Parts of Charlestown, East Boston, and South Boston (including Fort Point and the Seaport) are already at risk of significant flooding due to storm surges. By 2030, sea levels are expected to have risen nine inches over present levels, according to Next City, and by two to three feet before the end of the century.
Many waterfront neighborhoods of Boston have been built on, or expanded using, reclaimed land. Faneuil Hall was once on the waterfront (the bricks marked with squiggles and fish indicate where the land is over the former harbor), and neighborhoods like Back Bay, Bay Village, Beacon Hill's Flat of the Hill, Chinatown, Leather District, Fenway-Kenmore, the South End, and the Waterfront were among those using reclaimed land.
This land can settle over time, and as a result can be more vulnerable to horizontal flooding from storm surges. The street flooding in the Financial District and the Seaport in the January 2018 storm was a vivid reminder that these neighborhoods are perhaps more vulnerable to rising sea levels and storm surges. In addition to the waterfront areas, the Charles River Basin is also vulnerable, according to research from Boston University. In 1996, the Muddy River overflowed and flooded the Green Line tunnels up to the ticket booth at Kenmore Square.
In addition, the increasing development density along the waterfront areas puts more people, buildings, and infrastructure at risk given that sea levels will continue to rise, and storm surges will likely become more frequent and intense.