ELLSWORTH — What nuisance flooding is today — a storm surge that temporarily pools water over portions of roads, bridges and other impervious areas — will become critical as sea levels rise from climate change because of global warming.
Mitigate, adapt and plan. That was the message Tuesday from a virtual presentation and panel discussion on the city and sea level rise hosted by Green Ellsworth and facilitated by the Island Institute’s Kendra Jo Grindle.
While small, coastal communities can’t reverse global warming on their own, they can start planning for a future that makes sense for their town, said Tora Johnson, an associate professor and GIS director at the University of Maine at Machias.
She was joined by state marine geologist Peter Slovinsky and Jeremy Gabrielson, a conservation planner with Maine Coast Heritage Trust (MCHT), for the event.
Ellsworth is fortunate, Slovinsky said, because of the steep banks of the Union River, a built-in mitigator for sea level rise.
However, areas such as the Card Brook crossing could be affected by sea level rise, Gabrielson noted later on, along with developed areas on Water Street.
With the sea level exponentially rising in Bar Harbor between 1993 and 2021 compared to the period from 1947 to pre-1993, the rise aligns with the rest of the United States, Slovinsky noted.
“We’re mirroring sea level change [with the U.S.] over the short term and long term,” Slovinsky said. This includes changes in tide gauges that have occurred since 1990.
This year, January tide gauge levels in Bar Harbor were the second highest tide since 1947. In September, the level was the highest since 1947. A tide gauge is fitted with sensors that continuously record the height of the surrounding water level to produce data for safe navigation and habitat restoration and preservation, according to the Nation Oceanic and Atmospheric Administration (NOAA).
Using tools to track sea level rise, Slovinsky discussed how a 1-foot rise in sea level will change impacts to low-lying coastal communities from a 10-year storm event to what are now impacts from a 100-year storm event.
A 100-year storm event has a 1 percent chance of happening each year. But in downtown Machias, this has occurred four times in the past six years, Johnson said, flooding downtown areas and breaching the Sunrise Trail.
Johnson used downtown Machias, where sea level rise projections could put downtown underwater in as soon as 30 years, as a sort of blueprint for community planning. There, the Select Board and community are leading the charge to change, with assistance from the university and Johnson.
Funding expensive initiatives to strengthen coast lines through “green” erosion control and, in some cases, build walls is a challenge for communities, Johnson acknowledged.
The Island Institute can help, Grindle noted. Based in Rockland, the institute works with communities to plan for and find resources to preserve working waterfronts and coastal livelihoods and build resilience in the face of climate change.
Gabrielson showed mitigation methods at work on eroding marshes and coastlines but also said walls will need to be built in some areas, such as the Portland waterfront.
Closer to home, Old Pond Marsh, immediately south of route 1 in Hancock, is “a priority for marsh migration,” Gabrielson said, as erosion from storm surges expand the marsh into what was more solid land.
Maine Coast Heritage Trust, Frenchman Bay Conservancy and Hancock’s Crabtree Neck Land Trust are working on mitigation methods, Gabrielson said.
“As sea levels rise, habitats along the coast will change,” he warned. “Areas that are upland now will become multi-tidal.”