Arup has recommended enacting a new 1.5-mile-long protective wall following the results of a new study calling for an $877 million flood barrier protecting the central waterfront of Downtown Boston.

The recommendations call for a barrier to be put in place between Christopher Columbus Park and Congress Street in order to protect the city’s commercial, historic, and governmental structures from the devastating effects caused by an anticipated 51-inch rise in sea level that could cause some $3.9 billion in damages by the year 2070.

“It’s a really, really scary report to be honest,” Marc Margulies, principal of Boston-based architecture firm Margulies Perruzzi, told Banker & Tradesman. “Nobody wants to do this. Nobody wants to spend the money on it. But we have to do this.”

The report indicated City Hall could be susceptible to flood damage, which would also devastate the historic Faneuil Hall Marketplace and other important areas in the Long Wharf section of downtown — particularly after the year 2060. A previous report from 2016 had predicted sea levels to rise by 8 inches, leaving areas along the Charles River — including the campuses of Boston University, Harvard, and MIT — at risk of flood damage.

The U.S. Army Corps of Engineers has already been contracted by the city to conduct its own study of the flood defenses, which the Wharf District Council (who commissioned the new report) has requested to have theirs included in. Boston had previously done a total of five climate resiliency studies as part of then-Mayor Marty J. Walsh’s Climate Ready Boston initiative and is generally considered to be one of the five U.S. cities (along with Miami, New York, and New Orleans) whose commercial districts are the most at-risk to the devastating effects of sea-level rise.

“This is an extraordinary circumstance,” Margulies said finally. “Even though Boston has been moving eastward for 400 years, the ocean wants to move westward. And we have to deal with that.”

The results of the study can be viewed here.