New federal maps for Boston significantly expand the number of homes and businesses in areas considered at high risk of flooding, a change that could force thousands of property owners to purchase expensive insurance and complicate redevelopment along the city’s waterfront.
The proposed maps, released Friday by the Federal Emergency Management Agency, could more than double the number of residences considered in danger of flooding to about 18,000 from 8,000. The number of businesses affected would also balloon from 250 located primarily along the city’s wharfs to nearly 4,000 stretching as far inland as downtown Boston and encompassing much of the new development along the South Boston Waterfront.
“There are some significant changes,” said Kerry Bogdan, a senior FEMA engineer for New England. “People need to be aware of it, for development reasons. For insurance purposes. And, first and foremost, for what their risk is for their safety.”
This is the first significant change to Boston’s flood maps in decades, and it is expected to draw the ire of homeowners, developers, and business owners across the city. Similar changes to maps in coastal Massachusetts communities have spurred protests, and towns in Plymouth, Essex, and Barnstable counties have appealed the new flood designations.
Boston is planning to hold public meetings on the draft maps, which would likely take effect in early 2015. The city will hire a consultant to review FEMA’s data and ensure its accuracy, said Brian Swett, the city’s chief of environment and energy.
FEMA is updating flood maps nationwide using new technology and more precise engineering modeling. That refined assessment has found that more low-lying and flat areas are at risk of flooding during major storms. Historically, FEMA has made tweaks to flood maps after receiving appeals and hearing community concerns, Bogdan said.
In Boston, FEMA’s proposed changes would expand flood zones in East Boston, the Seaport and Financial districts, and parts of Dorchester. Properties designated in flood zones are usually required by lenders to carry additional insurance.
About 1,000 Boston property owners now carry flood insurance policies, paying an average annual premium of $911, according to the National Flood Insurance Program.
In East Boston, one of the city’s poorest neighborhoods, having to pay hundreds or even thousands of dollars in flood insurance could force working-class residents and immigrants from their homes, said Kim Foltz, the director of community building and environment for the Neighborhood of Affordable Housing Inc., a community development organization.
East Boston residents understand they are vulnerable to flooding, Foltz said, but the city should provide subsidies or other aid to help cover increased insurance costs. The flood zone would expand from piers jutting into the harbor to areas northeast of Maverick Square.
“Protecting the neighborhood includes affordability,” Foltz said, “and making sure residents aren’t displaced by rising costs.”
The new maps could further raise the city’s already high construction costs. New buildings and existing properties undergoing major renovations would have to meet stricter requirements and incorporate flood protection measures. It’s unclear how much these requirements would increase costs.
The change could also complicate development in the Seaport District, which is undergoing a building boom. Mayor Thomas M. Menino has reimagined the neighborhood as the Innovation District and encouraged developers to transform it from empty warehouses and piers to a hub for technology companies, restaurants, and towering office and residential buildings.
Swett said developers would have to put electrical systems on roofs, instead of in basements, and make sure that the lowest floors are above flood level. But, he added, “I don’t anticipate any slowdown in construction.”
Rick Dimino, chief executive of A Better City, an organization of business leaders, said he is withholding judgment on the maps for now. He wants to know how FEMA determined which neighborhoods to include and whether the agency’s methodology was accurate.
The final map will put “new lines in the sand,” Dimino said, and “inevitably have an impact on construction.”
With all the redevelopment happening in Boston, this is a good time for residents, developers, and city officials to look at the flood areas and try to protect lives and property, said Bogdan. The new flood zones take into account rising water levels in Boston Harbor.
In drawing the maps, FEMA did not consider the impact of recent storms, such as Hurricane Sandy, which hit the East Coast last year, Bogdan said. Predictions of rising sea levels due to climate change did not play a role in determining the new flood zones, she added.Deirdre Fernandes can be reached at deirdre.fernandes @globe.com. Follow her on Twitter @fernandesglobe.