The main objective of the WSM300 project is the development of a methodology which guides and supports an improved water resources management on the level of small watersheds (up to 300 km²). The developed methodology is to be implemented into a software based tool within the framework of a generic Decision Support System (DSS). (Leichtfuss 2003, Schröter 2004). Core of the DSS is a "decision matrix", which has been implemented as a web based application (www.wsm300.de). The management objectives are represented by the indicators labeling the rows. They will be the result of a discussion of the objectives and problems in the specific sub-basin, which is supported by the catalogue of indicators. The matrix, once the labels are defined, serves as a plot for the planning process, defining clearly which objectives have to be considered and which indicator-values have to be calculated. The DSS further includes a concept and tools for the combination of existing software components and supports the processing of model-outputs to indicator-values. Filled with the indicator-values, the matrix allows a comparison of the scenarios and provides a good basis for a decision. If desired, multi-criteria decision aid methods can further help find the optimal scenario and mediate between stakeholders. As a co-product of the web-based DSS, the "River-Information-System" was established informing the public about the newest developments in their catchment.
