Investigation of climate change impacts on flow regime in the Lucas Creek catchment using multiple CMIP5 ensembles

Climate change is projected to affect the flow regime in urban waterways adversely. This study investigates the climate change impacts on the flow regime in the Lucas Creek catchment under three Representative Concentration Pathways (RCPs): RCP 2.6, RCP 4.5 and RCP 8.5. Flow Duration Curves (FDCs) and Indicators of Hydrological Alteration (IHA) methods are used to assess flow regime variations. Results of FDCs show a maximum rise of 370% in peak flow under RCP 4.5 however, low flow increases by 40%. Monthly streamflow increases up to 380% except for October and December. Similarly, the majority of the IHA parameters also show at least a 10% increase in their magnitudes under RCP 8.5. However, some parameters such as high pulse duration and rise rate decrease by 50% under RCP 4.5. The catchment would mainly suffer severe impact variations under RCP 4.5 and RCP 8.5 in the future.