Water Concession Principles for Geothermal Aquifers in the Mura-Zala Basin, NE Slovenia

Demand for thermal water in the Mura-Zala basin, situated between Slovenia, Austria, Hungary and Croatia, is constantly increasing, with the sandy geothermal aquifer within the Neogene Mura formation being the most exploited. During the water concession granting process various problems were identified, together with the need for elaboration of the uniform concession granting principles. The latter were devised according to the specific hydrogeological settings and field inspection of 23 geothermal wells, performed through use of an adapted methodology. The inspection revealed changes in wells performance, low efficiency of energy abstraction and a lack of reinjection. The acquired information was applied to the development of particular principles, including the six key indicators. Firstly, a unified and integrated operational monitoring programme must be established, and upgraded by a national surveillance monitoring. Secondly, an application of the best available techniques is proposed. Stimulation of energetic and balneology efficiency is also needed, with recharge and reinjection conditions evaluated and applied where possible. Limited or full water concessions could be granted based on their fulfilment then. This continuous step-by-step approach should enable the implementation of adequate measures to meet the standards required for the thermal groundwater bodies according to the EU water framework directions.