Cost-effectiveness Analysis in Low Impact Development of Qinxin District, Qingyuan City, Guangdong China

In recent years, thanks to extreme weather like storms and downpours, flood events have occurred frequently worldwide, endangering the personal and property safety of citizens. Most developed regions use low impact development (LID) measures to prevent flooding and other water-caused disasters. However, the laying cost of LID is expensive, and the utility of LID is different based on different types of LID facilities. Given the flood news in the Qingxin District of Qingyuan City, which caused plenty of citizen lives and property losses, it is necessary and urgent to study the drainage system plan and construction in this place in order to prevent another blow from bad weather in the future. Therefore, this paper aims to study the cost-effectiveness of various types of LID by the precipitation data of Qingyuan so as to find out how to reduce flood inundation at the lowest cost. The results demonstrate that the covered area of vegetative swale is simply 600m^2, and it can reduce most runoff and outflow. Besides, multiple LIDs can reduce nearly 40% of runoff and overflow in the most significant gap. Based on the reliable simulation analysis and former research, it can be concluded that the vegetative swale is the most cost-effective facility toward other LIDs, and the permeable pavement is the worst efficiency measure.