Modeling the Impact of Climate Change on the Flow Regimes of River Sindh of Kashmir Valley

Climate change and its uncertainties may have profound impact on the hydrological regimes. In the  study, the authors have modeled the impact of changing climate on the hydrological regime of the river Sindh of Kashmir valley. The Hydrological Engineering Centre-Hydrological Modeling System (HEC-HMS) model was used to project future changes in the study area based on the Representative Concentration Pathways (RCP 4.5 and RCP 8.5) of Canadian earth system model (CanESM2) General Circulation Model (GCM) outputs. Statistical Downscaling Model version 4.2.9 (SDSM 4.2.9), which is based on linear regression, was used to downscale the maximum (Tmax) and minimum (Tmin) temperature, and daily precipitation (Pr) in the study area. The downscaled climate data indicated increase in the mean maximum temperature and the mean minimum temperature between the range of 0.4–2 °C and from 0.4 to 2.0 °C, respectively, under different RCPs. Also, under different RCPs, an increasing trend of 24 % has been detected in precipitation of the study area. Hydrologic Modeling System (HEC-HMS) was set up, calibrated (2001–2017), and validated (1992–2000) for the River Sindh, and then, discharge was projected for three future periods, i.e., 2030s, 2060s and 2090s. The simulated discharge of each period was correlated with the simulated discharge of the baseline period to find the variations in mean, median, high and low flow. Modeling results indicated these climatic changes will have a significant impact on the hydrological regime of River Sindh. It is thus impossible to plan proper management and utilization of water resource in the study area without considering the changes in the climate indicators especially temperature and precipitation.