The first area is Saint Aubin Island is located at the confluence of the Sarthe and Mayenne Rivers and the old Maine River, north of Angers. The island’s 600 hectares are used for agriculture and livestock grazing. Flooded every winter, this area has a significant biological diversity that has been recognized through various measures for several decades (Espace naturel Sensible, Zone naturelle d'intérêt écologique, faunistique et floristique, Natura 2000). The second area is the Balzac Park, located just downstream from the city center. It is an urban park whose management aims to reconcile flood risk reduction with recreational opportunities and biodiversity preservation.