Characterizing the Groundwater Flow Regime in a Landslide Recharge Area Using Stable Isotopes: A Case Study of the Urbas Landslide Area in NW Slovenia

Slope stability strongly depends on the prevailing hydrological and hydrogeological conditions. The amount intensity of precipitation changing groundwater levels are important landslide triggering factors. Environmental tracers, including chemical stable isotope compositions groundwater, were used to gain insight into dynamics Urbas landslide. is situated in a mountainous area with steep slopes high poses risk for safety Koroška Bela settlement that lies downstream. analyses oxygen-18 (18O) deuterium (2H) estimate mean residence time average altitude recharge area. This information will help plan prioritize remedial measures aiming reduce body and, thus, lower transformation sliding material debris flow. results analysis samples taken from springs piezometer show Ca–HCO3 water type. indicates low water–rock interaction composed Upper Carboniferous Permian clastic rocks points upper laying carbonate scree deposits as main Water ?18O ?2H collected rain gauge, springs, over two-year period (2018–2020). estimated at sampling was approximately 1700 1800 m a.s.l. 2–5 months.