Water has been scarce all summer and the record drought has made hydroelectric operations and the goal of balancing various water use interests very challenging for us. However, the moderate rain we had about two weeks ago may have helped us get through this extreme weather situation.
For the month of August, the average water inflow into the Puntledge River system was about 5 cubic metres per second (m3/s), compared to historical average of about 13 m3/s. BC Hydro has been able to provide about 7.5-8 m3/s down the Puntledge River for fish habitat.
The Comox Lake reservoir is currently at about 133 metres and that’s about 2 metres away from where we become concerned about providing suitable water discharges downstream. It hit a low of 132.8 metres towards the end of August.
The series of moderate storms over the last two weeks dropped some rain over the watershed, where in one week, about 100 mm of rain fall in the upper watershed. Given how dry the land is, there was only a moderate amount of run-off and little change in the drought conditions. But over the last two weeks rather than continue the downward march and dropping about 30 cm, it increased by 30 cm – a 60 cm overall difference. This has placed the reservoir level in a better position to last until the fall rains arrive. With the recent dry weather it has begun to drop again.
Our Puntledge River hydroelectric facilities will be returned from regular maintenance on September 17. On that day, BC Hydro will increase the river flow from a minimum of 7.5 m3/s up to 11 m3/s. This is still well below our water licence fish habitat minimum flow of nearly 16 m3/s. The slight increase, however, will assist migrating and spawning salmon.
BC Hydro has public safety awareness protocols for river flow rates year-round, with a particular emphasis from May to September when recreation use is at its highest. With the generating station remaining out of service, all the river flow will passed below the division dam and down past the Barber’s Hole, Nymph Falls and Stotan Falls areas.
Throughout this 5 km stretch of the Puntledge River, BC Hydro advises the public to be cautious from September 17 through to the end of September. Caution signage will be in place. The 11 m3/s flow rate in this section of the river is about double to typical river flow rate for this time of year.
We will continue to conserve water through October as needed. On October 1, BC Hydro is hopeful of increasing the river flow to 14 m3/s to further assist salmon and also bring the 24 megawatt powerhouse online, although only at 20% of capacity. This is subject to water conditions and weather forecasts.
We would like to thank the staff from the Comox Valley Regional District, Fisheries and Oceans Canada, and Ministry of Forests, Lands and Natural Resource Operations for their coordination and collaboration in moving through the driest spring and summer on record. With the increase in the river flow on September 17, through discussions with us on water abundance conditions, the CVRD may be making some watering restriction changes.
BC Hydro operated in a responsible and environmentally sensitive manner when looking back on what we knew and how we responded to this drought. That diligence will continue. The good news is that further moderate storm activity is forecasted for this week.