Understanding and Assessing Impacts
Climate change is expected to increase the frequency and magnitude of flooding, as precipitation patterns change and sea levels rise. Throughout the last 10 years, increased flooding in the Courtenay River system has demonstrated local vulnerabilities, and the need to assess and improve existing levels of flood protection. Flood events in 2009, 2010 and 2014 affected key transportation corridors, Lewis Park, the Ryan Road commercial area, and other private and public properties.
In response to the flood events in 2009 and 2010, the City conducted a Flood Management Study in 2012/2013, funded by a grant from Emergency Management BC. This study included an analysis of flood flows and tide levels at various flood return-periods concluding that peak flood levels could increase by 1.1m and 2.4 m by 2100 and 2200 respectively, and that storm surge peaks could increase by 15% by 2100 and an additional 15% by 2200. Flooding tends to occur in the downtown core with flood events greater than 1:20 years. Preventing damages from present-day and far greater 1:200 year flooding events will take a concerted large-scale, community-wide effort. The figure below depicts 2014 flooding in the downtown area.
The City experiences multiple flooding scenarios including those resulting from:
- High tides / storm surges coming inland,
- High water flows coming downstream as a result of precipitation, and
- River flows influenced by BC Hydro dams
These events can happen simultaneously during winter months or individually. Practically, this means that flooding can come from upstream or downstream of the business district. Orthographic information suggests that the flow of the river has been constrained and diverted from its historical trajectory. This may contribute to the scale and nature of the flooding and also present options for its relief.