Research on drainage and flood control benefits of green facilities under multi-factor coupling

Abstract

[Objective] To optimize the drainage and flood control system in urban self-draining areas and enhance their capacity to cope with extreme rainfall. [Methods] Taking the Central Business District of Qingpu New City in Shanghai as a case study, a 1D~2D coupled drainage pipe network model was constructed based on Infoworks ICM. The effects of multiple factors, such as river water level and layout proportion, on the waterlogging reduction benefits of green facilities were analyzed. Three typical types of green facilities were selected: sunken greenbelt, rain garden, and permeable pavement. The total waterlogging volume and waterlogging area under short-duration( 120 min) and long-duration( 24 h) rainfall conditions were simulated to quantitatively evaluate the benefits of these facilities under different layout proportions and water level boundary conditions. [Results] The result showed that under both short-and long-duration rainfall conditions, the reduction effectiveness of green facilities increased with increasing layout proportion. However, the waterlogging reduction benefit of the sunken greenbelt was significantly higher than that of rain gardens and permeable pavements. The three types of green facilities exhibited superior performance in reduction benefits under short-duration rainfall conditions compared to long-duration conditions. Variations in river water level had a minor influence on the waterlogging reduction benefits of green facilities. [Conclusion] The optimization framework for green facility layout proportion under multi-factor coupling proposed in this research provides an important reference for the optimized design of urban drainage systems and the construction of sponge cities.

Keywords

green facilities / Infoworks ICM / self-draining area / multi-factor influences / drainage and flood control / waterlogging reduction / extreme rainfall / sponge city