Storm-driven flood waters inundate Boston’s Long Wharf in December 2022. Photo by James Sanna | Banker & Tradesman Staff

It’s a multi-billion-dollar question lingering over the city of Boston’s plans to protect neighborhoods from rising seas: Who pays for the flood barriers?

Now, environmental consultants Arcadis will lead a study of the potential funding sources – as well as the costs of inaction in potential damages to property.

The Boston Green Ribbon Commission announced Monday that it hired Arcadis to conduct a 12- to-15-month study of costs and benefits related to climate resilience projects.

Previous climate studies estimate the cost of flood barriers and other resiliency measures in the Seaport District and South Boston’s Raymond L. Flynn Marine Park alone at $850 million, hinting at the magnitude of the financial burden for approximately 20 projects along Boston’s 47 miles of coastline from East Boston to Dorchester.

Arcadis will study costs and benefits, and the funding options from public and private sources, the Green Ribbon Commission announced. The consultant team includes Throwe Environmental and the Consensus Building Institute.

Arcadis issued a recent report on Seaport District flood protections including new elevated seawalls on Northern Avenue and Seaport Boulevard, and a flood barrier located in the marine park and next to Massport’s Cruiseport Boston.

The city is awaiting the recommendations of a U.S. Army Corps of Engineers draft report on flood barriers, due to be released this summer, that could unlock federal funding for projects.