The potential of green infrastructure (GI) for reducing stormwater runoff in a phnom penh neighborhood

Abstract

Any increase in impervious ground surfaces due to urban growth tends to intensify stormwater management problems. Partial urban flooding can occur any time when the volume of stormwater exceeds local drainage capacity. Phnom Penh has suffered from urban flooding for more than a decade because of the limited capacity of the city’s drainage system. Numerous studies have investigated and proposed the use of green infrastructure (GI) as a tool for mitigating flooding due to stormwater runoff. The purpose of this study is to investigate the potential of proposed GI features for reducing stormwater runoff in central Phnom Penh. By using the Rational method, the peak discharge was analyzed and estimated for Tuol Svay Prei Pir, a central Phnom Penh neighborhood that experiences frequent flood problems. The runoff peaks produced by the current practices (S1), and the proposed practices that integrate with the GI features (S2) were compared. The results show that an increase in pervious surface up to 48.14% by implementing the four GI features; trees, bioswales, permeable pavements, and green roofs, the runoff rate will be reduced by 37.90%, which is equivalent to a reduction of 1.55 m3/s during peak runoff.