The influence of a rock glacier on the riverbed hydrological system

Abstract. Climate change is accelerating cryosphere degradation in mountainous regions, altering hydrological and geomorphological dynamics in deglaciating catchments. Among cryospheric features, rock glaciers degrade more slowly than glaciers, providing a sustained influence on water resources in alpine watersheds. This study investigates the role of a rock glacier interacting with the Shár Shaw Tagà River (Grizzly Creek) riverbed in the St. Elias Mountains (Yukon, Canada), using a unique multimethod approach that integrates hydro-physicochemical and isotopic characterization, drone-based thermal infrared (TIR) imagery, and visible time-lapse (TL) imagery. Results assess that rock glaciers, due to their geomorphic properties, can constrict riverbeds and alluvial aquifers, and control shallow groundwater flow, leading to notable changes in channel structure and groundwater discharge. These disruptions promote downstream cryo-hydrological processes by facilitating aufeis formation and modifying the physicochemical properties of streamflow. Additional findings highlight the critical role of rock glaciers and proglacial systems in connecting mountain cryosphere and deep groundwater systems, with consequent implications for mountain hydrology and water resources.