On a sweltering day in August, the beach at Range Pond State Park in Poland is packed.
Kids splash in the water and families camp out underneath the pine trees, grilling hot dogs and trying to stay cool. But Bonnie Knightly says the water doesn't feel as refreshing as it should.
"It's warmer than I remember the lakes and ponds being this time of year," Knightly said.
She's been coming Range Pond for years, but can't remember the water being so warm this early in the summer.
"Maybe the end of August, but not the beginning. And it was even two weeks ago when we were here. It was like this. So, yeah, it's different," Knightly said.
Maine is home to almost 6,000 lakes and ponds, with some of the cleanest, clearest water in the country.
But many are under threat from climate change. Water temperatures are skyrocketing. The growing season for algae and invasive plants is getting longer. And intense rainstorms are accelerating erosion, injecting more pollutants into watersheds.
Average surface water temperatures in almost 100 Maine lakes rose 5.5 degrees Fahrenheit between 1980 and 2020, according to long-term monitoring by the Maine Department of Environmental Protection.
That’s faster than the annual air temperature increase and outpaces changes in the Gulf of Maine, one of the fastest warming bodies of water on the planet.
Danielle Wain, science director for Seven Lakes Alliance, a conservation nonprofit in Belgrade, said rapid warming means profound changes for lake health.
Lakes retain heat in the daytime. Now that nights aren't as cool as they used to, bodies of water aren't releasing as much heat at night either.
"They're just holding this heat and staying warm all summer long," Wain said.
That extended warm period makes it harder to form thick ice in the winter, magnifying the potential problems.
"The shorter ice on period means we have longer open water seasons, and more time in which light can penetrate into the lake which can impact both algae growth and growth of aquatic plants," Wain said.
Some predict that the problem will become worse over time as heavier rainstorms wash soil and debris into lake watersheds. Tristan Taber from Lake Stewards of Maine says stormwater flooding into lakes carries phosphorus, a nutrient that speeds growth of aquatic organisms and triggers algae blooms that can turn toxic.
"It certainly looks like we're going to have a higher prevalence of cyanobacteria blooms, they like warm water, we see a lot more cyanobacteria blooms further south," Taber said.
There's a lot at stake. Maine has a reputation for pristine freshwater. The state has so far avoided a warming climate's worst impacts on lakes and ponds. But Wain and others warn a body of water can turn bad quickly. And restoration is an expensive, time consuming struggle.
A University of Maine report this year valued the state's lakes at $14 billion annually. And multiple studies show that algae blooms and invasive plants can hurt waterfront property values and tourism spending.
"There is a slow gradual change that's going to take place in our lakes systems, and some lakes are going to be unfortunately lost as sort of beautiful spaces that they currently are," Taber said. "There are going to be casualties with this."
Despite mounting threats, lake advocates say money and resources aren’t keeping pace.
Last year state Representative. Bill Bridgeo, an Augusta democrat, filed a bill to put $18 million into the state’s Lake Restoration and Preservation Fund that had been empty for almost 40 years.
"I don’t think most people including legislators appreciate the vitally important need to invest in protecting our lakes," Bridgeo said.
That request was winnowed to $2 million in committee. By the time it left the appropriations table, there was just $200,000 - less than a quarter of the total cost to chemically treat algal blooms in Augusta’s Togus Pond, a process started this year.
Lidie Robbins, who formed the 30 Mile River Watershed Association sixteen years ago to conserve a chain of lakes and ponds near her hometown, Vienna, agrees public money is hard to come by.
Funding to combat invasive species and even monitor water quality is scarce, Robbins said. Looking wider, there's also scant resources to help local communities fix roads, undersized culverts and other infrastructure that could help prevent future stormwater pollution from hurting lakes further.
Instead, the state relies on a network of cash strapped nonprofits and volunteer lake associations to safeguard its waters, according to Robbins.
"These great ponds in Maine are a public resource, but when they're in trouble, it's mostly left up to private organizations and private individuals to take care of them, and there is really not a lot of funding available," Robbins added.
Back when she started the group, it was focused on keeping invasive plants out of the watershed. But now, the challenges feel existential and overwhelming.
"I have a daughter now who's 20, and I'm worried about what it's going to be like for her kids or for future generations," Robbins said.
"Are they going to be able to have the same experience swimming in a nice, clean, healthy lake here in Maine? Or is that going to be a thing of the past?"
According to the state's most recent inventory, 90% of Maine lakes and ponds have the highest water quality grades. And Robbins says its going to take aggressive action now to keep it that way.
