Hydrogeology of a complex karst catchment in Southern Dalmatia (Croatia) and Western Herzegovina (Bosnia and Herzegovina)

Our study focuses on a sizeable transboundary karst catchment in Croatia and Bosnia and Herzegovina, extending over 2000 km². A complex underground conduit system and extreme karst forms heterogeneity are the main characteristics of the area in question. Since determining the boundary of such a large and complex catchment is difficult, we used different kinds of data sets, of which the most relevant are the available geological data, hydrochemical data, hydrological data, and tracing tests data, to divide the regional catchment into six subcatchments. We also examined past archived reports and carried out new hydrological investigations of several major and minor springs. Our research results in a hydrogeological map that can be used as a base for establishing site-specific groundwater protection zones, for water balance calculations and the planning of new research in this area, especially the ones regulating combined cross-border efforts to prevent groundwater contamination and ensure sufficient drinking water.