As warm weather returns to the Dane County area, Madison city officials and public health experts are preparing to keep local beaches safe and accessible during the summer swimming season.

With a growing focus on public health, water quality monitoring and predictive tools, citizens can expect updates and proactive closures as a precautionary measure to avoid extensive exposure to blue-green algae in Madison beaches, according to the Wisconsin Department of Health Services.

Madison has 12 beaches that welcome residents looking to swim or relax along the shores of Lake Mendota and Lake Monona, according to Destination Madison. The beaches are typically open from early June until the end of September.

To ensure these activities are safe, Public Health Madison and Dane County monitor local beach water quality from Memorial Day through Labor Day weekly for traces of E. coli bacteria and blue-green algae, also known as cyanobacteria.

City officials have said that while most beach days can pass without issue, harmful algae blooms and bacterial spikes can occur, according to DHS.

Wisconsin DHS Public Information Officer Gina LaLiberte spoke on how weather can affect these blooms and spikes. The conditions in which blue-green algae tend to thrive are during periods of calm weather, LaLiberte said. This gives the algae time to develop, meaning beachgoers are more likely to see the surface scums floating in the water.

LaLiberte also said rain showers can make a difference in the amount of algae surfacing lakes and beaches. Rain brings nutrients like phosphorus and nitrogen into the lake, and the bacteria can grow on this organic material.

Ingesting water contaminated with these blooms can result in some side effects, including vomiting, stomach cramps and diarrhea, LaLiberte said. For this to occur, the toxin levels within the water need to be pretty high, she said. Usually, when that is the case, the water looks noticeably dirty.

Public health staff conduct weekly water testing during the summer, Communications Director for Public Health Madison and Dane County Morgan Finke said.

“During the summer months, our lab staff goes out and tests the water quality at the shoreline of local beaches,” Finke said. “We have our whole system for that, and we communicate the results on our website [and] also through email alerts.”

Residents can sign up to receive these email notifications, which are sent out daily during the summer months, Finke said. Along with notifications, beach condition updates are also displayed with signage at the beaches themselves.

When a beach is found to have unsafe conditions due to high E. coli or visible blue-green algae, notification is typically swiftly released, Finke said.

“As soon as those results come back, they will go and post the sign at the beach,” Finke said. “In terms of alerts, it’s pretty immediate.”

Public Health Madison and Dane County encourages swimmers to pay close attention to water conditions before entering — even if a beach has not been marked as closed, Finke said.

Certain visual cues can help residents identify a bloom, though it is not possible to know whether or not the water is harmful unless it is tested, according to the Centers for Disease Control and Prevention. The blue-green algae bloom can look blue-green, but can also appear green-brown, which makes water murky, Finke said.

“It’s [blue-green algae bloom] kind of a pea soup texture — floating blobs, sometimes a scummy layer on the surface and there’s often a strong musty odor near the water,” Finke said. “We say, ‘swim with your eyes first.’”

Not all algae are harmful, and some green growth seen near the shore may be naturally occurring and less concerning, Finke said. Still, when in doubt, beachgoers are encouraged to reach out to Public Health as the department accepts photos sent by residents of potential blooms, and it will send out staff to evaluate.

When communicating closures to the public, officials clarify that the beach is still open to sit on the sand and enjoy the view, though the water should be avoided, Finke said.

“The concern is really about entering the water, especially for children and pets who might accidentally ingest it,” Finke said.

Public knowledge on this matter is important as children and pets are more vulnerable to a blue-green algae bloom, Finke said. Adults are more aware of risks with swallowing water that may look suspicious, but children and dogs may not be.

Informing the public is the extent of the work Public Health Madison and Dane County can do as it does not monitor those swimming on beach sites. Finke added that it is up to beachgoers to be aware of the risks when swimming on Madison beaches and health officials remain committed to keeping residents informed.

“Wisconsin summers are great, and we have a lot of beautiful beaches in Dane County,” Finke said. “We just want to make sure people can enjoy them in a safe and healthy way.”