Good news and bad news: 30-year report details Upper Mississippi water quality

CATHY WURZER: Well, just before the newscast, we heard about the Science Museum of Minnesota's plans to make the Mississippi River a more central part of its programming. If you happen to talk to somebody who saw the river in the Twin Cities, say, 100 years ago, it would have been pretty disgusting.

I've got two words for you-- sewer worms. Sorry if you're eating lunch. It won't surprise you that since we stopped dumping raw sewage, sawdust, and other industrial chemicals into the river, its health has improved dramatically.

A new report from the Upper Mississippi River Basin Association looks at how water quality in the river has changed over 30 years from 1989 through 2018. There is some good news and some bad news. Joining us to explain is Glenn Skuta, Watershed Division Director at the MPCA. He's also a member of the association's Water Quality Executive Committee. Glenn, welcome.

GLENN SKUTA: Thanks, Cathy. How are you?

CATHY WURZER: I'm good. So far, so good. Let's start with the bad news first, shall we? I'm assuming that in the past few years, you probably are seeing much more in the way of road salt pollution into that river. Would that be correct?

GLENN SKUTA: That is correct, Cathy. That's one of the major findings of this report is that the amount of chloride-- salt is calcium chloride or sodium chloride. The chloride in the river has been increasing. There's a pretty significant increasing trend on that.

CATHY WURZER: And what does it do to the river?

GLENN SKUTA: Chloride and salt-- you just think about the difference between salt water and fresh water, right? The oceans are salt water. Our rivers, our lakes, are fresh water.

We're seeing a situation now where the amount of salt that we're using for deicing our roads and the salt that we use to soften our water in our homes-- as that salt gets discharged to our rivers, it's making the water more salty, and that has a negative impact on the aquatic life in the rivers and lakes because they're freshwater animals, not saltwater.

CATHY WURZER: Forgive my ignorance. Since the river is always moving, I can see issues with chloride contamination during the spring and winter. But as the water keeps moving, does that tend to ease up a little bit, say, in the summer and fall? Do some of the effects-- then, are they mitigated?

GLENN SKUTA: Yeah, that does happen. You're right. Flowing water flushes, right? Where you have a lake where the water remains there and resides longer, the chloride concentrates more and more and is flushed much more slowly. But yes, in a river system that's always flowing, it does get purged better.

The levels will drop past coming out of the winter, the salting season. But even in rivers, it's not fully flushed. And then big rivers like the Mississippi, you have backwater areas or side channels that don't flush as well, and you might have more significant impacts in those parts of rivers, even though they are flowing.

CATHY WURZER: Right. So obviously, still a problem. I know city governments are working to reduce their salting of roads-- at least the amount of chloride they use. What can the general public do to reduce the amount of chloride from road salt?

GLENN SKUTA: Yeah. When you're removing snow and ice in your yard, the first thing is to do the physical work first, the shoveling, the scraping. Don't just rely on the chemical to do it for you. And remember, too, that when we get to these very cold temperatures like we've been having, once you get below 15F, the salt really doesn't work very well anymore.

Salt reduces the freezing point. And at a certain point, it just can't reduce it anymore, and it just doesn't do the work. Putting more down thinking that that's going to help at a point where it's not working is not helpful at all. When you are using salt, if you can't mechanically remove the ice and the snow-- you need to use some salt to be safe-- then it's really about doing it smart.

Smart salting is the term is used. Really, only about a cup of salt is needed for about 10 typical sidewalk squares. You don't need to put more on than that. And still, you can do the do the safe thing by using that. I love coffee.

And if my coffee cup is full to the brim, it doesn't help if I add more to the coffee cup. It's just going to make a mess and not be helpful, and the same thing with salt. It doesn't help to put more down at a certain point.

CATHY WURZER: Good analogy. Say, I'm focusing on chloride, I know, and there's other things that are of a concern. Where are we on nitrogen? I ask that because, of course, there's so much talk about the dead zones in the Gulf of Mexico. With the attention around that, have industries and farmers been better in terms of nitrogen runoff?

GLENN SKUTA: Nitrogen is a very difficult chemical or pollutant to control. The way it behaves in the environment is difficult. So where we've seen really great improvements in the levels of phosphorus in the river, we haven't seen it with the nitrogen as much. Phosphorus is better able to be controlled for a couple of different reasons.

One, in our wastewater treatment plants-- our wastewater treatment plants around the state have done just a great job of adjusting their treatment technologies to remove phosphorus from wastewater. And then on the landscape, agriculturally, phosphorus attaches to soil, and farmers have been doing such a great job of reducing soil erosion that there's much less phosphorus going into our waters from agricultural purposes as well.

Phosphorus has been better controlled, I'll say. Nitrogen is more difficult, and there's a lot of work going on trying to get better on this because we need to. In the wastewater setting, it's not as easily removed from wastewater, and it's going to take different types of technologies than most treatment plans currently have, so that's a problem.

And then in the agricultural setting, nitrogen is soluble-- much more soluble than phosphorus. It dissolves. It gets into groundwater. It gets into surface water much more easily than phosphorus does. So while we're seeing improvements on the landscape, we need a lot more.

And really, to control nitrogen, keep this very simple or coarse, we really need a couple of things. One is we need more continuous living cover on the land, so traditional crops that are perennial or that are on the landscape longer like alfalfa, for example.

And there's new crops being developed by the University of Minnesota's Forever Green initiative, things like kernza and camelina and pennycress and things like that. So perennial crops that prevent that nitrate or nitrogen from leaching into the groundwater and prevent it from running off in big storms. So continuous living cover, cover crops, that type of thing is one.

And then the other is just better, more efficient use of nitrogen, whether it's in commercial fertilizer or in manure, making sure that it's being applied, again, not too much, in the right amounts, in the right places, and at the right time so it's not lost to the environment.

CATHY WURZER: It sounds like there's a lot of things that are going on to try to help the river. How would you rate the health of the ecosystem?

GLENN SKUTA: That's a big question, Cathy. Like you pointed out, 100 years ago, the Mississippi River through the Twin Cities was literally just a cholera-laden mat of sewage and sawdust and algae. It is not that anymore.

I remember just before the pandemic, going down to the Science Museum to actually watch from there the Red Bull Flugtag, the flying day that they have where people design these non-motorized flying machines. And they have a giant ramp that they put right in the middle of the Mississippi River right across from the Science Museum, and folks try to fly.

And just thinking about 100 years ago, if anyone would have thought of doing anything like that, they would have been just laughed out of town because it was just ridiculously polluted. Now, you can actually have people in the river, in the water, and that be OK. It's all relative, to a degree.

We certainly don't have the situation we had 100 years ago. But at the same time, we know more than we did then. There's the less visible pollutants like nitrogen, like chloride, that aren't what you would have seen back then in terms of sawdust and animal carcasses and everything else.

So we've made a ton of progress, and we should be really happy and proud about that. But at the same time, we have to be sober about that and realize that we do have a ways to go here.

CATHY WURZER: Say, a final question for you, and it's this. With climate change top of mind, how might the river be affected as we go forward with rising temperatures and a wetter environment?

GLENN SKUTA: Yeah. Good point, Cathy. One of the findings in the report is that the flow in the river is up from when you go all the way back to the records of the 1940s, that we are seeing more flow in the river. And that's a combination of, as you're saying, climate change, which has made Minnesota's climate here wetter, more precipitation in general, bigger storm events, that type of thing.

We have drained a lot of the landscape. We don't store as much water on the landscape as we used to both in the urban settings where we have a lot of impervious surface and for agricultural drainage as well. There is more water into the system, and that just points out that need to continue to do the good work that is being done to keep soil on the land to prevent erosion.

And again, cover crops, perennial crops, are a great benefit for that. There's been a lot more attention on water storage over the last couple of years, money being appropriated by the legislature for incentivizing more storage on the land and building soil health. So there are a lot of really good things happening to try to mitigate the impacts of climate change.

CATHY WURZER: Thanks for joining us, Glenn, and talking about this new report. We appreciate it.

GLENN SKUTA: You bet. Thanks to you, Cathy.

CATHY WURZER: Glenn Skuta as the MPCA's Watershed Division Director.