Due to the very high
groundwater fluctuations and despite the lack of space, a sealed ground water lake with a high water table was built. The lakes water-impermeable layers (
tertiary) are sealed around and create a dense run off trough. To avoid groundwater damming, three basic water transfers (
culverts) were built allow water to transfer from south to north, and in addition to the run off area, the groundwater is pumped out of the ground in the other surrounding areas and flows into the lake. Through an overflow area at the western end of the lake, the access water is purified in the infiltration basin and fed into the ground water. Through the exchange of water, consistent water quality can be ensured. == Security ==