The weir at Cowichan Lake resumed operations for the 2020 season on March 18.
Brian Houle is the environmental manager for Catalyst Crofton which operates the weir that regulates the flow of water from the lake to the river in order to sustain a minimum flow in the river through the entire dry season.
He said a review of current conditions at Cowichan Lake show the lake is currently less than full, the snow pack in the surrounding mountains is just a small amount more than last year, and the weather forecast is calling for no significant rainfall during the next two weeks.
“Everything remains the same today [March 17] except there is now substantial rainfall predicted for the week after next and, if I could depend on that rainfall, early control could have been delayed,” Houle said.
“From our experience in 2019, it is possible the region will receive little to no rainfall during the coming five months and, on that basis, and with an abundance of caution, weir operations will begin to store water early this year. While it is likely [as of March 17] that early control will again not be needed this year, weather is not predictable enough and with the low snow pack in the mountains, we need to store as much water as possible.”
Catalyst had to resort to pumping water into Cowichan River over the weir on Aug. 29, 2019, to maintain water flows in the river.
It was the first time the company, which depends on water from the Cowichan River to run its pulp and paper mill operations in Crofton, has had to take such action since the weir was first constructed in the 1950s.
The region was experiencing one of the worst droughts in decades at the time and water basins in the region, including Cowichan Lake, were only getting about two-thirds of the water they used to get in spring and summer.
Houle said the first action that will take place on Wednesday will be to lower the two boat lock gates at the weir.
He said that as soon as two days after the boat lock gates are lowered, the control gates on the south side of the weir can begin to operate and reduce the flow in the Cowichan River down to the seasonal requirement of 25 cubic meters per second.
“In the event that spring rainfall and snowmelt cause the lake level to rise to above full supply, the spill gates will be adjusted to release more water and to control the lake level to full supply; but not over full,” Houle said.
The monitoring and regulation of Cowichan Lake and Cowichan River’s water levels is part of the Ministry of Forests, Lands, Natural Resource Operations and Rural Development’s ongoing commitment to maintain stream flows for fish, First Nations, water licence holders and recreational water users.