HARPSWELL – Research conducted by the town of Harpswell using software from the National Oceanic and Atmospheric Association revealed several roads in Harpswell are at risk of becoming submerged as sea levels continue to rise.
Working with Midcoast Council of Government, Harpswell found four roads would be at risk if sea levels rose by a foot, and 16 roads would be negatively affected if levels rose by up to six feet.
Seas are now rising at one-seventh of an inch per year, 2.5 times faster than the rate from 1900 to 1990, according to a 2019 report issued by the Intergovernmental Panel on Climate Change. The report predicted sea level will rise three feet by the end of the century if steps aren’t taken to reduce emissions and slow global warming.
Rising sea levels are caused by a combination of melting ice caps and warming ocean temperatures – water volume expands when it’s warmed. As sea levels rise, water pushes farther inland, especially during storm surges, high tides and flooding events.
Harpswell has 216 miles of coastline with 20 percent of the land within 250 feet of the water, which makes it particularly vulnerable to rising seas and storm surges, according to the town’s report.
The four roads affected when the sea level rises by a foot are the Basin Point Road bridge on Harpswell Center, Wallace Shore Road on Sebascodegan Island, Little Crow Point on Sebascodegan Island, and Long Point Road on Sebascodegan Island.
Routes 24 and 123, which travel down the narrow peninsulas that make up Harpswell and connect Orr’s and Bailey Islands to the mainland, are at risk of being submerged when seas rise 3.3 feet.
If the bridge on Basin Point Road becomes inundated by water, it will cut off the only access point to over 100 homes and the Dolphin Marina and Restaurant.
The discovery of just how vulnerable Harpswell is to rising sea levels spawned the creation of the Harpswell Climate Resiliency Task Force, led by Mary Ann Nahf.
“In Harpswell, nobody is more than 2,000 feet from the ocean and we only have two ways to get to the mainland,” said Nahf. “We’re basically an island.”
In 2017, the town received a Coastal Communities Grant to determine how to address the flooding of the Basin Point Road bridge. The town’s engineering firm found three possible solutions – do nothing and risk the road collapsing, raise the road 3.3 feet at the cost of $691,000, or raise the road 6 feet at the cost of $1.4 million.
The Climate Resiliency Task Force met for the first time last Monday to begin assessing coastal flood hazards. The task force will meet again on Monday to begin drafting plans to mitigate the risks to Harpswell’s roads and recommend the best course of action, which will eventually be presented to the Harpswell select board, according to Nahf.
Donny Ulrickson, a lobsterman based in Harpswell, said he has seen evidence of the rising sea levels while working near mudflats.
“I know the water has been coming up higher, at least 6 inches,” said Ulrichson.
Ulrichson said when he was younger, certain areas of the mudflats used to be dry at low tide, but now they’re almost always submerged.
Arthur Howe, Harpswell’s emergency management agent, said another reason Harpswell should be concerned about rising sea levels, flooding and storm surges is because 85 percent of Harpswell’s roads are privately owned.
“Private roads aren’t held to the rigid standards of a public roadway in terms of construction,” said Howe. “They’re not as sturdy and can’t withstand getting washed away.”
“Drainage isn’t the best in Harpswell. The only way you correct that is to build up the road and ditching,” said Ronald Ponziani, Harpswell’s road commissioner. “Ditching is when you dig around the sides of the road so the water has a place to go. Ditching keeps a road from eroding.”
Ponziani, said he doesn’t see the rising sea level as an immediate threat to Harpswell, but said the flooding at the Basin Point Road bridge needs to be addressed.
“If the water comes up 2 or 3 feet, everyone in Harpswell is going to need a boat,” said Ponziani, who lives just over a mile away from the bridge.
Rising seas will also affect septic systems, according to Howe. With the exception of 93 properties served by overboard discharge systems, all of Harpswell’s residents and businesses also rely on individual septic systems to treat their wastewater before it is discharged to the groundwater, according to a report from the town of Harpswell.
Septic systems rely on soil to help remove bacteria from wastewater, but as the sea level rises, so does the water table, meaning the soil surrounding the septic tank becomes saturated. As a result, there is less of an opportunity for the soil to treat the wastewater before it reaches the groundwater.
kobrien@timesrecord.com
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