News of an impending weather system in the Comox Valley region is exactly what users of the Regional District’s water service did not want to hear.
In anticipation of the arrival of a subtropical weather system, BC Hydro is increasing its discharge from the reservoir into the Puntledge River.
While the discharge will have no effect on turbidity levels, the storm system coming through will not do any favours.
“For the Comox Valley Regional District, this is not what you’re looking for,” said Stephen Watson, stakeholder engagement and communications representative for BC Hydro. “The turbidity has slowly been going down, but this storm will put them a few days, depending on what happens. Like anything, forecasts can change, but … if we get what we think, it’s going to stir things up.”
Beginning as early as Thursday evening, BC Hydro will increase the water discharge from the Comox Dam to the 100 m3/s to 125 m3/s range. The current rate of discharge is about 32 m3/s. The high river flow rate may be in place through Wednesday. BC Hydro will adjust river flow discharges based on actual inflow conditions and ocean tides.
For public safety, BC Hydro advises the public to stay away from the Puntledge River beginning Friday through Wednesday next week.
Precipitation over the three days starting Thursday evening may amount to up to 100 mm. Friday and Saturday appears to be the heaviest aspect of the storm. In addition, temperatures will be quite warm, reaching up to 13 C, with the freezing level reaching up to 2,500-3,000 metres. There may be significant snowmelt from this system.
The ocean tides are very high on Friday through and Sunday at 5.3 metres – about 0.4 of a metre higher than the early December 2014 storms. These tides are known as the King Tides and are the highest of the year.
Storm ocean surge may also be a consideration as the winds are forecast to come out of the southeast and be up to 60 km/h on Friday.
BC Hydro will reduce the discharge from the Comox Dam to as low as possible during the high tides on Friday and Saturday.
The Comox Lake Reservoir is currently at 134.15 metres and has levelled off. There is over 1.2 metres of available reservoir storage to absorb this storm system.
While these storms look to be significantly weaker than the storms in early December, there will be more snowmelt in this case and that element of water inflow amounts into the river systems are more uncertain. Because of the timing of these highest ocean tides of the year, BC Hydro is a bit concerned about the Friday morning and Saturday morning tides. Should the natural flowing Browns and Tsolum rivers peak at the wrong time, there may be a risk for some isolated downstream flooding.
–With files from BC Hydro