Stakeholder priorities for multi-functional coastal defence developments and steps to effective implementation

To fulfil international marine conservation commitments, governments have begun to recognise the need for more proactive marine planning policies and legislation, advocating sensitive engineering design that can deliver secondary benefits above and beyond the primary purpose of developments. In response, there is growing scientific interest in novel multi-functional coastal defence structures with built-in secondary ecological and/or socio-economic benefits. To ensure research efforts and resources are invested effectively, it is first necessary to determine what secondary benefits can potentially be built-in to engineered coastal defence structures, and further, which of these benefits would be most desirable. It is unlikely that secondary benefits would be perceived in the same way across different stakeholder groups. Further, their order of priority when evaluating different design options is unlikely to be consistent, since each option will probably present a suite of compromises and trade-offs. The aim of this study was to investigate stakeholder attitudes towards multi-functional coastal defence developments across different sector groups. A preliminary questionnaire indicated unanimous support for implementing multi-functional structures in place of traditional single-purpose ones, despite disparate personal and professional opinions on flood and coastal erosion risk management in general. Responses submitted to this preliminary survey informed the design of a Delphi-like study, which revealed a more nuanced and caveated level of support from a panel of experts and practitioners. The study also elicited a degree of consensus that the most desirable secondary benefits that could be built-in to developments would be ecological ones – prioritised over social, economic and technical benefits. Here we synthesise these findings, discuss the perceived barriers that remain, and propose a stepwise approach to widescale and effective implementation of multi-functional coastal defence developments.