OPG to drain Niagara power canal
Welland River flow will temporarily revert to normal
It was carved out of rock and earth stretching nearly 14 kilometres through Niagara Falls, providing about a quarter of the water needed to run 10 massive generators.
And for most of the past century, the torrent of water flowing through the Queenston-Chippawa Power Canal has reversed the natural flow of the Welland River, causing its current to run backwards for 6.8 km from the Niagara River and the canal intake.
But in the years to come, the torrent will be slowed to a stop and drained away. And during the spring, summer and fall of 2021 and 2022, the Welland River will revert to its natural flow — spilling out into the Niagara River when work begins on a massive project Ontario Power Generation has planned in the next few years.
OPG project manager Mark Armstrong said the walls of the canal have held up quite well after a century exposed to the weather and a torrent of rushing water since the canal was built from 1917 to 1921, using some of “the largest shovels that were ever built on the planet, at the time.”
But there are telltale signs of erosion eating away at the concrete, rock and mud. And debris has been piling up at the bottom of the 12-metre-deep channel, impeding the flow of water and reducing the efficiency of the hydro generators.
“We’re doing the project to restore structural integrity to the
canal and reclaim degraded flow capacity by clearing out the debris,” Armstrong said, adding the cost of the project has yet to be determined.
It will mark the second time the canal will have been drained. It underwent its first major overhaul in 1964 and 1965.
A second refurbishment was needed in 1981, when 1,834 cubic metres of concrete, rock and other debris were instead dredged from the depth of the canal. That 17 days of work increased the flow of water by about five per cent, to 617 cubic metres per second.
But no major work has been done on the canal in the almost 40 years since that project was completed, “and we’ve had this steady degradation since then,” he said.
Debris is again clogging the channel, reducing the flow of water to about 549 cubic metres per second.
The rehabilitation project — it also includes refurbishing two of the power station’s 10 original generators that have been mothballed for several years — is expected to enhance the power station’s efficiency and add about 50 years of operating life to the canal.
Armstrong said OPG is conducting environmental studies, hoping to understand the impact the work will have on the Welland River.
“We’ve done a species-at-risk assessment for the canal proper, but depending on the scope (of the project) it will drive what other environmental studies we need to do to support the work,” he said.
Although it will be three years before the work is underway, Armstrong said the project has been in the planning stage for more than a year, to determine precisely what is wrong with the canal and how best to fix it.
While refurbishing the existing canal is the preferred option being considered, Armstrong said alternatives haven’t been ruled out.
“We’re going to make sure that we’re really diligent in looking at all the different options. I think we’re looking at whatever makes the most sense in terms of cost effectiveness for this for the ratepayer.”
OPG is planning public meetings to discuss the project with Niagara residents, likely to take place beginning this fall.