Table 1. Examples of uncertainties identified in each of the three knowledge relationships and objects of knowledge Unpredictability (unpredictable system behavior) Incomplete knowledge - lack of information - unreliable information - lack of theoretical understanding - ignorance Multiple knowledge frames - different and/or conflicting ways of understanding the system - different values and beliefs - different judgement about the seriousness of the situation, growth potential of problems, priority of actions or interventions Natural system - climate impacts - water quantity - water quality - ecosystem Unpredictable behavior of the natural system, e.g., How will climate change affect weather extremes? Incomplete knowledge about the natural system, e.g., What are reliable measurements of water levels? Multiple knowledge frames about the natural system, e.g., Is the main problem in this basin the water quantity or ecosystem status? Technical system - infrastructure - technologies - innovations Unpredictable behavior of the technical system, e.g., What will be the side-effects of technology X? Incomplete knowledge about the technical system, e.g., To what water level will this dike resist? Multiple knowledge frames about the technical system, e.g., Should dikes be built or flood plains created? Social system - organizational context - stakeholders - economic aspects - political aspects - legal aspects Unpredictable behavior of the social system, e.g., How strong will stakeholders’ reactions be at the next flood? Incomplete knowledge about the social system, e.g., What are the economic impacts of a flood for the different stakeholders? Multiple knowledge frames about the social system, e.g., Should water markets be introduced to deal with water scarcity or negotiation platforms?