Hydrodynamic and hydrochemical con - ditions at the groundwater source “ Pašino vrelo ” , with a focus on its development

At the “Pašino vrelo” source, groundwater is exploited by means of wells which tap a carbonate aquifer of Badenian age. The natural quality of groundwater complies with the provisions of the Regulation on health and safety of drinking water. However, anthropogenic impacts in the form of microbiological pollution have been observed. Extensive hydrogeological investigations have been conducted in recent years in the recharge area of the groundwater source with the aim of ensuring additional quantities of drinking water and protection of the source from pollution. The analysis of hydrogeological monitoring results for groundwater levels and discharges at the groundwater source confi rmed the existence of a hydraulic connection between the Quaternary alluvial and Badenian carbonate aquifers. Differences in the hydrodynamic conditions between the “Pašino vrelo” spring and “Bojanića vrelo” spring have also been observed, and are related to the infl uence of pumping on the groundwater discharge regime, but also to drainage conditions at the springs. Hydrochemical indicators also suggest the mixing of groundwater from both aquifers in springs and exploitation wells. Specifi c hydrogeological conditions at the groundwater source determined the concept of its development. Recent hydrogeological research was carried out in order to explore the possibilities of tapping deeper parts of the carbonate aquifer in order to minimise the infl ow of groundwater with anthropogenic impacts from the shallow alluvial aquifer during groundwater abstraction. Preliminary results for groundwater quality in the new well justifi ed the aforementioned investigation approach. Intensive exploitation of the well will show whether these conditions are sustainable in the long term.