English: Diagrammatic representation of the average flows of french rivers that feed via their estuaries a "coastal river" in the Eastern Channel, which is in France the subject of a proposed Marine Nature Reserve (subject to public inquiry in 2011). We see here the major importance of the Seine river. The mainstream "flatten" against the shoreline waters, creating a hydrographic (and ecological) feature wich consists of a water less salty and less dense, which behaves like a river along the coast of Picardy and Pas-de-Calais then tend to be diluted in the North Sea after the Cap Gris-Nez and Blanc-Nez. while mixing with the addition of Aa river, of yser riverr, and especially of the Scheldt river.