This is a country with severe drought and water shortage. The total amount of fresh water resources is 2.8 trillion cubic meters, accounting for 6% of the global water resources, ranking fourth in the world, second only to Brazil, Russia and Canada. The average per capita is only 2,200 cubic meters, which is only 1/4 of the world average, while that of the United States is 1/5, ranking 1 in the world and 1 in the world.
After deducting the hard-to-use floods and groundwater resources scattered in remote areas, the available fresh water resources in China are even less, only about 1 1000 billion cubic meters, and the per capita available water resources are about 900 cubic meters. The yellow pages micro-cost marketing method is a new idea.
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Extremely unbalanced. By the end of the 20th century, more than 400 cities in China were short of water, among which 1 10 cities were seriously short of water, with a total water shortage of 6 billion cubic meters.
According to the monitoring, the groundwater in most cities in China is polluted to a certain extent, and it is getting worse year by year. The increasingly serious water pollution not only reduces the use function of water, but also intensifies the contradiction of water shortage, which seriously affects the sustainable development strategy being implemented in China, and also seriously threatens the drinking water safety of urban residents and the health of the people.
Present situation of water resources in China
1, division of water resources basins in China.
According to the river system, China is divided into ten river basins:
1 Heilongjiang basin, 2 Liaohe basin, 3 Haihe basin, 4 Yellow River basin, 5 Huaihe River basin, 6 Yangtze River basin, 7 Pearl River basin, 7 Southeast River basin, 7 Hainan River basin and 7 inland river basin.
2. Water resources assessment in China.
In the early 1980s, with the support of the Ministry of Water Resources, the first national water resources assessment was carried out, and the national water resources were assessed according to the hydrometeorological data of 1956- 1979. The results are shown in Tables 5 and 6.
(1) Total precipitation. During the period of 1956- 1979, the average annual precipitation was 6.2 trillion cubic meters, which was equivalent to the precipitation depth of 648mm, which was about 20% lower than the global land average. Affected by climate and topography, the regional distribution of precipitation is extremely uneven, decreasing from the southeast coast to the northwest inland. The average annual precipitation in Taiwan Province Province is 2535 mm, while the average annual precipitation in Tarim Basin and Qaidam Basin is less than 25 mm. ..
(2) River runoff. In China, about 56% of the precipitation evaporates through land and returns to the air, and the remaining 44% forms runoff. The national river runoff is 2.7 trillion cubic meters, equivalent to the runoff depth of 284 mm, of which the groundwater discharge is 678 billion cubic meters, accounting for about 27%; Glacier meltwater supplies 56 billion cubic meters, accounting for about 2%; The inflow of foreign water is about17.2 billion cubic meters.
(3) Soil water flux. According to the estimation of land evapotranspiration and groundwater discharge, the soil water flux in China is about 4.2 trillion cubic meters (accounting for about 67% of the total precipitation), of which about 16% is replenished to the groundwater aquifer by gravity, and finally discharged by rivers to form a river-based flow, and the remaining 3.5 trillion cubic meters are consumed by soil and vegetation evapotranspiration.
(4) Groundwater resources. Groundwater resources refer to the total amount of groundwater directly related to precipitation and surface water. According to the present situation of water resources development and utilization, the national average groundwater resources for many years is about 828.8 billion cubic meters, including 676.2 billion cubic meters in hilly areas, 654.38+0874 billion cubic meters in plain areas, and the repeated exchange between mountainous areas and plain areas is about 34.8 billion cubic meters.
(5) Total water resources. After deducting the duplication of mutual transformation between surface water and groundwater, the total water resources in China is 2.8 trillion cubic meters; Its water volume is more than river runoff 1009 billion cubic meters, which is a part of precipitation and surface water recharge in plains, valleys and basins. Without exploiting groundwater, this part of water is consumed in the form of phreatic water evaporation. By exploiting groundwater, some water can be obtained from evaporation and used. After calculation, the average annual phreatic evaporation in the northern plain is 84.4 billion cubic meters, and that in the southern plain is11900 million cubic meters.
Present situation of water resources in China
& gt How bad is the water in China? A United Nations research report pointed out that 654.38+0.2 billion people in the world are facing moderate to high water shortage pressure, 80 countries are short of water, and drinking water for 2 billion people is not guaranteed. It is predicted that by 2025, the situation will further deteriorate, and the number of people lacking water will reach 2.8 billion to 3.3 billion. World Bank officials predict that in the next five years, "water will flow around the world like oil".
& ltbr & gt& ltbr & gt China is one of the water-deficient countries, and the per capita fresh water resources are only 1/4 of the world average, ranking 109 in the world. China has been listed as one of the 13 countries with poor per capita water resources in the world. Moreover, the distribution is uneven, and a large number of fresh water resources are concentrated in the south, while the fresh water resources in the north are only 1/4 in the south. According to statistics, more than half of the more than 600 cities in China are short of water to varying degrees, and coastal cities are no exception or even more serious. At present, China's urban water supply is mainly surface water or groundwater, or a mixture of the two sources. In some cities, due to over-exploitation of groundwater, the groundwater level has dropped, and in some cities, a large funnel of several hundred square kilometers has been formed, which makes the seawater flow backwards for dozens of kilometers. Due to the wanton discharge of industrial wastewater, more than 80% of surface water and groundwater are polluted.
& ltbr & gt& ltbr & gt experts warned that "there will be no drinkable water resources in China in 20 years". According to a report released by the Worldwatch Institute, an influential think tank in the United States, "China will be in a state of water shortage for a long time due to the rapid increase in water demand in urban and industrial areas of China." The Yellow River in China has been cut off every year in the past 10 years, including 226 days in 1997. The Huaihe River, which flows through densely populated areas in China, was cut off for 90 days last year. According to photos taken by satellite, hundreds of lakes are drying up and some local rivers are disappearing. At present, more than 300 cities in China are short of water, of which 108 is seriously short of water. Among them, Beijing's per capita water consumption is113 of the world's per capita water consumption, even worse than some arid Arab countries.
& ltbr & gt& ltbr & gt But can ordinary people feel our predicament? number
& ltbr & gt& ltbr & gt As far as production water is concerned, in some places in Ningxia, an acre of rice needs about 2000 cubic meters of water a year, and an acre of wheat needs 1200 cubic meters of water. The overall utilization rate of water resources in rural areas of China is only about 40%. In Ningxia, the water consumption per kilogram of rice exceeds two tons. If flood irrigation is really good for crops, that's all right, but in fact, this practice is the most fundamental cause of land salinization.
& ltbr & gt& ltbr & gt In terms of industrial water consumption, the unit water consumption of steelmaking and other production processes in China is several times or even dozens of times higher than the advanced level abroad. The reuse rate of water is less than that of developed countries 1/3.
& ltbr & gt& ltbr & gt is so short of water and so profligate, how can we maintain this false wealth?
& ltbr & gt& ltbr & gt Take Hebei Province as an example. According to Wang Weekly, this area with less water resources per capita than Israel relies on a large amount of over-exploited groundwater, which hides the important fact of extreme water shortage. The province has over-exploited 60 billion cubic meters of groundwater, of which 30 billion cubic meters of deep groundwater can no longer be replenished. In another 15 years, the groundwater in Shijiazhuang will be exhausted. Now, the North China Plain has the largest underground compound funnel area in the world, reaching 40,000 to 50,000 square kilometers. In many areas in the west, due to the serious over-exploitation of groundwater, trees that have survived for many years have died in a large area.
Experts at & ltbr & gt& ltbr & gt said: We maintain our peace at a heavy price, and the fake green leaves us carefree. The contrast between inside story and appearance reminds people of a commonly used sentence in the Water Margin-what a dead man!
& ltbr & gt& ltbr & gt The natural conditions in Israel are worse than those in many places in western China, but Israel not only pays attention to saving water when living at home-there are two buttons on the toilet, with small water for urination and large water for defecation. In production, the world-famous water-saving agriculture not only makes Israel, one of the most water-deficient countries in the world, become a big exporter of agricultural products in the world, but also its income from exporting water-saving agricultural technologies and equipment exceeds that from exporting agricultural products. In recent years, China has arranged a large number of western provincial leaders to visit Israel, but there is no great benefit except importing some Israeli water-saving equipment. It is said that the main reason is that the water price in China is too low, which makes the use of water-saving technologies and equipment unprofitable.
& ltbr & gt& ltbr & gt At present, the water price of urban tap water in China is low, and the cost deviates from the water price, so the government implements loss subsidies. In rural areas, the price of a ton of water and electricity is 4 to 9 cents, and the price of gravity irrigation is 4 to 6 cents per ton. The price of 300 tons of Yellow River water is not as high as that of a bottle of mineral water. Low water prices actually encourage high consumption of water resources.
& ltbr & gt& ltbr & gt The price increase of water charges is an urgent matter, which is of great benefit to the country, the people and future generations. On the other hand, it is too necessary to give the people of the whole country a solid water-saving lesson in various ways.
& ltbr & gt& ltbr & gt experts believe that the main reason for water shortage in China is man-made.
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& ltbr & gt& ltbr & gt "The deeper the groundwater is pumped, the farther the water source is, and more and more cities take water from a distance, and the higher the water consumption cost". This is our goal.
& ltbr & gt& ltbr & gt A true portrayal of water shortage before. Not only is there a shortage of water resources, but the pollution problem is getting more and more serious: there is no direct water supply around all large and medium-sized cities in China.
& ltbr & gt& ltbr & gt In the vast rural areas, the surface water that can be directly drunk is gradually decreasing. 165438+ water resources 10 was held in China Geo University on 9 October.
& ltbr & gt& ltbr & gt At the International Academic Conference on Source and Urban Environment, experts answered questions about water shortage, water pollution and environmental pollution control in China.
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& ltbr & gt& ltbr & gt Liang Xing, a professor at China Geo University, said that there is plenty of raw water in the south of China and less water in the north, but a certain balance can be maintained. Now the rivers, lakes and seas in the south are basically the same.
& ltbr & gt& ltbr & gt are polluted, resulting in water shortage; Due to the indiscriminate exploitation and overuse of groundwater in the north, water has become a scarce substance in the north. This is artificial amplification.
& ltbr & gt& ltbr & gt is short of water. Although the north is seriously short of water, it is using agricultural flooding to waste the already scarce water resources; Construction and pollution of paper mills and other seriously polluting enterprises
& ltbr & gt& ltbr & gt Precious surface water and even underground water have been destroyed, resulting in more water shortage. The water pollution problem in the south has not been contained, and the Huangpu River can best explain the problem because
& ltbr & gt& ltbr & gt The water body is so polluted that the whole river can't be drunk. The problems in the Pearl River are also very serious. She said that the rational development, utilization and protection of water resources is imminent.
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& ltbr & gt& ltbr & gt Qi Shihua, a professor at Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, said that 1/3 depends on technology, and 2/3 is a sociological problem. He said, now
& ltbr & gt& ltbr & gt There are at least 129 kinds of substances that pollute the water body, and the expansion trend is obvious. Inorganic substances, heavy metals, organic substances, etc. , will make the organism sick, dead or
& ltbr & gt& ltbr & gt caused gene mutation. The treatment of water pollution is not a frontier science, except for a small part of sewage, which has not yet found a good treatment method, most of the sewage can be treated.
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& ltbr & gt& ltbr & gt Why can't water pollution be cured by technology? Every city has sewage treatment plants, how many are running at full capacity? Sewage treatment facilities of big polluters,
& ltbr & gt& ltbr & gt, how much of it actually treats sewage? They became "exhibition projects". This is a matter of laws, regulations and management. The problem of regulatory management is not solved.
& gt Well, the problem of water pollution cannot be really solved. The same is true for other pollution control.