PROBLEM TO BE SOLVED: To provide a water-retaining/water-draining base material ensuring water retention in a water-retaining recessed part without making supplied water flow down to the downstream side when formed into a greening structure.SOLUTION: The water-retaining/water-draining base material 1 is provided with at least peripheral walls 2a, 2b, 3a, 3b, a water-retaining recessed parts 4, 4a surrounded by the peripheral walls, and a plurality of supports 10 set to the water-retaining recessed parts each in a standing posture. The support includes a first support 10a having almost the same height as that of the peripheral wall, and a second support 10b higher than the first support. Nonwoven cloth 20 disposed on the water-retaining/water-draining base material 1 is supported by the top parts of the supports different in height from each other so that the back side of the cloth is formed into a downwardly-recessed curved surface. The recessed curved surface ensures the water to fall down to the water-retaining recessed part 4 from the nonwoven cloth 20.COPYRIGHT: (C)2008,JPO&INPIT【課題】緑化構造体としたときに給水された水がそのまま下流側に流下することなく、保水用凹部内に確実に保水することのできる保水排水基盤材を得る。【解決手段】保水排水基盤材1は、周壁2a,2b、3a,3bと、周壁で囲まれた保水用凹部4,4aと、保水用凹部に立設する複数本の支柱10とを少なくとも備える。前記支柱は周壁とほぼ同じ高さの第1の支柱10aと、それよりも高さの高い第2の支柱10bとで構成される。保水排水基盤材1の上に配置した不織布20は高さの違う支柱の頂部で支えられて裏面が下に凸の湾曲面を形成する。それにより、不織布20から保水用凹部4への水の落下は確実なる。【選択図】図4
