Effects of the long-term thermal water utilizations on the aquifer in SE-Hungary

Abstract

Hungary has great (thermal)water potential, compared to the European countries. The water is utilized for different purposes, the most important and everyday usages are the: drinking water, balneological-, and agricultural/energy purpose utilizations. In SE-Hungary, in the Great Plain, the thermal water utilization has more than 60-70 history. In the Szentes and Szeged regions, the thermal water of the Upper Pannonian porous aquifer is used for greenhouse heating by several agricultural companies.
From the 1950s, only in Szentes about 35-40 wells, in Szeged region more than 70 thermal wells were established on the Upper Pannonian aquifer. The long-term and intensive thermal water production caused regional (from 10-15 to 30-40 meter) depressions in both regions in the cca. 1500 meter-thick porous thermal aquifer.
To determine the current state of the thermal systems, 3D numerical models were built. The finite element FEFLOW code was used, which combined and simultaneously managed the hydrodynamic and heat transport processes of the thermal system. The model buildings are based on the geological, hydrodynamic and geothermal characteristic of the aquifers. The models have been calibrated by the help of the thermal productions of the areas.
By the help of the numerical models we were able to examine and determine the effects of the more than 50 year-long operation of the thermal wells and the depressions formed in the two regions above. After determining the current state of the system and the aquifer, we examined the future effects of the agricultural greenhouse heating utilizations in both areas. In Szeged region, great system(s) with reinjection wells, while in Szentes region small system(s) (with 1-2 well(s) without reinjection) were examined.