Update: BC Hydro Spill Release Below Comox Dam
January 26, 2016
From BC Hydro:
"The wet weather and higher freezing levels over the next few days will increase the Comox Lake Reservoir level. The weather forecast, with uncertainties, shows 80-100 mm of rain expected today through Thursday and freezing levels rising to about 2300 metres on Wednesday. The reservoir is currently at 133.85 metres and slowly rising. BC Hydro is uncomfortable with the reservoir above 134 metres for flood risk management considerations and future storm systems. Water freespills over the dame at about 135.3 metres.
BC Hydro will be proactively managing the potential higher inflows. Beginning tonight, BC Hydro will increase discharge from Comox Dam to about 90 m3/s. The discharge may be adjusted higher or lower depending on inflows, lake levels and for managing the downstream high tides. Water inflows into the reservoir are forecasted to peak on Thursday at around 130 m3/s.
Beginning this evening and through Thursday, BC Hydro advises the public to stay away from the Puntledge River due to high river flows. Warning signage is posted along the river."
Previously from BC Hydro:
January 25, 2016
"BC Hydro will continue with a spill release today, similar to the release provided this weekend. We are targeting a flow rate of around 60 m3/s down the Stotan Falls section of the river. At the same time about 25 m3/s is flowing through the generating station. The total discharge rate from Comox dam will be around 80-90 m3/s.
BC Hydro will manage the Comox Lake reservoir by adjusting downstream discharge rates as needed at night.
A storm with moderate precipitation is expected for Wednesday/Thursday. The Comox Lake Reservoir is currently at 133.95m, and today’s spill will provide additional room in the reservoir in advance of the storm.
Tomorrow and Wednesday BC Hydro will be providing scheduled fish pulse flows, targeting a flow rate of 12-14 m3/s Gauge 6 for benefit of fish. Puntledge generation will also be reduced tomorrow to clean the trashrack. On Wednesday and Thursday generation will be shut down to clean the fish screen.
Due to high flow conditions we continue to advise the public to stay away from the Puntledge River today. The flow rates are about three times the typical river flow."
January 22, 2016
"The recent storm was not as significant as forecasted with less rain and lower freezing levels. But that’s a good thing. It means more snow on the mountains and less high water conditions for BC Hydro to manage.
The silver lining in all this is BC Hydro is providing kayakers, experienced kayakers such as the Vancouver Island Whitewater Paddling Society, with an opportunity to have good conditions on the Puntledge. We are targeting a flow rate of around 60 m3/s down the Stotan Falls section of the river from 9 am to 4 pm through Sunday. At the same time about 25 m3/s is flowing through the generating station. The total discharge rate from the Comox dam will be around 80-90 m3/s.
BC Hydro will manage the Comox Lake reservoir level by adjusting downstream discharge rates as needed at night.
Given the lower flow rates in adjacent and connecting rivers downstream, it’s unlikely we will need to adjust our operations with the high ocean tides. The flood risk is considered very low.
BC Hydro continues to advise the public to stay away from the Puntledge River given the dangerous flow rates through Sunday. These flow rates are about three times the typical river flow."
January 20, 2016
"After the 10-day monsoon at the beginning of December (about 500 mm of precipitation) it has since been cooler and drier. Even to the degree that we reduced generation to a third of capacity for a few weeks to conserve water. The silver lining is there’s been good snowpack accumulation for the spring freshet. However, things are going to change over the next few days with some forecasted heavy rains and milder alpine temperatures. It also means we will be spilling lots of water past the Comox dam perhaps through Monday to control the reservoir level.
Precipitation amounts may be up to 100 mm over a 36 hour period. And the freezing level may increase to about 2000 metres. This all starts tonight.
The Comox Lake reservoir is just above the middle elevation range and has come up the past week from some of the rain moderate rain events. The King Tides have also past us by though they will be coming up again this weekend; it’s always about timing. We currently do not see a downstream flood risk.
Beginning tonight, BC Hydro will initiate a water release below the dam for flood risk management. Discharges could be increased by up to five fold (to up to 160 m3/s) with both spillway gates wide open.
BC Hydro advises the public to stay away from the Puntledge River given the dangerous flow rates through Monday. We will be going up and down with our downstream discharges in consideration of the daily high ocean tides, and the Browns and Tsolum river flow rates.
As always, operations are subject to change based on actual water inflows and updated forecasts.
BC Hydro will provide an update by Friday."