Vulnerability and risk assessment for the management of changing water resources

Abstract:

Despite major concerns for the impact of climate change on water resources, conventional assessment methods depend on a cascade of climate, downscaling and hydrological models, each of which embodies large uncertainty. We suggest that there is a need to revisit current assessment frameworks and that alternative approaches based on analysis of system vulnerability to potential change can not only provide improved insight into the response of water resource systems to future conditions, but also quantify the corresponding risks.

We use the rapidly warming Saskatchewan River Basin in western Canada to demonstrate that a simple characterization of the flow regime can lead to powerful and easily visualized analysis of the vulnerability of a complex water resources system to likely scenarios of change. Furthermore, conventional analyses and their associated uncertainty can be mapped onto the visualized vulnerability domain. We extend this analysis to include a risk-based approach to hydro-economic performance, in which probability distributions are derived as a basis for evaluation and comparison of alternative scenarios of development and/or adaptive management. We conclude with a review of strengths, weaknesses and technical challenges in moving forward with this new risk-based framework.