Hydrological stochastic modelling of a basin affected by land-use changes: case of the Merguelill basin in central Tunisia

Several works in the area of water and soil conservation (WWSC) have been implemented in the Merguellil basin. In order to test their efficiency, an impact study of these works was carried out by hydrological modelling. The MODCOU model, which simulates both surface and underground flow at the same time, was used. The WWSC were considered through a parameterization of the production function. The calibration of the model was carried out with a multi-objective stochastic approach on several observation sites. The results show that the actual evapotranspiration is the largest component of the surface system. The groundwater system is largely overdrawn with outputs estimated to be four times higher than the inputs. This study has shown the improvement in model representativeness by assigning specific parameters to the production functions of the WWSC zones