Building on uncertainty : how to cope with incomplete knowledge, unpredictability and ambiguity in ecological engineering projects

Building with Nature (BwN) is an ecological engineering approach which actively uses natural materials and dynamic processes (e.g., sediment, wind and currents) in the design of flood defence projects for achieving both societal and environmental goals (e.g., providing flood safety while providing opportunities for ecosystem development). However, our understanding of natural systems is incomplete and natural dynamic processes are inherently unpredictable. Thus, the exact outcomes and consequences of a BwN project are highly uncertain on beforehand. This uncertainty may hamper decision-makers in their ability to decide and may even lead to hard discussions between project teams and stakeholders about the acceptability of a BwN initiative under consideration. In this thesis, the issue of uncertainty in the context of BwN projects is studied. The results from a case study show that ambiguity about the social implications of a BwN project can be a major kind of uncertainty, because this ambiguity can potentially hamper project development. The ambiguity seems to originate mostly from conflicting beliefs of the project team and stakeholders in the project. Furthermore, currently, the power of the actors involved mainly determines how ambiguity is coped with. While traditional uncertainty analyses strictly separate apparently different kinds of uncertainty, this research acknowledges that different uncertainties are often interrelated in so-called cascades of interrelated uncertainties. Incomplete knowledge about the natural system and unpredictability of natural processes are gradually re-interpreted from different societal perspectives, resulting in ambiguity in the social system. Using cascades for representing interrelated uncertainties in projects elucidates new possibilities for coping with uncertainty: as the uncertainties in the cascades are directly related, this implies that coping with one uncertainty in the cascade will influence those with which it is related. As such, the cascade informs a project team about the many possibilities it has to cope with uncertainty in its project. Moreover, cascades can assist to identify ambiguities that could manifest themselves during project development. Consequently, a project team is informed about which actors should be involved in an early stage of the development process to prevent these potential ambiguities from occurring.