The RougeMer dike is located on the lake-reservoir of the Der-Chantecoq. The RougeMer dike has a length of 550 meters and separates the Marne main reservoir from the South Watershed. It is a submersible embankment dyke, whose peak is approximately at the coast of 139 metres and its maximum height is 9 metres. The RougeMer dike is a dike within the work of Lake Der. The finding of disorders on the dam facings to the right of the slabs in the upper part (cracks in particular to the right of the joints) and the bituminous concrete in the lower part (deformations, degradation of surfaces) led in particular to the realisation of a diagnosis carried out by COYNE and BELLIER. It is a question of carrying out comfort work to secure this dike.