Water Balance Assessment under Different Glacier Coverage Scenarios in the Hunza Basin

Abstract

The potential impact of glacier recession on river discharge from the Hunza river basin was estimated as an indicator for downstream changes in the Indus river system. The J2000 model was used to analyze the water balance in the basin and simulate the contribution of snow and ice melt to total discharge at present and under three scenarios of glacier recession. Precipitation was corrected using virtual weather stations created at a higher elevation and a precipitation gradient. Snowmelt from the whole basin contributed, on average, 45% of the total river discharge during the modeling period and 47% of the ice melt from the glacier area. Total ice melt declined by 55%, 81%, and 96% under scenarios of glacier recession to 4000, 4500, and 5000 masl, respectively. The contribution of ice melt to river discharge decreased to 29%, 14%, and 4% under the three scenarios, while total discharge from the Hunza river decreased by 28%, 40%, and 46%. The results suggest that glacier recession in the Hunza river basin could have serious implications for downstream water availability. Understanding melt contribution in the basin based on ongoing and projected future climatic change can play a crucial role in future water resource management.

Predicting hydrologic responses to climate changes in highly glacierized and mountainous region Upper Indus Basin

“…Shrestha & Nepal [ 18 ] reported that out of the total discharge, 45% and 47% was contributed by snowmelt and glacier ice melt respectively from Hunza basin. Shrestha et al .…”

“…The precipitation in the Himalaya region remains poorly defined due to lack of reliable rainfall networks [ 18 ] and it does not provide a true depiction of the area particularly for elevation zones. Data for longer duration is only available at some stations because functioning of these stations starts after the mid-1990s.…”

“…The datasets were corrected by incorporating the orographic effect and improving the influences induced by higher elevation, available runoff data, glacier mass-balance and actual evapotranspiration. The precipitation data are the most important inputs in modelling studies of mountainous regions [ 18 , 23 ], and the results are strongly affected because of uncertainty in spatial distribution [ 22 ]. Furthermore, in this study, the elevation bands were used for better representation of the melt processes and assigned distributed melt parameters to different bands and sub-basins.…”

Space-time variability of soil moisture droughts in the Himalayan region

“…To support more complex data processing tasks that typically occur when processing large datasets or during model calibration, the framework provides parallel computing functions (Kralisch and 145 Fischer, 2012) and service-based simulations on remote computer servers. The J2000 model has been widely used in river catchments around the globe including in the Himalayan region (Eeckman et al, 2019;Nepal et al, 2017;Shrestha and Nepal, 2019).…”

Assessment of the Impact of Climate Change on Snow Distribution and River Flows in a Snow-Dominated Mountainous Watershed in the Western Hindukush–Himalaya, Afghanistan

“…Climatic variability is much greater in the Hindukush-Himalaya (HKH) mountainous region of Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal, and Pakistan, than in other parts of the world [2,3]. Glaciers are one of the most important indicators of climate change [4,5], and the HKH region is host to some of the world's largest glaciers [6][7][8], which are the major water source of the Indus, Brahmaputra, and Ganges rivers [9,10]. These river basins are extremely sensitive to both spatial and temporal changes in climate [3].…”