Spatio-temporal Snowmelt Dynamics and Hydrological Response in an Alpine Catchment

Abstract:

Spring snowmelt is a critical resource in mountainous and alpine regions. Accurate representation of snowmelt processes in hydrological models is thus necessary for water managing purposes, flood prediction and resource allocation, among others. This task, however, remains a challenge because of the complexity of the interactions between the different controlling processes. In this study, we combine local and distributed measurements of snowpack ablation at the Dischma river basin (~40 km²) near Davos, Switzerland, to study relationships between snow ablation, basin morphology, subsurface water routing and watershed response with the overarching objective of improving snowmelt representation in distributed hydrological models. Weekly terrestrial laser scans were performed to reveal spatial ablation patterns at slope scales throughout the melting season. Four local stations installed in representative slopes are used to continuously monitor snowpack temperature profiles, snowpack output, and soil moisture throughout the melting season. Basin response was captured at three stream gages, one at the outlet and two at smaller tributaries within the basin. Results for the 2015 spring season will be presented, including 9 weekly terrestrial laser scans and the continuous snowmelt and streamflow measurements. These measurements are compared to modeling results from the spatially distributed and physically based Alpine3D model to evaluate model accuracy and detect areas that require improvement in model representation of snowmelt processes. Insights of these comparisons and future directions will be discussed.