Waramaug Task Force turns lake from green to clean

Photo of Katrina Koerting

Lake Waramaug’s water quality has steadily improved for decades despite the threats both in the lake and to the watershed.

One of the most notable improvements is the decreased presence of blue green algae, or cyanobacteria, which can produce a toxin that can be harmful for people and pets. These blooms can cause irritation and kidney problems if ingested.

Since 1999, the lake has gone from an average of about 42,000 cyanobacteria cells per milliliter in 1999 to 15,000 cells per milliliter last year. The federal limit is 100,000 cells per milliliter.

In that time, the phosphorus levels have also decreased.

The improvements, several of which were outlined in a recent presentation on how the lake went from “green to clean,” are due to the efforts of the Lake Waramaug Task Force.

“I remember the lake when it was pea green and unswimmable,” said Molly Butler Hart, the task force’s chairwoman. “Now it’s clear, clean and swimmable.”

Blue-green algae, or cyanobacteria, is the biggest threat within the lake, said Sean Hayden, executive director of the task force.

Four aerators and the two associated compressors throughout the lake have helped lower the cyanobacteria levels by adding oxygen throughout the water column and mixing it to prevent the blooms from forming on the top layer of the lake.

The bacteria like to eat phosphorus and other nutrients in the water and soak up the hot sun near the surface.

The aerators are the size of school buses and are placed 15 feet below the surface. The oxygen produced combines with the iron in the soil and captures the phosphorus, pulling it down to the bottom.

“Aeration is a way to keep the blue-green algae in check by robbing it of its phosphorus,” Hayden said.

Another tool to fight the cyanobacteria is to introduce zooplankton, which is a natural predator.

The task force has a farm on Arrow Point that it empties into the lake monthly. Unfortunately, the zooplankton are eaten by the alewives the state Department of Energy and Environmental Protection stocked the lake with in hopes of making it a trophy bass location.

This prompted the task force to add brown trout to eat the alewives and give the zooplankton a chance to eat the cyanobacteria.

The task force also inspects boats entering the lake to prevent the spread of invasive plants and pulls or suctions out any invasive plants already in the lake. The most common invasive plant is curly leaf pondweed. They’re also training others on the lake to spot invasive plants.

“The more eyes out on the lake, the better,” Hayden said.

The task force is doing several projects to protect the watershed, including stabilizing eroded banks along Sucker Brook, which contributes about half of the lake's water.

“It's a lot cheaper to control what happens in the watershed and keep the pollutants out of the lake,” Hayden said.

Hayden and the task force work with land use offices to review building plans around the lake to ensure they are protecting the water. He will also do site visits to make sure the construction company is not adding soil or other material to the lake.

He and the task force are not a regulatory body though and will work with the zoning enforcement officers that surround the lake and are able to issue fines and other citations.

Richelle Hodza, Washington's enforcement officer said she has visited a lot of the sites around Waramaug since she took over the position last month and "can't distribute citations fast enough."

The task force is also studying the 140 catch basins around the lake so it can catalog and prioritize the basins that add the most storm water runoff to the lake. By identifying these spots, the task force can treat the water with a variety of methods before it enters the lake. This could include rain gardens.

Agriculture operations are also a main source for nutrients so the task force is working with farmers to use practices or technology to prevent those pollutants from getting in the water. This could be a storm water lagoon that retains the water runoff on a local dairy farm, and then that water is used on a nearby cornfield.

“You don't want nutrients to get into the lake to grow algae and weeds,” Hayden said.