Blue-green algae bloom offends Lake Monona residents’ nostrils
By Zoey Thomas
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Wisconsin (madison.com/Wisconsin State Journal) — Linda Thompson, 71, bought her condo for its view of the north shore of Lake Monona. But on Monday morning, she couldn’t open her window to admire it without an odor akin to “pig manure” filling her living room.
The culprit: a blue-green algae bloom spreading across the shoreline outside Thompson’s complex at the corner of Monona Drive and Buckeye Road. Though Thompson said the blooms have been ongoing since she and her husband moved to the condo nearly 10 years ago, this most recent instance was the worst she’d seen.
“The problem has been getting worse and worse each year,” she said. “It’s smelly, it’s very unattractive.”
On Monday, the powder-blue swath of algae floating on the surface of the lake outside Thompson’s window clustered thickly enough to obstruct the lake’s bottom entirely. People could even smell it across the street at a local wood sculpture festival, she added.
Blue-green algae isn’t an uncommon sight in the Madison chain of lakes, said Caitlin McAleavey, the watershed program director for the Clean Lakes Alliance nonprofit. The microscopic organisms aren’t actually algae at all, but a bacteria called cyanobacteria that can grow in single cells or irregular globs.
Rainfall brings soil, fertilizers and pet waste into the lakes in the form of runoff, McAleavey said. That means on the sunny, still days — like Monday — following a period of rain, conditions are ripe for the blooms to form. The north shore of Lake Monona, she added, is particularly susceptible.
“That area is a tricky one, because … the wind often pushes all of that material up into that bay, and it’s also very shallow,” she said. “So when you have shallow water, cyanobacteria is more likely to proliferate.”
The blooms produce toxins that can make people, pets and wildlife sick, McAleavey said. Though they can be found in any lake, they’re prominent in the Madison chain because its urban setting leads to the phosphorous and nitrogen runoffs that fuel blooms.
Identifying year-over-year trends proves difficult, she added, because the blooms mostly correlate with constantly changing weather patterns.
But Thompson and her husband, Allen May, 72, suspect the increased weeds, decomposing plants and blue-green algae surrounding their shore might be connected to the county’s weed harvesting program.
Under the program, the county hires seasonal employees to harvest aquatic plants between May and August in several bodies of water, including Lake Monona, in order to improve waterflow and recreational access.
Though the program hauls 80% to 90% of the weeds it collects to remote compost sites, May said those weeds remaining in the lake inevitably drift toward his swath of the shore.
“Whatever you don’t capture with your weed cutters, whatever doesn’t get captured in any other debris pickup on the other side of the lake, all of it moves into our area,” he said.
Search for solutions
As the head of his condo association, May has contacted the city, county and Department of Natural Resources and even attended an informal meeting at the DNR office to discuss the issue, he said. But none of those agencies have offered viable solutions.
“I can’t tell you how frustrating it is, but today is truly the apex of it all,” he said. “To walk across the street and have people go, ‘What is that smell?’ You have to say, ‘Well, it’s actually us.’”
May would like to see the county implement a program similar to its Suck the Muck project, which was first implemented in 2018 to remove phosphorous-laden sediments from streambeds in the Yahara watershed, or even dredge his portion of the lake entirely, in order to address the issue, he said.
In the meantime, May’s wife and another resident have taken it upon themselves to rake in some of the accumulated weeds with pitchforks as part of the county’s Pier Pickup program. Though they put in 10- to 15-hour weeks gathering nuisance plants for the pickup barges to collect, they say they’ve barely made “a dent.”
Dane County Lake Management Supervisor David Rowe said he doesn’t see a correlation between the amount of plants harvested and a blue-green algae bloom. Part of the DNR permit under which the county operates stipulates they can’t harvest so many plants as to change the lake’s ecology, he said.
Harvesters work together to remove nearly all cut material from the lake, which is another stipulation of the DNR permit, he said.
“If you go back and look at the records of the thousands of pounds of plants that have been removed through aquatic plant harvesting, all those nutrients that are removed from the system … the idea that we’re leaving it in the lake to decompose and fuel algae is completely inaccurate,” he said.
Nutrient-rich environment
Rowe said he understands the urge to point fingers at a specific program or person when blooms occur. The reality, he said, is that the lakes simply have too many nutrients, which cause excessive plant growth throughout the entire system. There’s no ecological correlation between plant removal and algae blooms, he said.
The county has no plans for a dredging project on the north side of Monona, he added.
Neil Stechschulte, the Monona city administrator, called the north Lake Monona shoreline an “obvious issue” but one larger than the city can resolve. Their jurisdiction, Stechschulte said, only covers the shoreline but doesn’t extend into the water itself.
When approached by residents, his approach has been to connect them with partners like Dane County and the DNR to find larger solutions — though none have yet presented themselves. But there’s not much the city can do directly, he said.
“We would love to see it get cleaned up as much as anybody,” he said. “We know those residents deal with it in their backyard every day, so we certainly understand that concern.”
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