WELLS — Even at its center, Little Lake St. Catherine looks like it’s only 4 feet deep.
That’s because there is literally dozens of feet of muck sitting just under the surface. Floating mats and vast forests of Eurasian milfoil cast shadows down onto a thick, heavy mass of sediment nearly reaching the surface, entangling boat motors with their long, frilled strands.
The growth part of the process of “eutrophication,” where the water becomes nutrient rich due to runoff and leads to overgrowth, essentially filling the lake in.
“What’s going on in Little Lake is years and years of plants dying back,” said David Emmons, president of the Lake St. Catherine Conservation Fund (LSCCF).
It was originally probably a large wetland that flooded when a dam was built in the early 1900s, according to Misha Cetner, environmental analyst and supervisor for the Lakes and Ponds Regulatory Program for the Vermont Department of Environmental Conservation (DEC). As such, all of the sediment, plants and soil that flooded are natural results.
But Emmons, a lakeside property owner himself, said his organization has been working hard to delay that process using aerification, or introducing oxygen bubbles to the sediment to stimulate bacteria growth and theoretically increasing the depth of the lake as the organisms eat away at the bottom sediment, reinvigorating healthy bacteria that would help digest what Cetna called the “soft bottom” of the lake close to the surface.
In June, Gov. Phil Scott introduced a new aeration system to Lake Carmi for the purpose of keeping the phosphorus levels bound and decreasing the levels of cyanobacteria and algae blooms threatening the water bodies and those who live near them.
Emmons said the aeration process has been working in Little Lake St. Catherine since 2012, with the implementation of 12 aerators to decrease sediment, providing less habitat for the invasive milfoil and clear the water for recreation.
“If you accept that that’s one thing that it does, then you have to accept that there are other things it can do,” Emmons said. “And the other things aeration will do is decompose the bottom sediment.”
But the LSCCF’s permit to aerate the lake expired this year, and they’re not authorized to switch the aerators back on unless the permit is renewed. Cetna said the state is working with the organization to formulate a study committee.
“The literature is inconclusive on (whether aeration works),” said Julie Moore, secretary of the Agency of Natural Resources. “They feel strongly that they’ve seen positive results. We have scientists who believe that it has simply redistributed the muck.”
On Tuesday, Emmons used his own instruments to measure the depth of the water to the soft bottom, and then a longer, heavier pole to measure down to the hard gravel bottom of the lake which, in some places, seemed to measure almost 30 or 40 feet.
But Cetna said Emmons’ measuring technique actually pushed aside sediment and produced a potentially inaccurate reading, and the DEC is trying to implement other methods of measuring the muck, including using a large tube that captures the depth of water to the point where it hits the sediment, without disturbing it or pushing it down.
Cetna and Moore maintained that the lake is a “shallow lake” with heavy flora and stable phosphorus conditions, and though growths were abundant in the lake this year, there is nothing really wrong.
In fact, they worry disturbing the sediment might actually harm the lake by increasing the amount of nutrients.
But Emmons cited both Dr. Alex Horne, professor emeritus of Ecological and Environmental Engineering, and Dr. Wayne Carmichael, professor emeritus at Wright State University, in claiming that aeration slows eutrophication of lakes and ponds, and has been used for years.
Meanwhile, the town has a dredging and a harvesting permit for its milfoil forest and does not use any chemicals to manage it, Cetna said, instead opting to suck out the beds of muck in certain places and mow the lawn under the water to reduce the risk to boat motors.
But the eutrophication of the lake poses other threats to the lakefront and its inhabitants.
“It’s horrible there (in the southern most part of the lake),” said Lori Winn, president of Lakeside Realty. “It is decreasing values. ... If it’s not taken care of, the property will be worth $0 soon.”
Though she’s had success with locals who grew up near the lake purchasing homes to be near their community, she said she has had prospective buyers come, see the mats of milfoil and carpets of lily pads, and leave.
Emmons said the goal of the LSCCF is to have the aerators turned back on, and work toward an ideal 46 aerators working in the lake at once. For that to happen, Cetna said the LSCCF would need to participate in a study committee to prove that aeration in Little Lake St. Catherine is both beneficial for the reduction in muck and non-harmful to the surrounding environment before a new permit will be issued.
Cetna said the state is still waiting for LSCCF’s application.
“We really look to the watershed,” Cetna said of alternative efforts to control temperatures and flora in the lake. “What does their shoreline development look like? Are there locations to start planting trees along shoreline? What is happening in the tributaries?”
Emmons said if they didn’t resume aerating the lake soon, the result would be a massive fish-kill, or species dying in large numbers because of the intensified and insulated heat.
“Fish-kills are natural occurrences,” Cetna said.
Emmons said he’s measured the dissolved oxygen levels of the lake to find terrifyingly low numbers, but Cetna said Little Lake has a high flush rate of water moving in and out of the greater Lake St. Catherine, and its oxygen levels were healthy.
Cetna credited this year’s overgrowth to the cold spring and rains, which put more nutrients into the lake, and the sudden, hot days that spurred rapid growth.
But the aerators aren’t on, and Emmons said when they were, last year, the water was clearer.