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Water Resources Degradation

论文类型 基础研究 发表日期 2005-12-01
作者 佚名
关键词 Water Resources
摘要 Water Resources Degradation China possesses two of the world‘s longest rivers, the Yangtze and the Yellow River with water reserves totaling 2,800 billion m3, the fifth richest in the world after Brazil, Russia, Canada an

Water Resources Degradation

China possesses two of the world‘s longest rivers, the Yangtze and the Yellow River with water reserves totaling 2,800 billion m3, the fifth richest in the world after Brazil, Russia, Canada and the United States. However, the uneven distribution of water resources in China has created severe shortages in certain areas. In the densely populated areas of southern China, the Yangtze River and the Pearl River Basin provide a relatively abundant water supply. However, areas north of the Yangtze which account for 60 percent of China‘s land mass and half of its population only receive approximately 20 percent of the nation‘s water resources. In particular, the Northwest region and the North China Plain suffer from grave water shortages.

As a result of the uneven distribution, China‘s water resources per capita is only 2,400 m3, one fourth of the world‘s average, and 109th of 149 countries. According to the International Conference on Managing Water Resources for Large Cities and Towns, held in Beijing in March 1996, of 600 surveyed Chinese cities, 400 are suffering from severe water shortages of over 16 million tons per day. Thirty cities are expected to face long-term water shortages, and a estimated 80 million people in rural areas lack drinking water.

In addition to uneven distribution, serious soil erosion, deforestation, land conversion and excessive water usage for agricultural production have aggravated water shortages. Since 1992 Lijin, located across 740 kms of the lower reaches of the Yellow River, has suffered droughts every year during the dry season. In 1992, the drought lasted 82 days, and in 1995, the drought lasted as long as 121 days--a record breaking drought period in the region. Converting the wetlands of lake shores into rice paddies has devastated China‘s rich lake resources. In recent decades, 815 lakes in central China‘s Hubei Province, once known as "Thousand-Lake Province" have dried up. Hunan Province‘s Dongting Lake, the second largest fresh water lake in China, has decreased by 2,350 km2 since 1949.

Overextraction of groundwater for industrial and domestic use in urban areas has lowered groundwater tables in urban centers. In Beijing, for example, water tables are lowered 1.5 - 2 meters a year. Lower tables not only aggravate water shortages, but also lower water quality and increase the risk of earthquakes and landslides.

Finally, the inefficient use of limited water supply has worsened the situation. China only recycles 20-30 percent of its industrial water, and water consumption per industrial product is 5 - 10 times higher than that of industrialized countries. Furthermore, according to Geology of China only 25-30 percent of irrigation water is effectively utilized due to poor irrigation facilities. It is estimated that 2.5 million tons of grain yield are lost each year due to water shortages.

According to the SSTC study, Projection of China‘s Water Supply Situation and Strategy In the Year 2000, China‘s agricultural water consumption will increase from 419.5 billion tons in 1980 to 514.7 billion tons in 2000; industrial water consumption will increase from 52.3 billion tons in 1985 to 100 billion tons in 2000; and municipal consumption will increase from 6.7 billion tons to 20 billion tons as the urban population reaches 400 million. The study estimates that $700 million in waste water treatment facilities will be needed to meet the projected municipal water demand. China is expected to incur 20 billion tons a year of water shortage by the year 2000 if present trends continue.

Current Policies and Initiatives
The Government has recognized the vital need to address water shortage issues in China in order to maintain the nation‘s development. In 1988, China promulgated its Law of Water Resources, which provided a legal basis for water resource management. In 1993, further legal support to ensure efficient water utilization emerged as China adopted water resource licenses. By the end of 1995, nearly 90 percent of the nation‘s water utilities were registered and licensed. Since then, China‘s water supply is estimated to have increased 1 percent per year. The Government is also promoting waste water recycling by increasing investments in water pollution prevention and treatment facilities. Finally, efforts to tap new water resources, such as sea water, are being initiated.

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