Climate Impacts on Water Resources in a High Mountain Catchment: Application of the Open-Source Modeling Workflow MATILDA in the Northern Tian Shan

Abstract. Applied glacio-hydrological modeling is crucial for the integrated water management strategies needed to effectively mitigate climate change impacts on freshwater resources fed by high mountain areas. We demonstrate the application of MATILDA-Online, an open-source toolkit for modeling glacier evolution and water resources in glacierized catchments. We showcase it's capabilities in data-scarce environments on a catchment in the Tian Shan Mountains in Kyrgyzstan, and outline a four-step multi-objective calibration strategy that integrates glacier surface mass balance, snow water equivalent, and discharge observations. Projections indicate severe glacier mass loss by 2100, significant reductions in runoff, and a shift toward earlier peak flow driven by snowmelt. The main sources of uncertainty in the catchment water balance are biases in precipitation data and inconsistencies in glacier mass balance datasets, highlighting the importance of adequate monitoring. Despite limitations in the model's representation of spatial variability and dynamic processes, MATILDA provides easy access to sophisticated modeling and can be a valuable tool for bridging the gap between advanced glacio-hydrological science and practical water resource management.