Since the beginning of summer this year, heavy rainfall has caused severe waterlogging in many cities, resulting in casualties and serious property losses. The phenomenon of "urban sea viewing" reflects the historical "debt" in urban drainage facilities. To address urban waterlogging, the Ministry of Housing and Urban-Rural Development issued a notice in early July, requiring all cities to compile and submit comprehensive urban drainage (rainwater) and waterlogging prevention plans.

 

　　The Ministry recently issued the "Outline for the Compilation of Comprehensive Urban Drainage (Rainwater) and Waterlogging Prevention Plans" (hereinafter referred to as the "Outline"), which clearly lists the planning content, including assessment of urban drainage and waterlogging prevention capacity and waterlogging risk, and planning of urban drainage (rainwater) pipe network systems. The Ministry also stated that it aims to complete the separation of rainwater and sewage in drainage pipe networks within 5 years, and to build a relatively complete urban drainage and waterlogging prevention engineering system within about 10 years.

 

　　An industry insider told the Foundation Engineering reporter that the Ministry's "Outline" is a correction of the shortcomings in urban construction in recent years, and more importantly, it urges localities to strengthen the construction of underground drainage pipe networks, which may drive trillions of yuan in investment.

 

　　Planning to Solve "Urban Sea Viewing"

 

　　The "Outline" requires that through comprehensive measures, the central urban areas of municipalities directly under the central government, provincial capitals, and cities specifically designated in the state plan (36 large and medium-sized cities) should be able to effectively cope with rainstorms with a return period of no less than 50 years; the central urban areas of prefecture-level cities should be able to effectively cope with rainstorms with a return period of no less than 30 years; and the central urban areas of other cities should be able to effectively cope with rainstorms with a return period of no less than 20 years.

 

　　The "Outline" sets mandatory requirements for urban drainage and waterlogging prevention planning objectives: when rainfall within the design standard of the urban rainwater pipe network occurs, there should be no obvious water accumulation on the ground; when rainfall within the urban waterlogging prevention standard occurs, the city should not experience waterlogging disasters; when rainfall exceeds the urban waterlogging prevention standard, the city should basically operate normally, and there should be no major property losses or casualties.

 

　　Shao Yisheng, Secretary-General of the China Urban Water Supply and Drainage Association, said that to thoroughly solve the problem of urban drainage and waterlogging prevention, it is necessary to promote and strengthen comprehensive planning of urban water systems, integrate the originally interconnected but plan-segmented urban water system plans, control runoff through multiple coordinated approaches, and coordinate solutions to prominent problems such as urban water supply, drainage, and waterlogging. Taking Beijing as an example, the drainage capacity of rivers such as the Qing River and Tonghui River is limited. If urban drainage capacity is blindly increased, once it exceeds the river limits, new problems will arise. Shao Yisheng believes that the "Outline" issued by the Ministry this time is a big step forward in emphasizing comprehensive system planning and has grasped the key to the problem. "We must consider not only how to drain and where to drain, but also how to use and where to use. Cities should make more use of natural conditions such as natural rivers, lakes, and depressions, and build more sunken green spaces and permeable surfaces. This will help strengthen drainage and waterlogging prevention, increase water supply sources, and also help rainwater recharge groundwater, solving the problem of land subsidence caused by overexploitation of groundwater."

 

　　Zhao Sidong, General Manager of Kunming Drainage Facilities Management Co., Ltd., said that the current design standard for municipal pipe networks adopted nationwide is the "one-year return period" standard, which is lower than that of surrounding developed countries, leading to a higher frequency of water accumulation in Chinese cities.

 

　　Multiple Cities Actively Repaying "Debts"

 

　　In conjunction with the Ministry's "Outline", localities are actively making up for the urban drainage debt. Recently, Kunming Mayor Li Wenrong revealed on Weibo that in response to the "July 19" waterlogging in Kunming, underground pipes will be inspected one by one, causes analyzed, and scientific rectification carried out.

 

　　"Under the guidance of the planning outline, Xiamen's drainage (rainwater) and waterlogging prevention plan is being compiled in accordance with local conditions. Large engineering facilities, low-lying areas, and rivers should reserve space for waterlogging prevention facilities," said Guan Tiansheng, Deputy Chief Engineer of the Xiamen Urban Planning and Design Institute and Director of the Municipal Institute. "The old urban area will adopt more engineering measures to strengthen maintenance, and enhance flood discharge capacity by adding flood discharge pumping stations and open channels; new area construction should reserve space for waterlogging prevention facilities through advance planning."

 

　　According to the Ministry's requirements, in the process of urban development and construction, the impact on the original urban water system and water environment should be minimized; the comprehensive runoff coefficient after old city renovation must not exceed that before renovation, and must not increase the extra burden on existing drainage and waterlogging prevention facilities; when hardening ground in new development areas, the proportion of permeable surfaces should not be less than 40%.

 

　　According to the "2009 China Urban Construction Statistical Yearbook", only 4% of fiscal funds for municipal infrastructure were invested in the construction and maintenance of drainage systems, making it difficult to carry out regular maintenance according to standards.

 

　　"China's urbanization process is very rapid, but its ability to prevent and control rainstorm floods appears extremely fragile. In modern cities, due to excessively high population and resource density, losses caused by floods are also rising," said Li Chunguang, a deputy to the Kunming Municipal People's Congress.

 

　　May Drive Trillion-Yuan Investment

 

　　Against this background, the upgrading and renovation of urban drainage systems led by the Ministry of Housing and Urban-Rural Development is breeding huge investment opportunities.

 

　　According to the Foundation Engineering reporter, to cope with this year's flood season, cities such as Beijing, Shanghai, and Chengdu have all increased investment in the upgrading and renovation of urban drainage systems.

 

　　China's urban drainage problem is mainly due to insufficient length of pipe network construction, resulting in low drainage standards in most areas. The national per capita length of rainwater pipes in urban areas is 0.47 meters, while Germany's per capita rainwater pipe length in 2001 was already 8 times that of China today. Driven by the separation of rainwater and sewage, it is expected that during the "12th Five-Year Plan" period, nearly 200,000 kilometers of municipal rainwater pipes will be added, and the total new length of drainage pipes will double compared with the "11th Five-Year Plan".

 

　　Industry insiders estimate that in the next 8 to 10 years, the upgrading and renovation of urban drainage pipe networks may attract trillions of yuan in investment. According to incomplete statistics, Chongqing plans to complete 22 billion yuan of water conservancy investment in 2013; Beijing has also proposed to invest 2.12 billion yuan during the "12th Five-Year Plan" period to basically complete a rainwater-sewage separation drainage system and renovate drainage pipelines in the central urban area; and in 2013, Tianjin Water Affairs will spend 10 billion yuan on livelihood projects.

 

　　A research report by Changjiang Securities shows that China's total investment in sewage pipe networks during the "12th Five-Year Plan" will reach 244.3 billion yuan. Generally, for every sewage pipe laid on a road, two corresponding rainwater pipes are built, so the investment in rainwater pipes is twice that of sewage pipes, accounting for 2/3 of the total drainage pipeline engineering investment. Therefore, it is estimated that during the "12th Five-Year Plan" period, the total national investment in drainage pipelines will be about 732.9 billion yuan, averaging 146.58 billion yuan per year.

 

　　Although there is a plan, fund raising and efficiency of use may become thorny issues for local governments. A municipal expert in Tianjin told the Foundation Engineering reporter that urban drainage funds are under the jurisdiction of local governments. Currently, local finances are tight, financing is relatively difficult, and drainage facility construction takes a long time and yields slow results, so it is easy for there to be much talk but little action.