled with churning nonnative fish, mainly common carp,” says Davis. “Afterwards, it changed significantly. The drawdown fortunately coincided with a few years of almost no spring run-off, which meant that the water wasn’t high or turbid in spring, which let light reach the bottom of the river and there were waiting seed banks of aquatic plants that just took off. Go out in the Weaver Bottoms in the middle of the summer now and you can see bottom in six feet of water very clearly. In most areas you can see little fish swimming around. It’s full of aquatic bugs hatching and feeding on all that. So, that’s been a miraculous change. Some people use the analogy of two crucibles: two steady states. If you’re in the turbid algae-choked state, it’s hard to get out of it, but once you can shift it back to the rooted plant communities in these backwater areas, those tend to be very persistent as well.”
Return of big-river rapids to the Twin Cities?
Davis is watching with interest as the Army Corps of Engineers evaluates its options for disposition of two major pieces of infrastructure in the river, the Lower St. Anthony Falls Lock and Dam, and Lock and Dam No. 1 (the Ford Dam). Among the actions being considered is removal of these structures, which could return the river here to a more natural state, restoring an 8-mile stretch of rapids and reconnecting 39 miles of river through the Mississippi Gorge in the heart of the Twin Cities. Many literal and figurative ripple effects could be expected, with benefits for species like the paddlefish and sturgeon, and for native flora and fauna overall, in response to greater complexity of available habitats. The prospect is exciting to Davis; but it’s not new.
“I started working on the idea of restoring those rapids 20-some years ago,” says Davis. In his role as a DNR aquatic biologist, he served on a writing team for a Fish and Wildlife Work Group of the interagency River Resources Forum, which advises the Corps of Engineers’ St. Paul District. The group was tasked with preparing Environmental Pool Plans for the Upper Mississippi, identifying desired future habitat conditions and scenarios by which they could be achieved. “Our plan for Pool 1 included removal of the dam and restoration of the rapids. We put together some scenarios and thought it was feasible to do. Although the plan was published as part of the 2004 Environmental Pool Plans report, the Forum didn’t endorse the Pool 1 section of the plan, which they said flew in the face of the Corps’ congressional mandate for navigation. But now it’s being taken seriously.”
As published, the 2004 report stated that, while the Pool 1 plan prepared by Davis and others “may have described a highly desirable environmental condition for the future,” it was not endorsed at the time but would be “reconsidered for endorsement if substantial changes in river use and laws provide an opportunity to do so.” That opportunity has now presented itself, since Congress directed the closing of the Upper St. Anthony Falls lock in 2015, effectively ending commercial barge traffic on the Mississippi above the river’s confluence with the Minnesota River at Fort Snelling. “To me, removing those dams would be a huge restoration win for the Mississippi River, says Davis, “and more and more groups are now on board with that concept.”
Large rivers, writ large
The challenges and burdens faced by the Mississippi are unfortunately far from unique. Davis recalls a 1994 international conference held in La Crosse, WI, which brought together over 500 scientists and natural resources managers from 20 countries to focus on sustaining the ecological integrity of large floodplain rivers in temperate regions. He was a coordinator of a companion workshop for the Upper Mississippi River System. Attendees shared their impatience with the slow pace of change, while at the same time recognizing a rapid revolution in the way scientists and river managers were thinking about rivers. As described in a summary report, there was broad agreement on guiding principles for management: that drought, the annual flood pulse, and channel-forming floods were major driving factors in large floodplain river ecosystems; that the degree of connectivity between a river and its floodplain was a primary structural attribute of ecological integrity; that rivers and their fauna can respond to measures taken to improve or rehabilitate them, if taken before critical levels are reached. Better progress toward sustainability goals, they agreed, required that they put collective effort into “identifying and quantifying the goods and services provided by a healthy and integrated river,” and better communicate to the public “the many ways in which these are compatible with human needs.” In short, if we are calculating the worth of a river to society, we must also consider benefits of rivers in their unaltered states.
“That was a great conference,” says Davis, “with some really good talks and important subsequent publications.” He enjoyed meeting and talking with then U.S. Secretary of the Interior Bruce Babbitt, who provided the keynote address. “I actually gave him a pair of high-top tennis shoes, each one with a mussel shell in it. I invited him to come wade in the rivers and look for mussels with me some day but he never took me up on it.”
“Although he did take the shoes,” Davis adds with a laugh.
In Babbitt’s keynote address, he asked attendees to reflect on the the extraordinary transformation of the Gulf of Mexico. Said Babbitt: “I don’t think anyone ever really imagined that a century-long system on the Upper Mississippi using dams, locks and levees to create slack pools for navigation, with the development sequence on the Lower Mississippi of dredging and levees for navigation, could someday, meaning now, threaten the complete destruction of wetlands systems of Southern Louisiana, which support a rich, wonderful Cajun culture, which support the largest marine shellfish and fishery in the entire United States, being threatened with destruction by the consequences of our development acts.”
So, all these years after the locks and dams were built, are we any more likely to fully imagine the potential consequences before transforming a landscape? Would it even have changed the outcome for the Mississippi, if the people of the era perceived their gains to be worth the cost? More to the point, has the harnessed Mississippi that most of us have grown up with muted our own ability to even conceptualize the benefits of restoring the dynamic nature of the nation’s largest river?
“I think that river advocacy groups get it more than ever,” says Davis. “Whether the general public has even been exposed to these issues is a bigger question. It’s complicated. In some parts of the watershed, we spent a hundred years trying to get rid of water, only to find out that we’ve gotten rid of way too much: the water flows off the land too fast, we’ve lost the capacity to store it. But trying to go back on some of those subsurface tiling projects, it’s so extensive now that figuring out how to undo what’s been done without eliminating crop land is a huge challenge.”
Having more people with first-hand knowledge of today’s Mississippi would help, he notes. “I mean, you go out here on the weekend its full of people on jet-skis and yachts roaring around, but if you out on a weekday there’s there’s almost no-one on the rivers or in the backwaters around here because most of us aren’t dependent on that anymore. People don’t engage in the same types of activities as they once did. Part of that for me when I was younger was that the changing conditions in the river stage created opportunities for me to exploit as a hunter, trapper, fisherman-type person, and I’m sure that was true for thousands of years on the Mississippi. Early American indigenous people knew way more than any of us ever knew, because for the most part they weren’t exploiting things to sell, they were gathering what they needed to survive for the next year. I’m sure that knowledge still exists to some extent, but over time, things can be obscured or lost completely.”
If you’re not out there to see for yourself what it was like before, you won’t necessarily recognize change when it happens. He offers an example. “It was probably in the 1970s when I was still doing some commercial fishing, maybe in the 80s. I saw where a beaver colony had built its house along the banks, right near the main channel, in a little bit of a side channel area. They had, as beaver do, created their own little canal from the main channel of the Mississippi into this backwater area so they could haul those willow branches out for their winter food supply. Well, that little beaver channel that started out being about a foot and half wide and a foot deep, has turned into a major side channel today. And that’s where it got its beginning. In the spring when it flooded that thing was suddenly 6 feet wide and 4 feet deep. And then, 50 feet wide and 12 feet deep, and now it’s several hundred feet wide and 20 some feet deep where it starts. And it introduced a huge flow of sediment into the Weaver Bottoms area that’s built islands that are now colonized by willows, and other trees are starting to spring up. It’s where the pelicans hang out and the cranes in the summer. It’s a very dynamic area, and the deep water entry area is a great spot for people to catch walleyes. It’s been very interesting to see how nature creates habitat for us and at the same time it’s destroying what used to be there, which was a 4-foot deep marshy area that really was created by the dam that flooded it all. So, some people don’t like it because it’s filling in what they were used to and creating these islands. But the wildlife and fish that take advantage of all that, to me, it’s fascinating. I watched it expand over the years. The Corps of Engineers has now termed it as Minnesota 7; they have all the inlets that have washed into the Weaver Bottoms numbered. So MN 7 is now the principle source of flow into the lower end of the Weaver Bottoms. And that whole sequence of events was set in motion by a beaver.”
Ask Davis where we might find a modern-day analog for the historic Mississippi to give us a sense of what a large-floodplain, freely-flowing river looks and acts like, he answers: “I’ve wanted to see the Paraná River in South America, which John Nestler has talked a lot about. It’s an intriguing one. John tried to get the Corps of Engineers to pay for all of us to go down there and have a trip on the river and talk to people studying it, learn more about it, but that never happened, unfortunately. I would have loved that. It even has about 50 species of freshwater mussels in it which is similar to what we have in the upper Mississippi.”
Maybe that would be an appropriate retirement gift after 30 years of working to conserve aquatic life in the Upper Mississippi, a trip to see the Paraná River? Davis pauses, then laughs. “Yeah, well, they’ve already given me a jacket and a wood saw.”
Further reading about the future of Lower St. Anthony Falls Lock & Dam and Lock & Dam #1