Author(s): Asif Khan; Mujahid Khan
Keywords: No keywords
Abstract: Millions of people rely on river water originating from snow and ice melt in the HindukushKarakoram-Himalayan (HKH). One such basin is the Upper Indus Basin (UIB), where snow and glacier melt contribution is more than 80%, therefore is highly susceptible to global warming and climate change. Accuracy of available hydro-climatic studies’results are vital for future precise policy making and sustainable water resource development. Therefore, this research evaluates accuracy of various ISI-MIP and FAO hydro-climatic studies results, during 1985–1998 and 1961–1990 respectively, for six sub-basins of the UIB. This research evaluates accuracy of bias corrected five GCMs’precipitation data sets, input of ISI-MIP hydrological models, and CRU data, input of FAO hydrological model, all based on basin-wide mass balance assessment. First the input precipitation data sets have been evaluated followed by comparison of modelled and measured flows. Basin-wide mass balance assessment show that all precipitation data sets used in ISI-MIP and FAO hydrological models significantly underestimate precipitation in the UIB, particularly in the Karakoram sub-basins. All ISI-MIP (6) and FAO hydrological models provide consistent but significantly low modelled flows (<50%) as compared to the measured records in all sub-basins, except for the Kharmong basin. FAO water scarcity shows severe water scarce conditions in the UIB. FAO and ISI-MIP under-estimated modelled flows (and water scarcity) are artefacts of use of under-estimated precipitation data use. This study shows that results of ISI-MIP and FAO are not true representative of hydro-climatic conditions in the UIB, therefore cannot be used in precise and accurate policy making and water resource management.