After one of Madison’s longest, coldest winters ever, swimming season is almost here — along with toxic algal blooms, bacteria, invasive milfoil and other pestilences of the lakes.
The Yahara lakes — Mendota, Monona, Wingra, Waubesa and Kegonsa — are no clearer than they were 30 years ago, despite intensive efforts to improve them. During that time, lake scientists said, the increased heavy rainfalls that are part of climate change most likely offset gains from better land use practices, by washing giant volumes of pollution into the lakes.
“They are flatlining,” said Steve Carpenter, a University of Wisconsin-Madison professor who has studied the Yahara lakes since the 1970s. “There are no trends in the lakes. The lake water quality is not getting better. It’s not getting notably worse. It’s as if the interventions we’re doing are just holding the line, running in place like the red queen in Alice in Wonderland.”
Now, the well-studied Yahara lakes are home to bold new experiments attempting to fix them, potentially providing lessons for other troubled waters around the world. Some are technological, like using manure digesters to remove pollutants. Others rely upon voluntary efforts to prevent pollution instead of just punishing polluters.
Beaches are the public face of the lakes; they are where residents meet water quality up close. And two decades of data on beach closures — a useful if imperfect metric of water quality — also show no apparent improvements or other overall trends.
Algae and bacteria, both caused by pollution, continue to be the prime causes for dozens of beach closures each year. People are responsible for the pollutants, but how much gets in and how much trouble they cause are “largely driven by weather,” said Trina McMahon, a UW-Madison civil engineering professor who studies the lakes. Invertebrate populations also play a major role.
“From year to year, day to day, the situation is highly variable,” said Kirsti Sorsa, who has been managing the Madison and Dane County Public Health beach monitoring program since 2001.
Since 1996, the agency has closed the 16 beaches it manages more than 1,300 days (one day’s closure at one beach), averaging about 75 closure days each summer, according to an analysis by the Wisconsin Center for Investigative Journalism. The shutdowns ranged from 26 total days in 1999 to 193 days in 2009. The monitored beach season lasts about 100 days.
The years 2008 and 2009 were “awful” for harmful algal blooms, Sorsa said, noting that nearly 90 percent of the closures in those years were from algae problems. In recent years, bacteria have been more likely to cause closures.
The 2012 drought brought less runoff, and in 2013 cool temperatures inhibited floating algae scums. Total beach closures those two years were just 43 percent of the two peak years.
But problems with the lakes’ water quality abound, as they do statewide.
Beach closures, statewide
Harmful algal blooms and bacteria cause state and local governments to caution beach users or close the beaches along the Great Lakes and at inland lakes across Wisconsin.
Algae can cause a slew of problems, including asthma-like symptoms; at worst, it can be fatal to people or pets.
Some bacteria cause gastrointestinal illness, but the strains of E. coli used in most beach tests are generally harmless and used as an indicator for other pathogens — bad bacteria, viruses, parasites or diarrhea-causing protozoa — that are harder to test for.
The Wisconsin Department of Natural Resources has listed or proposed to list 31 beaches statewide as “impaired” for exceeding the state’s E. coli water quality standard. That list includes 11 of the 16 Yahara lake beaches managed by the city-county health department.
Madison and Milwaukee-area beaches dominate the impaired list “just because we have so much data. The other ones are not as well known,” Sorsa said.
“Some people call here from local health departments asking what do you do about the cyanobacteria,” or blue-green algae, Sorsa said. “That gives me the sense that people don’t do much about it.”
From 2003 to 2012, Wisconsin beach managers reported the results of their tests for the bacterium E. coli from 127 Great Lakes beaches. The tests came back at or above a potentially unsafe level between 7 and 22 percent of the time each year.
At that concentration, the U.S. Environmental Protection Agency cites research suggesting there will be eight gastrointestinal illnesses for every 1,000 adult beach users. However, many factors make that estimate uncertain — for instance, children are more susceptible to illness and sand can also contain pathogens.
Between 2009 and 2013, the Wisconsin Department of Health Services received 144 complaints of human and animal illness associated with exposure to harmful algal blooms. The most common algae-related illnesses reported were gastrointestinal distress, rashes, and respiratory or cold-like symptoms. Health complaints came from at least 22 counties, all over the state; Dunn County had the most with 21.
The state “continues to suffer from insufficient funding levels to adequately maintain a comprehensive beach program,” according to a DNR report after the 2012 beach season.
Not easy being green
Even on a good day in Lake Monona, the beach water is generally too green for submerged swimmers to see their own feet. Peeling off their bathing suits later, they may well find that the suits and the skin underneath are covered with streaks of green, sludgy algae.
On a bad day, toxic algae scums float on the surface. Not all algae are bad — but both the kind that form scums and those that do not can produce harmful toxins.
They are symptoms of what ails the Yahara chain: Thousands of pounds of phosphorus flow into the lakes each year. About 80 percent of it arrives via manure or nutrient-rich soil from farms, and the rest from urban sources like dead leaves and construction erosion, according to Carpenter.
It is what allows the blue-green algae to flourish. Cleaning up the phosphorus would go a long way toward helping the beaches.
Doing so would take aggressive management of runoff, said Carpenter, who believes it would be possible to cut the phosphorus running into the lakes to 10 percent of what it is now. The current, ambitious goal is to halve the pollution.
In the 1830s, the lakes were so clear that boaters could see all the way to the bottom of Lake Mendota in July, instead of the three to nine feet that is normal today. The phosphorus pollution then was probably one-tenth of what it is today.
“We probably can’t go back to that unless we revegetate the watershed with the original savannah vegetation, which is not going to happen. But we could do a lot better than we’re doing now,” Carpenter said.
The beaches are plagued not only by algae and bacteria but also weeds, dead fish, trash and occasionally bizarre items from the urban landscape, historical data show.
Notes from 1996 include a “fecal event” at Vilas Beach that perhaps is best left uninvestigated.
Beach managers marked 1997 with a mysterious bullet point: “lard balls.” Newspaper archives revealed the sudden appearance that summer of thousands of grease balls, some as large as softballs, later determined to have floated down from a breached Oscar Meyer bacon-fat tank. The company was fined no more than $952.
Some snails in 1998 gave swimmer’s itch to triathletes at Mendota; they were traced to an Illinois lake. Two bodies were found at B.B. Clarke and Spring Harbor in 2002. That same year, jet fuel leaked from an F-16 that made an emergency landing in Monona. An accidental raw sewage release closed all Monona beaches for a few days in 2008.
Madison’s dirtiest beach
The data also reveal a sort of competition each year for the prize of ickiest beach.
Some years it is Lake Mendota’s Spring Harbor, which is near a large stormwater outfall that brings pollution from as far away as West Towne Mall. Some years, it is shallow, weedy Hudson, on Lake Monona.
Overall, the medal goes easily to Vilas Beach, on Lake Wingra, though it perhaps should go to the geese who produced so much waste there. In 2010 it was closed for 29 days at a stretch, and 43 total; more recently, closures have dropped. The city’s assiduous efforts to control the geese have aroused controversy.
Richard Lathrop, a retired DNR scientist with an honorary position at UW-Madison’s Center for Limnology, recalled the waste while working on a Wingra carp-removal project in 2007: “I had to wear rubber boots just to go to the bathroom.”
Geese are a prime source of bacterial contamination, but not the only one.
Streams and stormwater pipes bring fecal waste from pets and other wildlife into the lakes. And recent research from Milwaukee and Santa Barbara raises the possibility that in many cities, human sewage may be leaking out of old pipes, through shallow groundwater, into stormwater pipes and out to surface waters.
Prediction is hard
Since the bad years of 2008 and 2009, Sorsa and others intensified their efforts to more quickly test for and identify harmful algal blooms.
“Before, we had used other means but they were not as quantitative,” she said.
Pathogen testing has evolved since Madison started doing so in the 1930s. Back then beach managers looked for fecal coliform bacteria, which are not harmful but indicate waste. Later tests counted E. coli, which better correlated with illness.
But the tests take a day or more; by the time they prompt a closure decision, the water quality may have changed. And they do not guarantee the water is safe or unsafe.
One study estimated that from 2003 to 2009, 40 percent of the beach advisories and 60 percent of the closures in Wisconsin were unnecessary, while the water was probably unsafe 10 percent of the days beaches were open.
Unnecessary closures hamper the economy as well as fun, while unsafe water makes people sick. If both types of errors could have been avoided, “beach closures would have been reduced by a third,” according to a DNR study.
Recently a genetic replication technique called qPCR has emerged as a way for beach managers to assess E. coli more quickly. Racine was the first city to use it nationwide, but Madison has so many beaches that “it’s not very rapid,” Sorsa said. It is also expensive.
The EPA and the U.S. Geological Survey have developed software that helps beach managers nationwide predict whether the water is statistically likely to be high in bacteria. In Wisconsin it is being used at Ozaukee County and Racine beaches on Lake Michigan.
The sheer number of intertwined factors that influence what happens at the beach make predicting closures quite difficult, McMahon said.
Those factors include wind, rain, temperature, phosphorus, nitrogen, invertebrate population dynamics and human activities like farming practices and leaf pickup schedules, to name a few.
And while a bad year for blue-green algae in the middle of the lake is usually a bad year at the beach, too, conditions in the middle — where scientists take water samples — do not correspond neatly with those at the shoreline, day to day.
Global interest in Yahara
The Yahara watershed is one of the few places in the world where people are trying new ways to clean up the scourge of nonpoint pollution — that is, the kind that does not come from the end of a pipe, like agricultural and urban runoff. Nobody knows how to do it well, Carpenter said.
“People in the discipline pay attention to what happens in Mendota,” Carpenter said, noting that it is one of the most famous lakes in the world because of the long history of science and management.
“The world is watching, actually.”
One of those experiments is a regulatory tool. The Madison Metropolitan Sewerage District, under an EPA-driven hammer to reduce pollution that eventually flows into the Rock River, is trying something called “adaptive management.” Instead of installing expensive pollution controls at the sewage treatment plant, the utility can pay farmers to reduce nutrient pollution upstream.
Currently in a pilot phase, it is the first use of this tool in the nation to address point-source and nonpoint-source pollution. And nobody knows if it will work, Carpenter added.
As part of that effort, the sewerage district has coordinated many of the major players in the watershed — like municipalities, agencies, businesses and farmers — which is already a feat.
If adaptive management succeeds, it will aid another ambitious cleanup effort. A nonprofit environmental group, the Clean Lakes Alliance, has also drawn many players together and converged upon a 14-point plan to halve the phosphorus loading into each of the four Yahara chain lakes. The group plans to release its State of the Lakes report, assessing progress toward the phosphorus goal, at a Friday morning fundraiser.
Two manure digesters, one in Waunakee and one being built in Middleton, will together be able to handle 15 percent of the manure in the Mendota subwatershed. Digesters can separate phosphorus-rich solids from liquids; the solids can then be removed from the watershed or used in places where the nutrients in them will not endanger the waters.
Signs of hope?
Researcher McMahon said she has often wondered whether it is at all possible to clean up the lakes.
But the latest efforts have sparked some hope in several longtime lake watchers and researchers, including McMahon.
She added that there have been some promising biological signs. Blue-green algae are not all the same, and the species that began appearing in Mendota in June the past few years are different than their predecessors, McMahon said. They are more characteristic of a healthy lake.
“We think that they’re a hallmark of the lake recovering,” McMahon said.
She is not certain, and she is eager to see how the algae communities fare after this winter’s long ice cover.
Overall she is “cautiously optimistic, because there’s so much momentum now with the Clean Lakes Alliance, and the county and researchers.”
“I think it’s possible eventually,” McMahon said. “It’s just — is it on time scales that people would care about?”