ABSTRACT
Within the framework of European Union projects ENWAT and TRANSENERGY, Hungarian and Slovakian hydrogeologists cooperated on common descriptions, modelling and formulating proposals for the groundwater management of transboundary karstic aquifers, one of them a deep-seated geothermal aquifer and the other a classical plateau karst structure. Some notes from lessons learned during the work on both projects may be useful to other hydrogeologists trying to establish cross-border cooperation especially in Europe, such as maintaining two independent web portals for public use and for specialists. Keeping units to be constantly linked with the data in common databases of input parameters, and adequate (possibly metric) coordinate systems seems to be useful. Choice of software tools should be left for individual selection by working teams, while basic standards of data inputs and outputs seem to be the most effective common understanding for hydrogeologists managing transboundary aquifers.
