Résumé
In this work we present a modelling procedure in order to compute the confinement field of a lagoon. We improve existing models in order to account for tide oscillations in any kind of geometry such as non-rectangular lagoons with a non-flat bottom. The confinement can be defined at various scales (ocean, interior see, large bay, lagoons) and we shall introduce a suitable multi-scale numerical method for the computation of confinement.