Modelling the Influences of River Water Level on the Flooding Situation of Urban Areas: A Case Study in Hanoi, Vietnam

Urban flooding is one of the typical disasters in many cities, especially in riverside cities. This study has developed an integrated model to assess flooding in Hanoi, Vietnam, taking the water level impact of surrounding rivers into account. In the integrated model, the Mike Urban model is used to simulate the flow in the sewer system, the Mike 21 model is used to present the overland flow on the surface, while the Mike 11 model is used to simulate the flow in the river. The result of the study shows that the river water level has a significant influence on the drainage capacity of the system. When considering the effects of the river water level, the flooding depth becomes more serious as well as the flooding period. This result shows that, by operating the system of works to maintain the low water level of the surrounding rivers, the flood level of Hanoi city will be significantly reduced.