Identification of major sources of uncertainty in current IWRM practice. Illustrated for the Rhine basin

Integrated Water Resources Management (IWRM) can be viewed as a complex process in which the effect of adopted water management measures must be monitored and adjusted in an iterative way as new information and technology gradually become available under changing and uncertain external impacts, such as climate change. This paper identifies and characterises uncertainty as it occurs in the different stages of the IWRM process with respect to sources, nature and type of uncertainty. The present study develops a common terminology that honour the most important aspects from natural and social sciences and its application to the entire IWRM process. The proposed framework is useful by acknowledging a broad range of uncertainties regarding data, models, multiple frames and context. Relating this framework to the different steps of the IWRM cycle is helpful to determine the strategies to better handle and manage uncertainties. Finally, this general framework is illustrated for a case study in the transboundary Rhine river basin.