Squamish Integrated Flood Hazard Management Plan

Project Highlights

Squamish, BC enjoys a spectacular natural setting that supports economic and recreational opportunities but also exposes the community to an array of flood hazards.  In 2014, the District of Squamish retained Kerr Wood Leidal Associates (KWL) to complete a ground-breaking, three-year Integrated Flood Hazard Management Plan (IFHMP).  The integrated assessment considered how different responses to different sources of flooding could affect each other, the community, and the environment.

KWL reviewed the District’s existing flood hazard management program, completed detailed river and dike breach modelling, and developed new strategies and tools for managing coastal and river flood risk.  A new joint probability approach to coastal flood assessment provides more accurate flood level estimates that should save millions of dollars in mitigation costs over the life of the plan.

New tools and approaches allowed KWL to account for a dike breach occurring at any location along the dike, despite budget constraints that limited modelling to a small number of scenarios.  The high-resolution two-dimensional floodplain model supports detailed analysis of potential hazards along evacuation routes.  Its simple yet comprehensive assumptions about future development conditions and climate change ensure that floodproofing targets will remain constant as the community evolves over time.

The resulting IFHMP incorporates the latest flood management guidelines and best practices available, providing Squamish with a blueprint for long-term planning.  It is BC’s first comprehensive Integrated Flood Hazard Management Plan and should serve as a template for other communities seeking to mitigate their flood risks.