Comprehensive Optimization Framework for Low Impact Development Facility Layout Design with Cost-Benefit Analysis: A Case Study in Shenzhen City, China

Sustainable storm water management benefits a lot from low impact development (LID). The early-stage design of LID layout is critical for LID practices. However, the technology gaps still exist for an accurate, flexible, and systematic solution of optimal design. Literature works usually only consider the size and number of LID facilities in a given scenario or even totally empirical, which lacks integration of facility selection, connection, and size with multiple management objectives together. Therefore, this study proposed a generic and comprehensive framework for LID layout design with cost-benefit analysis. Powered by the computer coding scheme for the LID layout and a hybrid optimization algorithm, the framework was successfully verified in Sponge City of Shenzhen, China. The optimization results of genetic algorithm proved the stability of the novel coding scheme for LID layout. The best and worst scenarios are selected from the Pareto front through the entropy weight method. The variable cost weight method revealed the sensitivity from the cost preference of the decision maker. High construction costs and environmental effectiveness can be scientifically balanced in the procedure of early-stage design. The proposed design framework is expected to be widely verified and applied in storm water management practices around the world.