Streamflow Predictions of Hunza and Gilgit River Basins and its Impact on Hydro-Power Generation

Abstract

The alteration of regional water availability due to forthcoming climatic changes will stand as a critical societal impact. These hydrological shifts will exert comprehensive influences on various dimensions of human welfare, encompassing agricultural productivity, energy consumption, flood management, provisioning of municipal and industrial water, as well as the oversight of aquatic life and wildlife. The aim of this study was to assess the snow and glacier melt contribution in overall river flows of Hunza and Gilgit River Basins using hydrological Modeling technique under current and future climate change scenarios and analysis of the consequences of climate change impacts on hydropower generation using flow duration curves. The use of (SRM) snowmelt runoff model was satisfactory to compute the daily discharges of Hunza and Gilgit rivers. Modis Mod10a1 provides daily snow cover data with 500m spatial resolution used in this study to extract region’s snow cover. Hydro-climatic data was another major input for model, for this purpose the ERA5 satellite data provided by ECMWF was used to extract temperature and precipitation values on daily basis. After calibration of model for years 2009 and 2010, it was successfully validated for years 2013-2014. The Nash-Sutcliffe model efficiency coefficient was ranging from 0.85 to 0.89 and difference in volume was ranging from 1.09% to 2.91%. The shared socioeconomic pathways SSP2-45 and SSP5-85 scenarios of the Coupled Model Intercomparison Project 6 (CMIP6) was used to analyze the impacts of climate change on overall stream flows of Gilgit and Hunza river catchments. The application of future climate change scenarios suggests that by increasing mean temperature values the streamflow will increase 44% under SSP2 and a huge increase of 105% as 21st century reaches to end. The flow duration curves show the 62% increase in power generation for 50% exceedance of time by using estimated stream flows. The findings presented here can be used with any type of stream and hydrological system at the power plant.