The present invention is a structured body for drainage treatment which is an unit box composed of a top panel having multiple weep holes and downward cylinders provided therein and side walls having multiple weep holes and joints for connection, which can be spread to a desired size by connecting these unit boxes. The structured body for drainage treatment can be used as a material for drainage of sports grounds, roads, parks, golf links, stockhouses, riding grounds and the like, as an antifreezing material for roads in cold districts, and as a material for preparing tree-planting ground in the concrete portion on the roof, desert areas and the like. Furthermore, the present invention includes and impounding and flushing system to prevent muddy earth (sludge) from sedimenting in the concrete face of the like on the building roof which s the face that the structured body for drainage treatment described above is to be placed.
