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Battling Blue-Green Algae in Tonetta Lake

By Lorraine Samuels

An environmental firm presented results of two assessments of stormwater drainage and water quality impacting the general health of Tonetta Lake during the Southeast Town Board’s July 27 meeting.

Representatives of the Tonetta Lake Advisory Board, along with the environmental firm, recommended the repair of at least three of six stormwater drains to reduce pollution and improve the quality of water flowing into the lake. The Tonetta Lake group asked for financial support for the project, which could cost up to $40,000.

The town board discussed the issues related to the scope of the recommendations and projected costs, but made no decision on the matter.

According to John Tucci, president of Connecticut-based EverBlue Lakes, all lakes are plagued by fertilizers that enter via storm drains and then accumulate and feed algae and weeds, but noted that the town has “a well-designed stormwater handling system.”

Based on his firm’s report following an assessment last spring and two recent rounds of water quality data sampling, the lake is “at the edge of healthy, trending toward a lot less healthy and at more risk, fighting off blue green algae.”

In the report, it is recommended that of the six stormwater drains emptying into the lake, three should be prioritized, as they are the most degraded. Work on these drains would range from redesigning culverts that channel water through swampy areas to creating simple filters with natural materials such as small and large stones and vegetation, thereby creating a sustainable, lower cost biofilter system, similar to “engineering a beaver dam.”

Tucci indicated that, overall, the thoughtfulness by which the storm drains were originally designed was of the highest standard – way above average compared with drainage design in other communities – and that Tonetta Lake is in fairly healthy condition, although on the verge of unhealthy.

In June, the lake was fighting off blue-green algae, and by July during the sampling, an underwater algal bloom had begun to grow.

The town board asked if recent heavy rains affected the situation, to which Tucci said, yes, a significant amount of rainfall can help flush pollutants better. However, this doesn’t change the fact that as soon as there is a dry period, the lake resumes being stressed, he said.

He also noted that landscapers around lakefront homes should not use phosphorus and nitrogen fertilizers.

“We put so much pressure on a lake, in general, that lakes are no longer able to keep themselves healthy without proactive watershed and in-lake efforts on the part of humans,” he said.

The report also detailed dissolved oxygen levels needed to process compost at the bottom of the lake. In June, Tonetta was “fighting the good fight,” but by July, when oxygen levels had lowered, dead zones were starting to develop, said Tocci.

A member of the Tonetta Lake Advisory Board indicated that the lake is the only fresh water one in Brewster.

“We have been collecting data, working with New York State Department of Environmental Conservation, sampling twice a month to get a comprehensive profile of the overall health of the lake,” he said. “We studied water quality from the shallow to the deepest depths. There is a giant compost heap and invasive plants in the middle of the lake, and we need professional guidance.”

The man also indicated that not only should the board consider funding this project, but that a public awareness component will be critical to increase local knowledge of the community’s contributions to Lake Tonetta’s problems. He said people washing cars or caring for lawns think of runoff going down a drain without realizing that “phosphorous and nitrogen are going down that drain, too.”

Karl Lebitsch, also of the Tonetta Lake Advisory Board, said Tucci's recommendations need to be taken seriously. “We’re hoping the highway department can help us out,” he said. “We need to map out a schedule and, unfortunately, we have to ask your group for money.”

Costs would range from $3,000 to $10,000 per drain at the most, said Lebitsch.

The town board asked numerous questions to understand details of the proposed construction, costs, options and timing, as well as whether the projects would have a meaningful impact?

According to Tucci, the projects would “slow down the lake from getting worse, but they wouldn’t completely flip the lake around quickly. The town needs a viable strategy for several years and the key is prioritization,” he said. “I’m not saying your lake is dying or that it’s going to fall apart next year. I’m saying if you want it better, it’s going to take effort, and it won’t get better on its own.”

As to managing costs, there are different levels of grants and funding programs available for watersheds. Additionally, more money has been appropriated by New York State to deal with algal blooms. Lake Mohegan, for instance, has been awarded $200,000.

The board also asked about the awareness program and how it would include the community. One idea put forth was to have a consultant and the Tonetta Lake Advisory Board work with schools to provide information and training in water quality and drain sampling. Schools could also be assisted in producing flyers to educate the public.

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