Marblehead resident Bette Keva walks her neighbor’s dogs a lot through the town’s conservation lands. Over the past couple of months (especially during the summer), she noticed the shallow water levels in Marblehead ponds and bodies of water.
To convey just how bad the water level had gotten, she once suggested Joe Brown’s Pond should be renamed “Joe Brown’s Puddle.” She shared photos depicting the pond’s water level from the Barry Road entrance and from the Browns’ home and tavern.
“From the view, you can see just how dried up the pond is,” she said. “The ground was showing from the middle of it.”
Keva said she saw similar conditions in Steer Swamp, noting a trail entrance that is usually underwater was “completely dried up.”
“Several streams throughout the 48-acre woods are either completely dried up or muddy ground,” she said.
The Marblehead Conservancy, through a partnership with the Marblehead Conservation Commission, cares for the town’s conservation lands. The Conservancy’s deeply dedicated corps of volunteers that carries out the upkeep know the green spaces intimately.
“The Conservancy’s job is keeping Marblehead conservation areas and trails open year-round,” said Conservancy President Robert French. “We are around most ponds and are familiar with changes.”
Eutrophication what?
French, a 30-year resident, said he has never seen the water levels in Marblehead ponds as low as they have gotten in 2022.
“The simple answer as to what’s wrong is the drought, possibly enhanced by lower-than-normal precipitation over the winter,” said French. “However, there is another issue with most of these ponds, literally an underlying one: Eutrophication with the accompanying filling of a pond.”
Eutrophication occurs when “excessive richness of nutrients in a lake or other body of water – frequently due to runoff from the land – causes a dense growth of plant life and death of animal life from lack of oxygen.”
French said most of Marblehead’s ponds are not that deep; water gives the illusion of depth. Over decades and decades, the accumulation of organic material – debris, leaves, fish waste and dead algae – mostly through runoff that flows into a pond that has no exit plays a part in its disappearance (which French says will happen to some ponds in the distant future).
“Unless you get a steady stream of water coming through and exiting, you’ve got a build-up of muck,” said French. “That build-up isn’t notable until after years and years of dead leaves and sediment.”
Once it does build up, the ponds don’t take all that much to dry out. The pond muck attracts vegetation – as a nutrient-rich food source and a place to anchor their roots.
“As the water gets shallow enough, you can see excessive growth of vegetation,” said French. “Droughts only speed everything up.”
The loss of amphibious life
French said the Conservancy members have seen a certain degree of the eutrophication effect in Marblehead take hold, depriving amphibious animals of oxygen. The Marblehead Conservancy got a good first look at the vegetation issue that the effect spawns when Joe Brown Pond neighbors complained about an invasive species a little over a decade ago.
“It was covering the entire surface,” French said. “What we found 6 to 8 feet of muck underneath the water.”
He added, “That type of build-up of muck makes anything that needs oxygen to live in the water die.”
Years before, Joe Brown’s Pond teemed with life.
“We use to have fish and frogs in the pond,” he said. “They are all gone.”
Don Morgan, a Marblehead Conservancy member, said the low water levels presented challenges for Marblehead animals that rely on the ponds for water and habitat. Some residents whose homes abut ponds and wooded areas resorted to putting bowls of water out during the summertime.
He also mentioned the adverse effects that the drought has had on a Conservancy endeavor, its attempt to turn the Lead Mills into a pollinator-friendly native wildflower meadow.
“We’ve lost quite a few shrubs and wildflowers,” he said.
However, the drought has had one silver lining, according to Morgan.
“Babbling Brook in Steer Swamp has very steep embankments, so it is difficult for us to climb down to remove branches and other junk which ends up in it, disturbing the flow, without falling in,” he said. “The brook is now so low that we have been able to get them out over the last few weeks.”
Thank you Marblehead News and Will Dowd for calling attention to the problem of our disappearing ponds. I’d love to be part of a volunteer effort to clean out the muck from the ponds — if that is what is deemed necessary.