INVESTIGATION OF DRAINAGE WATER QUALITY AND WATER MANAGEMENT SYSTEM FOR ROOFTOP PLANTING

Quality of drainage water from rooftop planting is monitored at Kinki University. Drainage water from greening basement such as artificial soil is analyzed to detect the source of substances in it. These investigationsled to followingc onclusions: (1) Drainage water from rooftop planting is rich in NO2-N, NO3-N and PO4-P, which are eutrophic substances to public water bodies such as lakes and ponds. (2) These substancesc ome fromn ot only fertilizer or herbicide but also artificial soil and drainage filter. Extension of the rooftop planting area increases amount of water demand for planting and discharge of eutrophic substances in drainage water. Water recycle system that collects and reuses rain water and drainage water from rooftop planting is proposed to solve this problem.