Keep fighting phosphorus for clean lakes in Madison

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At first glance, it looks as if progress has slowed on keeping phosphorus pollution out of Madison’s lakes.

The annual State of Our Lakes report, released last week by the Clean Lakes Alliance, shows 14,000 pounds of phosphorus was diverted from lakes Mendota, Monona, Wingra, Waubesa and Kegonsa in 2017.

That’s significant, because phosphorus is the nutrient found in soil, manure and leaves that feeds stinky algae blooms during the summer. Just one pound of phosphorus can produce 500 pounds of algae.

But the 14,000 pounds of phosphorus that was diverted before it could reach the water’s edge during 2017 isn’t much more than the 13,500 pounds that local governments, farmers, businesses, volunteers and other lake advocates kept out of our waterways in 2016.

So what’s going on?

A lot, lake advocates say. Although last year’s total didn’t increase a lot, that’s mostly because several big projects are in the planning stage and will reap greater benefits in the next year or two.

That includes Dane County’s efforts to suck up a century of muck from the bottom of streams northwest of Lake Mendota. The stream beds were polluted by farm runoff long ago.

It also includes a treatment system at Starkweather Creek and improvements to a manure digester in Middleton.

The 14,000 pounds of phosphorus being stopped from reaching our lakes last year is 30 percent of the way to the Clean Lakes Alliance’s goal of achieving 46,200 pounds of prevention. Lake scientists helped set that goal, confident it would lead to clean lakes year after year.

Farmers have done a lot to stop manure from washing off their land into waterways. And they’re going to have to keep doing more.

The same goes for urban dwellers, who need to keep leaves out of city streets in the fall. A lot of that organic material washes into storm sewers that lead to the lakes when heavy rain falls. It’s better to compost leaves or to keep them in piles on the edge of your lawn for pickup — rather than in the street.

Most of Madison’s lakes had “fair” phosphorus levels in 2017 and “good” water quality, according to the annual report. Beaches and lake-access points were open 94 percent of the time.

One of the biggest difficulties will be intense storms. A large and sudden downfall of rain can wash tremendous amounts of phosphorus-laced organic material into the lakes and ruin months of prevention.

But more people across the county are pitching in to minimize runoff. Nearly 1,000 volunteers donated almost 3,800 hours of time to the cause last year — the most generous effort yet.

Lake advocates also have stepped up their monitoring of phosphorus levels in the water. Data collection is key to knowing what’s going on and how our community can further reduce pollution.

The Clean Lakes Alliance also plans to raise more money and issue more grants to local groups and municipalities to help promote innovative ways of protecting our lakes.

“I’m feeling as hopeful for the lakes as I have ever felt,” said Lloyd Eagan, chair of the Clean Lakes Alliance board. “The people care about them, and they’re willing to change their behavior to make a difference.”

We hope she’s right.