Alejandro Alonso Galva
Madison built an early version of the clean beach cooridor at Bernie’s Beach in 2011. Since then, the beach on Monona Bay has never closed due to water conditions.
A mild winter and a rainy spring don’t make for a good summer swimming season, not in Madison.
Algae and unclean beaches are a perennial problem in Dane County. Last summer Goodland County Park beach closed 19 times due to unsafe swimming conditions, and many other beaches met a similar fate. The city made headlines in Chicago last weekend when a toxic algae bloom closed Union Pier, Tenney and James Madison beaches.
“Unfortunately there are often a number of days every summer where different beaches close down because of some of the challenges we have with algae,” says Dane County Executive Joe Parisi. “We want to make sure our beaches are accessible to folks and we want to make sure people can count on them being open.”
Dane County has multiple initiatives aimed at cleaning up the lakes, including a biodigester for cow manure and efforts to prevent farm runoff. But the benefits of these programs will take years to notice. In the meantime, Dane County, UW-Madison and the Wisconsin Department of Natural Resources are experimenting to try to keep the beaches usable now.
They’re calling it a “clean beach corridor.” The initiative isolates beaches with a floating plastic barrier around swimming areas, separating it from the rest of the lake. Once isolated, the water is pumped into a treatment facility — housed inside a shed about 100 feet from the water — for cleaning and back into the swim area at more than 80 gallons per minute. This creates a swimming area with significantly better water quality than the surrounding lake.
The county ran a pilot program at Mendota County Park beach last year. “What we saw in Mendota Park in Middleton is that tons of people started using that beach,” Parisi says. “It was very popular.”
Now the program will expand to include Warner Park beach and Goodland County Park beach, which opens this week. The City of Madison built an early, similar version of the clean beach corridor, at Bernie’s Beach in 2011. Since then the beach has never closed due to water conditions.
According to John Reimer, a storm water engineer with the county’s Land and Water Resources Department, the treatment doesn’t use any chemicals. Instead it relies on a sand filtration system to weed out the algae particles as well as a double round of UV light treatment to kill bacteria.
“We have two reasons why beaches are closed. Public health tests for algae, which is more particulates stuff, and for e coli.” says Reimer. “This takes care of both.” The filtration system is also self-cleaning, only requiring sand to be replaced at the end of the summer.
“When the system identifies there’s a bunch of material in there… it runs a backwash. Water reverses through the system and removes all that material that’s accumulated in there, and flushes it to the sanitary sewer,” says Reimer, “It allows it to run all by itself versus a cartridge where you take it out and replace it with a new one.”
The plastic barrier runs about 75 to 100 feet out from shore, depending on the size and shape of the beach. Reimer describes it as a curtain in the water. They float on buoys at the surface of the lake and drape down to the water bed where they are anchored.
“It’s impermeable,” says Reimer. “The barrier prevents scum, algae, dead fish, or any other contaminants from coming into the beach area.”
The plastic barriers are critical to the success of the clean beach system and currently only certain beaches are eligible, depending on how protected the beach is by a cove or nearby man-made surf break.
“They wouldn’t be designed for Lake Michigan-type environments,” says Reimer. “For beaches like James Madison Park, now you’re getting more in the big lake environment, where you’d need some offshore breakwater before they come in contact with the curtain. We’ve designed them for bays and coves.”
Warner Park’s set-up will likely require a breakwater system such as a line of anchored buoys to help break up large waves or swells coming across Lake Mendota. The city and county hope to begin construction on the Warner Park site by spring 2018.
“When we have programs like this it’s always dependent on the resources the city or county have,” says Parisi. “As funding becomes available we’d like to do it as much as possible to keep more beaches open.”
Each clean beach set-up costs about $80,000 to create and less than $6 a day to run from Memorial Day to Labor Day each year. According to Reimer, the system shouldn’t adversely affect birds or fish.
“That’s part of the process, getting a permit from the DNR to make sure everything environmentally is safe and sound,” Reimer says.
The county says the filtration also removes nitrates, phosphorus and other fertilizer chemicals that run off into the lakes. But Parisi insists the clean beach program is not a replacement for other clean lake initiatives.
“This in no way takes the place of our cleanup efforts, our efforts to reduce phosphorus in our lakes which is the main cause of the challenges we have,” says Parisi, “In the medium and long term we expect those efforts to pay off with cleaner lakes in general. But until then we want to make sure our lakes are accessible to as many people as possible so they can enjoy summer and not worry about beach closures.”
