Concepts of decision support for river rehabilitation

River rehabilitation decisions, like other decisions in environmental management, are often taken by authorities without sufficient transparency about how different goals, outcomes, and concerns were considered during the decision making process. This can lead to lack of acceptance or even opposition by stakeholders. In this paper, a concept is outlined for the use of techniques of decision analysis to structure scientist and stakeholder involvement in river rehabilitation decisions. The main elements of this structure are (i) an objectives hierarchy that facilitates explicit discussion of goals, (ii) an integrative probability network model for the prediction of the consequences of rehabilitation alternatives, and (iii) a mathematical representation of preferences for possible outcomes elicited from important stakeholders. This structure leads to transparency about expectations of outcomes by scientists and valuations of these outcomes by stakeholders and can be used (i) to analyse synergies and conflict potential between stakeholders, (ii) to analyse the sensitivity of alternative-rankings to uncertainty in prediction and valuation, and (iii) as a basis for communicating the reasons for the decision. These analyses can be expected to stimulate the creation of alternatives with a greater degree of consensus among stakeholders. The paper concentrates on the overall concept, the objectives hierarchy and the design of the integrative model. More details about the integrative model, the stakeholder involvement process, and the assessment of results will be published separately. Because many decisions in environmental management are characterized by a complex scientific problem and diverse stakeholders, the outlined methodology will be easily transferable to other settings.