This web site demonstrates parts of the groundwater modelling exercises carried out at UNESCO-IHE within the Hydroinformatics specialisation in the academic year 2007-2009. The exercise presented on these pages is about an imaginary aquifer that needs to supply water for exploited for water supply of a nearby town. The wells and the zones with different K-values are presented in the image. After assuming that the southern river was vaery polluted several wells along the river needed to be switched off (W1,W2,W6,W7,W8,W9), and some wells were reduced in pumping (W10). A groundwater model was built to simulate the effect of these interventions. In this exercise we tested the influence of natural recharge R to the base flow to the southern river, BF, after switching off the polluted wells.