[EN] The objective of the study is to make a diagnosis of the water quality of the river Dender, noting the most important pressures in the river. In order to reduce these pressures in the river, the proposition of measures have to be done to improve the water quality. All this can be achieved by simulating the behaviour of the river, using a water quality model. Thus, the measures will be implemented in the model and it will be possible to verify which measures are the most relevant. Secondary objectives of this report are the explanation of the processes undertaken to build the water quality model and the subsequent simulation and analysis, in which measures are put in place. The main processes include the build-up of the model and its calibration and validation, based on the concentration of certain parameters. The validation and calibration of the model are steps that require a lot of time, but they are essential to ensure reliable operation of it. When the water quality simulator is ready, it is possible to assess the physico-chemistry quality and its spatiotemporal evolution along the river in a continuous manner. The calibrated model is a reliable tool that can be used to evaluate the effects of different proposed measures. This approach can be used to make decisions about the optimal set of corrective measures needed to fulfil the goals set by law. ; [CA] L'objectiu de l'estudi és realitzar un diagnòstic de la qualitat de l'aigua del riu Dender, prenent nota de les pressions més importants presents en el riu. Per reduir aquestes pressions, cal proposar mesures que milloren la qualitat de l'aigua. Tot això es pot aconseguir simulant el comportament del riu, utilitzant un model de qualitat de l'aigua. Per tant, les mesures s'implementaran en el model i serà possible verificar quines mesures són les més rellevants. Els objectius secundaris d'aquest informe són l'explicació dels processos empresos per construir el model de qualitat de l'aigua i la posterior simulació i anàlisi, en què s'estableixen mesures. ...