HARPSWELL — The town is joining several coastal communities in Maine and beyond that are starting to plan for the effects of sea-level rise brought on by global climate change. 

To kick off the process, the conservation commission and planning office are planning  an interactive workshop in late December or early January to review scenarios that show how sea-level rise will impact the town’s infrastructure and geography.

Harpswell is one of Maine’s most coastal communities, boasting 216 miles of coastline, or about a third of the entire coastline of Casco Bay. About 20 percent of the town’s land is within 250 feet of the water.

“We are going to see significant change in the next 30 years,” said Mary Ann Nahf, chairwoman of the town’s Conservation Commission. “In the long run, you’re going to have to deal with it, and it’s better to plan for it than try to play catch-up later.”

Town staff, working with a planner from the Midcoast Council of Governments, are using computer-generated geographic information system maps gleaned from state data and projects by the Casco Bay Estuary Project and Bowdoin College.

Residents will be able to see how Harpswell will be affected by sea levels that rise by 1, 2, 3 and 6 feet, and examine how it will affect their neighborhood using Google Earth, said Audra Caler-Bell, a planning consultant with MCOG. 

Planners are using 2 feet of sea level rise over the next 50 years as their “rule of thumb,” Caler-Bell said, although that prediction is still being debated. Groups from across the state are collaborating on strategies to cope with various sea-level rise scenarios, she added.

Even though the precise volume is uncertain, sea-level rise itself is basically guaranteed, and starting the conversation early means Harpswell can prioritize areas that may have to be addressed early, Caler-Bell said. 

“For example, if you can plan for replacing a bridge with sea-level rise factors in your head, its going to be a much more effective solution than if you go into it without taking that into consideration,” she said. 

From the early projections, it looks as though several parts of town will be affected by even modest sea-level rise, Town Planner Carol Eyerman said. 

In particular, low-lying roads, including parts of Route 123 that connect Harpswell Neck with the mainland, could be submerged, and the famous Cribstone Bridge that crosses to Bailey Island could also be impacted, she said. 

Briney marshes in town could also be overtaken with seawater, she noted.

Harpswell is not the only Maine community focusing on the consequences of rising sea levels. Earlier this month a design team in Bath presented different visions of what the city’s downtown might look like with a 3-foot sea-level rise. 

In Boston last month, designers showed off a concept to replace downtown streets with a series of canals as a way to compensate for rising waters. 

While sea-level rise brought on by climate change is something not everyone acknowledges, Caler-Bell said that most people in the communities she works with recognize its inevitability and the importance of planning for it. 

“It’s never been a question of what’s causing it, it’s that they understand that something is going on and they need to do something to prepare themselves for it,” she said.

Peter L. McGuire can be reached at 781-3661 ext. 100 or pmcguire@theforecaster.net. Follow him on Twitter @mcguiremidcoast.

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