Multi-instrumental monitoring of snowmelt infiltration in Vallon de Nant, Swiss Alps

Abstract. To gain a deeper understanding of the dynamics of the contribution of snowmelt to mountainous water cycles, it is necessary to better understand the processes controlling the infiltration of snowmelt into mountainous soils. This research uniquely combines snowmelt rate data with soil moisture dynamics, providing a comprehensive 3-year dataset. The integration of multiple measurement techniques and the estimation of the snowmelt rate through the measurement of snow resistivity offer a new perspective on snowmelt infiltration processes. The study area is located in Vallon de Nant, Swiss Alps. Measurement points are distributed at mid- to high elevations in various alpine environments. Besides demonstrating the instrumental setup, we also investigated the snowmelt infiltration dynamics in the study area. Results indicate that, although melt rates are considerably lower than soil saturated hydraulic conductivity values, the response times of shallow soil moisture and stream discharge to melt events are fast (from 2 to 5 h). At the point measurement locations, snowmelt hardly infiltrates below 30 cm. These findings highlight how the fast recession of soil moisture peaks to snowmelt may limit the capacity of mountain soils to retain water, potentially increasing their vulnerability to dry periods in the future.