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Last month’s nor’easter hit parts of New Bedford with over seven inches of rain, flooding some streets and washing out the region’s already ragged coastline.
And that was a relatively mild storm.
Climate researchers have been tracking the frequency of extreme rain storms and found that New England is about to get a whole lot wetter. But even as these storms become more common, FEMA floodmaps don’t take rainfall into account, an oversight some researchers say could lead homeowners to underestimate their flood risk.
Jake Huff is one of the scientists hoping to fill that gap. A research assistant at the Woodwell Climate Research Center based in Falmouth, Huff works with vulnerable communities to map local flood risks, including the risks that FEMA doesn’t measure.
Last year, Huff helped identify ways to reduce flood risk in New Bedford’s North End, east of Route 18 and north of Chaffee Street.
Federal floodmaps currently model flood risks using a combination of coastal sea level rise, storm surge, and stream and riverway flow. (They model how waterways behave in storms, but not the actual rainfall itself.) Mappers adjust the flood zones based on what’s called 100-year, 50-year, or 30-year events.
But 100-year rain events don’t just occur once every 100 years, Huff said. Rather, the term refers to a 1% chance of that extreme rainfall event happening in a year. So the size of a 100-year event changes over time. In New Bedford, a 100-year rain event today would be 7.6 inches of rain in a 24-hour period, Huff said — the equivalent of last month’s nor’easter condensed into one day instead of three. In 50 years, however, a 100-year rain event would be more like 10 inches in a 24-hour period, and 7 inches of rain in one day will seem much less unusual.
In other words, “100-year” events are not only becoming more common, they’re also becoming more extreme. And in those events, homes miles from the coast can be at risk of floods.
“There’s lots of different ways you could be flooded,” Huff said. “Either rainfall, sea level rise, or storm surge. It’s all those different factors that lead to different parts of the city being flooded, which is also something I don’t think a lot of people always think about.”
Draining the North End
In early 2025, the Woodwell Climate Research Center offered the City of New Bedford a pro bono risk assessment project. New Bedford Director of Resilience and Environmental Stewardship Michele Paul and conservation agent Chance Perks chose to look at one of the most notorious flooding areas in the city: a section of the North End east of Route 18 and north of Chaffee Street, a suburban neighborhood sitting between two protected wetlands.
If it weren’t for all the concrete, that neighborhood would be wetland, too. Wetlands play a critical role in absorbing excess rainfall, Perks said. They act like a sponge to help rain reach the soil and prevent water from rushing right into the city’s wastewater system.
It doesn’t help, Perks added, that the neighborhood is a hotspot for illegal dumping. People regularly drop leaves and other yard waste in the area, and some of it washes into the small stream between Glen and Abrams Streets.
“They’re throwing their grass clippings in the wooded lot next to them, but it’s not just the wooded lot next to them, it’s a wetland area,” Paul said. “It’s a drainage area.”
That further prevents the wetlands from doing their job of soaking up rainfall.
“Everything that people do has an impact on storm management,” Paul said.
Huff normally builds models of entire cities, often without ever visiting the places he’s assessing. This time, however, he took a tour of the area with Paul and Perks. He got to know the neighborhood and its flooding issues much more intimately, he said.
Huff found that flooding in the area could reach up to 1.6 feet during extreme rainfall. To mitigate the area’s present-day flooding, Huff recommended expanding the neighborhood’s culverts and creating a wetland area just south of Terry Lane to absorb more excess rainfall.
Perks and Paul hoped to use Huff’s findings to solicit funding for these projects from the state. But almost a year later, the project sits on the backburner, with no funding sources in sight. One reason is that the city focuses on projects downstream, where stormwater collects, Perks said.
In the meantime, the Department of Public Infrastructure has installed green infrastructure projects such as “rain gardens” — bowl-shaped patches of vegetation that absorb rainwater — across the city. Areas like Chaffee Street, Perks said, are particularly important for teaching city conservation officials when and how wetlands do their job.
“We see the neighborhoods in the North End as kind of the front lines,” Perks said.
When it rains, it pours
Often, homeowners’ main line of defense against flooding is flood insurance.
But without updated federal floodmaps, homeowners may not realize the true flood risk in their area.
A January 2025 analysis of flood insurance claims from properties outside the designated 100-year flood zone found that over 87% were due to rainfall. In Massachusetts, that number is closer to 100% — perhaps because Massachusetts’ coastline puts most homes in a 100-year flood zone, leaving few homes outside it.
Benjamin Nelson-Mercer is a Ph.D. student at the University of Michigan exploring the gaps in federal flood maps and examining ways to model flood maps that factor in multiple watery hazards. Currently, FEMA flood zones take into account flooding from the coasts and from rivers and streams, but not rainfall.
Yet, Nelson-Mercer’s work indicates that flooding due to rainfall could cause millions in damages each year.
At the same time, fewer properties outside flood zones are opting for flood insurance, perhaps due to a “false sense of security,” Nelson-Mercer wrote. When homeowners do opt for flood insurance, it’s often directly after a significant rain event.
“By then, it’s a little too late,” he said.
FEMA’s official flood maps show most of New Bedford outside of the 100-year flood zone. Yet, as Perks and now Huff can attest, flooding is a regular occurrence in many parts of the city.
New Bedford Department of Public Infrastructure Director Jamie Ponte said the city is always factoring in climate change when upgrading its wastewater infrastructure. The city regularly updates its 20-year infrastructure plans about every five years in case new needs come up, he said. Ponte pointed to the current sewer separation project on Coggeshall Street in the North End, which will install 16,500 feet of pipe and rehabilitate another 15,700 feet, reducing sewer overflows into the harbor by roughly 21 million gallons per year. (As a side benefit, the project will also repave approximately 14,500 feet of sidewalk and road.)
“We have a really good grip on what we need to do, and we push hard at getting as much done as we can,” Ponte said.
Perks said one change would go a long way in keeping homes safe from floods. Currently, realtors don’t have to disclose if a house lies within FEMA’s 100-year flood zone, leaving homeowners in the dark until it’s too late. If it was mandatory to report flood risk and homebuyers knew about flood risks from the get-go, the housing market would adjust accordingly, Perks argued.
“I do believe market forces would actually [help us] get ahead of what we’re trying to do in terms of mitigating risk,” Perks said.
Without that policy change, however, there’s still plenty the average New Bedford resident can do to prevent flooding — and it doesn’t cost a thing.
“This time of year, when the leaves are falling, it’s real easy to get the street all clogged with leaves and debris,” Paul said. “Just being able to take that broom out and do your part — it’s a big help.”
Email Brooke Kushwaha at bkushwaha@newbedfordlight.org.
