New Minas Basin Dikes

The halt of the rising tides due to the constructed dikes, barriers to convert marshland into fields fit for agriculture, dating back hundreds of years. The rising tides of the Minas Basin have been halted by these dikes ever since.


However, as sea levels rise and stronger storms become the norm, because of climate change, the 241km of dike structures along the coast and tidal rivers in Nova Scotia, become challenged. A team of geographers at St. Mary’s University in Halifax completed an assessment of the province’s dikes in 2018. This assessment found that over 70 per cent of the barriers were vulnerable to overtopping and coastal erosion by the year 2050. 


Danika van Proosdij, who led the team of geographers, indicated that a storm coinciding with a high tide would lead to rapid flooding of land protected by dikes. “If we were to have a large storm event that was equivalent to some historical storms, like the Saxby Gale for example, we would have overtopping of the majority of the dikes in our province,” she said in a May 2021 interview. 


In the past dikes have been raised beyond the original Acadian footprint, but van Proosdij said strengthening current structures is not the only solution. In some cases, reconfiguring dikes and creating a wider salt marsh in front of the barrier is a way of “buying time” from coastal erosion. 


Wider salt marshes “buffer the wave energy reaching the toe of the dike” said van Proosdij. “They [salt marshes] also are eroding in many areas because naturally the marsh would want to move back in response to rising sea levels, but when you have a dike in place that then limits what is referred to as accommodation space.” 


In addition to repairing and reconfiguring dikes, letting them go and allowing the original marshland to reform is another option. 


Tim Marsh, president of the Nova Scotia Federation of Agriculture, said that would be a loss for agriculture because fields protected by dikes are “probably some of our most productive land in the province.”  


“In some areas where the lands not being used anymore, I can see why they’d want to convert it back into the salt marsh environment,” Marsh said. “It’s an ongoing issue, and it's never going to go away unless we want to destroy all the dikes.”

 

By: Luke Ettinger


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