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Studies underway on how to replace old Maritimes causeways

Canso Causeway
Canso Causeway - The Chronicle Herald

They seemed like a good idea at the time.

Between 1950 and the early 1970s Atlantic Canadians were building causeways.

Cheaper than bridges and with less maintenance, they became the preferred way to get cars, trucks and trains across rivers at straits.

Four big ones were built across the Strait of Canso (linking Cape Breton to the mainland), the Avon River (near Windsor), the AnnapolisRiver (near Annapolis Royal) and the Peticodiac River (near Moncton).

“Then there were 30 or so smaller ones builtall around Nova Scotia, P.E.I and New Brunswick, often with just a small culvert,” said Graham Daborn, a biology professor

at Acadia University who has studied the effects of causeways on fish stocks.

“Obviously they change the flow of water and there are all sorts of ecological consequence. ”

As the federal and provincial governments wrangle with community groups and fishermen’s associations over how some of the 

damage can be undone on a case by case basis, they are also facing the question: Once we change the landscape, can we change it back?

“Tom cod want to get through in December and January, for sturgeon it’s May, June, July, the shad come in June and the salmon in the fall,” Darren Porter, a weir fishermen and spokesman for the Fundy United Fishermens Association, said of the Avon River.

“All of these species need to get into that river at different times to complete their life cycles. Then every one of them likes a different kind of passage — the eels for instance need like a long flat ramp.”

Even Porter doesn’t think replacing the causeway across the Avon with a bridge is a realistic suggestion.

Earlier this week the provincial and federal governments promised to split the $69-million price tag of twinning an accident-prone section of Highway 101 between Three Mile Plains and Falmouth.

Though not part of that funding announcement, the project will also involve expanding the causeway across the Avon River, opened in 1970, to accommodate four lanes of traffic separated by a concrete barrier.

Porter and groups like the Friends of the Avon River consider it their big chance to incorporate a fish passageway. What that passageway looks like and how much we’re willing to pay for it remain up in the air.

“The final design will provide improved fish passage, with modern technology, that meets all regulatory requirements and satisfies the conditions of the environmental assessment,” said Marla MacInnis, spokeswoman for the Department of Transportation and Infrastructure Renewal.

“This includes review of the completed design by DFO to ensure it meets fish protection provisions of the Fisheries Act.”

Fisheries and Oceans Canada’s intervention in the environmental assessment for the causeway expansion resulted in the requirement of a study for what species (and how many of them) visit the area of the causeway now and a “detailed design of the aboiteau structure to enable fish passage together with an analysis of any other options for fish passage . . .”

Porter, along with the Mi’kmaq and a scientist from Acadia University, are working on the baseline study.

“The consultancy firm they hired may be very good but they don’t have a fish passageway specialist and DFO’s fish passage specialist has retired,” said Porter.

“So what are we going to get?”

He wants to see partial free flow of water through the causeway.

Currently there’s a sluicegate in the causeway that opens in the spring to allow gaspereau to migrate into the river, but is closed much of the rest of the year.

Meanwhile the Department of Transportation also has to consider the human infrastructure upstream. Once the causeway was built, maintenance ceased on the dike system upstream.

MacInnis confirmed that a primary concern of the new design will be the protection of agricultural land and homes and businesses upstream Weighing the needs of fish against human infrastructure added after the causeways had changed the landscape is also a concern at the Peticodiac River and the Annapolis River causeways.

In New Brunswick, Moncton had built, filled and covered over a landfill in an area created by silt dumped from the water after the Peticodiac causeway was opened in 1968. People had built houses along a man-made lake upstream from the causeway.

Fishermen concerned with runoff from the dump ending up in the Bay of Fundy if the causeway was removed and owners of land on the man-made lake failed in their attempt to get a court injunction against the opening of the causeway gates in 2010.

Construction began last year on a 240-metre bridge that will cross the open waterway.

Meanwhile, at the other end of the Bay of Fundy, a power generating turbine was opened in the causeway crossing the Annapolis River in 1982.

A 35-year campaign by scientists and people like Porter, who say fish get chopped up coming back down through the turbine, led to that facility being placed under review.

“Fish have no trouble travelling into that river; it’s just coming out that they get killed in the turbine,” said Porter.

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