Evaluating the impact of climate change on stream flow: integrating GCM, hydraulic modelling and functional data analysis

Global climate change is an unequivocal reality that is immensely impacting the available water resources in many regions around the globe. For sustainable water resource management, the present research aims to evaluate the impact of climatic change on streamflow using both the global climate change and hydraulic models. This research presents a novel approach of applying functional data analysis (FDA) to highlight the commonalities and differences between the outcomes of various models for streamflow analysis. Observed temperature, precipitation and streamflow data from 1985 to 2014 of Astore catchment in the Upper Indus River Basin, in Pakistan, were used for this purpose. The precipitation and temperature results of three global climate models (GCMs) were obtained under two scenarios of greenhouse gas concentration, namely RCP 2.6 and RCP 8.5. Results of precipitation and temperature obtained under climate change scenarios were subsequently used to simulate the streamflow using the Hydrologic Engineering Centre-Hydraulic Modeling System (HEC-HMS). The FDA evaluated the Euclidean distances between the streamflow data predicted by various models. The diverging trend found in these distances identified some degree of dissimilarities in the streamflow results. The simulations manifest that the streamflow will increase in the study area (Astore) till 2070, while it is expected to decline in the distant future. The concerned agencies can adopt rational water resource management strategies based on the predicted streamflow in the region.