ACADIA NAT’L PARK — The Great Meadow, Acadia’s largest freshwater wetland, is beautiful but it isn’t very healthy, which is why an effort is underway to improve water flow and remove invasive plant species.
“That watershed is in fairly damaged condition; it has been pretty heavily manipulated over the decades,” said Brian Henkel, the Wild Acadia project coordinator at Friends of Acadia (FOA). The project is a collaboration between FOA and Acadia National Park.
“We are trying to right some of the wrongs of the past and apologize for some of the insults that have been done to that wetland,” Henkel said.
One of the biggest problems is the culvert under the Park Loop Road that was installed in the 1930s to carry the waters of Cromwell Brook out of the Great Meadow. That culvert is too small for the job, especially after a heavy rain, so water backs up and forms an ever-widening pool on the upstream side of the road.
“There shouldn’t be a pool of water there; there should be stream banks,” Henkel said. “When that culvert restricts flow, water washes up on the bank and then the culvert lets the water out and it washes back down. That keeps washing the banks into the brook, and the pool keeps expanding.”
After heavy rains four winters ago, the Wild Gardens of Acadia at Sieur de Monts Spring flooded and then froze. The gardens are part of the Cromwell Brook watershed, and the flooding was caused by the undersized culvert under the Park Loop Road.
Engineering and design work is being done this year for a much larger conduit to replace the culvert. Construction of the replacement is scheduled for next year.
Another possible remedy is to slow the flow of water into Cromwell Brook from the network of ditches in the 100-acre Great Meadow.
“Water is getting to the outlet [culvert] too fast,” Henkel said. “So, we want to slow the water down in the meadow and let the meadow work as a wetland. We’re looking at adding some curves to what are now straight ditches and let the water meander.
“There is also some old roadbed material in the meadow, and we’re hoping to take some of that out. And we’re looking at additional ways to allow the hydrology to act in a more natural manner.”
Climate change is seen as a significant factor in the ongoing changes in the Great Meadow ecosystem.
“We have more precipitation than we used to get on an annual basis,” Henkel said. “We get more intense storms. We aren’t getting the snowpack that we used to. We have a longer growing season. All that favors invasive species and puts other species at risk, those that can’t adapt to the changing climate.”
The result is a shrinking number of different types of plants, what Henkel describes as a “suppressed biodiversity.”
So, part of the restoration project is removing invasive plants.
Henkel said he and his colleagues are changing the way they think about restoration.
“When we started with Wild Acadia, we were thinking more of restoration as bringing [places in the park] back to some past condition,” he said.
“But, really, our idea of restoration has to shift. We want to restore health, but we need to consider future conditions because the climate has already changed and it’s probably going to change further.
“So, we’re looking at restoring health into some future condition versus restoring to some past condition that’s probably unattainable at this point.”