Climate Change Impacts on Water Resources: Coupling Glacier and Hydrological Models for the Vakhsh River

Keywords: Climate change; CWATM; OGGM; Vakhsh River Basin, Aral Sea

This paper presents a coupled large-scale glacier and hydrological and water resources model for scenario-based analysis of possible river regime alteration under climate change.  The proposed framework utilizes the Open Global Glacier Model (OGGM) v1.5.3 and the large-scale Community Water Model (CWatM) V1.08. The coupled model integrates glacier dynamics, precipitation, temperature, and runoff to predict streamflow and water storage changes by 2100. The analysis focuses on the Vakhsh River Basin, a key tributary of the Amu Darya, one of Central Asia's most significant transboundary rivers. This basin encompasses the Pamir Mountains and the Fedchenko Glacier, the largest glacier in the world outside the polar regions. The Pamir Mountains provide water to the arid region extending to the Aral Sea and help mitigate seasonal water shortages by melting snow, glaciers, and permafrost. However, the impact of climate change on the Pamir cryosphere remains poorly understood due to a lack of measurements in the past several decades. Our findings underscore the importance of considering glacier dynamics in water resource management, especially under future climate extremes, and suggest strategies for sustainable management in glacier-fed basins. The uncertainties in glacier-sourced runoff associated with inaccurate precipitation inputs highlight the need for the continued attention and collaboration of glacier and hydrological modeling communities, emphasizing the urgency of this research. The study provides valuable insights into potential changes in inflow to the under-construction Rogun Dam in Tajikistan. The findings are expected to aid in addressing future operational conditions of existing reservoirs, such as Nurek and Sangtuda, located downstream of the Rogun Dam, and assess water availability for irrigation in downstream countries.