New perspectives on urban stormwater management in China, with a focus on extreme rainfall events

Climate change, especially the rise in extreme rainfall events, combined with urbanization, poses significant challenges to traditional hydrological methodologies. These developments call for researchers to reassess conventional analytical and numerical approaches and make the necessary adjustments to address these evolving conditions. In this study, we begin by analyzing the patterns and mechanisms of the extreme rainfall event in Zhengzhou on July 20, 2021 (“7.20” extreme rainfall in Zhengzhou). Building on this analysis, we offer insights and propose solutions to key issues in urban stormwater management. A bibliometric analysis of the Zhengzhou event indicates that urban flooding is primarily driven by climate change, with urbanization being a secondary factor. Additionally, the integration of machine learning with traditional numerical hydrological models, such as the widely used SWMM model, has emerged as a research trend to enhance the accuracy and comprehensiveness of parameter estimation. New urban stormwater management techniques and strategies are essential for improving urban flooding resilience, including a three-level collaborative governance system, urban green-gray-blue facilities, smart integrated management, and digital twin technologies. Furthermore, fully coupled water management models and strategies that incorporate all elements of hydrological cycles are essential for addressing complex urban hydrological challenges.