With hot and dry weather conditions in the region ongoing through the summer season, water levels in Cowichan Lake and Cowichan River remain very challenging.
Brian Houle, environment manager at the Domtar Crofton mill which owns and operates the weir at Lake Cowichan, said on July 18 that with the weather predicted to continue to be dry and hot, the current flow of 5.5 cubic metres per second from the lake over the weir into Cowichan River is not sustainable.
He said a flow of 4.5 cms is now needed for the release of water from the lake to secure a sustained base flow until rainfall returns to the region.
“A meeting of the leadership group on the Cowichan watershed took place Thursday (July 17) with the key agenda item of scheduling the flow down to 4.5 cms as soon as possible,” Houle said.
“That meeting discussed both the very difficult low lake level condition and also the water quality concerns in the river at this time. With concerns for fish health, guidance to hold the river flow at 5.5 cms was provided [at the meeting].”
Houle said a water flow reduction down to 4.5 cms will again be the key agenda item for the stakeholder group to discuss first thing in August.
The decision was made to reduce water flows over the weir from 7.06 cms to 5.5 cms early in July when it was determined that the lake was less than half full due to continuing dry conditions.
This summer season is now becoming as challenging as 2023 when a severe drought lowered water levels in Cowichan Lake and the Cowichan River dramatically, which resulted in the deaths of approximately 84,000 fish in the river.
Bob Crandall, the Ts’uubaa-asatx fisheries director with the Cowichan Lake Salmonid Enhancement Society & Hatchery, recently said that the fact the water levels in the lake have dropped so much so early in the season this year is deeply concerning for fish survival in the lake’s tributaries and Cowichan River.
Domtar had to use 20 pumps for more than a month in September and October of 2023 to pump water over the weir to sustain water levels in the river.
Houle said in early July that it is likely that pumps will be needed again later this summer if the dry conditions continue, as is forecast, and Domtar is making arrangements for pumps to be available to be used later in the dry season.
The Cowichan weir is owned and operated by the Domtar Crofton Mill, under water storage and water diversion licenses issued by the the province’s Ministry of Water, Land and Resource Stewardship.
Crofton mill’s weir managers collaborate with the regulators of fish and fish habitat, provincial and federal fisheries organizations, and the Cowichan Watershed Board, which is comprised of elected officials from Cowichan Tribes and the Cowichan Valley Regional District, on water flow decisions.
