Simulations de rejet en rade de Brest d'ulves draguées dans l'anse du Moulin Blanc

This document deals with the 3D ecological model, tailor-made in 2001 (Leblond et al., 2001) to answer a contractual demand from the CUB on the origin of the nitrogen involved in the green tide on the Moulin Blanc beach. This mathematical model of the roadsted of Brest was especially designed for a precise study of the Elorn rivermouth (area where the mesh is square, 150 m long on each side), and enables not only a hydrodynamic study, but also a study on the fate of the nitrogen and phosphorus rejects in this area. Concerning the hydrodynamic part, this model, based on the IFREMER SiAM3D code, recreates a tide propagation validated by measures, in spring tide and slack tide, in terms of surface elevation and speed ranges, as well as the freshening plume of the Elorn and Aulne rivers varying according to the spring tide / slack tide cycles, with a stratification during slack tide and a quasi-homogenous water column during spring tide.