Madison's green and weedy water woes

It's shaping up to be a rough summer for our lakes

We were flying back into Madison last weekend following a trip to Montreal for a Great Lakes water quality conference and the view of our beloved Yahara Chain of lakes was a shocker.

From the air, you could see a weird, curling plume of bright green where streams flowed into the larger waterways. There were also bright green stretches rimming the shorelines.

Only after landing did I hear the news of a huge toxic blue-green algae bloom that led to several beach closings and a major fish kill downstream from the Tenney Park locks. Thousands of walleye, northern pike, bluegill and other species were estimated to have been lost.

It wasn’t a great kickoff to the summer of 2017, at least as far as the Madison lakes were concerned. And it also emphasized the magnitude of the challenges in trying to “clean up” the local waterways in farm country.

By most accounts, 2016 was a good year for the Madison lakes. Below normal winter snowfall runoff and moderate summer water temperatures led to fewer weeds, less algae and clearer water. Then again, long-term water quality records indicate that the same challenges keep cropping up, on Lake Mendota in particular.

The persistent spring rains this year are not doing the lakes any favors. Even Dane County’s fleet of floating weed cutters are having a hard time keeping up with what is largely a cosmetic effort aimed at improving boat navigation.

An additional problem is the explosion of the zebra mussel population in Lake Mendota, which experts at the UW-Madison are saying could lead to even more toxic algae blooms, fouled shorelines and repeated fish kills.

Zebra mussels infested U.S. lakes in the 1990s after arriving here from Europe and are commonly found in many inland waters including the Great Lakes. They were slow to find their way into Lake Mendota but have apparently taken hold over the past several years.

The dime-sized, striped mussels are a double nuisance since they filter the water, which makes the lakes clearer but allows more sunlight to reach the bottom sediment, spurring even more weed growth. When weeds—like the invasive Eurasian milfoil—die, they wash ashore and decompose in smelly piles along the shorelines adding loads of algae-fertilizing nutrients back into the system.

All of this comes as Dane County directs more taxpayer dollars into lake cleanup efforts and nonprofit groups work to raise money for the same noble cause. The Madison Community Foundation, for example, just announced the award of a $75,000 grant to the Clean Lakes Alliance to catalog the needs of all 25 Madison-area beaches and to fund a shoreline swim and lake loop bike ride.

There have also been efforts to reduce the amount of phosphorus—mainly in cow manure—from running off of farm fields into the Madison watershed. But things like manure digesters or voluntary management practices aren’t having much of an impact, according to Jake Vander Zanden, an aquatic biologist at the University of Wisconsin–Madison Center for Limnology.

“Whatever we’re doing, it’s not working,” he told the Wisconsin State Journal in a front-page story Sunday, June 25, that included a dramatic photo of dead fish floating on the Yahara River banks.

And while urban problems like construction site erosion, lawn fertilizer and tree leaves contribute to the problem, there is little dispute that the major source of contamination is animal waste.

Unfortunately, controlling farm runoff isn’t easy and getting tougher laws through the Legislature is a difficult proposition given the strength of the Wisconsin farm lobby. This is a state, after all, where DNR officials tell citizens to drink bottled water rather than clamp down on huge polluters.

The Dane County Board is now trying to bring the various stakeholders together looking for some way to reduce agricultural pollution pouring into Madison’s watershed.

Comprised of a dozen appointees, the “Healthy Farms, Healthy Lakes” task force will hold regular public meetings and create a report sometime in 2018 on how to meet phosphorus reduction goals and improve rural farmland practices. The goal is to come up with some practical and effective measures the Dane County Board can then implement.

Still, while cleaner lakes are certainly a laudable goal, there may be little that policymakers can do in the short-term. These are huge biological systems stretching over hundreds of square miles, scientists warn.

The challenge of lake improvement efforts isn’t lost on retired UW water chemist Steve Morton, who in 1976 authored a book titled “Water Pollution and its Causes” that is still relevant today.

I recently interviewed Morton, 84, who just donated his family’s 120-acre rural retreat near Mazomanie, for the newest Dane County park. Morton County Forest will be featured in an upcoming issue of Madison Magazine.

While driving out to visit the property, Morton and I got to talking about the Madison chain of lakes and he told me it’s foolish to think that any amount of human management will make them resemble the clear water found in the northern part of the state.

“Dane County has some of the most fertile land anywhere in the world, so why we would not expect the lakes to be just as fertile?” he asked.

That’s probably not what Madison lakes lovers want to hear. But it’s something to keep in mind this summer as you pull the weeds off your kayak paddle or fishing lure.

Mike Ivey writes the Footloose blog for madisonmagazine.com.


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