Danube Island - an aquifer for nutrient and water quality transfer into the New Danube (Vienna, Austria)
Kreuzinger, N.; Matsché, N.
Water from the River Danube moves into the New Danube flood-relief channel by hydraulic pressure, percolating through the gravel groundwater zone of Danube Island which separates the two parallel watercourses. Chemical changes in the water during its passage through the Danube Island aquifer were studied by intensive monitoring. The most significant changes in concentration occur in the transition zone from channel water in the Danube into the groundwater of Danube Island. Degradation of organic matter reduces dissolved oxygen and dissolved organic carbon, and increases carbon dioxide. The disturbance of the carbonate (TILLMANN'S) equilibrium leads to an increase in alkalinity. Photosynthetic production by plants in the New Danube leads to precipitation of phosphorus in apatite, which may exceed the phosphorus uptake by macrophytes. Semi-quantitative estimates were partly confirmed by chemical measurements at the three sites investigated (the Danube, groundwater, and the New Danube).