A Field Study of Green Roof Water Quality Performance
Keywords:Green roof runoff, water quality, water quality index
A green roof is a technology that is partially covered with vegetation and growing medium, planted over a filter and waterproofing membrane. Runoff water quality from the green roofs may have contaminants due to the effect from its surrounding or from the layer of green roof substrate. The objectives of this study are to analyze the water quality of the green roof runoff and to investigate the effectiveness of different vegetation treatments of the green roofs. Water quality experiments were conducted on runoff of four green roof test beds’ treatment. Three of the test beds were planted with three different vegetations, Alternanthera F. (Sample 2), Zoysia M. (Sample 3) and Sanseviera T. (Sample 4), while the other one test bed was used as a control roof that contained with only substrate known as non-vegetated roof (Sample 1). All results were compared to the Water Quality Index (WQI) and National Water Quality Standard Malaysia (NWQS) where the WQI results for Sample 1 is 59.41 (Class III), sample 2 is 55.91 (Class III), sample 3 is 54.03 (Class III) and sample 4 is 61.6 (Class III), respectively. It can conclude that the water sample from the green roof is suitable for fishery III (for livestock drinking) and water supply III which may require for further extensive treatment.