SCARBOROUGH — As global temperatures rise, increasing the likelihood of more unpredictable weather patterns and severe tides, a major blizzard or flood could inundate low-lying coastal land.
For a coastal community such as Scarborough, which also happens to have the largest contiguous marsh system in the state, the impact of sea level rise on property and roads is expected to be considerable.
Resident Peter Slovinsky, a marine geologist with the Maine Geological Survey and chairman of the Conservation Commission, believes adopting a plan of action is not an option, it’s a necessity.
National Climate Assessment data predicts the sea level will rise at least 3.3 feet in the next 100 years. In Scarborough, approximately 5 miles of public and private roadway would be under water during the highest tides of the year, if sea level rises by 2 feet, Slovinsky told the Town Council during a workshop in May.
With a 1-foot rise in the sea level, 2.2 miles of roadway would be under water at high tide, he said.
The impact on Scarborough’s marshes can be seen on the Maine Geological Survey’s interactive map. The MGS map shows the effects of rising sea levels across coastal areas of the state, using measurements from the highest tide of 2015, and factoring in increases of 1 to 6 feet based on storm-surge scenarios.
A rise of 1 foot, for example, could inundate most of Route 1 at the highest tides.
For roads that already flood occasionally, like Black Point Road near the Nonesuch River marshland, adaptation efforts could include raising that part of the road to a make it a causeway.
But elevating roadways is an expensive prospect, and, as a short-term goal, probably not the most viable, according to Town Manager Tom Hall.
In the Pine Point Beach neighborhood – an area already affected by flooding and expected to be more so over the next decade – elevating roads isn’t an option, either, Town Planner Dan Bacon said Thursday morning.
“You can’t elevate a roadway 3 or 4 feet and still have it relate to the rest of Pine Point,” he said. Instead, creating a high-volume drainage system is a more realistic measure.
Factoring in public and private buildings and roadways within Federal Emergency Management Agency flood maps, Scarborough has about $124 million worth of taxable value – about 1,200 structures – at risk in the 100-year flood map.
With added threats from sea level rise, Scarborough has about 600 structures, or $34 million worth of additional “potential risk,” Slovinsky said.
“We know things are changing, but what has the town actually done?” he asked councilors at the May workshop.
“What we try to do is present a scenario-based approach,” Slovinsky said in early July. “We know that sea level is rising faster than it has historically,” which has been approximately 8 inches in the last century, he said.
To believe that the rate at which it has risen since around 1900 is an accurate predictor of the next 100 years can “almost be brushed off the table,” Slovinsky added. Measurement estimates exceed inches and are now measured by feet: an increase of 1 foot by 2050, 2 feet by 2070 and 4 feet by 2100 are “good numbers to be thinking about,” he said.
Slovinsky and his team proposed to councilors that over the next year and a half or so, the commission should meet with planning and development officials, public works, town engineers, Community Services and fire and rescue personnel to discuss resiliency plans.
By November 2017, Slovinsky and the commission hope to have gathered information from each department head to present to the council.
The conversations taking place over the coming months will focus on short-term responses – “How prepared are (departments) to react to this situation?,” Hall said Thursday morning.
Longer-range planning, which would likely be built into the Comprehensive Plan, is the “more proactive part,” Hall said, which will be the “much bigger, costly approach.”
But for now, the conversation is still in its infancy, Hall said.
Slovinsky said the conversations with department heads in the coming months will help set a foundation for moving forward, and they’ll “help the town set a precedent.”
“The key about adaptation is creating something that’s transferable,” he said.
Conservation Commission Chairman Peter Slovinsky at Higgins Beach in Scarborough, one of many areas in the town that will be affected by rising sea levels.