Identifying uncertainty guidelines for supporting policy making in water management illustrated for Upper Guadiana and Rhine Basins

In recent years, guidelines have been developed for supporting water managers in dealing with uncertainty in integrated water resources management (IWRM). Usually such guidelines have concentrated on certain aspects of processes in IWRM, notably on uncertainty associated with the modelling process and monitoring data. While this is of undisputed importance for supporting water managers in making well balanced and informed decisions, less attention has been paid to guiding policy makers in where uncertainty may emerge when considering the whole water management process. In this paper it is assessed in what way the policy makers can benefit from support in accounting for uncertainty at various stages in the water management process. Point of departure is an analysis of a broad range of uncertainty guidelines and their categorization in the water management process using a recently developed framework. Emphasis is on linking sources of uncertainty to uncertainty guidelines from an applied point of view in water management by developing a way to assist water managers to deal with uncertainty in IWRM and make informed and robust decisions. To support this, the Upper Guadiana basin in Spain and three Rhine basins are used as cases for water management issues in which it is demonstrated how water managers potentially can benefit from uncertainty guidelines in support of policy making, for instance with respect to implementation of the Water Framework Directive (WFD).