Modeling of urban hydrologic processes in the context of climate variability and climate change

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The proposed research aims at the overarching scientific question: “How to predict accurately at the urban basin scale changes in precipitation, temperature, and runoff processes caused by climate variability and climate change?” ******To address this critical question, the main challenge is to develop an “integrated climate-urban hydrologic processes modeling framework” that could accurately describe the linkages between climate variables at global or regional scales and hydrologic processes at a local site or over an urban area. This necessitates the development of downscaling procedures for linking coarse-resolution climate model outputs down to much finer spatial grids, and even virtually point values if changes in local urban processes are to be assessed. Further, the time scales required for urban hydrologic modelling are usually less than one day. Another critical issue is the current limited ability of existing climate models in providing accurate and reliable precipitation projections since these models still do not contain an adequate description of the precipitation governing processes at the relevant scales for urban areas. Hence, to develop this integrated downscaling framework, the proposed research program involves three main components: (i) Modelling of sub-daily temperature processes: a multivariate statistical model will be developed for simulating hourly temperature extremes at many sites concurrently in the context of climate change; (ii) Modelling of sub-daily rainfall processes: stochastic models will be developed for simulating sub-daily rainfall series at a single site as well as at different sites concurrently; and (iii) Modelling of urban runoff process:a decision support tool will be developed to provide an integrated linkage between temperature and precipitation models and urban runoff model. This decision support tool will be used to examine the sensitivity of runoff characteristics to the changes in rainfall and temperature extremes due to climate variability.******It is expected that results of this research will enhance our collective understanding of climate variability and their effects in urban regions, will provide essential tools for developing more cost-effective design procedures and more accurate vulnerability assessment methods, and ultimately will help policy-makers in developing appropriate adaptive strategies for effective management of our urban water systems. The proposed research deals exclusively with issues that have been received considerable attention due substantial investment involved. For instance, climate variability can stress Canada's urban water systems leading to water supply shortages or disruptions, and extreme storms and floods have often caused severe substantial property and extensive economic damages in urban areas (e.g., recent devastating floods in the City of Calgary and in the City of Toronto in 2013).