Author(s): Mazlina Alang Othman, Aminuddin Ab. Ghani, Keng Yuen Foo, Chun Kiat Chang
Linked Author(s): Mazlina Alang Othman
Keywords: Water quality volume, water quality depth, percentile analysis, stormwater constructed wetland
Abstract: Water quality volume (WQV) is a storage that captures pollutant generated from stormwater. Maximized WQV should be greater or equal to 75 to 90 percentile runoff volume and these design volume are required to achieve specific reduction of pollutant. Percentile approach is used in WQV estimation because it determines the rainfall depth in term of water quality depth (WQD) for a specified percentage. Therefore, an investigation is conducted in the constructed wetland to investigate the relationship between WQD and constructed wetland performance. From the percentile analysis, WQD at 75th percentile is 24 mm. This is followed by 29 mm, 33mm, 42 mm and 54 mm for 80th, 85th, 90th and 95th percentile respectively. As stormwater went through the constructed wetland, Total Suspended Solid (TSS), Total Nitrogen (TN) and Total Phosphorus (TP) are reduced by 53%, 28% and 10% on average respectively. However, the design goal of 80% (TSS), 50% (TN) and 40% (TP) reduction are not accomplished because of low concentration of inflow that went through the wetland. The effect of rainfall depth on the performance of constructed wetland differs in every parameter. TSS recorded the highest performance in 86% with rainfall depth of 30 mm (between 80th to 85th percentiles). TN and TP recorded higher performance as rainfall depth is more than 50 mm and ranged from 6 months and 50 year average recurrence interval (ARI). Therefore, it is recommended that WQD in the study area to be in the range of 29 to 33 mm (80th to 85th percentile). To determine the applicability of this range, a case study should be carried out in differing sizes, geographic locations, site conditions and types of BMPs facilities
Year: 2017