Rising sea levels challenging New Bedford hurricane barrier

Harbor may have to cope with more water in future

THE HURRICANE BARRIER at the mouth of New Bedford harbor is closing more often as sea levels rise and could be closed one to two times a day by 2050, a new reportfrom the Trustees of Reservations says.

The report says harbor officials are aware of the challenges looming ahead but have determined that closing the gates that often would make it impossible to operate the port.

As a result, officials are exploring ways to live with more water in the harbor, which could mean flooding in low-lying areas of Fairhaven, retreating from the harbor’s edge in some areas, and reinforcing docks and infrastructure to withstand the higher water levels.

The report is the third in a series by the Trustees of Reservations examining how rising sea levels and storm surges are affecting coastal regions of Massachusetts. The first report, in 2020, focused on the North Shore. In 2021, the second report examined Martha’s Vineyard and Nantucket.

Most of the focus in all three reports has been on flooding, erosion, and the impact of rising sea levels on marshes. The latest report dealing with the South Coast examines the impact on New Bedford harbor and its hurricane barrier, which was built in 1966 to protect one of the nation’s top fishing ports. The harbor is now emerging as a key staging area for the offshore wind farms in development off the coast of Massachusetts.

According to the report, the barrier was designed to keep water levels inside the harbor at a set level during severe storms. Increasingly, however, water levels are exceeding the target level even at extreme high tides. The gate was closed 21 times in 2019, and closures are expected to rise steadily as sea levels are expected to rise 2 feet over the next 30 years.

The report said many areas of the South Coast are vulnerable to the rising seas. The report said a quarter of all buildings in Wareham could be damaged by a 10-year storm as soon as 2050. Daily tidal flooding could affect 1,400 structures across the region by 2050. And rising water temperatures and increased stormwater runoff could further deteriorate eelgrass beds, which are the home to bay scallops and other shellfish.