In the Comox Valley you only have to look up to see all that snow and the record-setting season for the Mount Washington Alpine Resort.
With the approach of May, BC Hydro will be closely monitoring how all that snow will melt.
The Upper Wolf River weather station towards Campbell River is also showing high amounts of snow, with a snowmelt-to-water equivalent of about 2,200 millimetres. This is about 160 per cent above normal and the second highest on record. An average snowpack year is about 1,350 mm water equivalent.
BC Hydro considers the annual snowpack along with about 50 years of inflow data to forecast potential inflows into the Puntledge River watershed. The Water Supply Forecast, done at the beginning of the month, indicates April to September runoff volume to be about 121 per cent of normal with a variance of about 20 per cent should it turn dry or wet.
This information is important so that BC Hydro can operate to conserve water in dry-looking years, such as 2008 and 2009, or in a wet-looking forecasts like this year, run the Puntledge River Generating Station at full capacity to create more room in the reservoir to absorb the melting snow.
The snowpack historically peaks at this time of year and then begins to slowly melt until depleted around the end of July. The Comox Lake Reservoir was at 133.75 metres and holding steady as of Wednesday. It is considered full at 135.3 metres.
"Given the large winter storms over the past few years, there is some community concern for the potential flood risk with the record snowpack," says BC Hydro community relations spokesperson Stephen Watson. "At this time of year there are a number of factors that are in our favour, and this includes lower high tides, a low-elevation Tsolum River watershed that should see limited snowmelt runoff, and smaller storm systems."
BC Hydro will run the generating station at full capacity but that will not be enough to control reservoir levels over the next few months. From May onward, this will translate into a significant number of controlled spills. To create more storage room, BC Hydro will increase the discharge from Comox Dam this weekend from 32 cubic metres per second to about 110 m3/s. This three-fold increase in the Puntledge River will begin Friday night and last through Sunday before returning to normal river flows.
BC Hydro's preliminary operational plan is to release the same amount of water on May 14 and 15, May 21 to 23, during the 2011 Puntledge River Paddle Festival on May 28 and 29 and June 4 and 5. BC Hydro advises the public to stay away from the Puntledge River during these high-water flows.
This proactive operating plan has a number of benefits, such as trying to stay ahead of potentially high rates of snowmelt, a consideration for fish rearing from mid-June onward, and by providing white water enthusiasts advance notice of ideal river conditions.
BC Hydro anticipates the reservoir to be hovering at full levels through July. The spring and summer temperatures, rate of the snowmelt, and rainfall amounts are large unknowns.
BC Hydro will continue to inform the community of any significant operational changes as it balances all water use interests over the next few months.
— BC Hydro