Submitted photo of the Puntledge Powerhouse.

Submitted photo of the Puntledge Powerhouse.

Puntledge River high flow conditions, siren initiation Thursday

BC Hydro is issuing a public safety notice of high Puntledge River flow conditions on Thursday, March 31. From those conditions, the public warning system will trigger from the Puntledge Fish Hatchery down to Puntledge Park. The higher- than-normal river flow will be in place to enable some powerhouse equipment tests.

Water discharge from the Comox Dam just prior to the test may be around 35 cubic metres per second (m3/s). This will increase to about 65 m3/s on Wednesday evening. The higher flow rate will be in place through the day on Thursday and then be moved back to 35 m3/s that evening. We are advising the public to stay away from the river Thursday given the high and changing water flows during equipment testing.

BC Hydro is testing the turbine inlet valve, which is located immediately upstream of the powerhouse and within the penstock that delivers water to the powerhouse to generate electricity. This valve passes water to the turbine. It is closed from time to time for maintenance and other conditions. For ongoing planning work for the Puntledge River Flow Control Project, the turbine inlet valve will be operated to move from open to closed on Thursday. Flow through the powerhouse to the river will then move from about 27 m3/s down to about zero fairly quickly. That means the water further upstream that’s entering the penstock will then shift from the penstock intake and spill over the diversion dam, and down the Barber’s Hole, Nymph Falls and Stotan Falls section of the river. River flows below the diversion dam and from the powerhouse will be fluctuating significantly over the day.

Hydro is providing extra water flows within the Puntledge during the equipment test so that all the river fish habitat is fully covered with water.

With the flow below the powerhouse being reduced and then about doubling quite quickly as water arrives from the diversion dam, the public warning system will engage below the powerhouse to warn the public of the rise in water. The sirens at Barber’s Hole, Nymph Falls and Stotan Falls area of the river will not initiate as flow rates will be above the thresholds that would initiate the sirens.

This equipment test is a reminder that the Puntledge is a hydroelectric system where flows can change quickly, whether planned or unplanned, and to obey safety signage and the siren system, when initiated, to move out of the river channel. Temporary safety advisory signage will be placed along the river system for Thursday.