A U.S. media report published Tuesday suggested the U.S. Army Core of Engineers had officially quashed discussions of expanding the seaway, a 600-kilometre long stretch of water spanning Montreal to where the Welland Canal connects with Lake Eerie.
A Core spokeswoman says the news story was premature, citing previously released reports that have not been officially approved.
Those reports, however, suggest the seaway and the broader system it belongs to have not been targeted for expansion.
In February 2010, the Core released a document outlining the challenges facing the Great Lakes Navigation System, a complex 3,700-kilometre waterway that moves about 200,000 tons of cargo per year. About a fifth of that cargo travels through the St. Lawrence Seaway.
The army core report identifies the navigation system as a key economic driver, but says it's subject to environmental concerns including shoreline erosion and the growing number of invasive species brought over on foreign ships.
The water system may be better served by maintaining the status quo, the report suggests.
"The future viability of the GLNS will come directly from maintaining the value and function of the existing infrastructure," the report reads.
Core spokeswoman Lynn Duerod says the report is under review until the end of August and does not represent the core's official position on seaway expansion. It represents the latest stage in a nearly decade-long dialog about the Great Lakes Navigation System and may not lead to any definitive conclusions, she said.
Canadian officials vetoed the idea of expanding the waterway "some years ago," said Andrew Bogora of the St. Lawrence Seaway Management Corp.
Environmental concerns played a roll in the Canadian decision, he said, adding sustainability has become an even more important focus in recent years.
Economic realities also made it clear that expansion was not necessary, he said.
"The present-day seaway is operating at 50 per cent capacity, and so we could double the flow of cargo within our existing locks and channels," he said.
The growing focus on the environmental issues plaguing the seaway comes as welcome news to the David Suzuki Foundation, which has long opposed expansion of the fragile system.
Science project manager Jean-Patrick Toussaint says increased dredging in the seaway would redistribute the water flow in the area, leaving some pockets deprived of oxygen and doing irreparable damage to the ecosystem.
Expansion could also lower water levels, which are already threatened by climate change, he said.