DNR to reduce noxious algae on waterways

Action on phosphorus will affect 21 counties, 108 treatment plants

State regulators have detailed plans to ratchet down a source of noxious, water-choking algae blooms on a series of popular reservoirs in the Wisconsin River.

The Department of Natural Resources is targeting phosphorus that flows into the state’s longest river from Rhinelander south to Lake Wisconsin.

Phosphorus has been a contributing factor in fish kills and blooms of toxic blue-green algae while making summer boating virtually impossible at times on some of the waterways.

In bad years, “it really gets ugly; it really gets smelly,” said Rick Georgeson, president of Petenwell and Castle Rock Stewards, an advocacy group, describing the thick mats that can cover a mile of water and are blown from bay to bay on Castle Rock Lake and

the Petenwell Flowage.

“People are plugging their noses.” The DNR’s action announced this week essentially puts the watershed on a diet and will affect 21 counties, 85 cities and villages and 108 wastewater treatment plants.

The intent of the plan is to improve water quality on flowages, which have attracted anglers, boaters and property owners for generations.

Created by a series of dams, they sprawl in segments covering more than 100 square miles.

In addition to Castle Rock Lake and Petenwell Flowage, they include Lake Wausau, Big Eau Pleine Reservoir, Lake Du Bay, Lake Delton and Lake Wisconsin.

A welcome nutrient for farmers, phosphorus comes from point sources like wastewater treatment plants, paper mills and vegetable processing plants, but also from non-point sources such as leaves, grass and soil, manure and fertilizer.

Agriculture runoff often makes up the largest share of phosphorus pollution in the river, with DNR data showing concentrations growing steadily as the Wisconsin flows south beginning at Wausau.

In regulatory parlance, the agency’s effort is known as Total Maximum Daily Loads, or TMDLs, and is one of several such projects in progress across Wisconsin, including the Milwaukee River basin.

All are triggered by the federal Clean Water Act when waterways fail to meet minimum allowable standards for phosphorus or other pollutants.

The effectiveness of the TMDLs, however, has been called into question at times, including a report from the federal General Accounting Office in 2013, which found shortcomings.

Matt Krueger, coordinator of river restoration efforts for the River Alliance of Wisconsin, said the DNR and county land conservation officials have accumulated an extensive base of understanding on the source of water pollution in individual watersheds that could lead to an impressive turnabout of the Wisconsin.

“(But) the report itself is useless unless something happens,” Krueger said. “The question remains whether we will see action and whether we see resources put into it.”

Plans call for phosphorus reductions on Petenwell of 63%; the main body of Castle Rock of 49%; and Big Eau Pleine of 84%.

“We feel it’s a big success to get the TMDL to this particular point,” said Georgeson of the Petenwell and Castle Rock Lake group.

His group has championed the project for years. Early on, members were frustrated by government inaction.

Then in the summer of 2007, they took seven members of the Legislature to see water conditions firsthand. They called it “Pontoons and Politics.”

In 2016, they did the same with about two dozen farmers.

Conditions along the reservoirs change from year to year, depending on factors like rainfall, which sends fertilizer-rich soil into the water, and temperature, which spurs algae growth.

Other reservoirs have faced similar problems and the Big Eau Pleine has suffered from periodic fish kills as algae grow and rot and deplete oxygen in the water.

An outcome of Pontoons and Politics: The Legislature allocated money to study where the basin’s phosphorus comes from.

Nearly $1 million in state funds — a total of $2.8 million in all, including federal sources — has been spent since 2014 tracing the source of pollution and modeling how reductions could impact the reservoirs, said Kevin Kirsch, a DNR water resources engineer managing the project.

“It’s a huge step in the right direction,” said Rep. Scott Krug (R-Nekoosa), who was one of the lawmakers on the pontoon ride a decade ago.

“All politics is local and when you get local groups involved, good things happen.”

Kirsch said it was premature to estimate the cost of the cleanup.

Meanwhile, Kirsch said a community with a wastewater treatment plant might try providing financial incentives to farmers to keep phosphorus out of the watershed — a potentially cheaper option than upgrading wastewater systems.

It could take a decade or more to see an impact, state officials said, because of the time allotted by regulators to allow a city or village to make upgrades or for farmers to shift to new conservation methods that keep soil from washing away.