Assessment of Possible Impacts of Climate Change in an Urban Catchment

Stationarity of rainfall statistical parameters is a fundamental assumption in hydraulic infrastructure design that may not be valid in an era of changing climate. This study develops a framework for examining the possible impacts of climate change on the urban infrastructure and natural ecosystems of small watersheds, and demonstrates this approach for the Mission/Wagg Creek watershed in British Columbia, Canada. Non-stationarities in rainfall records are first analyzed with linear regression analysis, and the detected trends are extrapolated to build future rainfall scenarios. The Storm Water Management Model (SWMM) is used to analyze the effects of increased rainfall intensity on design peak flows and to assess future drainage infrastructure capacity. Peak design discharges are projected to increase by in excess of 100% by 2050. In terms of impacts on the drainage infrastructure, the results of this study indicate that climate change would not create severe impacts in the Mission/Wagg Creek system.