Province's replacement for failed Hantsport aboiteau already eroding

The province's permanent replacement of the aboiteau in Hantsport that failed almost two years ago is already beginning to deteriorate.

The culvert completed in June is eroding around both the structure and embankment.

A coastal ecologist who wrote a report for the Department of Transportation and Infrastructure Renewal suggesting not to use a culvert — but rather to restore wetlands and upgrade roads — is not surprised the fix isn't withstanding the tidal power of the Bay of Fundy. 

"I'm not surprised that it has failed or is failing this quickly," said Tony Bowron, the director of the research firm CB Wetlands and Environmental Specialists. 

The department initially began working on his recommendations, but that was scrapped in favour of the $4-million culvert project, he said. 

"At the political level, obviously a different decision was made," Bowron told CBC's Information Morning. 

The erosion was discovered on Aug. 11, department spokesperson Peter McLauglin said Friday.

"The contractor is working to stabilize the structure and to determine the cause of the erosion."

The aboiteau, a type of dike, was in place for 100 years before it failed in late 2017.

Residents expressed concerns about flooding from the Halfway River that damaged private property, roads, vegetation, a cemetery, wells and put the bridge leading into town at risk. 

The province is installing temporary gates at the Minas Basin end of the culvert to block the tide while they do the repair work. 

The gates will block the passage of fish, but will be removed once the repair work is complete. The gates are expected to stay in place for up to eight weeks, McLauglin said. 

The gates will restrict salt water from entering the system, but Bowron doesn't expect that will greatly impact the habitat.

"We've had no storms and an issue has developed," said Bowron. "What's going to happen when we hit our fall and winter storms this winter to this structure? I don't think this is the last time in the foreseeable future they're going to have to go in and do something here."

During consultations, the community didn't get the full picture of what was happening in the water system, Bowron said. 

He said his report wasn't released to the community or Hantsport councillors at the time of the decision. 

West Hants Coun. Rob Zwicker said he favoured the culvert solution, but he didn't see Bowron's research paper until recently. 

The community asked to see concepts and designs, but the province told them the only fix was a culvert, said Zwicker. 

But Zwicker said the community is pleased with the culvert and flooding issues are clearing up.

"It dramatically changed things and it's recovering," he said.

Bowron said the province should not have expected different results with a culvert. 

"The structure that was in place failed and really what they've replaced it with is essentially a modern version of exactly the same thing," he said. 

With coastal communities facing the impacts of sea-level rise, he said the best available science and open discussions are needed to make decisions.

"I think in some cases the answer to that is we're going to have to not just build the walls higher, but actually step back from the water's edge in some cases," Bowron said. 

"Our salt marshes are our first line of defence against climate change, against sea-level rise, against those incoming storms that hammer our coast and are only going to be hammering them even harder in the future."