Algae latest in string of problems at Milton's Clear Lake
Now, there’s a new problem further mucking up the spring-fed lake north of Milton: blue-green algae.
Rock County Environmental Health Director Tim Banwell said Rock County Health Department officials observed blue-green algae earlier this week on surface waters at Clear Lake near Blackhawk Beach, a public campground along the lake.
Banwell said it’s the first time officials have found blue-green algae in Clear Lake. He described it as a turquoise sheen on top of the water.
“It looks like pea soup,” he said.
Blue-green algae, technically a form of bacteria, can make people and animals ill. The sighting at Clear Lake prompted the health department to put out an advisory earlier this week, urging people who come in contact with the algae to wash off afterwards.
According to Banwell and information from the Wisconsin Department of Natural Resources, blue-green algae grows in warm water containing phosphorous and nitrogen, nutrients which can come from:
-- Fertilizers and manure from agricultural runoff.
-- Aquatic birds releasing waste into water.
-- Leaky septic systems.
Floods in 2008 raised the water table at Clear Lake, resulting in an 8-foot surge in lake levels. Officials don’t know why the water won’t recede, but the flooding has left lakefront properties swamped, putting a handful of residences and septic systems under shallow, standing water for the last two years.
Officials believe the flooded areas along the shore, which warm quickly on hot, sunny days, have created a breeding ground for blue-green algae, Banwell said.
Banwell said it’s hard to pinpoint what’s feeding the algae at Clear Lake, but the most likely culprit is agricultural runoff.
It’s not clear whether the algae and submerged septic systems along the lake’s shore are linked, although Banwell said officials know the systems have “contributed nutrients at the lake.”
Banwell said the health department takes weekly surface water samples at Clear Lake and other local bodies of water. He said the Wisconsin State Laboratory of Hygiene analyzes the samples, checking for E. coli, a type of fecal coliform bacteria often associated with animal and human waste.
Readings taken as recently as May show surface water at Clear Lake had 147 E. coli bacteria units per 100 milliliters of water, according to county records.
“That’s one where you’re going to have to start looking at the level,” Banwell said, noting that E. coli readings of 1,000 bacteria units per 100 milliliters of water or higher result in mandated shutdowns of beaches and public swim areas.
Clear Lake is the first body of water in Rock County where officials have spotted blue-green algae this year, Banwell said.
“It’s something we normally see along the quieter rivers and in (Lake) Koshkonong,” he said.
Unlike Lake Koshkonong, which is an impoundment of the Rock River, Clear Lake is a spring fed kettle lake. It has no natural outlets.
Banwell said that means once materials that can spur blue-green algae growth enter the lake, they’re slow to disperse. He pointed to heavy annual weed growth in Clear Lake’s lakebed as evidence of nutrient-rich soil deposits.
“Whatever goes into Clear Lake doesn’t leave Clear Lake,” he said.
Raze orders pending
For months, Clear Lake Improvement Association, a property owners group at Clear Lake, has tried to get Town of Milton and Rock County officials to force property owners to remove three flooded homes along the lake.
The town board in June approved raze orders for the buildings, which have been swamped since 2008, when floods caused the lake levels to surge several feet. The lake has not receded.
This week, the board announced raze orders for the swamped houses are pending but have not been delivered to property owners, said Clear Lake Improvement Association president Joyce Szymberski.
Szymberski said the property owners group hopes to see the flooded homes removed by the end of the year.
Meanwhile, Szymberski said an owner has allowed volunteers to start removing appliances, household items and chemical containers from one of the flooded homes.