The Land Use Portfolio Model Applied to Flood Hazard Analysis in Squamish, British Columbia

The Transboundary Project is a cooperative effort between Natural Resources Canada (NRCan) and the US Geological Survey to provide a scientific basis for natural hazards management and mitigation along the Pacific coast boundary between the United States and Canada. Squamish is a coastal community about one hour north of Vancouver, in a zone of mountainous topography, and frequent rainfall. This project uses data compiled by Natural Resources Canada to estimate flood hazard in Squamish.

Historically, Squamish has had instances of severe flooding, occurring on average of every one or two decades. The population is expected to double from approximately 15,000 in the near term. Urban Planning for the future, needs to take into consideration flooding

Major flood events have occurred in 1921, 1940, 1955, 1968, 1975, 1980-1984, 1989, 1991, and 2003, and are tracked by peaks in the hydrograph.

A good plan to accommodate growth directs future urban development away from debris flow hazard and away from the areas of most severe flood hazard to an area of lesser flood hazard. This plan exchanges development in a hazardous area with conservation. The planning area includes both a green space and a development area. The green space is reserved for conservation and recreation, and is subject to flooding. The development area is set aside for current and future building.

Planning area with spaces reserved for conservation and development. The topography suggests vulnerability to flood hazard.

This phase of the project considers preliminary estimates of flood damage and loss in the planning area; sources of uncertainty that arise from data scale and precision, and vintage; and suggests improvements in the data to provide better guidance for planners. One improvement would be to base the flood depths on LIDAR. This would provide a more precise description of local flood plain topography that could predict sedimentation or changes in the water courses that are not reflected in the current elevation data.

Publications:

Bernknopf, R.L. et al, 2006, The influence of hazard models on GIS-based regional risk assessments and mitigation policies, in International Journal of Risk Assessment and Management, Vol. 6, Nos. 4/5/6, pp.369-387.

Dinitz, L.B. et al, 2005, A GIS-based decision support system for evaluating alternative natural-hazard mitigation policies [abs.]: 2005 GeoTec Event, Annual Conference, Vancouver, British Columbia. Feb. 13-16, 2005.

Wein, A.M. et al, 2005, Modeling natural hazards in Squamish, British Columbia: A workshop for planners, emergency preparedness officers and stakeholders in Squamish, September 22, 2005.

Wein, A.M. et al, 2006, Analyzing natural hazard risks for sustainable development of Squamish, British Columbia, Canada, European Geosciences Union General Assembly, Vienna, Austria, April 7, 2006.