Above-average inflow last month has lifted the level of the main source of public water for the Comox Valley.
The past month saw above average water inflows into the Puntledge River system, and the moderate storms also increased the snowpack on upstream mountains.
The March water inflow into Comox Lake Reservoir was 108 per cent of normal. This helped with near-term reservoir levels and improved the water supply forecast looking ahead to the summer. However, it is still below normal.
Water inflows from a series of moderate storms in March increased the Comox Lake Reservoir level to about normal for this time of year. Looking at the forecast for the week ahead, it looks to be fairly dry with warming temperatures. Water inflows are looking to be around 20-35 cubic metres per second (m3/s) this week.
Snowpack
The Snow Survey and Water Supply Bulletin for the month of April was issued by the Province, and for the Vancouver Island region, the snowpack is now 60% of normal – up from 52% last month. The snow pack at a nearby watershed is now around 65 per cent of normal, with it typically peaking in early May before the freshet or melting process begins.
Reservoir level
The Comox Lake Reservoir is currently at about 134 metres, and that’s about a metre higher than where we were last month around this time. The 135.3 metre level is considered full.
Power Generation
BC Hydro has been operating the 24 megawatt generating station at 20% to 40% of capacity since October to conserve water for downstream fish habitat. However, at the beginning of April with the improving water abundance situation, BC Hydro increased the power generation to full capacity, or around 32 m3/s. BC Hydro will continue to review the forecast and water inflows and adjust operations accordingly. Going into May and June, even in drier years like this one, this is a period of water abundance. The limited reservoir storage capacity of the Comox Lake Reservoir is expected to fill, potentially spilling over the dam from the snow melt.
Puntledge River Paddle Festival
In February, BC Hydro and the Vancouver Island Whitewater Paddling Society (VIWPS) were thinking about cancelling the annual May kayak event because of the dry winter conditions and the very low snow pack. However, conditions have changed enough in the past two months for BC Hydro to confirm with VIWPS that the kayak event can proceed. The event is timed for late-May when there is typically water abundance in the system. The paddle festival was the result of a community water use planning process that included First Nations, local government, agencies and stakeholders. About 200 white-water enthusiasts descend upon the Comox Valley each year for the planned kayak festival. The event is a condition of BC Hydro’s water license with the Comptroller of Water Rights.
VIWPS and Fisheries and Oceans Canada are co-ordinating the event timing so the Puntledge River Hatchery’s chinook salmon smolt release can take place at the same time. The higher river flows enhance the success rate of the out-migrating fish reaching the ocean.
Long-term water supply forecast
BC Hydro’s updated February to September water supply forecast, now into April, shows water inflows into the Comox Lake Reservoir are forecast to be about 82% of normal. This forecast considers snow pack, precipitation, and historical water inflows from the last 50 years. Should the weather be dry or wet, the water inflow variance can be +/-15%. Ultimately, the challenge will be to maintain various water use interests in the system from July through September. The lower than normal snow pack may be depleted by early summer.
BC Hydro will provide an operational update around mid-May.
— BC Hydro