Hydrogeological Expert Basis to Water Permitting in the Low Temperature Geothermal System in the Mura-Zala Basin in the NE Slovenia

Abstract

Thermal water demand is constantly increasing in the Mura-Zala basin, a part of the Tertiary Pannonian sedimentary basin. The shallowest Mura formation geothermal aquifer is the most affected. To preserve existent water capacities guidelines for thermal water permitting were elaborated by inspecting 23 geothermal boreholes in 2008. Interpretation of obtained data enabled assessment of current and long-term state of thermal water availability. Results show that in some cases changes in well operation are already evident. Efficiency of thermal energy abstraction is not sufficient, and no reinjection is applied till now. Current operational monitoring is not satisfactory, plus no national surveillance monitoring is yet applied.
Proposed legal actions for water permitting focused primarily on mandatory, unified and integrated operational monitoring establishment. Secondly, stimulation of better efficiency of thermal energy use, best available technology application, sustainable aquifer management, and national surveillance monitoring were proposed. This should enable implementation of adequate actions regulated from the national Environmental agency to meet good status of thermal groundwater body according to the EU Water Framework Directive.