In order to better understand the impacts of flooding in the Calgary area the IBI Group along with Golder Associates were tasked with creating a flood damage model for the City through the Flood Mitigation Options Assessment Summary. This model visually represented land which would be affected by floods ranging in size from those with a likelihood of occurring every 100 years (1:100) up to those that may occur sometime within the millennium (1:1000). While a wide range of flood sizes were considered, intentions were to address those up to a 1:200 occurrence probability. This model enabled a scenario analysis which considered flood mitigation options against various flood events. This analysis incorporated a robust cost-benefit analysis which was conducted by overlaying various hard engineering interventions onto models of a 1:200 flood scenario in the City of Calgary. Ultimately the cost-benefit analysis showed that neither hard engineering nor buyouts of land in high-risk areas alone could completely mitigate the costs of future damages. Buyouts were also seen as cost-prohibitive, further nullifying this option. The above-mentioned detailed analysis well exceeds current standards and aided in informing future flood mitigation planning and analysis.
Building flood resiliency is a top priority for the City of Calgary, following the extreme flooding event of 2013 that resulted in $6 billion in damages, including over $400 million to infrastructure. The City’s approach to reducing flood risk uses multiple lines of defence at the watershed, community and property levels. The City’s 2017 Flood Mitigation Measures Assessment Report focuses on increased protection in critical areas, such as the downtown core and neighbourhoods with high flood-risk. The plan is supported by a combination of barriers at existing reservoirs and protocols related to flood-control, and also depends on upstream reservoirs to provide a high level of flood protection.Read the Full Story