Abstract:
Bias and scarce distribution of climate station along with high elevations are significant obstacles for reliable appraisal of distinct hydro-climatic regime of Chitral basin for devising future management and engineering policies. Here in our examination, we have evaluated the impact of hydrologic and climatic changes on basin by appraising the modern gridded dataset reanalysis ERA5 Land and IMERG V06 satellite reference by reconciled Dahri et al. 2018. Gridded precipitation dataset were cross validated by Dahri et al. 2018 precipitation addition to model flow simulation data derived by ARC-SWAT for selecting suitable and reliable product for future climate change analysis. The ERA5 Land has overall provided the best estimate in both precipitation and flow simulation counter to IMERG V06. Also, statistical evaluation of uncorrected precipitation data was able to detect spatial biases in products across the Chitral. Still, ERA5 Land retained the upper hand contrary to IMERG V06. For future climate change ERA5 Land was recommended, and future climate series was devised based upon the future projection of RCP4.5 and RCP8.5 derived using GCM MIROC5. The result of the temperature, precipitation and flow reveal the increase in average temperature up to 2.4°C and 4.34°C for RCP4.5 and RCP8.5 while for precipitation, analysis seems to suggest decrease up to -10.75% and -29.73% in respect of RCP4.5 and RCP8.5. Flow measurement have interestingly shown the increment of 2.40% and 0.64% for RCP4.5 and RCP8.5. In consideration of overall inferences, reduction in average precipitation and increment in flow suggest high stress over the snow and glaciated regions as implicit source of water considered during modelling additionally this statement is also supported by the decline in recession time of flow presumably by snow during less frequent periods, which is shown in FDC. FDC show RCP8.5 scenario is the foremost extreme to cause frequent flooding and drought conditions.
