Morrell Lake in Morrell Nature Sanctuary is about to be drained to repair a bent shaft on an emergency release valve.
The valve, positioned about 20 metres from the dam that forms the lake and about seven metres under water, can be opened to decrease the lake’s water volume in case of severe flooding or an earthquake.
Patrick Ansell, Morrell Sanctuary Society director, said the problem first came to light during a recent test when the valve cock proved really difficult to open.
A team of divers was sent down to investigate the problem and found the 15-metre long shaft that opens the valve is bent about 2.5 metres above the valve body.
The valve itself appeared to be in good shape.
“We don’t know how that bend occurred,” Ansell said. “It’s a straight rod about 40 or 50 feet long and theoretically nothing could bend it. It’s an inch (diameter) cast-iron rod, but something did. It could have been a log or ice – we don’t know.”
Vancouver Island University uses Morrell Lake for biological research since it is home to a wide variety of native amphibian and insect species that thrive there because there are no fish in the lake that prey on them.
The last time Morrell Lake was drained was for valve testing in 2004. The outflow, some of which connected to the Chase River and Colliery Dams, from that test was minimal and went mostly unnoticed.
Ansell said since Morrell Lake is a breeding water for the western toad, repairs have been timed to follow the toad’s breeding season.
Work is scheduled to start Friday (Aug. 30) when divers open the valve to drain the lake. Draining will take about three weeks before the water level is low enough to access the shaft and complete the repairs. Water levels in the lake should return to normal by January. The work will not affect access to the wildlife sanctuary.