In the summer of 2020, southern China suffered historic torrential rains and floods, especially in the middle and lower reaches of the Yangtze River. From the extent and scope, it appears that the damage caused by the floods is likely to exceed that of 1998. According to Vice Minister of Emergency Management Zheng Guoguang, as of July 13, 38.73 million victims were reported in 27 provinces, autonomous regions, and municipalities across the country, with 141 dead and missing. 29,000 houses collapsed, and direct economic losses account for approximately RMB 86.16 billion. In addition, the area of farmland with no harvest reached 516,000 hectares. As the moved northward to the Huai River Basin, the battle against the flood in China has encompasses the two regions the Yangtze River and the Huai River. If large-scale precipitation occurs in northeastern China, there may even be a situation where China has to face flooding in three regions. For China, which has just been recovering from the Covid-19 pandemic and took the lead in resuming work and production, the floods are undoubtedly a second blow to the country.
Torrential rainstorms certainly are the main cause of this year's floods. However, overemphasis on natural disasters conceals some problems in China's development. We have noticed that in this year's rainy season, before floods constituted a major disaster, many cities in China had experienced an old problem in recent years, namely urban waterlogging. In many Chinese cities, there are serious waterlogging roads and flooded houses, which seriously affects the operation of the city. Cities in China, in fact experiencing flooding every year, and waterlogging has become a general governance problem that urgently requires to be resolved. In the past ten years, many cities such as Beijing, Shanghai, Guangzhou, Chengdu, and Wuhan, have experienced increasing rain waterlogging incidents. According to the 2010 survey of waterlogging in 351 cities in 32 provinces by the country's Ministry of Housing and Urban-Rural Development, since 2008, 213 cities have experienced waterlogging to varying degrees, accounting for 62% of the surveyed cities. 137 cities in China experience at least 3 waterlogging disasters each year; and this even happened in western and northern cities in the country, such as Xi'an and Shenyang, which are dry and less rainy.
Many cities in China struggle to counter flooding every year. On the surface, this is caused by continuous rainfall, but what lies behind is that the infrastructure construction is seriously lagging, especially the debt-filled drainage system. In the event of heavy rains and other extreme weather, many cities will be prone to urban waterlogging. Cheng Xiaotao, part of the National Committee on Disaster Reduction expert committee and the chief editor for the Journal of Hydraulic Engineering, is of the opinion that, "the entire waterlogging prevention system (in China) does not match the needs of modern urban development. The lack of a modern urban waterlogging prevention system is not only due to insufficient pipeline network construction, there is also the lack of support in comprehensive measures such the storage, separation, purification, infiltration, adjustment, and river and lake water system improvement."
The causes of common waterlogging in Chinese cities can be roughly divided into these following:
(1)The urban drainage system is seriously lagging behind with low design standards. Data from the State Flood Control and Drought Relief Headquarters shows that the current drainage standards of cities above the provincial capital in China are generally only 1-2-year frequency, and the drainage standards of other cities are lower, which is very different from developed foreign cities. New York is 10-15-year frequency, Tokyo is 5-10-year, and Paris is 5-year. According to the requirements ofOutdoor Drainage Design Specification GB50014-2006, the design rainstorm return period of the drainage system in general urban areas is 1-3 years, in important areas it is generally 3-5 years, and especially important areas use 10 years or more. However, the average return period of the rainstorm designed in Wuhan is one year, and that in Beijing is only 2-3 years.
(2) There is the blind urban expansion, causing the decrease of ground water seepage, the decrease of urban natural water surface, and the decrease of water storage capacity. Large-scale, irrational urban development and construction are an important cause of frequent flooding. The expansion of urban construction has caused the depression landforms, ponds, lakes, and reservoirs that originally had the function of natural water storage and flood diversion to be damaged by artificial filling or filled for other purposes, thereby reducing their function of rainwater regulation and diversion. For example, Wuhan, nicknamed "City of a Hundred Lakes", has water area accounts for about 25% of the city's land area, ranking first among provincial capital cities in the country. However, with rapid urbanization, especially since the 1990s, various water bodies, including lakes, have been filled up continuously, and the lake's "reservoir" function has become increasingly weakened.
According to Xu Huiyan from the School of Geographical Sciences of Shanghai Normal University, the water area of the main urban area of Wuhan in 1990 was 216.88 km2, and by 2010 the area had dropped to 171.25 km2, a reduction of 45.63 km2 within 20 years, and a 4.78% decrease in the regional area ratio. In terms of the amount of change, the area of lake water body reduced in the later 10 years is greater than that in the first 10 years. The important reason for the decrease of lakes is lake filling, i.e. converting lakes into construction land. Due to the reduction of lakes, the heavy rains and floods in 2016 caused 323 enterprises in Wuhan to be affected by flooding, with a direct economic loss of RMB 351 million, paralyzing railway transportation, urban rail transit, and road traffic. In addition to the natural causes of precipitation, the reduction of lakes is considered to be an important cause of urban waterlogging in Wuhan.
(3) During the development, more emphasis is given to what is on the surface than beneath the ground. As the benchmark for measuring urban development and cadre assessment of some places in China focuses more on economic growth, the result is that high-rise buildings, wide streets, grand squares, and business prosperity have become signs of political achievements. Therefore, urban underground drainage systems that are expensive but not visible receive far less attention. The experience of developed countries shows that the ratio of urban underground and above-ground infrastructure investment is about 1:1, but according to theStatistical Yearbook of Urban Construction in China, currently only 4% of the fiscal funds used for municipal infrastructure in China are invested in the drainage system maintenance.
(4) The investment in underground drainage pipe network in urban construction is seriously insufficient. For a long time, the main body of urban infrastructure investment has been financing platform enterprises under local governments and their subordinates. However, as the debt burden of local governments has become heavier, local governments have become unable to expand investment.
In response to the problem of urban waterlogging, in 2013 the State Council successively issued various rules and regulations, emphasizing the need to strengthen urban drainage infrastructure construction. However, the extensive urbanization in China still maintains strong inertia and neglects the corresponding urban infrastructure. As a result, urban waterlogging still occurs frequently. Lin Hongchao, director of the Emergency Management Law and Policy Research Base of China University of Political Science and Law, believes that the seriousness of urban waterlogging has a lot to do with the unreasonable urban planning, in both planning concepts and planning infrastructure. Therefore, in order to completely resolve the urban waterlogging, it is necessary to actively promote the implementation of the main responsibility of the city government and paying attention on urban drainage and waterlogging prevention. On the other hand, relevant authorities should invest financial resources to formulate detailed construction plans and improve urban planning.
The severe urban waterlogging issue in China reveals the acute problems of the country's cities, from planning to infrastructure construction, from urban water area protection to maintaining ground permeability, from urban drainage system standards to sewer construction. All in all, there is a necessity to re-examine the construction and development of cities. In the opinion of ANBOUND researchers, the problem of urban waterlogging in China actually raises the issue of urban renewal for the country's urban development. Faced with multiple urban planning and construction quality issues, with problem no less than huge losses caused by waterlogging for years, this clearly shows that the failure of urban construction in the past must be corrected by urban renewal.
It is worth mentioning that China is now vigorously advocating "new infrastructure", in an attempt to locate technological innovation through investment in 5G, the internet, electric power, charging piles, etc. Ironically, when these "new infrastructure" that are the talk of the town becomes the focus, some traditional and ordinary "old infrastructure" in the cities are in less than satisfactory condition. Premier Li Keqiang recently pointed out the problems in urban construction at a meeting of the State Council that some areas that are not old communities or shantytowns are demolished under the pretext of urban beautification, but the issue of the huge financial burden is not being considered. Urban development's area of focus should be urban renewal, and improving the basic functions and systems that are lacking in urban construction is the truly important "new infrastructure." Therefore, ANBOUND believes that the core of the "new infrastructure" should be promoting urban renewal, not just focusing on 5G and the internet. After all, regardless the quality of the internet, it will not prevent cities from being flooded.
Final analysis conclusion:
The seriousness of flood in China once again exposed the shortcomings of waterlogging in its cities, and revealed the neglect of many aspects of urban construction in the past rapid urbanization stage. Nowadays, as China engages in "new infrastructure", it should not just focus on 5G and the internet. Instead, urban renewal is extremely crucial as well to make up for the shortcomings of the urbanization process in the past. This will be an urgent problem for cities to resolve.