ABSTRACT Due to increasing disruptions in rainfall patterns, stormwater management, and pollution accumulation brought on by urbanization and climate change, urban hydrology faces significant challenges. Although the demand for sustainable solutions is rising, limited research has focused on integrating stormwater management practices, such as Low Impact Development (LID) stormwater controls, in areas where rainfall variability and pollutant accumulation are pronounced. This study investigates the effectiveness of Low Impact Development (LID) stormwater controls, specifically bioswales, in improving stormwater quantity and quality in Ver Dominic Heights, a newly developed residential area in Palo, Leyte, Philippines. Using the EPA Storm Water Management Model (SWMM), simulations were conducted to approximate existing site conditions and evaluate the performance of bioswales under varying green‐to‐gray (GG) land use ratios, ranging from 1% to 99% at intervals of 10%. Rainfall scenarios were modeled for the 85th, 90th, and 95th percentiles, with bioswale surface areas compared to impervious structural coverage. The study incorporated pollutant data, including Total Suspended Solids (TSS), zinc (Zn), and lead (Pb), sourced from literature and site‐specific assessments. Results highlighted that frequent use of motorcycles and tricycles contributed to localized pollutant buildup despite minimal overall traffic. SWMM simulations revealed that runoff peaked at 30%‒40% green coverage before stabilizing at 90%. At the same time, infiltration remained consistent, achieving a maximum of 10 mm under the 95th percentile rainfall scenario at a 90:10 green‐to‐gray ratio. The significance of context‐sensitive approaches in stormwater management planning was highlighted by a comparative examination of site‐specific and literature‐based pollution data, which showed that localized data gave more realistic and moderate results. This study highlights the integration of bioswales and green infrastructure in urban development to reduce rainfall‐induced runoff and pollutant accumulation successfully. The findings provide important insights into optimizing green‐to‐gray ratios for sustainable stormwater management and underline the necessity of site‐specific assessments to handle the variability of rainfall and pollutant dynamics.
Lopez et al. (Thu,) studied this question.