Nature-based flood defence is an innovative design alternative for achieving protection against flooding. Despite significant advancements in science, models and concepts, routine implementation beyond pilot projects remains limited. To better understand why, we have looked into the complexities of nature-based flood defence implementation and its resolutions, modelling decision-making situations using game theory in three nature-based flood defence cases: The Markermeer Dikes, the Afsluitdijk Dam and the Sand Engine. We observe that nature-based flood defence games are of a multi-level and nested nature. While the decision of whether to employ a nature-based flood defence is seemingly made at the project level, this can only happen when it is coherent with the institutional context that is determined at the policy level. A social dilemma is apparent: while a multi-functional nature-based solution is attractive to a coalition of actors, it is not the most beneficial option for individual actors. Hence, they are faced with the dilemma of opting for their maximum benefit or opting for the greater societal benefit which is less favorable to them. This social dilemma can be tackled by making ‘smart moves’, as inspired by the Sand Engine case. The nested nature of the problem requires structural change in the institutional context to enable favourable conditions for nature-based flood defence implementations.

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In Nederland zijn honderden kilometers aan waterkering toe aan versterking. De aanleg van begroeide vooroevers, zoals schorren en kwelders, is een mogelijkheid om de belasting op dijken te verminderen. Daarmee dalen overstromingsrisico’s en gaan natuurwaarden omhoog.@en

Deze Handreiking presenteert het participatief instrument Meerwaarde van Samenwerken dat binnen de kaders van het Hoogwaterbeschermingsprogramma (HWBP) is toegepast in het gebied Noard-Fryslân Bûtendyks in opdracht van de POV Waddenzeedijken. Het instrument is geschikt voor alle situaties waarin (meer) samenwerken gewenst is, binnen of buiten de wereld van waterveiligheid. Samenwerking succesvol vormgeven is niet vanzelfsprekend, het is vaak nieuw, soms eng en brengt risico’s met zich mee voor planning en budget. Tegelijkertijd is samenwerken tussen HWBP, Waterschappen en Rijkswaterstaat en andere partijen een juridische verplichting en vaak onontkoombaar. Samenwerken kan winst opleveren, denk aan ‘bouwen met natuur’ oplossingen die meerdere functies bedienen. Zoeken naar de mogelijke win-win oplossingen is tevens het uitgangspunt van Meerwaarde van Samenwerken: samenwerken gaat vooral werken als het alle partijen meer oplevert dan de huidige situatie. No regret dus en rekening houdend met de belangen van de partijen. De Handreiking Meerwaarde van Samenwerken geeft een praktische richting hoe het instrument te gebruiken aan de hand van een beschrijving van de voorbereiding en vijf processtappen (Figuur 0.1.1). Na een kennismaking brengen partijen de kansen voor samenwerken in beeld, waarna iedere partij deze waardeert. Op basis van de individuele waarderingen wordt de meerwaarde van samenwerken voor de groep bepaald en bekeken hoe de meerwaarde van samenwerken kan worden bereikt. In gesprek gaan staat hierbij centraal, ondersteunt met speltheoretische analyses en concepten. Zo helpt dit instrument partijen om samenwerkingsmogelijkheden te verkennen door de belangrijkste elementen en kansen te identificeren en belangrijke logische consequenties te doordenken en bediscussiëren. @en

Nature-based flood defence (NBFD) by means of vegetated foreshores is an innovative flood protection strategy. In contrasts with traditional hard structures it combines nature and flood protection functions and employs natural dynamics. Introducing such an innovation into actual flood protection projects requires not just proper understanding of the physical aspects of the approach. Equally important is the understanding of governance implications as NBFD decision-making implies involvement of different actors and actor interactions and requires alternative governance arrangements to enable implementation. Moreover NBFD implementation is far from self-evident; in fact most of the time traditional solutions are preferred. In this report we look into the actor interactions that are associated with NBFD and aim to improve understanding of NBFD implementation in flood defence projects. For that purpose we develop and apply a game theory based research approach. The objective is to: 1) systematically describe actor interactions in NBFD decision-making and the benefits of potential actor coalitions in NBFD projects; 2) identify exemplary NBFD games; and 3) understand solutions to the NBFD games and factors that may foster NBFD implementation. The approach is applied it three Dutch NBFD case studies: the Sand Engine, Markermeer dikes and the Afsluitdijk.@en

Greening flood protection (GFP) is increasingly recognized as an adaptive and flexible approach to water management that is well suited to addressing uncertain futures associated with climate change. In the last decade, GFP knowledge and policies have developed rapidly, but implementation has been less successful and has run into numerous barriers. In this paper, we address the challenge of realizing green flood protection goals by specifically considering knowledge in the decision-making of a Dutch flood protection project in Lake Markermeer. In this project, an ecological knowledge arrangement and a traditional flood protection knowledge arrangement are compared and their interactions analysed. The analysis provides insight into the specific difficulties of implementing GFP measures and identifies ways to realize GFP goals. The primary challenge is twofold: First, a self-reinforcing cycle of knowledge production and decision-making in the flood protection domain inhibits the introduction of innovative and multifunctional approaches such as GFP; second, the distribution of power is severely unbalanced in terms of ecological enhancement and flood protection, favouring the latter. Implementation of GFP requires structural change and the integration of ecological and flood protection knowledge and policy. Potentially rewarding routes towards this integration are the exploration of shared interests in GFP and the creation of mutual dependency between knowledge arrangements. The case study and the insights it provides show that GFP is far from mainstream practice and that implementation requires serious effort and courage to break with historical practices.@en