Since the late 1970s, scientists have repeatedly said the water in the Yahara lakes would become cleaner if the amount phosphorous running off the land into the water could be cut by half.
Over time there would be fewer days when the water smelled terrible, was too weedy to navigate or too thick with bacteria for swimming.
Millions of dollars have been spent, but the 50 percent reduction hasn't happened.
Now there is talk of new approaches and more ambitious goals -- and possibly greater accountability -- aimed at stopping the flow of the nutrient that comes primarily from intensive livestock operations upstream.
“If Wisconsin is going to have swimmable, fishable, drinkable water in 30 years, we need better farm policies,” said Stephen Carpenter, emeritus director of the UW-Madison center for lake studies. “What we’re doing is not working.”
That's all the more remarkable, given how much has been done already.
Each year, farmers, government agencies and advocates have tallied up the thousands of pounds of phosphorus being kept out of the water by agricultural and urban runoff controls.
“If you add up all the phosphorus being kept out of the water by improved practices going back to the 1980s, we would have an astronomical number — it would be a 300 percent reduction,” said Todd Stuntebeck, a U.S. Geological Survey Wisconsin Water Science Center hydrologist.
“My fear is that when we get to 100 percent of our goal, people will say, ‘Hey, why aren’t the lakes clean?'” Stuntebeck said. “We’re not going to get where we want to go by just doing the things we’ve done so far.”
The prominent nonprofit Clean Lakes Alliance recently announced that nearly one-third of needed phosphorus pollution reductions had been achieved in the last few years, but the group’s leaders also acknowledge that current goals and methods may no longer be enough.
One reason for that is is that conditions have been changing. Weather has been getting wetter for decades, so there’s more rain to wash phosphorus into streams.
Still, the major underlying problem is nothing new. Phosphorous, one of the basic building blocks of life, has plagued the lakes since at least the late 1800s.
The nutrient helps things grow. But when rain carries too much of it into the lakes it sends plants and hazardous bacteria into growth frenzies. The results are smelly mats of rotting aquatic vegetation, and blooms of hazardous bacterial blue-green algae and e. coli that force beach closings.
Close to one-third of the phosphorus that gets into the lakes comes from urban areas. Seventy percent runs off farmland. The biggest single source is manure from dairy cows on large livestock feeding operations in the basin that drains into the lakes.
And livestock numbers in the Yahara watershed have been increasing. In 2012 there were an estimated 78,600 head of cattle, 13 percent more than 20 years earlier.
Ninety percent of the animals are on land that drains into Lake Mendota at the top of the chain of lakes. Fewer than half are dairy cows, but the cows produce 40 percent more phosphorus-laden manure than other livestock.
Each day, the average Dane County dairy cow produces 75 pounds of milk and more than 144 pounds of manure, according to U.S. Department of Agriculture and the American Society of Agricultural and Biological Engineers.
The manure is disposed of on fields, even when the soil has enough nutrients.
Farmers’ soil tests are seldom available to researchers or the public, but a rare 2011 study of soil nutrients in part of the Lake Mendota watershed found three-quarters of the acreage had excessively high phosphorus concentrations — up to 500 parts per million.
If no manure was added to those fields, it could take 100 years for crop harvests to lower the level to the recommended 30 to 35 parts per million, said the researcher, UW-Madison soil scientist Laura Ward Good.
Large animal feedlots with thousands of animals have been replacing small farms. The trend means millions of gallons of manure are being concentrated in fewer locations.
Opportunities to dispose of it are limited. Laws aimed at protecting the water set limits for spreading manure on fields. Spreading in rainy or freezing weather heightens runoff risks. Spreading during the growing season would kill crops. That leaves just a few months each year in which to dispose of the waste.
Managing all that manure is costly. Livestock owners must build manure storage pits. They often lease land miles away from their herds where they can safely spread the manure.
“This manure management is such a tough nut,” said Richard Lathrop, a UW-Madison expert on how farming affects lakes. “The farmers have to get rid of the stuff. Their (storage) pits are full; they are cleaning out their barns and they have to get rid of it.”
Yet, solutions have proved elusive.
Starting in the 1970s, the U.S. Clean Water Act set strict limits that forced sewage plants and industry to dump less phosphorus and other pollutants into public waters. Water quality improved for a while.
In 1987, the law was amended to require states to control pollution that rain and snowmelt washed into public waters.
By the 1990s in Dane County, people were complaining about algae and scum in Dane County waters, and use of city beaches was dropping.
A 1997 Wisconsin law made counties responsible for ensuring that farmers controlled phosphorus runoff.
But the standards are all but impossible to enforce — even for short periods — unless farmers are given financial assistance, and funding has never been adequate, the state organization for county conservation officers said last year.
There are stricter regulations on the books for big feedlots, but enforcement has been lax, according to state and federal regulators.
The good news — and there is good news — is that phosphorus concentrations in lake water have gone down quickly several times in recent decades.
It happened when there were two years in a row of below-average rainfall. If there aren’t large new supplies of phosphorus washing into the lakes month after month, the water will become less fertile, Lathrop said.
“The lakes will clean up if we give them a chance,” Lathrop said. “But we’ve got to cut the phosphorus loading.”
Data vs. reality
Some other initiatives have also shown promise.
The nonprofit Yahara Pride Farms last month announced farmers in the group had dramatically reduced the flow of phosphorous to nearby waterways last year through such practices as composting manure, injecting it into the ground and planting crops in ways designed to prevent phosphorus from reaching the water.
In 2017, participants reduced phosphorus delivery by an estimated 18,000 pounds, the group said in its annual report. That followed a reduction of 11,000 pounds in 2016 and 15,872 pounds from 2012 through 2015.
The group’s chairman, Jeff Endres, declined an interview request through a spokeswoman who said Endres “doesn’t want to be in the position where fingers are being pointed at farmers.”
The group uses an established computer model to estimate how much runoff is stopped by each practice. But scientists who study phosphorus pollution questioned the numbers for several reasons — chief among them is that no sustained reduction has been measured in the actual amount of phosphorus coming out of farm fields on their way to the lakes.
On average, about 77,000 pounds of phosphorus have flowed through Lake Mendota tributaries annually since the 1980s, according to an analysis of U.S. Geological Survey stream monitoring stations.
Something may be canceling out the farmers’ efforts to limit runoff, said Chris Kucharik, a UW-Madison professor of agronomy and environmental studies.
“All it takes is a handful of big disproportionate polluters to skew the whole thing,” Kucharik said.
Increased rainfall also may be washing enough nutrients into ditches and streams to wipe out gains that Endres and others have worked toward.
And, because farmers usually don’t publicly disclose soil phosphorus levels, it’s possible that the best environmental practices are being used on fields that aren’t causing the biggest problems.
The Geological Survey’s Stuntebeck said better data and more stringent testing of the effectiveness of runoff-control practices is essential.
Driven by consumers
UW-Madison agronomist and engineer Eric Booth has been tracking nutrients coming into the Lake Mendota watershed in the form of livestock feed and commercial fertilizer, and the amount going out in dairy products.
“The phosphorus is kind of building up in the soils and probably in the stream channels, but mostly in the soils,” Booth said. “If we are building up more and more phosphorus, it just makes keeping phosphorus out of the water harder and harder as we go forward.”
Farmers see criticism about nutrient pollution as an attack on them, when all they are doing is feeding the world, Booth said.
“What’s driving this is consumer demand,” Booth said.
In its annual report this year, the nonprofit Clean Lakes Alliance announced that 30 percent of needed phosphorus pollution reductions had been achieved in the last few years.
But the group’s leaders say there needs to be a community discussion about more ambitious goals.
“Our suspicion is that we might not get to cleaner lakes until we adjust our goals and actions,” spokesman Adam Sodersten said.
The alliance helped found Yahara Pride Farms, has drummed up support from business interests and raised $500,000 to pay for improved agricultural practices, said executive director James Tye.
No matter what the numeric goal, it will take a cultural shift to keep the lakes clean, similar to the societal changes that made recycling a routine activity and cigarettes less acceptable, Tye said.
Spending to protect the lakes, he said, should be as automatic as, say, spending to renovate the state’s beloved Capitol building.
“We see a future where everybody sees the lakes are the center of the community,” Tye said. “I think there’s a deep well of passion (for the lakes) that we are just starting to tap into as a community.”