The « storm network » as a participative network for monitoring the impacts of coastal storms along the littoral zone of the Gulf of Lions, France

De la Torre Y, Balouin Y., Heurtefeux H. and Guérinel B., 2013.The “Storm Network” as a participative network for monitoring the impacts of coastal storms along the littoral zone of the gulf of Lions, France

The French coast of the Gulf of Lions is a low-lying coastal plain where humans have strongly developed infrastructure and urbanized the coastal zone, disregarding the potential impact of extreme events. This results in an increase of coastal vulnerability to extreme storms with damage to harbor facilities, coastal tourism infrastructures, and urban infrastructures. To improve the management and prevention of such threats on the coastal zone, a monitoring network of coastal storms and the resulting impacts was created. The aim of the “Storm Network” is to obtain good quality and homogeneous data along the entire Languedoc-Roussillon coastline to enhance the regional knowledge on coastal extreme events and their impacts and to validate morphological models. According to the analysis of all historical events, an assessment of three thresholds of morphological impacts was done, basing on the offshore significant wave high indicator. A monitoring program was defined with three corresponding levels of intervention such as: level 1 (3m<Hs<4m) for physical information gathering with no field visit required; level 2 (4m<Hs<5m) qualitative field observations; level 3 (Hs>5m) additional quantitative surveys and numerical modeling. In order to anticipate the event, an operational model for wave forecasting is used (WW3 Mediterranean model, by Ifremer). When reaching the defined levels, an automatic email is sent to the operators of the network to prepare the intervention. The Storm Network was implemented in 2011, was activated during the winter 2011/2012 and is currently running. It permitted to localize precisely the storm impacts and to analyze their spatial variability.