Abstract:

To cope with the severe flood challenges caused by extreme meteorological events in the western part of Shanghai, an effective water level control strategy was proposed. The Qingsong region of Shanghai during the “Fireworks” typhoon was selected as the research object. The actual rainfall and working condition data were comprehensively analyzed, including rainfall, water level of the river outside the polder, water level of the secondary polder, and water level process of the river outside the polder. Two strategies were proposed, namely, over-storage of rivers and lakes in the secondary polder area and controlling of drainage after the rain peak in the polder area. The effectiveness of alleviating the high water level was evaluated by using digital topographic analysis and numerical simulation of flood control. It is found that the implementation of the above strategies can greatly enhance the storage capacity, and the theoretical estimate is to increase the capacity by about 11.7 million m³ and 2.46 million m³, respectively, which can reduce the water level of the river channel in the area by about 30 cm, and effectively alleviate the high water level. This study not only verifies the effectiveness of the strategy, but also adds new controlling methods to the existing flood control and drainage system, which provides a scientific basis for the city’s scheduling decision-making when facing major water challenges, and has important practical value and theoretical contribution to building a more resilient water management system and ensuring the safe operation of the city.

Key words: flood disaster, typhoon, causes of high water, western Shanghai