This lake stretches along the course of the Semnon, a river which rises in Mayenne and flows into the Vilaine to the north of Pléchatel. The rugged landscape and presence of numerous outcrops of schist on the shores of the lake are just two of the characteristic features of the area and they have produced a particular type of aquatic flora. It is easy to identify the differences in vegetation corresponding to the type of soil. Footpaths, angling and water sports areas, and a bird sanctuary...