Within a catchment many activities take place that influence the water system. Different sectors and claim space, water and various ecosystem services. Because of their limited area, amount or carrying capacity decisions have to be to which claims receive priority. These claims need to be situated within the eco-physical reality of the catchment. Because of a lack of knowledge, spatial planning and policy many water systems have been deteriorated. As a result economical and ecological functions are threatened with all social results. Integrated catchment management is a methodology that tries to find systems and solutions to these problems.  The integrated catchment management is in need of policy support systems that can capture the complexity of the different relations between human society and ecosystems.
 
Within this PhD a model will be developed that supports the development of policy scenarios on the basis of eco-physical, social and economic data with special attention to ecosystem services. Different river functions will be set as well possible measures that can ensure the sustainable exploitation of these functions. Different function and measure maps will be generated based on fuzzy set rules. The model will evaluate the different demands, functions and possible measures and generate maps with optimal geographic implementation of these. A multi-stakeholder platform of future users will assist in the development of the different maps and model and ensure the quality and applicability of the results.