Influence of the Reconstruction of Rainwater and Sewage Diversion Pipe Networks on Urban Inundation

To investigate the impact of well point layout in pipe networks on surface inundation and rainwater/sewage discharge during the reconstruction of rainwater and sewage shunting, a coupled simulation using the stormwater management model and the graphics processing unit-accelerated surface water flow and associated transport model was conducted to compare the overall impact of different new pipe network methods. The study assesses the effects of well point distances and pipe network diameters on the overall system in different rainfall return periods. Research shows that, irrespective of whether new rainwater pipes or new sewage pipes are implemented, the transformed schemes involving different well point distances and pipe diameters yield positive effects compared to the pretransformation state. The solution that uses original combined pipe as a sewage pipe and builds a new rainwater pipe is more effective in eliminating surface inundation. Notably, the approach utilizing the original combined pipe as a sewage pipe while introducing a new rainwater pipe proves more effective in mitigating surface inundation. Specifically, a pipe network with a well point distance of 30 m and a pipe diameter of 1,000 m demonstrates the most effective results in preventing inundation among the two transformation methods. By comprehensively considering the influence of well point layout in the pipe network across various rainwater and sewage diversion reconstruction strategies, this study aims to offer theoretical support for the revitalization of old city pipe networks.