In case of reclamation with pump-dredged soft bottom materials, it is important to estimate the level of Suspended Soild concentration in the effluent from the over flow weir.
　Authors carried out model tests as a part of study on effluent SS concentration estimation to study the relationship between the effluent SS concentration and the state of progress of the reclamation work. And authors also carried out tests to study the influence of the type of the basin and the SS concentration of the influent on that of the effluent.
　In the former tests, the effluent SS concentration increased greatly in the latter period of the reclamation work. In the latter tests, an experimental equation of the effluent SS concentration could be applied. As for the sedimentation in the basin, fly-ash did not disperse so widely and sedimented above the water level around the inlet zone. Kibushi clay did not sediment so high as fly-ash and its sedeimentation slopes were small.