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A major part of the largest restoration project ever in Acadia National Park is nearing completion, part of a sweeping effort to address more than a century of human disturbances and to adapt to a changing climate.
The Great Meadow, a 116-acre wetland located next to Park Loop Road near downtown Bar Harbor, at the foot of Dorr Mountain, is undergoing an expansive, multi-year restoration to reclaim its natural water flow, disrupted by years of human-made modifications and the intensifying effects of climate change.
One of the most significant project components is almost complete: crews have replaced a failing culvert at the outlet of the wetland with a much wider, more open span that will improve flood management and wildlife passage.
The wetland’s altered water flow has made the surrounding area more vulnerable to flooding, which has limited trail accessibility and even shut down the nearby Wild Gardens of Acadia in the spring of 2023 for four months, among other times.
Some of the infrastructure built specifically to enhance visitor experience in the park over the decades has damaged the wetland’s hydrology.
“The park has a dual mission of protecting cultural and natural resources and providing good visitor experiences. That’s why it’s very difficult to manage a park,” project scientist Chris Nadeau said. “Because those two things are often in conflict.”
The project is a partnership between the park, local nonprofit Friends of Acadia’s Wild Acadia initiative, which funds conservation projects focused on preparing for future climate conditions, and the research-oriented Schoodic Institute, and the Wabanaki Nations. Before European settlers colonized the area, Wabanaki people had relied on the Great Meadow for fresh water.
The Wild Acadia initiative also is helping a restoration effort on the summits of Cadillac, Penobscot and Sargent mountains, where tourists have trampled native vegetation.
At the Great Meadow, years of manipulating water flows — through construction, drainage ditches and other alterations — have hampered the wetland’s ability to mitigate flooding and limited what vegetation can survive there.
Acadia has been harmed by climate change, mostly by heavy rains and stronger storms that pound the coastline. The Gulf of Maine is among the fastest warming part of the world’s oceans, aggravating those impacts on the park. The gulf’s warming rate is three times the global ocean average, according to the Gulf of Maine Research Institute.
Nadeau, a scientist with the Schoodic Institute who is working on the project, said the wetland needed restoration regardless of climate change, given the damage caused by decades of human disturbance.
Since the park needed to invest in the restoration anyway, Nadeau said, it was more cost-effective to design the project to be resilient to climate change. About a decade of monitoring the wetland’s hydrology preceded the project.
In their attempts to beautify the park, some of Acadia’s earliest stewards altered the hydrology of the wetland, according to Catherine Schmitt, a science writer at the Schoodic Institute who also has worked on the project.
George B. Dorr, a co-founder of the park who served as its first superintendent, spearheaded several early infrastructure projects around Great Meadow, such as the Wild Gardens of Acadia. But they significantly altered the wetland’s natural water flow.
Around 2016, after an overgrowth of algae appeared outside the nearby Sieur de Monts Nature Center, testing revealed a leaky septic system was causing the problem. That was among the first of Wild Acadia’s projects.
Lauren Gibson, a project coordinator with Friends of Acadia, said the septic infrastructure’s placement was one of several human impacts that altered the wetland’s water flow.
“A septic system shouldn’t necessarily be built in a wetland,” she said, adding that the system can leach nutrients into the surrounding groundwater. The septic system has since been rehabilitated, though there’s an ongoing effort to connect the bathrooms to Bar Harbor’s wastewater system, Gibson said.
“Friends of Acadia was looking at the whole watershed because all these waters are connected,” Schmitt said.
Climate change has since aggravated the wetland’s water flow problem. Erratic weather has pushed wetland conditions to alternating extremes — excessively dry and excessively wet.
The wetland has experienced a sequence of freezing, thawing and flooding that has caused damage to the nature center. In January 2018, heavy rains followed by a drop in temperatures created a thick sheet of ice that allowed for ice skating among nearby trees and on the surrounding paths.
Although the park has undertaken smaller climate-related projects, like the removal of invasive plants and fish passage measures at Seal Cove Pond, the Great Meadow restoration is its most sprawling effort yet to address heavier rainfall and more frequent flooding.
The wetland project doesn’t mimic a traditional restoration, where the goal is to revert conditions to a past state, Gibson said. Instead, given the “uncertainties and certainties about climate change,” researchers are aiming to make the wetland more adaptable for future conditions, Nadeau said.
Friends of Acadia was awarded $308,000 in state funding in February for the ongoing, multi-year project. The funding will support the portion of the project that will restore the historic Abbe Stream, which now passes through a maze of man-made structures, to a more natural streambed, Gibson said.
The meadow is a popular attraction for Acadia visitors, who can hike trails like Hemlock and Jesup paths and contribute to scientific monitoring efforts by submitting their observations of animals, plants and fungi to iNaturalist and eBird, two online platforms that are helping scientists understand the ecosystem’s biodiversity and track the restoration’s progress. The area is particularly beloved by avid bird watchers.
“There’s over 1,100 species in total that have been documented by citizen scientists with iNaturalist,” Nadeau said, adding that close to 10,000 volunteers have contributed.
Overall, Acadia has healthy forests and wetlands, in part because of work completed by the park’s invasive plant management team, in collaboration with scientists from the Schoodic Institute and other partners, researchers said.
Although Great Meadow, which sits in the middle of the Cromwell Brook watershed, is in need of restoration, many of the park’s other “word class wetlands,” which cover more than 20 percent of Acadia, are generally healthy, according to Schmitt, who is releasing a book later this month on the history, ecology and future climate challenges facing Acadia’s trees.
The Gilmore Meadow, at the base of Sargent Mountain, has an ecological profile similar to Great Meadow, except it was left largely undisturbed by humans, apart from its proximity to a carriage road on one side. Although much smaller, it provides scientists with a comparable wetland for how the Great Meadow could drain during flooding events once it’s properly restored.
During large rain events, the old culvert at the outlet of the wetland would become clogged from too much water and debris, leaving the meadow flooded for long periods of time. The former culvert was also too low, so too much water left the meadow during dry periods. The new culvert will function like a tunnel beneath Park Loop Road, wide enough for animals to safely pass through, with a more natural stream bed that will also improve fish passage.
The goal is not to eliminate flooding altogether, but to lessen the duration, Gibson said.
Nadeau said it won’t take long for the new culvert to take effect and improve the wetland’s hydrology.
Scientists have conducted extensive monitoring of the Great Meadow, known for its diverse mix of wetland habitats, to evaluate how altered water flow has affected vegetation. Their research revealed a “degraded plant community,” according to monitoring results published by researchers at the Schoodic Institute.
The project also involved installing the Hemlock Path’s new boardwalk, completed last fall by experienced volunteers and a park trail crew, which improved accessibility to the meadow and water and fish passage, according to Perrin Doniger, spokesperson for Friends of Acadia.