Climate Change Impacts on Water Sensitive Urban Design Technologies

Water Sensitive Urban Design (WSUD) technologies are green infrastructures that aim to restore the hydrological balance of urban catchments. This research aimed to investigate the impacts of climate change in an infiltration-based WUSD, called soak-away, at residential allotments from a Village Green townhouse complex, Aldinga, South Australia. To do so, specific rainfall data for the study area were collected and then projected for the years 2030, 2060 and 2090, considering the RCP 4.5 and 8.5 pathways. The projections were determined using CSIRO's Climate Futures tool, as suggested in the Australia Rainfall Runoff guidelines. The rainfall's projected impacts on the soak-away performance and dimensions were analyzed in terms of the Village Green catchment conditions, using the MUSIC model and stormwater source control principles. When analyzing the RCP 8.5 pathway for different years, the distinction in soak-away design was more evident and was directly related to the peak flow percentage of the increase obtained in the MUSIC model. On the other hand, for RCP 4.5, the years 2030 and 2060 presented the same characteristics, and 2090 had an equivalent rainfall projection as RCP 8.5 2030. Regarding treatment effectiveness, the soak-away dimensions reached almost 100% of pollutant removal, which indicates that the approach might oversize the system. Nonetheless, when comparing all soak-away designs, the recommended soak-away system tends to be conservative due to the uncertainties surrounding future climate projections.