Transport of sediment particles from the source of their origin to a deposition area is of utmost importance, especially in catchments very prone to erosion. Especially, since future climate changes are predicted to enhance severity of the sediment transport issues, particularly in catchments with dammed reservoirs, which capacity and water quality can be extremely altered. In the current study we tracked, with a monthly step, two mineral and one mineral/organic sediment fraction delivered from the Carpathian Mts. catchment (Raba River) to the drinking water reservoir (Dobczyce). This was possible by combining SWAT and AdH/PTM models on the digital platform - Macromodel DNS. Moreover, we have applied a variant scenario analysis including RCP 4.5 and 8.5, and land use change forecasts. The results highlighted the differences between the two analyzed hydrological units and showed large variability of the sediment load between months. The predicted climate changes will cause a significant increase of mineral fraction loads (silt and clay) during months with high flows. Due to the location and natural arrangement of the reservoir, silt particles will mainly affect faster loss of the first two reservoir zones capacities, which is consistent with their intended use as traps for larger fractions. The increased mobility of the finer particles (clay) in the reservoir may be more problematic in the future. Mainly due to their binding pollutant properties, and the possible negative impact on drinking water abstraction from the last reservoir zone.