Karst aquifer restoration after abandonment of bauxite mines at Nyirad region, and conclusions

摘要

Ten years ago, bauxite mines have been closed at Nyirad region, Hungary. These mines applied preventive water drainage (4-5 m~3/s). The water was utilized for water supply, hatcheries etc. At that time, the governmental decision to close the mines was based on the strong rechargedecreasing of the therapeutic thermal lake Heviz. This paper presents extracts from the analysis of karst water pressure/head rebuilding, as well as conclusions on the features of the impacted aquifer system with special attention to the impacts of the mine drainage to the recharge of Heviz thermal lake. The observations on the rebuilding period have displayed strong differences between the water pressure rebuilding at different tectonic blocks. This feature of the aquifer did not appear during drainage due to the coincidence of a long dry period. The observations refer to quasiseparated recharge conditions of Heviz thermal lake from Nyirad region. The restoration of the quasi-virgin conditions of the Heviz thermal lake should consider the role of new thermal water outputs at the close surrounding area. Some non-site specific conclusions were also derived.