The aims of this thesis were to create a (historical) terrain model of the river Traun in Upper Austria from the situation before 1885, runoff simulations for different intensities and finally their analysis. This has been the basis for the calibration of abiotic parameters of the decision support system RiverSmart. Using the digitalised historical and actual data, collected from historical maps and actual land survey of the river section and the surrounding area, a digital historical terrain model was set up with the software ARCGIS and the interpolation method Kriging. Then the runoff simulations were carried out using the 2-dimensional runoff simulation model Mike21C. The following evaluation was caused by the parameters of the calibration for the transformation curves from RiverSmart. Together with the analysis of the rivers actual situation (Niederbichler, 2005) the results were connected and the calibration of the transformation curves (Dox, 2006) were carried out.