Transcripts

text | pdf |

---

KATHLEEN HALLINAN: From Minnesota Public Radio, I'm Kathleen Hallinan. A federal agency has given the Forest Service permission to speed up the removal of downed trees near northeastern Minnesota's Gunflint Trail. The Council on Environmental Quality's decision means timber salvaging and other efforts to reduce fire danger can proceed with far less environmental review.

Minnesota environmental groups are supporting the decision. Betsy Daub with the Audubon Society says the public will still have a chance to react to the Forest Service's plans.

BETSY DAUB: It's going to be everybody's responsibility to make sure we're active and involved and following along what's being proposed.

KATHLEEN HALLINAN: The Forest Service is concerned about the danger from millions of trees downed in a July 4 storm. The environmental waiver will not extend into the nearby Boundary Waters Canoe Area.

The Minnesota Campaign Finance Board has cleared lawmakers in a gift ban complaint. The board found the lawmakers didn't violate state restrictions on gifts when some ate for free at a series of teachers' union dinners last winter.

The political watchdog group Common Cause Minnesota had complained that the legislative dinners, sponsored by Education Minnesota, violated the state's gift ban. The board found most lawmakers paid for their meals, and those who didn't may have been exempt from the rules.

Bloomington-based Toro Company reports a strong third quarter. It credits strong sales of lawn-grooming and irrigation equipment. Toro earned $10 million for the quarter. It lost nearly $2.6 million in the same period a year earlier.

Dense fog is forecast today in the Arrowhead. Hazy sunshine is expected in central and southern Minnesota. It will be mostly sunny near Moorhead. That's the news from Minnesota Public Radio. I'm Kathleen Hallinan.

GARY EICHTEN: Thank you, Kathleen. It's 6 minutes now past 12 o'clock. Programming on MPR is supported by Gedney, the Minnesota pickle, home of crispy, crunchy, hand-picked pickles for over 100 years.

[MUSIC PLAYING]

Good afternoon. Welcome back to Midday on Minnesota Public Radio. I'm Gary Eichten. Glad you could join us.

This year marks the 75th anniversary of one of the nation's biggest and most popular wildlife areas, one that's right here at Minnesota's front door, the 200,000-acre Upper Mississippi National Wildlife and Fish Refuge starts near the Twin Cities and stretches all the way to Illinois.

This hour on Midday, as part of our Voices of Minnesota interview series, we're going to take a tour of a portion of the refuge near Winona with Calvin Fremling, an authority on upper Mississippi River ecology. Here's Minnesota Public Radio's Dan Olson.

[MUSIC PLAYING]

DAN OLSON: Cal Fremling is a tall, broad-shouldered man with arms tanned a deep brown from spending hours on the river on sunny days. People curious about upper Mississippi River ecology, from American eels to zebra mussels, call on Fremling. The retired Winona State University biologist prefers to talk about the river while on it.

50 years ago, the upper Mississippi was something closer to an open sewer than a healthy river. But the water is much cleaner now and supports healthy populations of game fish, including walleye. Birders flock to the river every fall to watch for tundra swans and dozens of other migratory waterfowl or to catch a glimpse of double crested cormorants that make their home in the refuge's rookeries.

Our trip begins in Cal Fremling's fishing boat. He motors through backwaters the size of lakes. Islands with clumps of willows and towering cottonwoods block the view of any signs of civilization.

Is the river water and the water we're on right now in your boat, is it cleaner than it's been in, what, 20 years?

CALVIN FREMLING: I think it is. But other biologists and chemists would say, no, that's not quite right. Here's my contention. I know that I can swim here, anywhere around here. Everybody swims in the river because we don't allow industry to put their sewage in.

And every city on the river in this area has a modern sewage treatment plant. And the backwaters, these vast areas, provide sewage treatment, really. And the dam aerates the water. And then you have another pool, another pool. So you get primary, secondary, tertiary treatment all the way down the Mississippi.

And from the Twin Cities, first it's impounded, aerated, impounded, aerated, lagooned in Lake Pepin, impounded again all the way down. So the impact of the Twin Cities is negligible way down here. It's just nutrients, yeah. But that's been recycled again and again and again.

I'd say the water quality here is much better from that standpoint, the sewage stuff. But somebody else would tell you, well, but there are things in here that weren't here 30 years ago. There's more atrazine. There are more agricultural chemicals and so on. Can I show you something here?

DAN OLSON: Talking to Dr. Cal Fremling in his boat here on the Mississippi, but in a backwater. And Dr. Fremling, we are coming up to a massive root system on a tree that has toppled over.

CALVIN FREMLING: Again, it's a very shallow root system. And when the tree topples over, that root system is thrown up like a wall. But if you notice in that root system were all these white objects. Those are zebra mussels. Did you ever think you'd see zebra mussels on a tree root?

DAN OLSON: Now, these are the zebra mussels that have gained a really bad reputation, I suppose. Is it a bad rap? They are harmful?

CALVIN FREMLING: They're harmful. And we can't fish the Mississippi without getting zebra mussels on our line, catching them on our monofilament line and on our lures.

DAN OLSON: They're an exotic. They were not here naturally.

CALVIN FREMLING: Right. They came in from Eurasia. And they came in through the Great Lakes, down the Illinois and up the Mississippi. I'm going to turn the engine off here.

DAN OLSON: We're just pulling up to the roots. And as you get closer, it's like a city. It's like a metropolis of zebra mussel.

CALVIN FREMLING: And the current undermined the roots on the channel side and undermined the whole root system. So there was water flowing under the roots of that tree. And the zebra mussels latched onto that and grew there. And that's about as big as the zebra mussel gets. They're about, what, an inch long or so. And they're all over the tree.

And finally, a big storm came. And since the tree wasn't attached anymore on the channel side, like a barn door hinge, it let the tree keel over onto the island. And there is the zebra mussel population exposed.

DAN OLSON: Actually's about half a dozen of these trees toppled over in that same fashion.

CALVIN FREMLING: Oh, yeah. Within sight of us in the next block or two, there are six or eight big trees that have toppled inland.

DAN OLSON: Why are zebra mussels harmful?

CALVIN FREMLING: Well, for clams. They are covering the clams and prohibiting whatever clams do in the way of getting oxygenated water and all those things and feeding.

DAN OLSON: But they're a mussel. I assume they're somebody's food source.

CALVIN FREMLING: I personally have never opened the gut of a fish and found zebra mussels in it. But some biologists say that freshwater drum eat a few, carp eat a few, and maybe some ducks do. I don't know that for sure.

DAN OLSON: Do they have a natural level? Will they just keep proliferating but then reach a plateau?

CALVIN FREMLING: Well, on the Illinois River, apparently they've peaked out. And they've had die-offs of zebra mussels in the Illinois River. But they're an interesting animal in that they filter the river water. And since they've arrived here, which has only been a few years, to me, this is anecdotal, but the river water is clearer because of the zebra mussels. I really feel that.

DAN OLSON: And we attribute clearer river water to being good and cleaner river water.

CALVIN FREMLING: Right. But I should say, along that way, that river water-- the Mississippi River, even in its most pristine condition, was never colorless. It was tannin stained by bog water. So it ran brown even before the white man came here.

DAN OLSON: And as we look at it over the side of your boat here, this is clearly muddy-looking water. But when people look at this river water and say, oh, Dr. Fremling, this is dirty water, that isn't all bad.

CALVIN FREMLING: No, uh uh. The water here has some turbidity in it from recent rains. But a lot of the lack of transparency is due to naturally occurring tannins in the water. Right now, though, I would suspect most of it's clay particles that have washed in from the watershed.

DAN OLSON: There are people who say we should, at the very least, allow the river water to resume something closer to its natural flowage, prehistoric flowage. And obviously, in western states, this is a huge issue out in Oregon and Washington, where they actually want to remove dams. I gather we're not considering removing dams, locks and dams along the Mississippi, but--

CALVIN FREMLING: Some would like to.

DAN OLSON: Some would like to. But what-- explain why that might be helpful if river levels and flowage were allowed to change, increase, decrease.

CALVIN FREMLING: Well, before we channelized the river and dammed it up, the river could wander in its old floodplain, in its glacial floodplain. And the river was constantly making new channels and losing old ones. It was a braided river at this point.

It was overloaded with natural sediments, so it kept changing the braiding pattern. And its water level fluctuated so much so that it would dry out some of these islands. And the organic matter that had accumulated would be oxidized. It would be turned into carbon dioxide and water and would disappear.

And there were fires out here. One of the bad things was that the water level fluctuated so much that many fish were stranded in little backwaters. And for a long time we had fish rescue programs on the Mississippi, where the Fish and Wildlife Service and DNR-type people went out and netted the fish in the backwaters and put them on railroad cars and shipped them all over to stock inland lakes.

DAN OLSON: Did many of them live in those rescues?

CALVIN FREMLING: Yeah, they were quite good at it. They stocked a lot of fish. But then when we dammed up the river, especially, then the river lost its ability to wander and to make new channels and to rehabilitate old islands and to oxidize its sediments.

So it's permanently flooded. And we have all the backwaters we're ever going to have, I think, right now. We're not creating any new ones. And the ones that we have are disappearing. If we do have a situation where land is accreting, we see willows move out onto it first. Like over here to your left, the willows move out first, and then the silver maples. And they come behind.

Another plant that's interesting here is poison ivy. Walking through these floodplain islands right now would be terrible because you'd first be walking shoulder-deep through wood nettles, broad leaf nettles that are just-- burn you like fire and poison ivy that grows like a-- you'd think Tarzan could swing from the vines.

They grow up in these trees 50 feet up into the treetops. And poison ivy gets 4 inches in diameter out here.

DAN OLSON: So beware setting foot on these islands.

CALVIN FREMLING: On these islands, right. But when we go out to the main channel and see the sand islands, then you see that's the place where most people go to picnic. And nobody picnics here because the mosquitoes would get you, too.

DAN OLSON: But I gather the Mississippi-- or am I wrong in this, Cal-- is not stocked. This is a natural fishery. It rises. The population rises and falls on its own.

CALVIN FREMLING: Right. It isn't. Well, there are some exceptions of stocking. In the farther south, they've stocked striped bass and some other things, wipers and others. And over the years, carp were stocked. Atlantic salmon were stocked.

DAN OLSON: Carp, of all things, were stocked. Many people think of carp as kind of the throwaway fish you don't want in your water.

CALVIN FREMLING: Well, at first they were the queen of the river. Carp, back in the late 1800s, were stocked surreptitiously so people wouldn't know where they put them in because they didn't want them to be caught that quickly. And then they multiplied.

And at first, they became an important thing in the commercial fishery. And they still are. But their numbers have plateaued. But they're still considered bad actors by aquatic ecologists because they root around in the aquatic vegetation and root it up.

[MUSIC PLAYING]

DAN OLSON: We're touring the Upper Mississippi River National Wildlife and Fish Refuge near Winona with biologist Cal Fremling. It's the 75th anniversary of the creation of the refuge by an act of Congress in 1924. Fremling is an authority on the river's ecology.

600-foot-high limestone bluffs on either side of the river mark where rushing waters started carving the Upper Mississippi Valley. Fremling says sediment, the sand carried by the water, is choking the backwaters, threatening the river's biological diversity. Let's return to the river tour with Cal Fremling.

For people who don't know this area of Minnesota, this is a pretty dramatic descent into a portion of geology that we know little about. How would you describe it?

CALVIN FREMLING: This is a plateau, a flat sedimentary rock plateau that extends all the way out to the Rocky Mountains, virtually from the Alleghenies to the Rocky Mountains. And the Mississippi waters have cut their way down through it to this level. So as we look up at these cliffs-- and there are spectacular cliffs here. This is rugged country.

But we're not looking up at hills. We're down in a hole looking up at level land. And it's not been glaciated. That's what makes it unique from the rest of the Minnesota. This wasn't glaciated. If it had been, the glaciers would have rounded all these cliffs off. And there would be glacial, erratic boulders in the fields. And there aren't any.

The glaciers missed this, especially the last time, maybe lightly, a couple other times. But the last time, the glacier missed us. But the meltwater from the glacier, were ponded in northwestern Minnesota and glacial Lake Agassiz, which is now the Red River Valley.

And that water came rushing down through here. And Lake Superior was draining at that time into the Mississippi. It doesn't now, but it did through the Saint Croix then. And those two torrents from glacial Lake Agassiz through the Minnesota River and Lake Superior through the Saint Croix, emptied into the Mississippi and carved this tremendous valley, mostly, that was 200 deeper than it is now.

DAN OLSON: And it's now filled in 200 feet because of sedimentation?

CALVIN FREMLING: By natural sedimentation. Because this valley is so deep, the tributaries are very steep. And because they're steep, they cut themselves back rapidly. So they brought in more-- after the glacier torrents stopped, the tributaries could bring in more sand and gravel than the Mississippi could wash away. So the valley aggraded. It came up to its present level.

DAN OLSON: The arrival of intensive farming, I gather, greatly speeded up this sedimentation process.

CALVIN FREMLING: Oh, yeah. The coming of the white man was like a great climatic change that buried the land. We cut the forests, especially the pines in the Saint Croix, Chippewa, Black watersheds. And we farmed this area intensively for wheat and small grains early on and farmed as far over the bluff tops as we could with horse-drawn equipment, which you can go places you can't go with a tractor.

So all this was intensively farmed. And the tributary valleys had flood after flood. And soil was washed into the Mississippi. But surprisingly, most of that soil didn't make it to the Mississippi. It's stored in the lower reaches of the tributaries. And there's enough stored in the lower reaches of the tributaries to fill these navigation pools.

DAN OLSON: And it will stay there and support tree growth and other kinds of growth, or will it eventually wash down?

CALVIN FREMLING: Well, for a long time, it will support tree growth and remain stabilized. But the potential is there for that stored soil in the valley floors of the tributaries to wash into the Mississippi. If we change our land-use practices, we could-- if we farmed that area, for example, logged it and farmed it as would be feasible, it would make it vulnerable to erosion, by bank erosion, especially.

DAN OLSON: But I gather that's not going to happen. We know, through your work and the work of others who study the river, we know that it would be foolhardy. And I presume there is considerable protection in place so that we won't be logging those tributary valley bottoms that will stay treed and thus perhaps we're in a better spot in terms of the rate of sedimentation. What do you think?

CALVIN FREMLING: Well, I'd like to think that you're right, but I'm not sure. I don't have that much faith in the environmental conscience of the people that are in control of those. We could change that situation quickly by putting housing in or by other types of construction.

But the big picture is when the white man came here, this valley was aggrading slowly. And it's aggrading today. And we have sped it up. But it will continue to aggrade into the foreseeable future for 1,000 years whether we're here or not.

But we have the ability to slow it up or slow it down a little bit. But filling of these pools, navigation pools, is inevitable. But by wise use of the pools and imaginative planning and construction of sand traps and barrier islands and things and artificial islands, we can make this resource last longer.

DAN OLSON: Have the farming practices up top on the plateau changed now? Are they good enough? Are that much better so that the rate of erosion, the rate of runoff of soil has slowed substantially? Or is there still a pretty high rate of runoff?

CALVIN FREMLING: There's still a high rate of runoff. But the farming practices have changed dramatically since the 1930s with strip cropping and contouring and no-till agriculture. The farmers, I think, do an excellent job in the unglaciated area.

Really, if they don't, they don't stay in business very long because they can't afford to lose their nutrients and their soil. And so this area on top of the bluffs is beautiful because it is contoured and strip cropped.

DAN OLSON: Far below us, however many hundreds, maybe 1,000 miles south of us, the delta, that is not, I gather, soil from Minnesota and Iowa. Or is it?

CALVIN FREMLING: Well, some of it is. But most of the soil that washes down into the Gulf of Mexico and has created the big delta down there has come from the Missouri and the tributaries to the west. They are the soil-producing tributaries more than the tributaries that come in from the east.

DAN OLSON: Why is that so?

CALVIN FREMLING: Well, the ones from the east come through forested areas. So the Ohio tends to run clear, the Chippewa, the Wisconsin. But the tributaries to the west, like the Red River of the South, and the Missouri, especially.

The Missouri classically was Big Muddy. People say this is Big Muddy. But that's not correct. This was never the big muddy stream. The Missouri was. It was the one that was too thick to drink and too thin to plow. And it cracked when it went around the bends and all those stories that Mark Twain told.

DAN OLSON: And that has not changed appreciably, apparently, although some conditions have changed along the banks of the Missouri. But that's still a big contributor.

CALVIN FREMLING: No, that's a good point. I should have said it's changed dramatically with the building of the big reservoirs, the power and irrigation reservoirs that were built on the Missouri. They stop the sediment, trap lots of it. And so the sediment input of the Missouri has dropped way down. And that's one of the reasons why the Mississippi Delta is disappearing at about 40 square miles a year.

DAN OLSON: I did not know that. I assumed the delta was growing. It is, in fact, disappearing.

CALVIN FREMLING: Yeah. The delta in Louisiana is right at this time disappearing. And a lot of people are working hard to try to salvage it. But they're losing about 40 square miles of wetlands in Louisiana per year that way.

DAN OLSON: It's going out to the Gulf? It's flowing out to the bottom of the Gulf?

CALVIN FREMLING: The barrier islands, especially, that protect the delta from the ocean waves and hurricane forces and so on are degrading. And because of that, the delta itself is attacked. So there are a lot of bad things happening down there. The ocean is advancing on New Orleans. And New Orleans can't afford to have the ocean beating at its doors.

New Orleans right now is about 90 miles upstream from the mouth of the Mississippi and the Gulf. But the Gulf is advancing toward New Orleans. So when we when we think we have problems here, our problems are very small compared to theirs.

[MUSIC PLAYING]

DAN OLSON: You're listening to a Voices of Minnesota conversation with retired Winona State University biologist Dr. Calvin Fremling in his boat on a stretch of the upper Mississippi River near Winona. I'm Dan Olson.

This is the 75th anniversary of the Upper Mississippi National Wildlife and Fish Refuge, a 260-mile stretch of land and water from Read's Landing near St. Paul all the way down river to Rock Island, Illinois.

The Mississippi today bears almost no resemblance to how the river looked 200 years ago. The Mississippi between Minneapolis and St. Louis is a collection of 26 lakes, huge pools of water stoppered at their lower ends by locks and dams. The Army Corps of Engineers structures make possible barge traffic on the river.

But two centuries ago, an unfettered river ultimately raged or trickled, depending on the season. In a few places, farmers tilled the river bottom. With Cal Fremling at the helm, let's return to our boat trip on the river.

Now, you could argue that those folks shouldn't have been down there farming that [INAUDIBLE], cutting down those trees because that was destroying what I gather was a portion of the ecology of the river. But I mean that in its most simplistic way. But there must be something more complicated than that. By flooding it, we've also lost part of the ecology, I gather.

CALVIN FREMLING: Yeah, it was a completely different river prior to the flooding, in that water levels fluctuated a lot. And a lot of this area was in prairie. The biggest islands out here didn't even have trees on them. It was a prairie environment.

And they burned frequently. Accidentally or on purpose, they were burned. Well, first, they were burned purposely by Native Americans to keep-- this whole area was burned frequently to keep it in forage for elk and bison, to keep it in grass. And then when the white man came, he did that same thing. He burned it frequently to keep it for his cattle and his sheep and goats and things.

And it's taken a lot of years for us to stop that burning, except in certain areas where we want a prairie to exist. Then we do controlled burns. But the river, before it was dammed up, was shallow, extremely shallow in a lot of areas, so that the first steamboats that came up here just had about maybe a 3-foot draft.

They didn't draw much water at all. And the steamboats were really engines on rafts in that their whole engine was above water level. So the steamboat was a unique craft for very shallow rivers. But a lot of the time-- in a drought period, they couldn't even operate.

And then In 19-- or 18, I should say, 1878, then the Corps of Engineers began a program to make this, the main channel, 4 and 1/2 feet deep. And they did that by putting in rock structures called wing dams or winged dikes or constriction dikes that extended outward perpendicularly from the shore to make the river run down a narrow channel.

And that was channelization. And it made the river scour its channel deeper. And then the sediment collected in between the wing dams, so we ended up with a 4-and-1/2-foot-deep navigation channel. All the side channels had dams on them too, made of rock and willows, that kept the flow out in the main channel.

And until 1907, we had a 4-and-1/2-foot channel. And then they modified it to try to make it about a 6-foot channel. In 1912, they decided they're never going to make it with that type of construction to keep it a 6-foot channel.

So in the 1930s, they did the 9-foot channel project, where they built 27 of these large locks and dams and made these big impoundments and without an environmental impact statement. You'd never do that today. You'd never, ever be able to do that project now. But that was during the 1930s, during the depths of the great economic depression.

And people were out of work. And this was a tremendous make-work project. And it was going to revitalize traffic on the river and make the towboats competitive with the railroads. And so it was done.

DAN OLSON: And now, 1999, I believe Congress has sitting before it a proposal to enlarge the locks, the dams. And theoretically, what will that do, in your judgment, if it is done? It's by no means a certainty that it will be done. It's a hugely expensive proposition. What will that do if the locking system is expanded?

CALVIN FREMLING: It would increase riverboat traffic. I'm not sure that they would increase the size of the locks up here yet. It's mainly farther south to speed the passage of boats up the Illinois River because it's really-- the Illinois is really the busiest of all.

DAN OLSON: Well, to hear you speak enthusiastically about the fishing resource here in the Mississippi, you make it sound like the Mississippi biologically is doing very well. There's a healthy fishery. There's wildlife on land. So apparently, we've turned the corner in protecting the Mississippi. Is that right?

CALVIN FREMLING: No. When the dams were first put in, people were really excited that this was a real boon to the river. Because suddenly, we had all this tremendous waterfowl habitat. And duck hunting was incredible in this area then. And fishing was better than now in these areas.

What we're seeing now is a physical loss of the water itself being displaced by sand and sediment that's coming into the watershed. And I'll show you some spots up here that are really quite dramatic.

The sand comes down the main channel, but then it comes in through side channels into the backwaters. And even though we'll be a mile from the main channel, you'll see the sand plumes encroaching on these pools. So lakes are temporary features on the land and in the geologic landscape.

And we've made the Mississippi into a series of lakes, which are now mortal. And they are going to disappear sometime. And I'd say they're about halfway there, a third or a halfway there.

DAN OLSON: In fact, I think I've heard people speculating that in the case of Lake Pepin, one of the best known, maybe the largest lake along the Mississippi, that the sedimentation rate is quite fast. How much time does a lake like Lake Pepin have left, do you think?

CALVIN FREMLING: Well, Lake Pepin used to extend all the way up to the Twin Cities. And by the time the white man came, the sedimentation, natural from sand and so on, had encroached in it and filled it all the way down, almost to Red Wing.

[MUSIC PLAYING]

DAN OLSON: No conversation about the ecological health of the Mississippi River is complete without a report on the status of the mayfly. And it's mayfly research that helped put Cal Fremling up there among those others listened to when talking about the river.

Fremling says, better than any chemist, the mayfly measures Mississippi River water quality. The insect has floppy, transparent wings and a drooping tail and a very short life span as an adult. It is the mayfly nymph that is the real environmental sleuth. We return to our conversation on the river with Cal Fremling.

Why is the mayfly-- or is the mayfly a big indicator of a river's biology, a river's health?

CALVIN FREMLING: Well, the adult mayfly, the one that collects on cottages and blocks bridges and causes all those nuisance problems, is the adult that only lives for about a day, long enough to lay eggs and die. It doesn't even have any mouthparts. But the eggs hatch into tiny larvae that live in the sediment, in the organic sediment of lakes and rivers where it's oxygenated.

And they grow very slowly for about a year, in the north, maybe two years. But they grow slowly and shed their skin and get bigger and bigger. And while they're down there, they eat roughly about the same thing that an earthworm would eat. They eat the organic material from the sediment.

And they convert that organic matter into high quality fish food. And those nymphs or larvae are in the environment all year round so that they're there all the time for fish. And they come in various-- in all gradations of size as they grow.

So even for tiny fish, they are food. And fish feed heavily on them. I guess most fishermen know that if there's a big mayfly hatch on the Mississippi, you may as well forget about fishing for a day or two. And that happens in the border water canoe areas. If you have the misfortune to be up there during a mayfly hatch, you don't catch many fish.

DAN OLSON: And if the mayfly is not thriving, it tells us what about a river or about a lake?

CALVIN FREMLING: Well, if they are there-- and we cuss them because they are a nuisance. They cover our cars and everything. We cuss them. But really, we should rejoice because they are there, because they are telling us that our river or lake has been of mayfly quality for a year.

And better than a chemist who can go out and take a chemical sample today, the mayfly samples for everything, really, that's toxic. Let me explain that. If I, as a chemist, I go out and I sample for arsenic and mercury and lead and PCBs and all kinds of other things, but I forget to sample for some other toxicant, I wouldn't know that it was there, and everything would be dead.

Hard to pinpoint what kills things. But the mayfly would tell us if he's there, it's been of mayfly quality for a year. And we know that it's been oxygenated for a year. And if clams are there, we may know that it's been of clam quality for 17 years or maybe more because they live longer.

DAN OLSON: Clams are another sensitive indicator of a river's health.

CALVIN FREMLING: Right. And there are all different gradations of sensitivity. But clams and mayflies are subject to the worst things we can put in the river because they settle out in the bottom. And that's where the clam and the mayfly larvae live.

DAN OLSON: So they're the barometers. They're the--

CALVIN FREMLING: The canary in the coal mine.

DAN OLSON: And how are they doing, the mayflies?

CALVIN FREMLING: Mayflies-- when the 9-foot channel project was put in, that was a big deal for these burrowing mayflies that live in the sediment because we suddenly made all kinds of area for them to live. So their populations went way, way up.

And now, however, we are losing the volume of these backwaters and reducing their habitat, although they're still very abundant. But even more, in this pool, for example, we're covering the bottom with sand. And sand is a very poor substrate for most things to live in.

[MUSIC PLAYING]

DAN OLSON: You're listening to a Voices of Minnesota interview with Cal Fremling. The retired Winona State University biologist grew up in Brainerd. When he wasn't hunting or trapping, he was fishing. Biology forms the plot for many of his fish stories.

There's the one about the 4,000-mile odyssey of lovesick American eels as they head down the Mississippi to mate with partners in the Caribbean. 118 species of fish live in the upper Mississippi. Fremling says an angler can expect to catch any one of nine, including the wily walleye.

How about you personally? You're an avid fisherman. You fish many, many days of the year. What's your consumption? Do you worry about the accumulation of mercury and other chemicals in the fish?

CALVIN FREMLING: I eat fish from the river at least once a week, very often more than that. And the advisories that are done by the Minnesota DNR are very good. They're probably, in my opinion, the best in the United States. They're very careful, very conservative.

And they tell me that in this area, which is probably the nicest area in the whole river, from the foot of Lake Pepin down to [INAUDIBLE] that I can eat bluegills and crappies anytime I want. That's about what they say.

But the advisories say that we shouldn't eat big old oily fish, carp, catfish, flathead, channel cats because they have high levels of PCBs in them and other chlorinated hydrocarbons. Those PCBs got in there from industrial uses, transformer oil and so on. Nobody uses them anymore. It's illegal.

So the PCB levels are decreasing. But since they don't degrade, they're still in the environment. And they're concentrated in the fish at the top of the food chain. So the big old fish that ate the fish that ate the fish that ate the fish have a lot of PCBs in them. So my friends and I don't keep big old fish. We keep small fish.

Here the size limit on walleyes is 15 inches. And we don't keep them over maybe 17 inches. If they're bigger than 17, we let them go. And the advisory tells me I can eat walleyes 15 inches long one meal a week. And we do.

And we fillet them. And they're excellent, which then people would say, well, I don't ever eat fish out of the Mississippi River. I'd just eat ocean fish. Well, if you eat tuna, and if the tuna were checked by the Minnesota DNR, I think that there would be a fish advisory for canned tuna because the tuna is contaminated with mercury, as are the fish in the glaciated areas of Minnesota in the north.

Mercury, unlike PCBs that came from point sources mainly, mercury comes from the atmosphere. The mercury is a gas. Hard to believe a heavy thing like mercury could be a gas, but it is. And it comes from incinerators and coal-burning power plants but also from fungicides that were used in latex paint. And as latex paint chalked off houses, it released the mercury into the atmosphere.

And then when we have a low-pressure system, we have counterclockwise circulation around the low, and that can pump the mercury from the Ohio River basin all the way up and dump it in northern Minnesota. So in the soft water lakes, especially, the mercury enters the food chain up there.

So the same advisory would exist for, I like to say, La Isabella, but also Snowbank and all those nice lakes that I know well too. The same advisory-- eat one meal of 15-inch walleyes a week because of mercury. Down here, you eat one meal a week of 15-inch walleyes for PCBs.

DAN OLSON: Happily for us, I believe, mercury is no longer a component of latex paints.

CALVIN FREMLING: I don't think so.

DAN OLSON: But it must give people pause. However, I think you, among others, have said that-- so in the sediment of the river bottom, there are still PCBs.

CALVIN FREMLING: Yes. Oh, yeah. PCBs are entombed, hopefully, in the river bottom. And hopefully, they'll get covered up with sediment and stay there forever.

DAN OLSON: Really? And that's what's to be done. There is not a realistic way of cleaning out, either biologically or in any other way, the PCBs from the river.

CALVIN FREMLING: No, I don't know of any other way. But that's happening in Lake Pepin. It has happened. The bottom of Lake Pepin has all kinds of bad stuff stored in it and is slowly being entombed by sediment coming into the lake.

But of regarding eating the fish, maybe I rationalize because I like to eat fish so much. And I would guess your listeners would say, well, that guy likes to eat fish, so he rationalizes. But by risk assessment studies that I've seen, I'm safer eating a meal of walleye a week from the Mississippi River than I am riding a bicycle or playing soccer or smoking cigarettes or breathing secondhand smoke or all of these things that we do all the time.

[MUSIC PLAYING]

DAN OLSON: Boating with biologist Cal Fremling on the upper Mississippi is more than an ecology or fish-consumption discourse. It's a history lesson. And thanks to Fremling's skill as a river pilot, there's no collision with history. Hundreds of wing dams separate the river's backwaters from the main channel.

Like teeth in a dragon's mouth, the wing dam rocks are just below the surface of the water. They can gouge hulls and render propellers useless. We motor through a backwater called Honeymoon Slough, across the main channel from Fountain City, Wisconsin. Fremling cuts the engine.

Dr. Cal Fremling, leaning over the edge of the boat. I'm not going to follow you that far, but you're in about a foot maybe, at most, of water.

CALVIN FREMLING: Trying to find a rock small enough to pick up. Most of these are one-man rocks. They're the kind that one man could handle easily. And they brought them out to these locations on a barge in the old days or by a sled in the wintertime through the ice. And they drop these rocks on a willow mat and sank the mat.

And then they made another big willow mat out of fascines, out of bundles of willows. And then they sank that with rock. So they made a rock, willow, rock, willow sandwich from the bottom of the river up to build these. And I forget in this pool how many there are. I think there are 140 of these wing dams and then plus the closing dams.

It's like one of the wonders of the world when you consider how many of these structures were built from St. Louis to Minneapolis or St. Paul.

DAN OLSON: This is a chunk of limestone.

CALVIN FREMLING: Right. It was quarried from the bluff top. In this town of Fountain City, there is a big quarry up on top where they quarried the limestone or dolomite and took it down on a little railroad, right straight down the bluff to the waiting barges.

Then the barges, steamboats pushed them to the construction sites. And every bluff virtually that comes right to the river has a quarry like that in it all the way down, down the length of the upper Mississippi River.

DAN OLSON: Now, as you're coming out in a watercraft from one of these channels out into the main stem, looking across, this is a pretty little river town, Fountain City. This is just about as beautiful a sight, as scenic a sight as you can find.

CALVIN FREMLING: Oh, yeah. I think so. People have told me this looks like the Rhine. I was on the Rhine last September. I think this is prettier than the Rhine. It's bigger, a lot more interesting watercraft on it. You surely don't see towboats like this on the Rhine or strings of barges this big.

Well, a lot of people don't find the towboats attractive. But I do. I've traveled on them all the way to New Orleans on tow boats. And they're really interesting. And--

DAN OLSON: You don't see them as competition and as degrading? I mean, maintenance of the 9-- I gather it's still 9 foot, not 12 foot yet.

CALVIN FREMLING: Well, when we say 9, it's more than that. They have to maintain it about 10 or so. Otherwise, if you maintain it just at 9, you wouldn't have enough water under the bottom of your barge. So you'd have so much friction that it wouldn't work well, especially if the barge gets ice on the bottom of it, as they do.

DAN OLSON: And to do that, they have to dredge that channel. I have no idea how often, but that must be a huge disruption to a river's ecosystem.

CALVIN FREMLING: Well, the dredging that is done in this area is primarily sand. And in the old days, they used to dump the sand, the closest spot, the handiest place. And that was a disaster because they dumped it in the beautiful backwaters that they created.

And years ago, that was my pitch to the Corps of Engineers and anybody that would listen that we're losing those backwaters. You're filling them up with your sand. And I was told by a representative of the Corps that unless I could prove all this analytically, I shouldn't say those things anymore.

And in addition, if the Corps made those backwaters and wanted to fill them, we made them. We can fill them. That's the old philosophy. The Corps giveth. The Corps taketh away kind of thing. But really, in truth, the Corps has changed.

DAN OLSON: The dredging is still--

CALVIN FREMLING: The leopard has changed its spots, I think. I hope.

DAN OLSON: The dredging is still taking place, to be sure. Where is the dredge spoil being put now?

CALVIN FREMLING: Well, now in this area-- by the way, we dredge more sand in this area than most other pools because of the influence of the Chippewa River. Farther down, the Wisconsin brings in sand too. But now they do some imaginative things.

They temporarily put it in one place and build a big bathtub with a sand berm. And they pump the sand hydraulically into the middle of the bathtub. And from there, they push it higher with dozers, bulldozers or push it into other means of conveyance, into trucks and haul it away. And they try to get it out of the river system and do something beneficial with it.

And the big one they like to do is build islands with it. And there have been some disasters with building islands out of sand. But it was part of the learning process. And I was involved in one at the Weaver Bottoms farther upstream, where we wanted, as a part of our recommendation, some small islands built.

But they weren't small islands when the Corps built them. They were monstrous things that were 8 feet high or more. And they've been a disaster, I think. That's my opinion. They've been a disaster.

[BOAT MOTOR WHIRRING]

DAN OLSON: Our Mississippi River tour with Cal Fremling is nearly over. He revs the outboard motor, and we head down river toward Winona. Right in the middle of the main channel is a huge riverboat. The Army Corps of Engineers crew on board is sucking sand off the river bottom to maintain the navigation channel.

That looks like the Delta Queen painted in yellow with a huge iron superstructure on top.

CALVIN FREMLING: That's the Thompson. That's the big Corps of Engineer dredge that's been used ever since the 1930s. And really, the operating part of that hydraulic dredge isn't that big. But that old dredge has living quarters on it and a mess area and all that that modern dredges don't have.

DAN OLSON: And in front, we have what looks to me like a tug, although I confess--

CALVIN FREMLING: Yeah. It's a work boat pushing pontoons with dredge pipe on it. He has four pontoons and maybe 75 feet of dredge pipe on it.

DAN OLSON: And then all of us--

CALVIN FREMLING: And then over at the left, we can see there must be a quarter of a mile more of pontoons and dredge pipe. And the noise you hear is the rail, the train going by.

DAN OLSON: And they're going to suck sand off the bottom.

CALVIN FREMLING: Right. The Corps of Engineer dredge will have the cutting head of its dredge nozzle down in the river bottom. And it turns like an egg beater, churns up the bottom. And then the big diesel-driven pumps in the dredge suck the water and sand up through the pumps into these floating pipelines.

And then it'll go somewhere onshore. Now, I'm not sure where they're going to do it. But I have a hunch.

DAN OLSON: I see a huge pile--

CALVIN FREMLING: Down here about a mile downstream. And looking down there, we see a huge spoil. We call it spoil. They don't like that term. But we still call it spoil.

DAN OLSON: It's just sand.

CALVIN FREMLING: It's sand.

DAN OLSON: And there's nothing particularly spoiled about it at all. It's pretty good sand.

CALVIN FREMLING: Right. It's good sand. It isn't very good for concrete because the particles are too round. They've been tumbled around. But it's good for icing for on roads and filling and doing all kinds of things.

But they'll pump all the way down to that pile of sand and store it there temporarily. And then later, they'll come. They'll take a lot of that sand out of there and do something with it.

DAN OLSON: We have a lot of uses living and working on this river. There's you, the biologist, the angler and the hunter and the recreational boater and the towboat operator. You seem to come down as a moderate saying, we can all live together, and the river will have a life for quite a long period of time.

But do you sometimes kind of sit at the end of the day and think, gosh, you know, we're not doing quite enough? Maybe the river is going to be dead before we know.

CALVIN FREMLING: Well, there have been-- you hear wild ideas. One wild idea is let's take out the dams and let the river be like it used to be in the good old days. Well, that's crazy. It's not even an option. If the dams were taken out today, this river wouldn't be like it was in the old days. Because since the old days, this river has accumulated uncountable tons of sand and other sediments in the pools.

If you drop the water level, it wouldn't look like it did in the old days. And the river would adjust by trying to get rid of that sand. And the sand would move inexorably downstream. And it would fill harbors and all kinds of problems that-- you can't imagine what would happen if the pools were suddenly dewatered.

Another one is, well, let's lower the pool level and dry out some of the backwaters so that the sediments can consolidate, get denser, and the oxidizable organics can oxidize. That makes sense to me. And I think it'll be done, but it'll cause some problems. Areas today where we touch bottom, we'll really touch bottom.

But here's the big picture. The Mississippi River has been rising ever since-- the bed has been rising since the last glacier. Every obstruction we put in it hastens the rise. We did that with the channel training structures, the wing dams, closing dams. And we did it with the 9-foot channel dams.

So we made it rise faster. And it's going to continue to rise. But we can maybe decrease the rate of rise, but it's going to rise. 1,000 years from now, the river won't even know that we were here.

DAN OLSON: You think in 1,000 years, human activity will have changed so that we won't be relying on river traffic. We might still be down here enjoying recreation. But our human impact on the river will be negligible.

CALVIN FREMLING: Well, maybe I'm more pessimistic than that, even. I think maybe we may not even be here. Nobody knows. I'm speculating. But geologically, someday we're not going to be here. And the Mississippi won't give a damn. And the Mississippi will still be its own-- doing its own thing and won't even remember that we were here. And somehow, I find comfort in that. It doesn't bother me a bit.

DAN OLSON: Dr. Cal Fremling, thanks for your time and the trip on the river.

CALVIN FREMLING: Thank you. It was fun. I always like to get out.

[MUSIC PLAYING]

GARY EICHTEN: Cal Fremling is retired Winona State University biologist. He talked with Minnesota Public Radio's Dan Olson.

[MUSIC PLAYING]

By the way, we'll be rebroadcasting this program at 9:00 tonight here on Minnesota Public Radio. Programming on MPR is supported by Mount Royal Pines III, assisted living apartments, Duluth, for seniors desiring independent apartment living while receiving additional care and assistance. 218-724-5500.

That's it for Midday today. Tomorrow, we're out at the State Fair. Hope you can join us. Mark Seeley, Christine Jax will be our guests.

ANNOUNCER: This week, it's our favorite food scientist, Shirley Corriher. No one talks yeast molecules quite like Shirley. Join us for The Splendid Table Saturday at 2:00 and Sunday at 7:00 on Minnesota Public Radio, KNOW FM 91.1.

GARY EICHTEN: You're listening to Minnesota Public Radio. We have a sunny skies, 79 degrees at KNOW FM 91.1, Minneapolis and St. Paul. Partly cloudy skies forecast for the rest of this afternoon. It's about as warm as it's going to get. Clear tonight with a low in the low 60s. And then there is a 40% chance for some rain by tomorrow afternoon with a high temperature in the middle 80s.