The INTERREG IIIB NWE funded 'nofdp' project promotes a nature-oriented approach towards flood damage prevention (www.nofdp.net). It addresses a combination of both technical and non- technical measures to reduce the risk of flood damage and to improve nature at the same time. One of the project's key deliverables is the interactive planning and communication software nofdp IDSS (Information and Decision Support System) which is open source and free of charge for the user. The software is designed to assist water managers in the interactive and iterative process of developing and communicating alternative flood risk management strategies, which keep track with a balanced view on the often conflicting issues of spatial planning, flood damage prevention and ecological development. Eight project partners from The Netherlands and Germany were directly involved in the development process. A consortium formed by Björnsen Consulting Engineers (GER) and WL | Delft Hydraulics (NL) implemented the descriptive concept that was developed by the nofdp project partners. A first key functionality of interaction enables the user to position 22 different types of measures of flood control on a map within a GIS environment. At the same time, the user can assess existing and new spatial conflicts. Individual measures can be grouped to form variants and evaluated interactively. The nofdp IDSS provides four different methods of evaluation, ranging from very simple (Ranking) to more sophisticated methods (e.g. Value-Benefit Analysis). This paper describes how the nofdp IDSS can interactively support the development of flood control plans. It demonstrates how measures can by positioned and how they can be composed and managed to arrive at alternative flood control strategies. Secondly, the assessment and evaluation methods will be presented. Using an example, the effect that the use of a specific evaluation method can have on the decision to be taken is demonstrated.