A Flexible Adaptive Framework for Decision Making in Design of Multifunctional Flood Defence Structures Under the Condition of Deep Uncertainty (PAP014393)

Código

PAP014393

Autores

Flora Anvarifar, Chris Zevenbergen, Wil Thissen

Tema

Flood risk management in mega cities

Resumo

A large proportion of primary flood defences in the Netherlands do not comply with safety standards and need reinforcement. Often, the land required for reinforcement has to be shared with land development plans resulting in a growing need for integrating flood protection measures and spatial planning interventions. One alternative approach is the concept of Multi-Functional Flood Defences (MFFD)", where the flood defence has a secondary function in addition to flood protection. Long term planning for MFFD, as a complex and interconnected system is directed by different dynamics that are inherently uncertain in their behaviour. The degree of uncertainty across the myriad of uncertainties varies widely from known quantifiable uncertainties (e.g. model uncertainty) to the so called 'deep uncertainties' defined as known unknowns (e.g. magnitude and rate of climate change) and unknown unknowns (future surprises and shocks) that cannot be quantified and interpreted by probability distributions. Moreover, these uncertainties can result in serious outcomes and consequences on the system performance and its users. This leads to the need to investigate and cope with these uncertainties. To support long term planning for MFFD to more than a few decades into the future while actively dealing with deep uncertainties, the plan should not only achieve the desired targets and outcomes, but it should also be flexible to adaptively respond to unforeseen or unexpected changes. Alternatively, development and planning of MFFD under the condition of deep uncertainty requires a method that acknowledges the dynamic and non-linear behavior of the MFFD system. Whereby, stationary approaches require judgment and prediction about which of the multiple and constantly changing plausible futures of the system may be the most likely. In presence of deep uncertainties, adoption of an iterative, interactive approach provides the analytic framework to think creatively and systematically about the potential future surprises and makes it possible to actively response to them. This can potentially be achieved by adoption of a flexible adaptive decision making frame that appreciates the learning through the time processes and allows the existence of decision points over time. The adopted flexibility-oriented design options (via an incremental design) provide the decision maker with the opportunity, but not the obligation, to take future actions when uncertainties are likely to be reduced or diminished. The approach can accommodate multiple sources of uncertainty via none-probabilistic scenario development. Respectively, this paper describes the flexible adaptive framework developed for decision making and design of MFFD structures. Thereafter, the method is tested in a case study and lesson learned are discussed."