BC Hydro’s annual public warning system tests that will take place from May 17 to May 19, with a significant increase in Puntledge River flows on May 19.
The public is being asked to stay away from the river system over the testing period with the individual sirens tested on May 17 and 18, and all sirens fully engaging on May 19. Temporary safety awareness signage will be placed along the river system.
“Public safety is very important to BC Hydro, and it’s one of the primary reasons why we communicate regularly about our Puntledge River operations,” said BC Hydro stakeholder engagement advisor Stephen Watson in a press release. “Awareness of the potential hazards from the Puntledge River hydroelectric system is through our public warning system. The sirens and strobe lights are placed along the Puntledge River from the Comox Dam to Puntledge Park, and will engage to warn of quick river flow changes. Permanent river safety signage is in place to advise what the siren sound means, and when heard, to move out of the river channel.”
The upcoming tests are scheduled, and conducted to ensure the warning system is operating correctly.
“We will manually test each siren on May 17, make any repairs as needed on May 18, and then release extra water from Comox Dam to engage the siren system on May 19,” said Watson. “BC Hydro staff will also be along the river to monitor the warning system.
On May 19, at around 10 a.m., the water discharge from Comox Dam will increase over about 15 minutes before dropping back down again to provide a pulse of water that will move downstream and cause the various sirens to activate. The discharge from the dam may be around 27 cubic metres per second (m3/s), and at various times on that day the Puntledge River flow will increase to a brief peak of about 50 m3/s. River flow hydraulics and under-surface currents can be dangerous.
“This test is a reminder that this is a hydroelectric system where river flows may change quickly, whether planned or unplanned,” said Watson. “With the warmer weather, people will begin to gravitate to water to cool off and enjoy the summer. About 500 people have been counted throughout the Puntledge River system at one time. Only 15 centimetres of fast flowing water is enough to knock a person off their feet.”
The Puntledge River hydroelectric system includes the Comox Dam, which impounds the Comox Lake Reservoir, where the water released travels 3.7 kilometres down to the Puntledge River Diversion Dam. From there, a minimum fish habitat flow is provided down the river with the majority of water directed down a five kilometre penstock to the generating station.