ADGEO Advances in Geosciences ADGEO Adv. Geosci. 1680-7359 Copernicus Publications Göttingen, Germany 10.5194/adgeo-31-31-2012 Integrating heterogeneous landscape characteristics into watershed scale modelling Julich S. 1 2 Breuer L. 1 Frede H.-G. 1 Institute of Landscape Ecology and Resources Management, Justus-Liebig-University Gießen, Germany now at: Department for Soil Science and Site Ecology, Dresden University of Technology, Dresden, Germany 06 07 2012 31 31 38 Copyright: © 2012 S. Julich et al. 2012 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://adgeo.copernicus.org/articles/31/31/2012/adgeo-31-31-2012.html The full text article is available as a PDF file from https://adgeo.copernicus.org/articles/31/31/2012/adgeo-31-31-2012.pdf

Two versions of the SWAT-model with different dominating runoff generation processes have been applied. One version comprises the original available SWAT version where only the basic input data are used. In the second version SWAT has been modified, by the integration of an impermeable layer at the subbasin level, in order to better reflect the boundary between soil and bedrock that results in increased lateral flow in low mountain ranges. As well, since conventional German soil maps do not describe soil horizons beyond 2 m depth, we also added a 4 m fixed depth in the lowland areas in order to reflect the deep loess deposits in this region. The decision for the location of the impermeable and the additional loess layer was based on a GIS analysis of additional geologic information. <br><br> This study revealed that both model versions produced acceptable and comparable results regarding the evaluated goodness of fit measures. The GLUE analysis showed that the SWAT model set up with additional information about the distribution of impervious soil layers and the loess depth in the lowlands produced the highest simulation quality and the lowest uncertainty. Moreover, SWAT II version was able to better represent the spatial extend of the dominating runoff processes best. This leads to the conclusion that the SWAT II version is better suited for scenario analysis than the original model version.

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