Effect of the construction of ski runs on changes in relief in a mountain catchment (Inner Carpathians, Southern Poland).

In the last decade increasing popularity of winter tourism in mountain areas in Poland influenced development of ski infrastructure. This type of human activity may induce changes in mountain relief. The purpose of the study was to quantify ongoing change patterns via: (i) a determination of spatial and quantitative changes in catchment covered by new ski runs, (ii) a determination of the effect of new ski runs on the rejuvenation of relief in valleys adjacent to ski runs, (iii) an identification of changes in the surface runoff pattern before and after the construction of ski runs. The research was carried out in the Remiaszów catchment on two ski runs (southern Poland). Airborne Laser Scanning (ALS) data from 2013 and 2016 were also used in the study along with Terrestrial Laser Scanning (TLS) data from 2015. LiDAR (Light Detection and Ranging) point clouds were interpolated to create multi-temporal DEMs and then these DEMs were used to derive DoDs. These were used to identify erosion and accumulation zones. The Convergence Index (CI) was used to determine the direction of surface runoff. The largest changes in relief were observed in areas with ski runs, with ski run E lowering an average of 0.07m (±0.03m), and ski run N an average of 0.12m (±0.03m). The entire area lowered about 0.02m. The construction of new ski runs resulted in a rejuvenation of denudation valleys located in the vicinity of existing ski runs. Valley incisions reaching 1.5m (±0.15m) were observed. Both the convergence and divergence zones for surface runoff were identified, which made it possible to show changes in the geometry of flow direction. The identification of these sites may help forecast erosion and deposition zones. In general, this may make it easier to identify areas substantially susceptible to relief change.