Snowmelt Contribution to Seasonal Baseflow Dynamics: Multi-Catchment Analysis of Hydrological Responses in Mountain Catchments

Mountain catchments serve as critical water towers, where the interplay between snow dynamics and baseflow plays a fundamental role in regulating water availability across both seasonal and interannual timescales. While current mesoscale studies have challenged traditional conceptualizations of baseflow and revealed diverse landscape roles, the mechanisms linking snow conditions to baseflow generation across elevation gradients remain poorly understood. This study examines these mechanisms using the HBV model applied to 93 catchments across Czechia and Swiss mountain regions (1965-2019). Our preliminary findings revealed elevation-dependent patterns in baseflow generation, with increases in annual and summer baseflow fractions during periods of increased snowfall. Snow water storage (SwS) emerged as a critical buffer in high-elevation catchments, maintaining stable baseflow patterns despite changing climate conditions. We identified distinct temporal lag effects between snowmelt and baseflow generation that vary with elevation, leading to significant differences in seasonal flow dynamics between lower and higher elevation catchments. These insights advance our understanding of mountain snow hydrology and offer valuable implications for water resource management in snow-dominated regions under increasing climate pressure.