For the Record: Examining the health and future of Wisconsin’s waterways

Wisconsin waterways glisten in the setting sun

MADISON, Wis. — Wisconsin’s waterways have long been a vital resource for those who call this land home; from providing fresh food and water to playing a key role in the state’s economy, the Badger state’s lakes and rivers have been the lifeblood of the land for thousands of years.

While the state’s waterways aren’t facing the same existential threat as some in the Western U.S., climate change is already causing significant changes in the 15,000 lakes and 32,000 miles of streams and rivers scattered throughout Wisconsin.

Experts with the Wisconsin Department of Natural Resources and UW-Madison’s Center for Limnology recently sat down with News 3 Now meteorologist Dana Fulton to talk about how shifting weather patterns are impacting some of the state’s most valued resources and how warming temperatures are transforming Wisconsin’s fishing industry.

Heavy rains and runoff

Experts with the Wisconsin State Climatology Office say climate change, in simple terms, can be described as a northward shift of traditional weather patterns. For Wisconsin, especially in southern parts of the state, that means more rain.

“That is one thing we’re seeing with climate change: more and more rain,” Katie Hein, a water resources management specialist with the Wisconsin DNR, said. “Overall this last decade is the wettest decade we have on record, and we’re seeing more of these extreme rain events, really large amounts of precipitation in a short amount of time.”

Paired with the state’s widespread agriculture operations, heavy rain events can wash various nutrients and sediments into area waterways, giving potentially harmful blue-green algal blooms exactly what they need to grow and thrive. (Anyone who’s ever tried going for a swim in one of Madison’s lakes is probably familiar with the stuff.)

While it’s not necessarily deadly for humans, some types of blue-green algae create toxins that can cause irritable skin on contact and more serious health issues — difficulty breathing and vomiting — if ingested.

“One of my colleagues recommends: if you can’t see your feet when you’re in knee-deep water, you shouldn’t be swimming,” Hein said. “If you see that green paint slick on the water, don’t get in the water.”

RELATED: Madison, Dane County announce new program aimed at keeping beaches algae-free

Despite an increase in heavy rain events that can lead to harmful algal blooms, Hein said there are ways — both individual and governmental — to address the issue.

On the individual level, planting trees and building rain gardens are easy ways for homeowners to make a local difference; by creating more opportunities for local water retention, heavy rains are less likely to flush contaminants into lakes and rivers.

Rains don’t follow property lines, though, which means governments of all sizes should consider larger efforts to minimize runoff, according to Hein.

Green infrastructure — which the Environmental Protection Agency defines as infrastructure that uses plants and soil systems to lessen the amount of stormwater runoff into surface waters — can come in different forms, including rooftop gardens, trees alongside roads and other forms. By planting cover crops during off seasons, farmers can help retain water during heavy rain events too

Some of the best solutions come from the natural environment though, Hein said. That includes wetlands like swamps and marshes.

“Think about it kind of [like] your safety button,” Hein said. “Wetlands can hold onto that water and process the water and kind of clean the water up for us.”

In recent years, Dane County leaders have taken steps to restore local wetlands to give area communities a buffer against increasingly common heavy rain events.

Differing effects of drought

Balance is part of any healthy ecosystem, and that’s especially true for our local waterways. Despite their reputation as a devastating phenomenon, droughts have an important role to play in Wisconsin.

While recent droughts in Western states have caused reservoirs like Lake Mead to fall to historic lows, Hilary Dugan — an assistant professor with UW’s Center for Limnology — said droughts have a different effect in Wisconsin. Because of the state’s vast expanse of water, droughts rarely have an impact on the amount of water available. They do, however, greatly impact the water quality in our lakes and rivers.

According to Dugan, dry spells in the Midwest can create unexpected consequences for a waterway’s overall health. Dugan said one of the major factors researchers look at in terms of lake health is “residence time,” which is the amount of time a single molecule of water sticks around in a body of water before moving downstream.

In Lake Mendota, that number is roughly four years; during periods of drought, though, water sticks around longer because there’s less flow from rivers and streams.

When water sticks around for longer stretches, it can have interesting feedback on the water’s chemistry, which Dugan said can be beneficial in some situations. On the whole, though, Wisconsin’s climate has trended wetter over the past decade.

“Climate change is really interesting because we know a lot about what’s happening with temperature; it’s warming. In Madison and Southern Wisconsin, we’re seeing more warming in winter months, which is going to have impacts. Our summers haven’t necessarily gotten hotter, but they will, and we’re very confident in that,” Dugan said. “Precipitation is more of an unknown; is it going to get wetter? Is it going to be overall wetter, but most of that rain comes in really big short-term events, which would be a problem for water quality when you have these high-intensity rain events that really do flush everything off the land? So that’s a bit more of an unknown.”

It’s important to note, Dugan said, that droughts and floods are not exact opposites; droughts stretch over a long period of time while floods are rapid events. That has implications on how often runoff makes its way into our waterways, an issue Dugan says impacts our water more than any other.

Drier periods can help prevent excess runoff from making its way into local lakes, which is better for lake health. It could, Dugan said, set the stage for massive deposits of potentially damaging chemicals when large storms eventually do hit, essentially delaying the inevitable.

That can have far-reaching impacts on all kinds of aquatic habitats.

The future of fisheries

Small changes to one part of an ecosystem can have wide-reaching impacts on the system as a whole. Wisconsin’s fisheries are no exception.

As air temperatures continue to increase because of climate change, the same is happening to waterways throughout the state. With species like walleye and brook trout reliant on cool or cold water, those rising temps can seriously reduce the viability of some of Wisconsin’s hallmark species.

As waters trend warmer, cool-water species will start to be replaced by warm-water species like bass and bluegill, according to Zach Feiner, a fisheries ecologist & research scientist with the Wisconsin DNR. All species, though, are still vulnerable to the seasonal impacts of climate change.

A change of just a few degrees in either direction from the norm can have massive impacts on spawning times, quickening or delaying a population’s growth by a month or more. If fish hatch too early when waters haven’t warmed for the season or if they hatch too late when too little food is available, populations can seriously struggle.

Those small changes can have big changes on the habitat as a whole.

“These aquatic ecosystems are related to the terrestrial ecosystems around them. The types of fish that are available — not just to anglers, but to other animals that might feed on fish, or what species of fish are there to consume insects and other species that are in the water — are really important for keeping those linkages in place,” Feiner said. “As those linkages start to break down, you can see changes and, for example, water quality — if you don’t have the predatory species of fish that are eating maybe zooplankton or other species, you can see increases in algal blooms, for example.”

According to one recent study conducted in part by researchers with the Wisconsin DNR, a couple-degree change in trout stream temperatures can lead to a two-thirds decrease in trout habitat availability.

To counter that, the DNR regularly stocks waterways with fish to help maintain a healthy population. Feiner said even those efforts are under threat, though.

“What we’re actually seeing in a lot of places is that climate change is starting to outstrip our ability to actually resist it in a lot of areas, right,” Feiner said. “So we’re doing a lot of stocking and a lot of harvest management to try and resist climate change, but in places where climate change has become so pervasive and so strong that our ability to resist it is reduced, we can start thinking about maybe doing other things: Maybe managing warm water species and trying to promote other fisheries in those places to still have places for people to go and fish.”

Feiner said avid fishers may need to accept that their hobby is changing. That means a need for more flexibility. Some people may not be able to fish on their backyard lakes like they once could, but that doesn’t mean the most-impacted species are at risk of total collapse.

More information about climate change’s impacts on Wisconsin waterways — and how warming temperatures are shaping other parts of the state’s natural resources — is included in the Wisconsin Initiative on Climate Change Impacts’ 2021 assessment report.

Find more News 3 Now climate coverage below: