Today, water authorities face a set of water management challenges, related to new European policies, climate change adaptation, land use planning, urban wastewater and storm water management. In response to these evolutions and anticipating on fast changing IT-technologies, Flanders Environment Agency has developed a set of next generation tools for operational hydrology. These tools are flexible, open and integrate all major components of the water system (principle toolbox). Rather than just providing a set of tools, the toolbox is integrated into existing information systems by the latest technologies using open standards and web protocols. Currently, the toolbox is used to establish a regional hydrological model set for Flanders. This large scale model will produce information on the hydrological status (runoff, subflow, infiltration, soil storage, etc.) at any location in Flanders. Furthermore, an interactive web-application of the toolbox was developed to enable hydrological modelling through the internet. Besides the fulfilment of the modelling needs of the Flanders Environment Agency, the initiative aims to foster collaboration, not only between governmental agencies with operational duties in water management, but also between the different communities in support of operational hydrology.