Ucker Watershed

Based on exact process studies in selected validation areas (like the redox studies in the Oderbruch region) chemical indicator elements can be used to characterize the environmental conditions with sufficient accuracy. Using the GIS data model, the interpretation of the region by characterizing distinct geohydraulic properties of the different catchment parts in connection with the derived hydrochemical conditions enables a comprehensive spatial hydraulic-chemical characterization on basis of the main chemical characteristics in the identified aquifer complexes. Considering the results of the hydrochemical calculations in the anoxic aquifer in the Oderbruch and at the interface between this aquifer to surface waters, iron measurements in connection with the common hydrochemical parameters can be used to characterize the redox con- 

In addition, analysis data and calculation results of individual measurement points can be regionalized by geostatistic approaches (Schafmeister, 1999). Chemical analyses of installed groimdwater observation wells as well as data of public institutions, for example Geological Surveys and Environmental Offices, are used. 

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Figure 8.10 Calculated average residence times of groundwater in the Ucker watershed (2400 km ).

The method was validated by hydraulic calculations carried out in a pleistocene aged watershed covering 220 km (Stoebber river) and applied for the calculation of groundwater residence times in the mesoscale watershed of the Ucker river (covering 2400 km ) and planned for modelling substance balance in the Oderbruch region (800 km2). 

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