Sooke Water Supply Area is located northwest of the City of Victoria in the Sooke Hills and supplies water to approximately 350,000 people in Greater Victoria. Sooke Lake Reservoir lies within the boundaries of the Greater Victoria Water Supply Area, land that is owned and protected by the Capital Regional District (CRD). In spite of the large watershed area, storage in Sooke Lake Reservoir is limited and we depend on winter water stored in the reservoir to supply our needs throughout the year.
Sooke Lake Reservoir has been in active use since 1915 and supplies almost 100 percent of the water currently used by supply system customers. Sooke Lake Reservoir has a total volume of 160.32 million cubic metres, of which 92.7 million cubic metres are useable for water supply. Useable storage in the source water reservoirs in the Greater Victoria Water Supply System is the volume of water that is available to the water supply intake.
The Sooke Water Supply Area consists of 8,620 hectares of forested terrain. Two long ridges on either side of the reservoir define the watershed. Sooke Lake Reservoir can also receive water from the 546 hectare Council Lake watershed through a diversion pipeline and channel. The main tributary to the Sooke Lake Reservoir is Rithet Creek. It supplies about 25% of the water entering the reservoir. The drainage area of Rithet Creek is about 1,740 hectares. The 100 year peak flow is about 44.7 cubic metres per second or 850 million gallons per day. The low flows in Rithet Creek are about 0.05 cubic metres per second (one million gallons per day) in June to September. These flows can drop considerably in the driest summers.