International audienceThe SMaRT-OnlineWDN project ́s main objective is to develop an early warning system and a decision support toolkit for emergencies and the deliberate contamination of water distribution networks. There are four parts in this Project. One is to find an optimal sensor network as a combination of different sensor types e.g.: quality and hydraulic sensors and an optimal sensor placement. Another one is developing an online running model, which is automatically calibrated to the measured sensor data and simulates the current hydraulic status of the WDN. The third part is developing a model with more accurate transport and mixing mechanisms. Once a contamination event has been detected, the source identification tool will locate the contamination source by using the inverse transport model. Then, the spread of contamination is found out by simulating the future hydraulic status and using a forecast on water demand. For validating the models, the methods and the data acquisition, experiments are done at a real world test track. The fourth part of the project is a Risk analysis by studying the likelihood and impacts of deliberate contamination and how to behave in this case and also how to inform customers. The decision support toolkit is completed by combining all parts together