Scenario‐based hydrodynamic simulation of adaptive strategies for urban design to improve flood resilience: A case study of the Mingzhu Bay Region, Guangzhou, Greater Bay Area

Abstract The Pearl River Delta is a complex ecological‐artificial system. The low‐elevation landform and land subsidence make the Guangdong‐Hong Kong‐Macao Greater Bay Area (GBA) more vulnerable to heavy rainstorms with sea‐level rise in the future. Therefore, this study discussed how to optimize the delta‐related built environment based on locality via cooperation between urban designers and hydrology researchers so that urban development in the GBA can adapt to water disasters. First, this study proposed three adaptive spatial strategies for urban design to improve flood resilience: (a) adding more sunken space and rearranging the locations of manholes; (b) adding more retention space to the waterway system; and (c) improving foundation elevation for suitable development intensity. With the prediction of sea‐level rise and land subsidence, four different scenarios were defined. Second, a coupled 1D/2D hydrodynamic model was built for scenario‐based urban inundation simulations. Third, a Python workflow was developed to reveal the water volume exchange, and an ArcMap workflow to realize the impact of inundation. The simulation results show that (a) more sunken space can lower the peak runoff discharges and decrease the runoff coefficient; (b) more retention space can extend the capacity of the urban drainage system and adapt to the rise of sea level; and (c) improving foundation elevation and more sunken green space can direct the surface water to submerge urban land in reasonable order, which can protect the significant infrastructures and development lands. This paper suggests that these adaptive spatial strategies can serve as solutions for resilience development.