Wildfire
Large forest fires in the Greater Victoria Water Supply Area are considered a significant risk to water quality. A large-scale fire has the potential to increase the amount of surface erosion and nutrients entering the reservoir, which could dramatically affect water quality by stimulating algal blooms and increasing turbidity and colour.
Ignition of forest fires results from two sources. First, lightning associated with natural thunderstorm activity ignites fires. In general, thunderstorms in the Pacific Northwest are considered mild compared with other parts of Canada and the United States. The second source of ignition are those fires caused by humans both accidentally or intentionally. These types of ignitions can be associated with industrial activities, trespass, including hunting, fishing and camping, or can be deliberately set through arson. As the population of Greater Victoria grows and moves closer to the boundaries of the Greater Victoria Water Supply Area, there is an increasing risk associated with human-related fire ignitions.
It is important to note that lands in the Greater Victoria Water Supply Area are not managed in isolation of the adjacent network of land ownership, and that fire management efforts are co-ordinated between the Water Department and outside jurisdictions. The Greater Victoria Water Supply Area is part of a complex network of private and public lands that have significant economic and social value. A large fire that occurs within any portion of this network has the potential to threaten human safety and destroy valuable property and resources elsewhere in the network.
Fires in the Water Supply Area have the ability to vary greatly in severity and size. Both fire severity and fire size are a function of the quantity of fuel, topography, and climate. Fires can range in size from <1 ha to 10,000 ha depending on the conditions of the fire environment and the capability of fire suppression resources to detect and act expediently to suppress the fire. Under conditions of extreme fire behaviour, suppression resources may be incapable of containing a given fire. Additionally, multiple fire starts may result from a lightning storm providing a situation where suppression resources are limited in their capacity to quickly suppress all resultant fires. Typically it is these conditions that result in large landscape-level fires.