Here & Now

Allison Madison on Cutting Winter Road Salt to Protect Water

Zac Schultz:

Unless you’re new to Wisconsin, you’ve seen the snowplows out this winter, not only cleaning the roads but laying down salt. While this makes it safer for drivers, it’s becoming a problem for our state’s freshwater bodies.

Hilary Dugan:

One thing we’re seeing in a lot of urban areas in Wisconsin is increasing salinity in our freshwater lakes and rivers. That’s a problem because historically we were blessed with a lot of freshwater in Wisconsin. Often we take that for granted and as we increase salinity in our water bodies, that causes problems for aquatic organisms that have evolved to be in freshwater environments. It also causes problems for humans if that’s the drinking water source. If we’re seeing increase in salinity in lakes, we’re likely also seeing it in groundwater. So this kind of goes beneath the surface. But thinking about salt inputs, the biggest input is road salt by far. We use in every county in the state. All of that salt ends up in the environment. Nothing is being picked up so all of it is going to be washed into our waters eventually.

Zac Schultz:

To learn more about impact and mitigation, we turn to Allison Madison, program manager at Wisconsin Salt Wise. Thanks for joining us.

Allison Madison:

Thank you so much for having me.

Zac Schultz:

So what is Salt Wise and who are you working with?

Allison Madison:

Salt Wise actually began in the Madison area with the city of Madison, Dane County, Madison Dane County Public Health, the wastewater treatment plant, the water utility, all seeing salt concentrations increase in our lakes and our streams and our drinking water. So those organizations came together and said we need to do something about this, right, and initially the goal was reach out to some of the biggest users of salt, the cities, different municipalities within the county, the county themselves and they started to train operators, anybody who’s putting salt down on best practices. And then from there, Salt Wise kind of grew because some of the operators were saying, you know, this is great, but we also have private contractors, they’re putting down a lot of salt on parking lots and sidewalks. They need to understand, and then also the audience of just the general public came up, right? Like if the public doesn’t understand why we might want to kind of calibrate in and consider salt use, not just that more isn’t always better, we need to make sure that message gets out to the public so they understand why we’re making changes at the municipal, county, state level.

Zac Schultz:

So what’s the tradeoff here between making roads safe and keeping our groundwater safe?

Allison Madison:

So actually I’m so glad you asked that question, because I really — with Salt Wise, what we want to do is kind of break that apart. Break apart that dichotomy of we’re either safe or we have pure freshwater going forward. Because really a lot of the best practices that the Salt Wise partnership encourages are practices that do not reduce the level of service on our roads. So things like calibrating your salt spreaders so you understand how much salt is being put down and you can really make precise applications based on road temperature and weather trends. Also using liquid brines. You may have seen those lines on the highway before a storm, sometimes on municipal streets as well. Those work to put down a very, very thin layer of salt. I like to describe it like putting pam spray maybe, cooking spray, on your skillet before you cook. So if you can prevent that bond from forming between snow and the pavement, when the plow comes, the snow comes up so much more readily, they use a lot less salt afterwards, right? I think you probably sometimes put some food on right before oiling that skillet and then you’re scraping and scraping afterwards. So some of these practices, like using liquid brines, calibrating equipment, they don’t actually reduce the level of service. They don’t make the pavement less safe. Sometimes we can actually make it safer because of the work of liquid just working so much more quickly than solid rock salt. So it’s not a question of safe, again, or, you know, protecting the environment, but it’s really just adopting those best practices.

Zac Schultz:

So climate change is a big factor here. It’s changing what our winters look like in terms of size of storms, when snow runs off. Does that change the formulas people have been using for years about how to lay down salt?

Allison Madison:

Yeah, so one of the biggest problems is we haven’t necessarily used formulas in the past. We’ve kind of just thought salt is good, some is good, more is better, let’s crank it up, put the salt down, right? So we’re seeing those conversations start to change. Part of it is the environmental aspect of this issue, right, really seeing salt concentrations increase in our freshwater, but another piece of it is the growing cost of salt itself, and also the fact that salt is super corrosive, right? I think a lot of us see that maybe on our personal vehicles, but salt also really prematurely ages roads and bridges, and so we’re paying a lot more for salt these days and we’re starting to see the cost of that. So I think that this work is really just starting to have applicators, those biggest applicators are seeing it first, kind of how do we dial in and right-size our salt use as the climate continues to change and we have more maybe snow event followed by warm spell with rain. You know, we see that if there’s any extra salt that’s been put down on pavement, it’s just washing away, right? Into our streams.

Zac Schultz:

So for individuals at home. We have just a few seconds left. What should they think about when they salt their sidewalk or their steps?

Allison Madison:

Thank you. So we really encourage people to shovel, scatter, switch, and then sweep. So first shovel, get out there and move as much snow as you can possibly move kind of manually or mechanically with a snowblower. So shovel, scatter. If you do need to use salt, just apply it as needed, because every teaspoon of salt pollutes five gallons of water. So if you’ve got extra salt left over, you want to make sure you’re sweeping that up and then using less the next time. The switch comes in at colder temperatures. If you drop below — if the temperature has dropped below 15 degrees Fahrenheit, salt is not effective anymore. So we need to switch and use sand for traction or a different de-icer.

Zac Schultz:

That is all we have, Allison Madison, thanks for your time.

Allison Madison:

Thank you so much. It was a delight to be on.