Karst water resources and their complex utilization in the Bükk Mountains, northeast Hungary: an assessment from a regional hydrogeological perspective

The cold and thermal karst water resources of the Bükk Mountains play a significant role in the hydrogeological setting of northeastern Hungary. Although there is much geological and hydrogeological information available, the regional hydrogeology of the Bükk Mountains had not been described in a standalone study involving all this information. The drinking water supply of the city of Miskolc and some other neighboring cities is based on the cold karst water resources of the Bükk Mountains. The thermal water resources have been getting more important, in terms of balneology and geothermal energy production, in this region over the last decade. An evaluation of the measurements of a 27-year-old groundwater quantity and quality monitoring system was performed. As a result, several types of new field hydrogeology, meteorology and spring discharge measurements were added to the monitoring scheme to provide information for studying the tendencies connected to extreme weather conditions. This will help to achieve sustainable utilization of the karst water resources. The main conclusions drawn in this study underline the importance of the strict measures associated with the water management of the Bükk Mountains because of the limited natural recharge and the continuously increasing demands on the cold and thermal water resources. A success story is found in Miskolc, which demonstrates the sustainable utilization of the deep thermal karst water; Miskolc hosts the largest geothermal heating plant in Central Europe with 60 MW t capacity.