The dikes along the Tantramar Marsh have done their job for 250 years, but with rising sea levels the fear along the Nova Scotia-New Brunswick border is that they will soon be overwhelmed.

“These dikes were built back in the 1700s … they're not going to hold back the salt water from the Bay of Fundy an awful lot longer,” says Amherst Mayor David Kogon. 

The dikes were built by the Acadiens to keep the highest tides in the world at bay. They protect the only corridor between Nova Scotia and New Brunswick, either by rail or road.

Kogon says $50 million in trade crosses the border every day. He says if the dikes were to give way, Nova Scotia would become an island and an economic disaster would follow.

Kogan, along with mayor of Sackville, N.B., and the warden of Cumberland County, have sent letters to both provinces and the federal government asking for a meeting to develop a plan to fix the dikes.

“It will be a multi-million dollar project, I assume, to refurbish the dikes to and adequate level to meet the rising sea level,” says Kogan. “Certainly will pale in comparison to the cost of not doing it.”

In an email to CTV News, New Brunswick’s Department of Transportation says it is aware of the situation.

“We're committed to working with our municipal and federal partners to move this project forward and look forward to meeting with the area mayors to develop a plan,” the email reads.

Professor Jeff Ollerhead of Mount Allison University says there are roughly 88 kilometres of dikes between Sackville and Moncton. Some have been repaired and are in good shape, but others are eroded and need work.

“An assessment of the dikes and a strategy to maintain them and/or abandon them in some cases is long overdue,” says Ollerhead.

Ollerhead says the dikes are checked and maintained on a regular basis, but the budget the New Brunswick government has allocated for this work is enough for only a Band-Aid fix.

Kogon believes it would only take one storm of the century to breach the dikes and wash over the highway.

With files from CTV Atlantic’s Jonathan MacInnis.