Водные ресурсы и устойчивое развитие Пекина

Beijing's transformation from a small residen­tial village to a modern megacity with a population greater than 10 million did not occur by chance. Beijing sits at the northern edge of China's great plains, and is surrounded by mountains to the north, east and west. Low lying plains extend out from the southeast side of the city. This area is home to 5 main river systems: the Yongding, Chaobai, Beiyun, Daqing, and Jiyun Rivers. Only the Beiyun River originates in Beijing, while the other rivers originate in Shanxi, Hebei, and the plateaus of Inner Mon­golia. Heading southeast, the rivers wind their way through tall mountains and across the plains. Beijing is located in the floodplain of the Yongding River.

1. Beijing's Aquatic Environment: A His­torical Perspective

Abundant water resources supported the city of Beijing for over 3,000 years. Historically, the Yongding River flowed north-south, forming a key transport route. The river helped to form the Beijing valley, and its delta created a good environment to settle in. As a result, the village of Beijing was established along the river. The Yongding River and surrounding waterways made up the Lianhua Chi and Gaoliang River Systems, and they provided a stable source of water for Beijing from its origin through the Liao, Jin, Yuan, Ming, and Qing Dynasties. In the 1950-1960s, Beijing's government construct­ed the Guanting and Miyun Reservoirs to store and control the flow of water, and to limit down­stream flooding.

2. Beijing's Aquatic Environment: Pres­ent Conditions

From the 1950s to 1970s, Beijing transi- tioned from a consumption-oriented city to a production-oriented city. During those decades, Beijing's population grew enormously, the size of the city's urban area expanded rapidly, and many industries with high water demands were established. These factors contributed to increas­ingly severe water shortages and Beijing experi­enced 4 water related crises:

The first crisis occurred in 1960 and 1965. For many years, Beijing's average annual pre­cipitation was 595 millimeters (mm). During the first half of 1960, precipitation was only 61 mm, half of the average precipitation for the corre­sponding time period in previous years. In 1965, annual precipitation was merely 377 mm. Due to the drought, water inflow into the upper reaches of the Yongding River decreased, water in the Guanting Reservoir began to dry up, and the Res­ervoir's water level fell far below normal storage levels. To meet urban demand for water, Beijing began to draw water from the Miyun Reservoir through the newly built Beijing-Miyun Diver­sion Canal.

The second crisis occurred from 1970 to 1972. For three years, average annual precipita­tion was 508 mm. Inflow of water into both the Guanting and Miyun Reservoirs decreased. In re­sponse, Beijing drilled over 30,000 wells on the plateau within several years. Beijing's demand for water from the Guanting and Miyun reser­voirs increased, and urban Beijing replaced the surrounding rural areas as the main recipient of water from the reservoirs. Following this transi­tion, farmers had to rely primarily on groundwa- ter resources to supply their water. While the first water crisis only affected the Guanting Reservoir, the second crisis had a major impact on both the Guanting and Miyun reservoirs.

The third water crisis took place from 1980 to 1986, when Beijing suffered from seven years of drought. During this time, the average annual precipitation was only 498 mm, nearly as low as precipitation levels during Beijing's most severe recorded drought. (From 1857-1870, average an­nual precipitation was only 492 mm). By July 1981, the combined water storage of Guanting and Miyun reservoirs was down to 510 million m³. Surface water was not replenished quickly enough to meet demand, and groundwater re­sources were also rapidly depleted over a large area. To weather this crisis, in 1981, the State Council ruled that the Miyun Reservoir would be used to meet the demand of water for Beijing, and the Luan River would be responsible for supplying water for Tianjin. Beijing's govern­ment began taking measures to conserve water resources and more carefully plan water usage patterns. They adopted a policy to restrict water consumption by industry and agriculture in order to ensure domestic water supply.

The fourth water crisis began in 1999, when another continuous drought began. The average annual precipitation during the next twelve years was little more than 400 mm. By November 2003, Miyun Reservoir stored only 760 million m³ of water, and Guanting Reservoir held 210 million m³, representing a decrease of 2.08 billion m³ and 320 million m³ respectively from 1999 lev­els. In the summer of 2007, Guanting Reservoir held only 90 million m³ of water, less than one fortieth of its 4.16 billion m³ storage capacity. This was the lowest water level since the reser­voir was built 53 years ago. Due to low water volumes and severe pollution, the Guanting Res­ervoir could no longer be used to supply potable water for Beijing's population. To address the ur­gent water shortage, Beijing's water authorities built four emergency water sources in Huairou, Zhangfang, Pinggu and Changping. Meanwhile, they incorporated several additional medium- sized reservoirs into the urban water supply sys­tem. The government also began diverting water from new sources: Cetian Reservoir of Datong in Shanxi province, Baihebao Reservoir of Yanqing near Beijing, Youyi Reservoir in Hebei province, Huliuhe Reservoir, Xiangshuibao Reservoir and Yunzhou Reservoir.

In the 1970s, water rushed rapidly down the turbulent Yongding River. 'Yongding' means 'to settle down forever' in Chinese. Unfortunately, the dry Yongding River has finally 'settled down'. When a large electric power plant was construct­ed and the river was dammed, several key water sources were affected. Two springs in the upper reaches of the Yongding River, also known as Sanquanwan and Shentouquan, dried up. For 70 miles downstream of the plant, the river runs dry year round, and its banks are desertifying. The Dong Yulin, Da Niwan, and Cetian Reservoirs have all dried up. The Yanghe River, Hongtang River and Qingshui River also run dry. Even the Guishui River, originating from Heihanling of Yanqing near Beijing, has little water left.

Years of illegal extraction of sandstone from the Yongding River left numerous ditches along the river channel and much of the riverbed is exposed to air. During winter and spring, north­west winds transport sand from the exposed river banks toward the city and sandstorms plague western Beijing. Since the Guanting Reservoir did not have water to replenish the Yongding River, and groundwater was continually overex- ploited, groundwater resources in western Bei­jing, which have existed over the last 2 million years, have now been almost entirely depleted. The Yongding River ecosystem has been criti­cally damaged.

Another important waterway, the Chaobai River, was dammed to create the Miyun Reser­voir. Water was not allowed to flow through for years, and since 1999, the Chaobai River dried up. After the river was dammed, the nearby envi­ronment deteriorated rapidly, sand in the riverbed was exposed to the elements, and winds dredged sand from the riverbed. High water demand led to the overexploitation and eventual complete extraction of groundwater. In the 1665 km² area surrounding Beijing's No.8 Tap Water Facility, land has begun to subside due to the excessive extraction of ground water. The water table fell 15 meters from 1998 to 2001, and it continues to fall. Along the river, most of the shallow wells used by farmers are no longer usable. Most of the trees in the riparian zone have died, and the condition of the natural environment continues to deteriorate.

Beijing's water table began falling rapidly starting in the 1970s. Today, Beijing's water table sits 20 meters below ground, representing a 13meter drop and cumulative 7 billion m³ de­crease in underground water stores since 1980. The area where groundwater has been seriously overdrafted has reached 2960 km². Surface water resources and water storage in Miyun and Guant- ing reservoirs decreased sharply over time (Table 1). Many lakes in Beijing have become fields; during the dry season, even Kunming Lake in the Summer Palace, Fuhai in the Yuanmingyuan Park and Weiming Lake in Peking University dry up. The lack of security and reliability of water sources in Beijing has reached a crisis level.

III. The Causes of Beijing's Water Shortage

For many years, Beijing's growing urban area, its expanding population and its rapid eco­nomic development have altered the aquatic ecosystem's natural cycles and ability to recover from disturbances.

1. 1. The built regions of Beijng have ex­panded enormously. In 1949, the highly devel­oped zone of built Beijing was only 109 km² in size. By 1980, this area expanded to 346 km². By 2000, the developed area of Beijing reached out in all directions, covering an area of 1040 km². Beijing is expected to expand to 1650 km² by 2020. Beijing's water resources cannot bear the weight of this large scale urban sprawl.

   2. Beijing's population grew rapidly. Beii- jng was home to 4.14 million people in 1949, 7.32 million in 1960, 7.71 million in 1970, and 8.85 million in 1980. By 1990, the population had ballooned to 10.32 million, and the official census in 2000 reported a population of 11.07 million (probably more like 13.64 million, in­cluding the unregistered migrant population). At the end of 2007, Beijing was officially home to 12.13 million residents (closer to 17.14 million, including the migrant population). The ever ex­panding population's per capita water use also increased rapidly over time. Today, per capita water consumption in Beijing is 259.7 liters, compared to 7 liters in 1949, representing a 37 fold increase. The expanding population and wa­ter consumption patterns have intensified exist­ing water shortages.

3. Beijing's economic expansion has led to significant changes in water usage. In 1949, Bei­jing's gross national product was less than 780 million RMB. Today's GDP is greater than 1.3 trillion RMB, a 1667 fold increase! Beijing had very little industry before 1949 and had low wa­ter demands. By 1963, Beijing had constructed metal smelting, chemical, mechanical, textile, paper and electrical plants. Industrial water con­sumption skyrocketed by approximately 26% an­nually, from 30 million m³ in 1949 to 640 million m³ in 1963. When industrial water use reached 1.35 billion m3 in 1980, it became clear that wa­ter was a limiting resource. In 1949, 14,200 ha of land was irrigated in Beijing. By 1958 that area increased to 95,300 ha, and during the Great Leap Forward, irrigation was done so inefficiently that 573 million m3 of water was used. 3.05 billion m3 of water was used to irrigate an area of 340,300 ha in 1980.

According to official statistics from the city's water authorities, in an average year (50% guar­anteed rate), the amount of usable surface water is 1.67 billion m3/ year. This number falls to 1 bil­lion m3/ year in dry seasons, and although guaran­teed rates increase in drought conditions, overall levels of usable surface water falls (Table 2).

Not including treated water from the sew­er system, inner city Beijing has access to 3.25 billion m3 of water, including up 800 million m3 from the Guanting and Miyun Reservoirs and 2.45 billion m³ from groundwater. In 1980, Beijing's readily usable surface and groundwa­ter resources totaled 3.768 billion m³, yet the city consumed more than 4.889 m³ of water that year, greatly surpassing the city's water carry­ing capacity. The additional 1.1 billion m3 of water were obtained through over-extraction of groundwater resources. To maintain a balanced and healthy water table, a certain percentage of groundwater resources must not be extracted. Yet Beijing continues to extract groundwater at unsustainable rates, depleting reserves to the point of ecological collapse. The water table has dropped significantly, leading to the formation of depression cones (areas where withdrawals have lowered the water table immediately beneath the well head).

The problems resulting from limited water resources are becoming increasingly obvious in Beijing. The city has adopted increasingly ex­treme measures to meet its growing water de­mands, to the point that water must be diverted from the distant Yangtze River basin. Overcon- sumption and exploitation of Beijing's water resources, far beyond the region's natural carry­ing capacity, leave Beijing's water system on the verge of total collapse.

IV. Moving Towards Sustainable Devel­opment:

According to the principles of ecology, a re­gion's water resources can only sustain a popula­tion of a certain size. Once this finite natural car­rying capacity is surpassed, the population must decrease or the ecosystem will fail. "The carry­ing capacity of water resources in a given river system or region determines not only the health of the entire ecosystem, but also the scale of fea­sible economic and human development." [Wang Shu Cheng] To achieve the successful sustain­able development of Beijing, it is necessary to widely establish water conservation practices and to limit economic development intensity and population growth.

1. 1. 1. Beijing's ability to survive and grow will be limited by available water resources. Bei­jing must develop based on available resources rather than forcing development regardless of the ecological consequences.

      2. Beijing is located in one China's most water scarce regions, with fewer than 200 m3 of water per person. Beijing's population and water usage has already far exceeded the locally avail­able resources. Water shortages have already be­gun to limit the city's growth and land use pat­terns. Thus, proper water management must be a top priority.

      3. Industries with high water consumption needs should be moved to areas of China with richer water resources. This would help control the growth of Beijing's population and allow the natural ecosystem to recover by reducing the pressure on Beijing's overexploited water resources. Beijing must continue to improve its industrial structure by limiting resource intensive industries and developing policies that no longer incentivize the use of migrant laborers.

1. 1. 4. Currently, the city of Beijing serves many purposes and does not have a well defined identity. It is China's political and cultural center, yet it also a center of intellectual and financial activities, science and technology, education, high tech research and development, financial investment, and an internationally facing megac- ity. The city's social and financial development should take into account Beijing's key role as China's political and cultural center, and some of the other functions should be carefully evaluated and reconsidered.

      5. Beijing should depend upon local re­sources, rather than utilizing huge scale water diversion projects to supply its residents. Beijing should use water diverted from distant sources to help recover its natural water resources, but it should not use this water to fuel continued urban sprawl and population growth. The city should strictly limit outward expansion and construction projects, and carefully consider the ecological consequences of its development in order to safe­guard local rivers, restore the natural hydrologic cycle, and initiate meaningful restoration of the natural environment.

Table 1. Average Annual Inflow into Guanting and Miyun Reservoirs Decreased Over Time
(hundred million m3)

Table 2. Beijing’s Usable Surface Water Resources (hundred million m3/year)

 Цзянь Ван¹, Сиан Чжан²

¹ Пекинское управление охраны среды, Китай; ² Лесная служба округа Тиели, Китай

источник http://damba.org/novosti/materialy-k-vi-mezhdunarodnoj-nauchno-prakticheskoj-konferencii-reki-sibiri-krasnoyarsk-2011-god.html