"Scaling effects on Groundwater Flow Models in the Donauried Region, Germany"A globally applicable decision support system to evaluate the impacts of Global change on hydrological cycle is under development by the interdisciplinary research co-operation of GLOWA Danube. The Institute for Hydraulic Engineering of the University of Stuttgart is dealing with a ground water flow and transport and a water supply model. The information exchange between various disciplines involved in the study is a raster based grid size of 1000x1000 m. This grid size is a coarse grid to represent the actual wells, streams and rivers and the head and flow distribution in the ground water system accurately.
This study is aimed at evaluating the influence of using coarse grid in the development of decision support system "DANUBIA" with regard to surface water and ground water interaction. Conceptual model is developed at regional level for Donau-Iller-Lech. The Donau model is calibrated with the flow data of inflow river gauge station at Neu Ulm and out flow gauge station at Donauwörth to a grid size of 1000x1000 m.
Further conceptual models are developed to the local study area Donauried at grid sizes of 1000 x 1000, 500 x 500 and 250 x 250 m. MODFLOW simulations are run. Comparisons are made between the results of head distributions and flow budgets of the three model grid scales.
Results of the study are described and interpreted. Finally conclusions and recommendations are given.
It is strongly believed that, the result of the study is useful in a further attempt to exclusively study the problem of up-scaling.