Evaluate The Effect Of Low Impact Development Stormwater Management System On The Hydrologic Cycle

For areas that are urbanized rapidly, the practice of Low Impact Development(LID) has gained an important place in stormwater management and urban planning due to its capability and beneficial effects in restoring the original hydrological cycle. The performances of LID alternatives can vary substantially due to different climate conditions. This study investigated the performances of five LID alternatives under a semi-arid climate in northern China on water balance and flood control. A numerical model, USEPA SWMM5, was employed to run 10 years' rainfall events for these objectives. Two evaluation methods were proposed in this study including the efficiency index for water balance(Iw) and performance radar chart(PRC). The investigation of the five LID alternatives revealed that these LID alternatives functioned differently in flood control and water balance, and porous pavement performed best in all indices except the lag time. The two evaluation methods, in conjunction with the long-term numerical simulation, can facilitate design and decision making by providing a clear picture of the performance and functions for these LID alternatives.Data mining is an important method for extracting useful hidden information from large data. This data mining approach has made contribution for researchers and decision makers to make exact decisions. Therefore, this study used data mining approach by SWMM simulation to analyze the LID and get optimum combination solution. In this paper, Tianjin Airport Economic Zone was also choosen to study and present this methodology. This study showed the procedure of methodology application, this method demonstrate hydrological cycle improvement, which embodied in improving infiltration and interception capabilities through assessing the effectiveness of LID for hydrological cycle. Meanwhile, through three LID facilities(rain harvest, bioretention pits, and porous pavement) adoption as examples to present the procedure of optimum combination solutions based on SWMM modeling, by which the model was employed to run 11 years' rainfall events for realizing long-term assessment for design objective. In the view of long-term numerical simulation, the data mining methodology and these evaluation methods, the procedure shows a practical scheme in LID design, and it is useful to make decision in the urban Master plan, also to provide more perfect performance and functions for these LID alternatives.