Discussion on the urban flood and waterlogging and causes analysis in China

With the development of economy and society, China has stepped into the rapid urbanization process with the population urbanization rate rising from 36.22% in 2000 to 54.77% in 2014. Under the background of global climate change and rapid urbanization, urban flood and waterlogging hazards become more frequent in this country. In this paper, the mechanism of how global climate change and urbanization affect urban precipitation including extreme rainfall was preliminarily analyzed and the effect of urbanization on flood process was also explained from the aspect of surface runoff yield and flow concentration process. Then, the causes of frequent urban floods in China were analyzed systematically. Moreover, main tactics of urban flood and waterlogging prevention and alleviation were stated. Firstly, the urban infrastructure should be strengthened guided by the idea of low impact develop (LID). Thus, sponge cities with good defense ability for rainstorm could be constructed. Secondly, the urban flood management systems with 3-dimension urban flood monitoring, dynamic forecasting and warning and real time operation should be established to raise the scientifically decision-making for flood disasters reduction. Thirdly, to intensify the disaster relief and recovery for urban flood, the emergence plans should be drawn and improved.