Rising water levels are causing delays in the St. Lawrence Seaway that could cost the economy more than $1-billion, shippers and port operators say.
A new study from the Chamber of Marine Commerce warns that opening the floodgates further at a dam in Cornwall, Ont., to relieve high water levels upstream would wash away between $1-billion and $1.75-billion in revenue for businesses on both sides of the border.
A board of control recently increased the flow at the Moses-Saunders Power Dam – the only control point on the St. Lawrence Seaway, which includes the Great Lakes – to allow a near-record 10,400 cubic metres of water a second out of Lake Ontario. The rate – equivalent to about four Olympic swimming pools going over the dam each second – follows heavy spring snow melt and rains that created record water levels on the Great Lakes.
The rapid outflow interrupts navigation because swift, swirling currents near the dam force a slower movement of ships through the locks, Bruce Burrows, president of the Chamber of Marine Commerce, said on Wednesday.
“The approach is a delicate operation,” he said, noting the locks are 80 feet wide for ships with widths that range up to 78 feet. “You have to squeeze in tight.”
About a dozen cargo ships carrying roughly $180-million in bulk pass through the lock near Cornwall each day, Mr. Burrows said. But with higher outflows affecting currents, ships are taking an extra two hours to make the trip between Lake Ontario and Montreal, ordinarily a 24-hour voyage, he said.
“We’ll probably lose a ship a day, potentially, going through.”
Mr. Burrows estimates that it costs businesses up to $4 million every day the current outflow is in place, citing the study commissioned to Pennsylvania-based Martin Associates consultancy. The International Lake Ontario-St. Lawrence River Board will consider boosting the outflow this Friday.
“Any flow over 10,400 requires some kind of stoppage – either temporary stop-and-go or full stoppage,” he told The Canadian Press.
“It’s an incremental benefit in terms of additional water being taken out of the system. It pales in comparison to the economic hit,” he said, pointing to the diverse range of products carried on the Seaway including grain from the Prairies and steel and car parts from Central Canada.
Upping outflow toward the threshold of 11,500 cubic metres a second – more could exceed capacity at a 104-year-old Hydro-Québec generating station west of Montreal – would prompt sustained stoppages at the locks, six weeks of which would rob businesses of nearly $1.8-billion in revenue, Mr. Burrows said.
“This is a key international trade corridor … so I think this is a reputational issue as well.”
He approved of the current outflow – a heightened level reached on June 13 and maintained since – because of flooding problems for homeowners on Lake Ontario and the Thousand Islands, but called on Ottawa and the provinces for a study into water levels and their causes along with a water management plan.
Lake Ontario rose to nearly 90 centimetres above average this spring, reaching a record 75.92 metres above sea level before stabilizing. Lakes Erie and Superior also hit record heights.
Overflowing rivers also took a toll on residents in Quebec and New Brunswick, where at least 17,350 homes were hit by flooding or deemed at risk, according to Statistics Canada.
Higher outflows in the St. Lawrence would add pressure to already flooded areas around Montreal and result in minimal decreases in Lake Ontario.
“Every possibility is on the table. At any given moment it may choose to increase the flows,” the control board’s Canadian secretary Rob Caldwell said in an interview. “But they’re still looking at potential effects. They’re making every effort to do their due diligence.”
Shipping stoppages are not the only way to deal with greater outflows, though even a slight increase beyond current levels “would be unprecedented territory,” he said.
“We could just keep increasing flows slowly but surely and basically test and assess the impact as we go,” said Mr. Caldwell, who added that he has received a dozen letters from shipping interests requesting lower outflows.
Both the board and shippers highlighted alarmingly high water levels since 2017.
“There are obviously natural cycles, you see that over the years … but this is the second time in two years that we’ve had a one-in-100-year event,” Mr. Burrows said.
“I think there’s a certain consensus that climate change is probably connected one way or the other.”