"Development of a large scale two-dimensional groundwater model of the Upper Danube Basin with special regard to boundary conditions"The upper Danube catchment Area is one of the case study locations of the GLOWA projects. The catchment covers an area of about 77, 000 km2 and is located mainly in the southern German states of Baden Wurttemberg and Bavaria, with small parts located in neighbouring countries of Austria, the Czech Republic, Switzerland and Italy. The study aims at determining the possibility of constructing a two-dimensional conceptual groundwater flow model of the catchment using simple assumptions and data. The main input data used in the model construction are the digital elevation model of the area, recharge, wells and river network. The model represents only the quaternary formation in the catchment which forms the topmost formation in an area of several geological formations. Due to the complex geology and mountainous nature of some parts of the model area, the need arose to reset the boundaries of the model, which does not coincide with the natural boundaries of the catchment. The study determines the possible ways of representing these new boundaries of the model. The main modelling tool used in the investigation is Groundwater Modelling System (GMS) software, which uses USGS MODFLOW code.
With the considerations of uncertainties involved in modelling processes in general, it can be concluded from the study that; representing the catchment with a 2-D flow model is possible, but can only be used as a first impression of the flow pattern and in determination of perimeter of the model domain. The model can also be used as a first stage in the determination of necessary field data and modelling approach for a comprehensive modelling of groundwater flow and transport process of the area.