Ski tourism as land use change: Assessing impacts on Alpine surface runoff generation

Ski slope development represents one of the most intensive land use and land cover changes (LULCC) in Alpine environments, involving large-scale soil disturbance, vegetation removal, and terrain modification. While these transformations are evident, their consequences for hydrological regimes remain poorly quantified.

We analysed more than 20 years of artificial rainfall simulation data from 74 experiments conducted in 12 Alpine ski regions. Surface runoff generation on ski slopes was directly compared to adjacent reference areas with comparable environmental characteristics, allowing robust attribution of observed differences to ski slope development. We complement this experimental design with random forest regression to identify the key site characteristics that most strongly control runoff generation on each surface type.

Surface runoff coefficients on ski slopes (median 0.57) were approximately six times higher than on reference areas (0.09), indicating a substantial reduction in infiltration capacity following ski slope development. Model results indicate contrasting hydrological controls: soil properties and land use are most important for reference areas, while geological factors dominate on ski slopes.

These findings suggest that land use change shifts hydrological sensitivity from near-surface conditions to substrate and geomorphic context. By integrating long-term experimental data with machine learning, this study provides a framework to quantify land use impacts on Alpine hydrology and to support sustainable land management and planning in mountain environments.