Abstract ID: 3.9383 | Accepted as Poster | Poster | TBA | TBA

Mountains are significant water towers, with generally steep gradients, seasonal snow-driven hydrology, and elevation-dependent climate zones that impact different hydrological responses. Understanding runoff mechanisms in mountain catchments is critical, especially given the context of climate change. Snowmelt runoff dominates mountain catchments when compared to liquid precipitation, highlighting its vulnerability to changes in snow accumulation and early snowmelt. The interactions between snow and baseflow dynamics are critical in managing water availability over seasons and interannual periods. However, there is a gap in relating snow conditions to baseflow across elevation gradients, as current mesoscale research have questioned traditional baseflow concepts. This work aims to address this gap by utilizing the HBV model applied to 93 catchments across Czechia and Swiss mountain regions (1980-2020). The model was modified with a non-linear function, reducing outflow to two boxes for improved fast flow and baseflow representation, better capturing storage-discharge dynamics in snow-dominated catchments. 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.