The Dutch Delta Program is currently developing new government policies for flood protection and fresh water supply. Decision support instruments have to address the program’s technical and political complexity. The water system functions are highly interwoven and would benefit from an integrated approach on a national level, with decisions supported by a scientific Systems Analysis. Politically, there is a tendency towards broad participation and decentralization, and decision-making is typically supported by Conflict Resolution methods. To connect these two sides of the Delta Program’s task, an outline is presented of an internet community-based interactive instrument, preliminarily named SimDelta. On-line interactive maps and elements of serious gaming intuitively provide local Delta Program participants insight into the interaction between scenarios, problems, and solutions. SimDelta uses the internet to more frequently and efficiently present conceptual designs by architects and engineers to the Delta Program stakeholders, record their preferences, and “crowdsource” corrections, improvements and new ideas.