An innovative hazard assessment for an exposed community

Cowichan Lake North Shore Debris Flow Runout Model

The steep North Shore of Cowichan Lake is part of the Cowichan Valley Regional District (CVRD), home to approximately 1,700 people exposed to potential debris flow hazards from adjacent slopes. A hazard assessment of the North Shore identified 462 historic landslides in the broader region.

Our team recommended that landslide runout modelling be conducted for debris flows and debris slides to better discretize the hazard. We used our DebrisFlow Predictor to estimate the extent of debris flow hazard to residents and properties along the North Shore. After modeling over 70,000 debris flows in the area of interest, our team was able to define a credible runout limit of debris flow hazards. We identified properties within and beyond the hazard limit and provided an estimated landslide depth and destructive potential for these properties within the potential runout zone.

The results were used to modify the zoning bylaws and identify areas within which additional geotechnical studies were required.