BC Hydro Puntledge River update #3: High water spill from Comox dam to end on Wednesday
January 29, 2018
From BC Hydro:
The public safety notice of higher Puntledge River flows is being extended from Tuesday to Wednesday.
The forecasted storm for Sunday and Monday was not as significant as forecasted. In anticipation of the potential for high rain and snowmelt, we were able to lower the Comox Lake reservoir level down to about 133.05 metres on Sunday, and provide about 2.3 metres of available storage room to hold back water during the high tides. The reservoir is currently at 133.45 metres and slowly rising. The discharge from the Comox dam is currently about 50 m3/s, or about 150% of the typical water release, and it may likely remain at that flow rate through Wednesday. Please stay away from the river through Wednesday.
January 23, 2018
BC Hydro Puntledge River update #2: High water spill from Comox dam extended to Jan 30
We had very high precipitation over the weekend and significant water inflows into Comox Lake reservoir. We are extending our public safety notice to stay away from the Puntledge River through next Tuesday.
One of the measurement gauges off the Cruikshank River measured an incredible 148 mm of rain over a 24 hour period. Thankfully the precipitation fell as snow in mid-elevations and above. The huge rainfall in the lower elevation provided for a very high Tsolum River flow peak of 278.3 m3/s on Sunday, which was near a record high. The Browns River didn't react too much.
The current water release from the Comox dam is about 200 m3/s, or about six times the normal flow rate. BC Hydro will reduce flows, as needed, for the daily morning high tides for flood risk management.
The Comox Lake reservoir is currently at 134.75 and slowly dropping. It hit as high as 134.93 metres. Water fee-spills over the dam at 135.5 metres.
We will release extra water flows, up to about 200 m3/s, through to Tuesday next week. There are some modest storms in the forecast and we will adjust operations as needed.
Previously: January 17, 2018
BC Hydro Update on Puntledge River: High water spill from Comox dam tonight
We are watching the forecasted storm activity for today and tomorrow and how it may affect water inflows into the Comox Lake reservoir. With the rising reservoir level we plan to increase the water release from Comox dam to upwards of 100 m3/s beginning tonight. We ask the public to stay away from the Puntledge River from Wednesday evening through to Monday.
Since yesterday, about 65 mm of precipitation has fallen in the upper watershed. Temperatures have dropped this morning so more mid-elevation snow, though the temperatures are expected to increase today before dropping again over the next few days.
The Comox Lake reservoir is currently at 134 metres and slowly rising. We prefer the level to be around 134 metres, particularly below 134.4 metres, at this time of year for flexibility in our flood risk management operations. Water begins to free-spill over the dam at 135.33 metres. The forecasted daily water inflows into the reservoir for today and tomorrow are over 100 m3/s given the storm activity. We need to increase the water release from the dam this evening to control the reservoir level.
The ocean tides are modestly high at around 5 metres and there will be some ocean storm surge up the estuary from the southeast winds. The Browns and Tsolumn rivers should not react too much from this storm, though if they do, we will significantly reduce the water release from the Comox dam during the morning daily high tides.
Water releases from the dam are expected to be as high as 100 m3/s, or about three times the typical water flow for this time of year, on Thursday before potentially moving downward into the weekend.
We see very low downstream flood risk at this time.