Incorporating qualitative indicators to support river managers; application of fuzzy sets

In evaluation of river management strategies it is generally difficult to deal with the loosely structured and uncertain information at hand. Due to the increasing number of interests and objectives involved in river management it becomes more important to find a way to deal with such information. This paper explores to what extent fuzzy set theory can help in the modelling of relations between river management measures and their effects. The authors conclude that fuzzy logic can provide a valuable contribution because of the relative transparency of the method, the possibility to include qualitative knowledge and the incorporation of uncertainty. Particularly the latter requires further study before a broad application in river management is feasible.