Study of flooding hazards in highly urbanized area based on a coupled one- and two-dimensional hydrological-hydrodynamic model

Under the background of climate change and urbanization, urban flooding occur frequently.In this study, based on the Wuxi Economic Development Zone as an example, a one- and two-dimensional hydrological-hydrodynamic coupled model was constructed based on MIKE FLOOD, aim at exploring the impacts of different magnitudes of rainfall on urban flooding. A 3-hour short-duration rainfall was designed to assess the drainage capacity of the rainwater network and a 24-hour long-duration rainfall was designed to simulate urban flooding under different rainfall return periods. The results showed that 49.81 % of the pipes had a capacity of less than 1 in 1 year, mainly in the old urban areas, and 31.53 % of the pipes had a capacity of more than or equal to 1 in 5 years, mainly in the new urban areas.In addition, as the rainfall return period increases, the inundated area and inundated water volume also increase, but when the return period exceeds 1 in 10 years, the increasing trend tends to level off. This study not only reveals the relationship between the rainfall return period and urban flooding, but also puts forward countermeasures for flood prevention, which provides a reference for the study of urban flooding in similar areas.