PURPOSE: To use effectively the waste together with manufacturing of a reinforcement construction for revetment of rivers, etc., at low cost by mixing and filling the sludge deposited at the water bottom of rivers, lakes and marshes, dams, and the like together with the inorganic hydrates into a bag constituted of a permeable sheet.

CONSTITUTION: The sludge 1 deposited at the water bottom of rivers, lakes and marshes, dams and so on, is dredged, and it is condensed and deposited by means of a sedimentation basin after passing through a multistage sieve 3. The inorganic hydrate-matrix composed mainly from the ettringite phase is added to the muddy sludge obtained in this way to be mixed by a mixer 7. It is impregnated and filled into a bag 8 constituted of a permeable sheet such as a synthetic textile cloth, etc., by a pump 9. Then, it is molded and hardened into the bag to form the surface reinforcement construction.