Modelling daily streamflow in a temporary karst river system: comparing three approaches using the SWAT model

This work tests different options for simulating hydrology in basins with karst areas. The Soil and Water Assessment Tool (SWAT) model was applied to the Canale d'Aiedda (Puglia, Italy), a Mediterranean temporary karst river basin. Different basin delineations and model parameterizations were adopted that include: (i) cutoff of the karst areas (configuration A); (ii) basin set-up including the karst areas (configuration B) and (iii) model parameterization considering a bypass flow in karst sub-basins (configuration C). The model performance was satisfactory for daily streamflow for configurations B and C and good for A. A better simulated large floods. C presented the best fit for monthly streamflow from May to July. Regarding the water balance, C showed higher values of surface runoff and lower values of total water yield than A and B. Bypass flow proved to be a valid option to improve the simulation of the hydrological processes in karst areas.