Long-Term Monitoring of an Urban Stormwater Infiltration Trench in South Korea with Assessment Using the Analytic Hierarchy Process

Abstract

Evaluating the functionality of small and decentralized low-impact development (LID) technologies often requires extensive labor, time, and costs for water quality analysis. In order to reduce these in an infiltration trench in South Korea, monitoring data gathered over a period of 8 years were used to determine its long-term performance, establish a stormwater quality estimation model, and develop a comprehensive evaluation tool. Our findings show that the infiltration trench can treat up to 90% of the stormwater runoff from a paved road but would require annual maintenance to minimize the reduction in infiltration capacity. The facility was able to remove an average of 83% of total suspended solids (TSS), 75% of biochemical oxygen demand (BOD), 80% of chemical oxygen demand (COD), 76% of total nitrogen (TN), and 79% of total phosphorus (TP), with the highest removal efficiencies observed after maintenance was conducted. Rainfall depth and air quality parameters (i.e., PM2.5 and PM10) were found to be positively correlated with TSS, COD, TN, and TP. These parameters were then used to develop a model for the estimation of influent stormwater quality, which can help in estimating the effluent water quality based on the average removal efficiencies. Furthermore, a comprehensive evaluation tool considering indicators such as treatment efficiency, cultural benefits, and facility and operating conditions was established through the analytic hierarchy process (AHP). Aside from determining the facility’s overall efficiency, this can also serve as a diagnostic tool to identify whether maintenance is needed or not. While atmospheric and hydrological characteristics differ in different regions, and the results may vary if applied in other facilities, this study can serve as a guide to the effective and efficient evaluation of similar stormwater management facilities in South Korea.

Performance of Sand and Mixed Sand–Biochar Filters for Treatment of Road Runoff Quantity and Quality

“…Stormwater filters have been widely reported to achieve the effective net removal of total P when phosphorous is primarily bound to particles [14,24,46]. Reactive filter materials reach moderate levels of dissolved PO 4 removal [14], but the leaching of PO 4 from the filters has been reported to be an issue in some cases [24].…”

“…The mechanisms of these changes are not entirely known or well documented; therefore, repeated surveys are necessary to provide information regarding the life cycle and maintenance needs of the filters. Jeon et al [46] gathered monitoring data from a roadside infiltration trench over a period of 8 years and they found that annual maintenance was needed in order to avoid a reduction in the infiltration capacity and treatment performance. It is evident that the filtration of stormwater at times of sustained runoff generation and limited source area concentration leads to the filters being rather a source than a sink for common water quality constituents.…”