According to the National Defense Statistics, over 360 cities in China have experienced waterlogging in the past three years, which has directly caused huge economic losses. At present, "waterfall every rain" has become one of the major disasters in China's cities. With the enhancement of the "heat island effect" and "turbid island effect" caused by the rapid development of urbanization in China, the frequency of urban rainstorms continues to increase; there are a large number of hard pavings in the city, such as asphalt roads and cement roads, and the water permeability is not Good; there are few water storage bodies, and it is unable to hold up the short-term sharp increase of rainwater. At present, the design standards of drainage pipeline networks in many cities in China are generally low. In some places, drainage facilities are not perfect and imperfect, and the construction of drainage systems lags behind. The reduction has caused the dual pressure of increasing runoff and decreasing storage capacity of urban drainage, which is an important reason for frequent urban waterlogging in recent years.
According to the statistics of the Ministry of Housing, Urban and Rural Construction, more than 300 of the 657 cities in the country belong to the "severe water shortage" and "water shortage" cities in the evaluation criteria of the UN-HABITAT. Most of them are located in the temperate and subtropical monsoon regions of China. Therefore, in the rainy season, there is often urban waterlogging caused by concentrated rainfall. At present, more than 99% of cities in China belong to the rainwater concentration and rapid drainage mode, and natural precipitation has very limited relief from urban drought.
Pipe network reconstruction costs are high, construction is difficult, and the cost-effectiveness ratio is low. Although many cities suffer from severe waterlogging due to rain due to low design standards and lagging construction of drainage facilities, they are constrained by the complexity of urban pipe network lines, large volumes of reconstruction, and high capital demand, making it difficult to improve the situation in a short time. Most cities in China are located in the monsoon area. For many areas with insufficient rainfall, rainfall is concentrated in a few short time points. Therefore, the city-wide "surgical" reconstruction is not cost-effective and difficult to obtain. Sufficient support.