Impact of Land Use on Karst Water Resources—A Case Study of the Kupa (Kolpa) Transboundary River Catchment

This paper presents a qualitative approach for assessing land-use pressures on the water resources of a transboundary Dinaric karst catchment of the Kupa River in Southeast Europe. Spatial analyses of the water quality indices for surface water and groundwater were carried out in a GIS environment, as well as a detailed assessment of man-made hazards based on recommendations of COST Action 620. The produced maps provide an insight into the qualitative status of water resources at a regional scale by indicating areas of potential negative impacts of land use through the identification of point and diffuse sources of pollution. Higher values of the water quality indices for surface water and groundwater are observed in lowland areas, karst plateaus and poljes, where the impacts of anthropogenic activities such as agriculture and quarries take place on karstified permeable carbonate rocks. Hazard assessment showed how transport infrastructure induces a low hazard level. Settlement areas without proper sewerage systems impose moderate hazard levels, while direct wastewater discharges into groundwater and waste illegally disposed in karst swallow holes and caves located near settlements were classified as having high hazard levels. The applied methods proved to be suitable even in challenging karst environments where the complex properties and structure make the exploration and monitoring of groundwater resources difficult and scarce.