Dikes built 275 years ago link Nova Scotia to Canada. They could be in peril

AMHERST, N.S.—Ottawa says it will study ways to protect the 275-year-old dikes that connect Nova Scotia to the rest of Canada from being washed away by rising sea levels, storm surges and other effects of climate change.

The $350,000 study will look at how rising water levels could affect key infrastructure in the Chignecto Isthmus trade corridor, including the Trans-Canada Highway, the Canadian National rail line and electricity transmission lines, Nova Scotia MP Bill Casey said in a statement May 14.

The study will involve an engineering assessment of existing infrastructure, consultation and options to protect the corridor, which carries an estimated $50 million worth of trade a day between Nova Scotia and New Brunswick.

“Trade between our two provinces is the lifeline that keeps our economies growing and our goods moving and this is why we must do all we can to protect the Chignecto Isthmus trade corridor from climate change,” Casey, the MP for Cumberland-Colchester, said in a release.

The initiative comes amid increasing calls for something to be done to maintain the land link between New Brunswick and Nova Scotia by raising and reinforcing dikes at the narrow isthmus that joins the provinces and allow goods to travel to and from the busy port of Halifax.

The dikes in the Tantramar Marshes were built by Acadian settlers for agricultural purposes in the 1700s. The Chignecto Isthmus was cut off for several days in an 1869 storm, according to a 2008 study by Memorial University geologist Norm Catto.

The study said the odds of a recurrence would increase as sea levels rise.

Last month, the NDP in Nova Scotia said it would introduce a private member’s bill requiring the province’s agriculture minister to take steps to maintain the low-lying area where the Trans-Canada Highway goes over the Tantramar Marshes. The party said the governing Liberals should spend at least $10 million per year on maintaining the dikes in each of the next five years.

Last fall, the mayor of Amherst also raised concerns about the condition of the historic Acadian dikes and their ability to hold back rising sea levels occurring due to climate change.

Mayor David Kogon has said sea levels are projected to rise in the Bay of Fundy over the next two decades to the point where the Chignecto Isthmus will flood even when there is no storm surge, leaving Nova Scotia cut off.

The area where flooding could occur includes 20 kilometres of the Trans-Canada Highway, 20 kilometres of CN Rail, 35 kilometres of electricity lines and 35 kilometres of dikes. The isthmus itself is a narrow, low-lying strip of land that is about 20 kilometres at its narrowest point.

At the time, he said he wanted all three levels of government to work together, adding the first step would be an engineering study to determine the scope of the required repairs.

The Nova Scotia government has said it is developing new design standards that incorporate sea level rise and storm surge into dike maintenance and construction.

The province has also said that in the Amherst area specifically, it has allocated $10 million be spent to replace the Laplanche aboiteau for local farmland.