Karstification is considered as one of the most common reasons for interbasin
groundwater flow (IGF). IGF in some karst areas could be si
gnificant such that it must be accounted for in hydrolo
gic modelin
g. In this study, the Soil and Water Assessment Tool (SWAT) was modified to explicitly account for IGF in karst areas. The modified model uses two conceptual models to simulate hydrolo
gic processes in karst and non-karst re
gions. The modified model was applied in the karst-dominated re
gion in the southwest Harz Mountains, Germany. Multisite streamflow data and satellite-derived actual evapotranspiration (ETa) were used for model calibration. Results show that (1) the modified model can be satisfactorily calibrated and validated for streamflow and ETa (2) the model performance for ETa and streamflow at some
gau
gin
g stations are hi
ghly correlated, and (3) the use of satellite-derived ETa does not affect the model performance.