Climate-related storms increase runoff into Maine lakes and worsen water quality
On a forest road from a seasonal camp down to the Great Pond in Belgrade, a small but important construction project was underway.
A trio of Youth Conservation Corps workers struggled to dig a shallow trench. After removing the stubborn roots and rocks, the trench would be lined with gravel and mulch.
The improved trail doesn’t look like much, but looks can be deceiving, says Max Comis, a third-year student at the University of Maine and a member of the team.
“The mulch and rocks we put on top filter the water. We have another filter underneath that prevents the bad things from getting into the water,” Comis said.
Human-caused climate change is overheating Maine’s lakes and ponds, altering their biology and endangering their health.
But the state’s climate future also includes heavier rains like those experienced in western Maine last December. Heavy downpours and flooding can destroy roads and bridges and further erode shorelines, flooding Maine lakes and ponds with nutrient pollution, according to a 2020 assessment by the Maine Climate Council.
Given these challenges, nonprofits and homeowners are working harder than ever to limit coastal erosion and stormwater runoff.
Because the water in some lakes is 2.5 degrees Celsius warmer today than it was in the 1980s, less pollution is enough to trigger water quality deterioration, says Tristan Taber, water quality program manager for Lake Stewards of Maine. The group trains volunteers to monitor water quality and collects data from lakes and ponds across the state.
“The warmer water accelerates the lake’s productivity increase,” Taber said.
“So if large amounts of phosphorus are being washed into the lake by erosion processes or fertilizers on people’s lawns, and the water is also warmer, the likelihood of an algal bloom will definitely increase,” he added.
Stronger storms bring additional problems.
“You know, we have these big, high-volume rains where the water is moving through the landscape at high velocity (and that) causes a lot more erosion because the water is picking up more material at higher velocity and carrying it further,” Taber said.
Given the increasing sources of stormwater runoff and phosphorus pollution, Taber and other advocates are arguing for finding and fixing erosion far from the shoreline.
While reducing erosion is very important to people around the lake, the lake’s watershed could extend for miles upstream, Taber said. And unless erosion and sediment runoff are addressed at the upstream source, lake property owners have limited ability to directly prevent pollution from entering.
“I think this concept of large-scale watershed connectivity needs to be considered for lakes as well. We really need this more holistic view,” Taber said.
About an hour and a half southwest of Belgrade, Susan Gallo toured a camp in Otisfield on the western shore of Thompson Lake.
Gallo, executive director of the advocacy group Maine Lakes, said the responsibility for protecting the state’s large public ponds often falls on landowners.
Strengthening shorelines and improving storage facilities can be costly, and very few public funds are available. The federal government provides grants to repair erosion, but only for lakes and ponds whose water quality has already been determined to be impaired. There are only a handful of such bodies of water in Maine.
Gallo said there is an unfair perception that lakefront property owners are so wealthy that they do not need help maintaining a public resource.
“Imagine if there was a national park somewhere that we all had access to,” she said.
“But then you told all the surrounding homeowners that they are responsible for the health of the state park. That would be really weird. But that’s what we do with lakes,” Gallo added.
When Cary Phoenix and her husband bought the camp in Otisfield a few years ago, there was a broken septic tank and a buried cesspool. Rainwater flowed directly down a sloped asphalt driveway.
“Little by little you realize that the water is just flowing into the lake, and I know a lot about phosphorus. And that’s not good,” Phoenix said.
She contacted her local lake association to get certified under the Lake Smart program, a program that assesses erosion of shoreline properties and promotes measures to control runoff.
Phoenix failed to achieve a passing grade in its first attempt at certification last year.
But after building gravel steps down to the water, removing drip lines from the camp’s roof, applying erosion mulch and creating a plant buffer along the shore, Phoenix believes her chances are much better this time. She’s even volunteered to help look for problems at other camps on Thompson Lake.
“I feel like we had to work hard to get a spot on the lake because we had the opportunity to own it,” Phoenix said.
All this work may seem excessive, but Gallo said that’s exactly what it’s all about. Maine Lakes coordinates the Lake Smart program and recently tightened its standards to match the predicted intensity of future storms. As lake waters overheat, Gallo said, the risk of phosphorus pollution is greater than it once was. Any opportunity to counteract erosion is critical.
“This lake is healthy, but a thousand little cuts along the shoreline will destroy it because every little source of phosphorus adds up and makes a difference,” Gallo said.
If everyone covers these cuts with a Band-Aid, it could help Maine’s lakes survive, Gallo added.
This article appears as part of a media partnership with Maine Public.
