The parameterisation and calibration of complex hydrological models like SWAT [Arnold, J.G., Srinivasan, R., Muttiah, R.S., and Williams, J.R. 1998. Large-area hydrologic modeling and assessment: part I. Model development. J. American Water Resour. Assoc. 34, 73-89.] is a time consuming process. The use of simple models can shorten this effort substantially because they enable us to identify the important processes in the catchment very fast and thus facilitate the parameterisation of the complex model. We used the models SWAT and SIMPEL [Hormann, G., 1997. SIMPEL - Ein einfaches, benutzerfreundliches Bodenwassermodell zum Einsatz in der Ausbildung. Dt. Gewasserkundliche Mitteilungen 41, 67-72.]. SWAT is a complex, meso-scale eco-hydrologic model, SIMPEL is a set of spreadsheets with a one-dimensional soil water model where runoff is calculated with a unit hydrograph. The parameterisation of the SWAT model was very time consuming because many parameters had to be estimated due to the scarce data situation (e.g. of land use data). To avoid long test runs, we first implemented and tested possible solutions in SIMPEL and finally transferred it to SWAT.
