Environment Minister Barry Penner says recent heavy rainfall in many parts of the province has eased some of the water supply concerns that had developed earlier this spring in many communities.
However, Penner says there are still areas where the water supply is low and with the summer season approaching, he encourages British Columbians to conserve water to protect water sources and help manage water demands.
Significant rainfall during the month of May occurred in many parts of the province, somewhat easing the water supply challenges that had developed this spring in some areas as a result of the low winter snowpack. Large rivers are continuing to rise slowly and are anticipated reach their peak water levels near mid-June, depending on weather conditions in June. Many smaller rivers have already experienced their freshet peaks and have been declining. In some cases, particularly in the Southern Interior and the South Coast, May rainfall has produced notable increases in water levels and lake levels.
At the peak of the snow accumulation season near the end of April, snowpacks were below normal or well below normal across most of the Interior and above normal on the South Coast and Vancouver Island. Since then, snow-melt has been proceeding steadily, although at a slower than normal pace due to the cool weather of the past month. All low- and mid-slope snow has melted, and only high-elevation snow remains to melt. With the precipitation in May, some new snow accumulations occurred at a few high elevation sites across the province, but most high-elevation measurement sites continued to decline steadily. At some high-elevation locations in the Interior, the snowmelt has been delayed by two to three weeks as a result of the cool May weather. This delay prolongs the snowmelt period into mid- and late June.
Water Supply Outlook:
Current conditions indicate a likelihood of well-below-normal freshet runoff, and low risk for freshet flooding in the major river basins (Fraser, Thompson, Skeena, Bulkley, Nass, Peace, Liard, etc.). Water levels on large rivers throughout the province have been rising, with local variations due to changes in weather. All rivers are currently well below flood level. With the cool weather and prolonged snowmelt, the freshet peaks on the major rivers are expected to peak near mid-June. Many smaller rivers experienced their freshet peaks in May and have been receding.
But rainfall during May has caused the water levels on many of these smaller rivers to rise. The delayed melt and the May rainfall have been beneficial to summer water supply, extending runoff into the beginning of the summer season.
The well-below-normal May 1 snowpack conditions across much of the Southern Interior (Okanagan, Nicola, Kettle, Similkameen, West Kootenay, East Kootenay) resulted in potential for low stream flows and water-supply challenges to develop during the summer. These areas were classified as Drought Level 3 (very dry conditions) on May 1. The widespread and above- normal rainfall during May in these areas has significantly increased the amounts of water into rivers, lakes and reservoirs and has helped alleviate some of the water supply concerns. As a result, they are now being classified as Drought Level 2 (dry conditions).
These areas, and much of the Central and North Interior (including the South Thompson, Cariboo, Upper Fraser, Skeena, Nass, Bulkley and Peace), have early indications of potential low stream flow and summer water supply shortages. Voluntary water conservation and planning at the local level is still urged.
One area in the Cariboo near Williams Lake, Chimney Lakes, is particularly dry. This watershed was recently put on an alert indicating that regulatory action under the Water Act may be necessary. Near-normal June and July rainfall will be needed to further reduce water supply concerns in most of B.C.