PROBLEM TO BE SOLVED: To provide a water-absorbing/draining mat with a novel structure which can be laid on a ground surface without requiring large-scale construction, and can speedily, forcedly and optionally drain stored water to outside of a system by simply connecting the mat to a pipe connected to outside； and a drainage mechanism in a waste dump using the same.SOLUTION: A water-shielding layer is disposed on the ground in which wastes are collected, and the water-absorbing/draining mat 1 is laid on the water-shielding layer to collect wastes on the water-absorbing/draining mat 1. When it rains, water absorbed in the water-absorbing/draining mat 1 is sucked from a filtration pipe 2 of the water-absorbing/draining mat 1 to be drained to outside of the water-shielding sheet. Further, a water-permeable water-retaining layer is disposed on the water-absorbing/draining mat 1, and a plant culture layer is disposed on the water-retaining layer. Moisture in the culture layer is sucked through the filtration pipe of the water-absorbing/draining mat 1 to be discharged to outside, or moisture is fed to the culture layer from the filtration pipe 2 and/or the water-retaining layer, so that the moisture content in the culture layer is adjusted.【課題】大掛かりな設備工事は不要で、地盤面に敷設して、外につながるパイプに単に接続するだけで、溜まった水を滞留させることなく、速やかに、かつ強制的に、任意自在に系外に排出することができる新規な構造の吸排水マットとそれを用いた廃棄物集積場の排水機構を提供する。【解決手段】廃棄物を集積する地盤の上に遮水層を設け、遮水層の上に吸排水マット１を敷設し、吸排水マット１の上に廃棄物を集積して、雨天時、吸排水マット１が吸収した水を吸排水マット１の濾過管２から吸引して遮水シートの外に排水することを特徴とする。また吸排水マット１の上に通水性を持つ保水層を、保水層の上に植物の培養層を配置して、培養層の水分を吸排水マット１の濾過管で吸引して外に排出、あるいは濾過管２あるいは／および保水層から培養層に水分を供給して、培養層の水分量を調整する。【選択図】図２
