The recent significant rainfall in the Cowichan Valley might delay the use of pumps at Lake Cowichan’s weir.
Brian Houle, environment manager at the Domtar Crofton mill, which owns and operates the weir, said on Aug. 19 that the rain slowed the drop in water levels in Cowichan Lake considerably.
“This is the first time in my 15 years that, when we really needed rainfall in middle of dry season, that rainfall of substance arrived,” he said. “From predicted lake level drop given the current river flow, I would have expected the lake to go down by 10.5 centimetres over the previous 14 days, but the lake level went down by 5.1 cm, equating to the rainfall adding about 5.4 cm to the lake’s (water storage capacity).
"This equates to an estimated eight days of water in the lake, delaying when river pumps will be needed into September a bit further.”Domtar is planning to rent 20 large water pumps to pump water from the lake into Cowichan River to sustain the river’s base-water flow in the Cowichan River after dry and hot weather conditions during the summer saw water levels in the lake plummet.
The pumps were originally expected to be needed on or about Sept. 15.
“Each week into September we delay the use of pumps brings us closer to the next substantial rainfall event, and substantial rainfall will come,” Houle said.
But Houle cautioned that the weather forecast is not calling for much rainfall in the next two weeks.
“Discussions (on Aug 19) with regulators and stakeholders (of the watershed) resulted in an agreement to hold the flow (over the weir into the river) at 4.5 cubic metres per second for now,” he said. “Weekly meetings with the regulators and stakeholders will continue for the coming weeks.”
