Associated with the port construction and/or coastal reclamation, it is sometimes required to construct new tidal flats or rehabilitate damaged tidal flats. Experiences on construction and rehabilitation along Japanese coasts are reviewed. Understanding of the physical systems which support benthic ecoIogical activities is necessary. Five elemental conditions can be pointed out for the supporting system. In the field, natural fluctuations of these elemental conditions are inevitable. For the self-stability of the ecosystem, negative feedback mechanisms and/ or environmental gradient and variety are important for designing and management in both constructions and rehabilitation of coastal tidal flats.
