During the annual meeting of the European Geophysical Society in 2001 a special session was organized around the design and application of decision-support systems for integrated water management. There is a growing realization among policy makers and scientists that ecological, social-economic and physical aspects of water management cannot be dealt with separately. This has lead to a growing number of tools to support the decision-making process in water management dealing with the water system in an integrated way. Example applications are flood forecasting, multi-reservoir operation, urban waste-water management, and integrated river-basin management. The design, which is ideally based on intensive communication between scientists, system designers and envisaged end users, is often a tedious process. In general, it can be concluded that, in despite of the effort invested in process modeling, data collection, and the growing experience in developing integrated system models, practical application of decision-support systems still runs behind the availability of these tools.