Mineral and Thermal Waters in the Croatian Part of the Pannonian Basin

Abstract

Favourable geothermal properties which are characteristic of the major part of the Pannonian Basin System also extend into its south-western margin where Croatia is situated. Owing to a thin lithosphere, the geothermal heat flow is high, which enables groundwater to heat up. Some of the natural geothermal springs have a millennial tradition in different modes of utilization. The mode of utilization varies according to the temperatures, e.g. waters of lowest temperatures (17–20 °C) are used for fish farming, while waters of the highest temperatures (68–98 °C) are utilized for space heating and hot water preparation. In total, thermal waters in Croatia are utilized in the following ten activities: recreation, balneotherapy, water heating, space heating, greenhouse heating, fish farming and directly as sanitary water, public water supply and bottled table and mineral water. According to the major ionic composition, waters belong to the NaCaMg–HCO₃SO_4, CaMgNa–HCO₃SO_4, CaMgNa–HCO_3, CaMg–HCO_3, NaCa–HCO₃ or Na–Cl-type. Despite significant potential confirmed through multiple professional and scientific studies, the utilization of both thermal and mineral waters remains at low levels and traditional applications.