Glaciers in the Hindu Kush Himalaya (HKH) are important freshwater resources. Glacier recession may lead to a significant decrease in summer runoff. This study focuses on Afghanistan in the western Himalayas with an arid to semi-arid climate, where, despite strong societal and ecosystem dependance upon mountain water resources, the contribution of glacier melt is poorly known. This study used a new conceptual precipitation and ice melt-runoff model to assess current and future streamflow, taking into account the effects of debris-covered ice. Three catchments with varying glacier cover are considered: Sust (4,609 km2, 15.6% glacier cover) in eastern Afghanistan; the Taqchakhana (264.4 km2 area, 2.8% glacier cover) in northern Afghanistan; and the Bamyan (325.3 km2, 0.7% glacier cover) in central Afghanistan. Results identified different annual hydrological regimes, with glacier runoff dominating Sust (76%), rain and snow runoff dominating Taqchakhana (50%), and baseflow dominating Bamyan (61%). Future climate scenarios under RCP 2.6 predict an increase in mean annual glacier runoff until 2050, followed by a decline due to temperature stabilization and cooling in Sust and Taqchakhana. Meanwhile, Bamyan's runoff is predicted to decrease throughout the 21st century. Under RCP 8.5, a more pronounced glacier runoff increase is projected in Sust and Taqchakhana.

  • Applies a new ice melt-runoff model including a debris-covered ice representation.

  • Shows glaciers' influence on summer streamflow for data-scarce catchments.

  • Suggests climate change impacts water availability in diverse glacier-sized catchments.

  • Illustrates debris-covered ice impact on glacier runoff.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licence (CC BY 4.0), which permits copying, adaptation and redistribution, provided the original work is properly cited (http://creativecommons.org/licenses/by/4.0/).

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