Study of the interrelationships between groundwater and lake water at Neusiedlersee, Austria

Neusiedlersee (area 300 km2, average depth 1 m) is a steppe lake situated in the Pannonian plain at the eastern border of the Alps. The lake has only little surface inflow and no natural surface outflow, and its water balance is mainly determined by precipitation and evaporation. The subterranean inflow, of which little is known because of the complicated hydrogeological conditions, is an important factor in this water balance. The current activities represent an attempt to learn more about the subterranean inflow by means of investigations concerning the groundwater conditions in the lake-side area and the interrelationships of groundwater and lake water applying environmental isotope methods. The paper deals with the eastern lake side and the seepage springs in the western reed belt. The results of the isotope investigations indicate that there is no continuous and homogeneous shallow aquifer at the eastern lake side of Neusiedlersee and therefore inflow to the lake is very small. Seepage spring water in the western reed belt is assumed to come from a widely ramified karst- and/or crack-water system with its catchment area situated in the highest ranges of the Leithagebirge. (author)