Rising sea levels threaten New Bedford fishing port and could put South Coast towns under water, according to new report

“These low-lying communities, especially in areas along the coast, will potentially begin to see sea water hitting low-lying roads and these areas on a daily basis, or several times a year,” said Brittany Hoffnagle, climate resilience specialist. at Woods Hole Group, an international environmental services company based in Bourne, who conducted the analysis in the report.

The projections in the report are based on a worst-case, high-emission scenario in which the world is fails to stop fossil fuel emissions. The state recommends planners use that scenario to chart future growth in their communities, Hoffnagle said.

To produce the report, the Trustees and Woods Hole Group took publicly available state and federal data on future flooding, saltwater marsh hazards and erosion and overlayed it with community data on where buildings and roads are located.

The report covers the coast from Seekonk to Falmouth, focusing on the 14 towns bordering Buzzards Bay and Narragansett Bay. While seas have risen by about 9 inches over the past 75 years, that’s miniscule compared to the 2.6-foot rise that could occur by mid-century.

Floods expected on the south coast

On the map below of The Trustees of Reservations, click the arrow to see the floods forecast in 2030, 2050 and 2070.

Some communities in the area they studied are more vulnerable than others, said Cynthia Dittbrenner, director of Coast and Natural Resources at the Trustees of Reservations.

“Due to the orientation of Buzzards Bay, a kind of southern exposure, when storms come, the water enters the bay and creates a funnel effect that has a greater impact on the northernmost cities because the water concentrates in those areas, “Dittbrenner said.

The worst effects are expected on Bourne, Marion, Mattapoisett and especially Wareham.

According to the report, Wareham, a town of about 22,000 people located in the heart of Buzzards Bay, would suffer dramatic impacts not just during a storm, but during daily high tide. Twice a day, when the tide reaches its peak, 250 buildings in the city could be flooded. A 10-year flood could impact 4,326 buildings, more than a quarter of those in the city, and put 61 miles of road under water.

Kenneth Buckland, Wareham’s director of community planning and development, said the report highlights the intensity of the problem, “making the number of people affected by the enormity of the problem more real.”

At Wareham, they have tough choices. “Where people can afford it, we need to look at the withdrawal and displacement of property, the relocation of people out of the floodplain,” Buckland said. Those decisions, he said, will largely be left to individual homeowners and their bankers, and whether they can justify further investment “before the sea starts lapping at their door,” he said.

But there are also neighborhoods of environmental justice in the floodplain, with people who can’t afford to get up and move. “We will have to find places where the population density can be increased and place them there if they want to move,” she said.

In New Bedford, home to the nation’s most valuable fishing port, a hurricane barrier that has long protected the area from the high seas could introduce new challenges.

The New Bedford Barrier has been protecting New Bedford Harbor from hurricanes since it opened in 1966. When a storm or real tide threatens dangerous sea level, officials can close the gate and maintain the water level and protect the water. it costs. It is already closing more and more as sea levels rise due to climate change, and when the gates are closed, fishing boats cannot enter or exit.

By 2050, the barrier could be closed once or twice a day as tides push water levels higher than the current threshold, according to the report.

“You can’t have a functioning waterfront like that,” said Michele Paul, director of resilience and environmental management at New Bedford. “We will have to, at some point, decide to keep the gates open unless there is a real hurricane.”

This means that docks and industrial buildings will need to be prepared for the higher seas and that New Bedford’s neighbors in Fairhaven, where homes are built along the coast, may need to consider relocating.

In addition to the impacts on towns and cities, the report also projects a terrible future for the coastal environment. About a third of the 250 miles of coastline that make up Buzzards Bay and Narragansett Bay are brackish marshes and are at particular risk of rising sea levels, according to the report.

Salt flats are among the most productive ecosystems on the planet. They also play a crucial role in protecting the planet by absorbing and sequestering huge amounts of carbon – more than 10 times the amount that forests sequester.

But swamps along the southern coast are in danger of being flooded by 2050, about 20 years earlier than swamps in other parts of the state, according to Dittbrenner. “We need to go in and make sure we restore those swamps to give them a chance to fight against rising sea levels,” she said. “And we also need to look at areas adjacent to swamps that are slightly mountainous where we think swamps might migrate, and protect and prepare those areas.”

Looking ahead, Dittbrenner hopes cities will use this report to help with their planning work in tandem with the resilience work they are doing with the state. “We don’t want this to be just a relationship that sits on a shelf and then nothing ever happens,” he said. “We want him to be able to help communities and help increase resilience work in the area.”

Clarification: This story has been updated to reflect that the report focuses on the south coast.

Dharna Noor of the Globe staff contributed to this report.

Sabrina Shankman can be reached at sabrina.shankman@globe.com. Follow her on Twitter @shankman.

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