2019 CSCE Annual Conference - Laval (Greater Montreal)

2019 CSCE Annual Conference - Laval (Greater Montreal) Conference

A Decision-Support Tool for Assessing Climate Change Impacts on Design and Management of Urban Water Systems

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Mr. Truong-Huy Nguyen, McGill University (Presenter)
Dr. Van-Thanh-Van Nguyen, McGill University

In recent years, climate change has been recognized as having a profound impact on the hydrologic cycle at various spatial and temporal scales. The global and regional climate models have been extensively used in many studies for assessing the potential impacts. However, due to current limitations on detailed physical modelling and computational capability, these models could only provide output scenarios at macro and meso scales and on a daily time step which are ineffective to inform decision-making at the micro (or local) scales. Thus, resolving the spatial and temporal scale issues are crucial, so that local decision makers can possibly evaluate what the likely climate change impacts are, such as maximum rainfalls, at the urban or local scales. Downscaling techniques in both space and time have thus been proposed to resolve the scale discrepancy issues. Of particular importance for urban drainage system design are those procedures dealing with the linkage of the large-scale climate variability to the local-scale historical observations of short-duration extreme rainfall processes over a given urban watershed. If this linkage could be established, then the projected change of climate conditions available at global or regional scales could be used to predict the resulting change of the local precipitations and the resulting urban runoff characteristics. In this paper, a decision-support tool (hereafter referred to as SMExRain) was proposed to address these issues. The tool has been developed to consolidate the weather extreme data and to help visualize the descriptive and predictive scenarios. This software is also capable of establishing the linkage between climate projections of climate change available at large-scale to local scales (i.e. to see smaller regional impacts of climate change) with and without empirical data. The feasibility and accuracy of the tool were evaluated based on the climate simulation outputs from 21 global climate models that have been downscaled by NASA to a regional 25-km scale for different representative concentration pathway scenarios and the observed extreme rainfall data over Ontario region, Canada.