For the simulation of hydrodynamic changes and pollutant dispersion in the study area, an appropriate model was applied using the DHI series software. Flows were modelled using the hydrodynamic model and the hydrological model, and water quality was modelled using MIKE 11 ECO LAB. The paper presents a simulation for the water quality of the Bahlui River. Mike 11 contains a GIS map and simulation editors. Water quality parameters such as temperature, dissolved oxygen and biochemical oxygen demand were simulated. Modelling results can be used as a planning tool to help decision makers during different phases.