The EPBT-B Seine Grands Lacs will update the topographic and bathymetric surveys of 2003 as part of a better management of the storage volumes of the Marne Reservoir Lake.In the first step, measurements of the bowls to the coast of danger and also complete belt measurements will be carried out. Then, on the basis of the data collected, a numerical field model will be created (construction of vector curves-Altitude etc...). Finally, a comparison with previous surveys will be carried out in order to identify the main changes.