Optimization of Low Impact Development Facilities in Beijing CITIC Complex

Phase I project of Beijing CITIC Complex was completed in 2010. Its pipeline drainage system was built to convey 1 year storm event. But the new regulation heightened the design standard to 3 years for any new development. Phases II and III projects upstream of Phase I project site are under planning, and their conveyance system connect to the drainage system built for Phase I project. Therefore the bottleneck is how to convey the runoff of 3 year storm event without causing downstream flooding. This paper discusses various solutions including construction of underground detention tanks and low impact development (LID) facilities. The performances of various combinations of LID facilities and detention facilities were evaluated by SWMM model. The total cost including construction, operation and maintenance for each combination is also calculated. The optimal schemes were finally decided in favor of the LID facility deployment without underground detention tank based on the performance and cost. The types of LID facilities and the configurations are also identified.