Climate-Resilience of Dams: Canadian Perspectives and Design Flood Estimation Guidelines

Canada has a long history of recurrent flooding, which has resulted in significant damage and large government disaster assistance disbursements. The most expensive flood in Canada was the 2013 Alberta flood, which resulted in total estimated losses of over five billion dollars, according to the Canadian disaster database. There is an increasing body of literature, suggesting that future climate change will alter precipitation and streamflow characteristics, snowpack, and snowmelt timing and magnitude. Extreme inflows that exceed dam discharge and storage capacity can lead to dam breach, posing significant risks to lives and properties on the downstream. Dams constructed decades ago are specifically vulnerable to unprecedented flood events. Therefore, in addition to other actions, an important step for enhancing and assessing climate-resilience of dams is to develop climate change informed approaches for estimating design floods and associated guidelines. For the development of design flood estimation guidelines, a variety of literature was explored, including journal articles, national and international guidelines, technical reports, and documents pertaining to regional climate change and catastrophic events. In addition, outcomes from a number of targeted dam vulnerability assessment case studies, involving development of physics-informed non-stationary flood frequency relationships and flood envelop curves, were also considered. Through a systematic review of traditional design practices, careful examination of regional climate change vulnerabilities, and outcomes of targeted dam vulnerability assessment case studies, it was realized that a variety of approaches will be required to ensure future climate-resilience of dams of all sizes, ranging from low-risk small dams to high-risk large dams. Therefore, traditional design flood estimation methodologies need to be innovated, following new design philosophies, advances in climate change science, and improved understandings of regional flood generating mechanisms. This presentation will discuss the steps taken to develop design flood estimation guidelines and the outcomes of various research activities, including the development of physics-informed non-stationary flood frequency analyses and creation of regional flood envelop curves to support design of critical water infrastructure.