The invention relates to a method for dredging without the significant causing of pollution nor significant consumption of water. The invention concerns the field of civil engineering, the dredging of impoundments and of watercourses. Common techniques have a number of drawbacks among which: waste pollutants, considerable consumption of water, and difficulty in manipulating the displaced silt. The inventive device is preferably characterized by the combination of the following processes that rectify the aforementioned drawbacks: vibrating the silt to be treated; cutting the silt by a cutter at a speed sufficient for obtaining, while adding water, a homogeneous mixture; pumping the mixture; injecting a flocculation product that causes, at the moment of release, the segregation of the mixture; release or recuperate clean water; manipulating, without hydraulic drive, and reusing the flocculated silt. Variants consist of modifying, according to the specific case, the relative impact of diverse combined processes. The inventive method is particularly suited for dredging dammed lakes.