34

In the Arcachon Bay, researchers and local players are reflecting together on the ways to deal with the broadly acknowledged risk of coastal flooding and its management methods. The latter waver between the currently implemented harder management method and a softer one based on different levels of depolderisation. The depolderisation technique is being investigated through an interdisciplinary, comparative and multiscalar approach. If handling risks of coastal flooding through depolderisation may seem paradoxical, scientific studies have highlighted the interest of this defence approach, especially to curb swell and reduce defence costs. In the south-eastern part of the Arcachon Bay, the Barcasub programme (Liteau, MEDDE) is thus investigating the positive and negative effects of potential management methods as regards defence, economics, landscapes and ecology. Locally, the policies and uses regarding reclaimed areas have turned markedly green since the 1970s. However, both the social perception of the risk and of depolderisation, cannot be said to have turned green as well. In fact, this defence method would certainly lead to a change in polder management or in territorial uses. The study also leads us to reflect on the overall defence of the Arcachon Bay currently in process through hard and soft coastal protection measures. Through its comparative as well as multiscalar approach of the reclaimed areas, our research programme aims to establish the scales at which depolderisation actions could be relevant.