Conquering complexity - Dealing with uncertainty and ambiguity in water management

Water management problems are embedded in a natural and social system that is characterized by complexity. Knowledge uncertainty and the existence of divergent actors’ perceptions contribute to this complexity. Consequently, dealing with water management issues is not just a knowledge uncertainty problem; it is a problem of ambiguity too. This PhD-research focuses on decision-making processes for complex water management issues. We investigated how a decision-making process, for a complex water management issue, influences the creation of a knowledge base, the development of actors’ perceptions and the formulation of a problem-solution combination. Three case studies of complex water management issues are presented, two explorative case studies from practice and a comparative experiment. The first case study focuses on the decision-making process for the impact assessment of the extension of Mainport Rotterdam. This process can be characterized as an analytical decision-making process, as it is based on rationality and objectivity. The second case study focuses on the sustainable development of ecology, economy and society in the Delta region, in the southwest of the Netherlands. This project is a typical example of a participatory decision-making process, which actively involves actors and is open to divergent perceptions of the problem. In our third case study, two decision-making processes – analytical and participatory – are compared using an experimental setup. The comparison between the two decision-making processes was carried out within the framework of a multidisciplinary design project for Civil Engineering Bachelor-students of the University of Twente.