Quantitative risk management process for debris flows and debris floods: lessons learned in Western Canada

Abstract

Debris flows and debris floods are common in mountainous regions of Western Canada, but there is no provincial or national standard for debris-flow/flood hazard or risk management. Instead, each local government manages hazards in its own way. Quantitative Risk Management (QRM) is being increasingly adopted, largely due to the effort of practitioners promoting its use. QRM uses numerical estimates of risk parameters to help risk managers within local government answer the following questions: Are present and future residents of my community safe enough? Is debris-flow/flood protection needed? How much should my community invest in debris-flow/flood protection? After roughly a decade of application, the benefits and challenges of QRM are emerging. This paper presents examples of the QRM process applied to debris-flow/flood risk management for communities, with a focus on debris-flow/flood mitigation decision making and remaining challenges.