BC Hydro provides the following update on a water release this weekend for flood risk management and to benefit kayakers, with a safety warning to the general public to stay away from the Puntledge River on Saturday and Sunday.
There is no risk of downstream flooding.
BC Hydro advises the public to stay away from riverbanks and dangerous river flows from Sunday through Monday, unless you are registered with the Vancouver Island Whitewater Paddling Society (VIWPS). The Puntledge River flow will increase by more than twofold over the current water release below the dam.
VIWPS advises upwards of 30 kayakers may take advantage of the kayak river flow this weekend. Various water features and flows will be ideal on one of the best kayak rivers on the Island when conditions are right.
When able to do so, BC Hydro targets a 110 cubic metre per second (m3/s) release downstream to lower the reservoir level and to provide an opportunity for river recreation.
With the current calm weather, BC Hydro will lower the reservoir level in preparation of future storm systems that may hit the watershed. Increased storage room in the reservoir increases BC Hydro's ability to mitigate flood risks.
The Comox Lake reservoir is currently at 134.3 metres, Stephen Watson of BC Hydro said Wednesday. The significant increase in reservoir elevation from last weekend's storm now places it about one metre (three feet) from where water free-spills over the dam.
When water begins to free-spill over the dam, BC Hydro's ability to control downstream water flow diminishes. By the end of Monday, BC Hydro would like to see the reservoir in the 133.5-metre range.
BC Hydro's ability to controlled water releases during large storms also benefits fish. Last weekend's storm had inflows into Comox Lake Reservoir peak at 502 m3/s, yet BC Hydro released just 20 m3/s to 45 m3/s downstream. This greatly limits gravel movement in the river.
This is a sensitive time in the salmon life cycle with incubating eggs in the gravel, and their susceptibly to mortality at high flows. River flows in the Puntledge that exceed 120 m3/s at this time of the year are a concern for Fisheries and Oceans Canada.
Understanding flood risk management comes first, but fish habitat is another important issue that BC Hydro considers in its operations, watson concluded in a news release.
— BC Hydro