Beijing, the capital of China, is characterized by intense water scarcity during the long dry season as well as heavy flooding during the brief wet season. Beijing is one of the most water-scarce cities in the world. Total water use is 3.6 billion cubic meters, compared to renewable fresh water resources of about 3 billion cubic meters. The difference is made up by the overexploitation of groundwater. Two-thirds of the water supply comes from groundwater, one third from surface water. Average rainfall has substantially declined since the 1950s. Furthermore, one of the two main rivers supplying the city, the Yongding River, had to be abandoned as a source of drinking water because of pollution. Water savings in industry and agriculture have compensated for these losses and freed up water for residential uses.
Water tariffs have been increased to provide an incentive to curb residential water demand, but the impact has been limited. Residential demand increases due to population growth, and the city taps new water sources. For example, water reclamation has been aggressively promoted since the turn of the century. The city's 15 central municipal wastewater treatment plants and more than 300 small, decentralized plants now provide reclaimed water for non-potable uses. An additional 1.2 billion cubic meter is expected to be provided through the southern section of the South-North Water Transfer Project's central route from the Han River, more than 1,000 km to the south, until the end of 2014. The supply of desalinated seawater from existing desalination plants near Tianjin is also being contemplated.
Climate and population Annual average precipitation in Beijing is only 578 mm, compared to 1,090mm in New York City. There is virtually no rain from September to April. About 60% of rainfall occurs in only two summer months. In dry years, precipitation can be as low as 242 mm, recorded in 1869. There has been a long-term decline in precipitation, with an average of only 428 mm recorded in the period 1999–2008. Beijing municipality covers an area of more than 16,800 square kilometers, roughly half the size of Belgium, including the city of Beijing and surrounding rural areas that account for most of its area and about a third of its population. As of 2010 the municipality had almost 20 million inhabitants, up from 10.8 million in 1990.
Water resources
Historically, since the Yuan dynasty Beijing received its water mainly through canals from springs in the mountains north and west of the city, feeding a system of lakes designed by Guo Shoujing. This allowed the city to thrive although it was located far from a major river. However, the yield of these springs declined as a result of deforestation and the springs do not supply Beijing with water any more. They were replaced by groundwater and by reservoirs from dams built during the 1950s in the areas surrounding Beijing as the major sources of water supply for the city.
Beijing has about 150 cubic meters of water resources per capita, making it a water-stressed city.
Water resource Billion cubic meter per year Remarks Groundwater 2.0 Local Rivers 1.0 Variable Reclaimed Water 0.3 Estimated South-North Water Transfer 0.3 Northern section of central route Total 3.6
Groundwater Today the major water source for Beijing municipality is groundwater, which accounts for about 75 percent of water use. The safe yield of the aquifer is estimated at between 2 and 2.5 billion cubic meter per year, depending on rainfall. Thus abstraction is greater than the replenishment of the aquifer, resulting in a decline of the groundwater table that causes the sinking of ground surface (i.e. land subsidence). In addition, groundwater infiltration has declined because urban areas have been increasingly built up, sealing the surface.
For municipal water supply, the share of groundwater is much lower and the share of surface water is much greater. In 2009 Beijing had 19 water treatment plants, including many relatively small ones that treat groundwater, while surface water treatment plants are much larger.
Surface water
Small to medium-sized rivers provide the remaining water resources for Beijing municipality in the amount of 1 billion cubic meter per year during the 1980s and 1990, down from about 2 billion cubic meter per year during the 1960s and 1970s for all uses, including agriculture. By comparison: The Hudson River in the United States carries almost 20 billion cubic meter in an average year, 20 times as much as the rivers in Beijing municipality. The Yangtse River carries about 600 billion cubic meter per year, 600 times as much.
The most important river in terms of drinking water supply is the still relatively unpolluted Chaobai River in the East. It is impounded by the Miyun Dam. The Miyun Reservoir provides water to Beijing over a distance of 95 kilometer, initially through an open canal that brings the water to the Huairou Reservoir and then through a ductile iron pipe and three steel pipes to Beijing. The location of industries near the canal is prohibited to prevent accidental pollution. The Miyun Reservoir is the city's largest single source of water. It also provides water for Beijing's numerous lakes that used to be fed by springs that now have dried up. The dam used to also provide water for agriculture, but in 1981 the government decided that its water would only be used for domestic water supply. In 1986 the first plant in Beijing to treat surface water, the 9th water treatment plant, was established to treat water from the Miyun reservoir. As of 2009, it was Asia's largest water treatment plant with a capacity of 1.5 million cubic meters per day (0.55 billion cubic meters per year). While the plant was designed as a surface water treatment plant, when surface water is scarce groundwater is also treated in the same plant. Because of the higher salinity of groundwater and the hardness of surface water this leads to problems in the treatment process, causing limescale and the clogging of pipes.
The Guanting Dam on the Yongding River in the West is unable to provide drinking water to Beijing since 1997 because of pollution. However, the reservoir still provides water for irrigation and for industrial uses that do not require high water quality. The quality of the reservoir's water has improved slightly in the 2000s, when it was reclassified as class IV from class V of five water quality categories, I being the best and V being the worst. The government aims to improve the quality to class III.
Both reservoirs now receive only a fraction of the amount of water that they used to receive. In the case of the Guanting reservoir, it receives 90 percent less water in 2000 compared to the 1950s. Both rivers are dry for most of the year downstream of the reservoirs. A third river, the Wenyu River, rises in the suburbs of Beijing and is heavily polluted. The State Council has imposed restrictions on water use in Hebei Province that surrounds Beijing, and in Tianjin further downstream, to secure the water supply of the capital. For example, the Miyun reservoir stopped serving Tianjin in 1982 and Heibei province in 1985.
Since 2003 Shanxi and Heibei provinces continuously transfer water from reservoirs to Beijing, following a decision by the Ministry of Construction. No mechanism to compensate the two provinces for the water has been set up. Since 2008, Beijing receives an additional 0.3 billion cubic meters per year from four new reservoirs in Hebei through the northern section of the central route of the South-North Water Transfer Project. This increases the available resource by about 7 percent.
Water use
Water use Billion cubic meter/year Residential 1.5 Industry 0.7 Agricultural irrigation 1.3 Environmental flows 0.1 Total 3.6
Water use in Beijing municipality was about per year in 2010, including 1.5 for residential uses, 1.3 for agriculture, 0.7 for industry, and 0.1 for environmental uses. Water use declined from 4.8 billion cubic meter/year in 1980 to 3.5 in 2002, then increasing slightly to 3.6 in 2010. The reduction was achieved by halving industrial and agricultural water use, while domestic water use increased five-fold from 0.3 to 1.5 billion cubic meters from 1980 to 2010. About 90 percent of domestic water supply is provided by the Beijing Water Bureau as piped water, while the remainder is taken by households directly from wells. Agriculture relies almost entirely on groundwater. When a drought hit the area in the 1980s the government imposed limits on the implantation of water-intensive industries, even relocated some industries and stopped irrigation from the two large reservoirs in the region.
Sanitation and use of reclaimed water Wastewater collection and treatment in Beijing is mostly through an extensive sewer system and 15 large, centralized municipal wastewater treatment plants. New housing developments, hotels and public buildings are equipped with 300 to 400 smaller, decentralized wastewater reclamation systems with a combined treatment capacity of about 55,000 m3/day, or about 50 times less than the combined capacity of the large plants. The decentralized systems allow the reuse of reclaimed water near to where the water is used and treated. Reclaimed water from the municipal treatment plants is sold at only 1 Yuan per cubic meter in order to provide an incentive to use reclaimed water instead of fresh water. This tariff is only about one quarter of the freshwater tariff and is insufficient to recover the costs of the distribution of the reclaimed water.
Regulations Beijing has made substantial progress in the use of reclaimed water for non-potable uses. According to preliminary regulations issued in 1987, when there was almost no wastewater treatment in the entire city, hotels and public buildings above a certain size had to have their own wastewater treatment and reclamation systems, either for grey water or for wastewater for reuse in or near the premises. In 2001 a new regulation mandated the construction of reclamation facilities also for residential areas exceeding 50,000 square meters. These preliminary regulations were replaced with more advanced permanent Beijing Drainage and Water Reuse Regulations in January 2010.
The Chinese water quality standard for reuse corresponds to the Chinese surface water quality standard III (suitable for aquaculture and recreational purposes). It is apparently less strict than effluent standards in the US that correspond to the more stringent Chinese national surface water quality standard II. Another source lists in detail standards for four types of non-potable municipal uses (toilet flushing, road cleaning/firefighting, car washing and construction) as well as landscaping, clearly showing that there is more than one standard for reclaimed water in Beijing. The microbiological standards for the various uses are the same, but the standards in terms of turbidity and dissolved solids vary depending on the intended use. As of 2011, 100 residential communities used reclaimed water in toilet flushing.
Wastewater treatment