Why does China want to transfer water from South to North? Why transfer water from the Yangtze River? Why does North China need water?

North China, with its dense population and developed industry, is also an important grain, cotton and oil producing area in China. However, the serious shortage of water resources is increasingly restricting the development of industrial and agricultural production in this area, and even has a significant impact on people's normal production and living activities. First, the main factors causing the shortage of water resources in North China

1. The uneven distribution of water resources in time and space in China is the main reason for the shortage of water resources in North China. The total annual runoff of rivers in China is 2.7 trillion cubic meters, ranking sixth in the world, and it is a country rich in water resources in the world, but the temporal and spatial distribution of water resources in China is seriously uneven. From the perspective of regional distribution, there are few things, more in the south and less in the north. The population of five provinces (cities) in North China accounts for 24% of the whole country, and the cultivated land accounts for 45% of the whole country. The industrial output value of Beijing-Tianjin-Tangshan industrial base accounts for 10% of the national total industrial output value, while the total water resources only account for 6% of the national total. The per capita allocation ratio of water resources and soil and water resources is far below the national average. For example, China's per capita water resources are about 2,500 cubic meters, while the Haihe River Basin is only 250 cubic meters, which is only equivalent to110 in the Yangtze River Basin and1/8 in the Pearl River Basin. According to the seasonal distribution of precipitation, precipitation in most areas of China is concentrated in May to 10, while precipitation in North China is highly concentrated in July and August. The precipitation in these two months accounts for 80% of the total precipitation in the whole year, while there is a continuous drought in winter and spring. Moreover, the precipitation in North China changes greatly every year. For example, in Beijing in recent 50 years, the year with the most precipitation reached1.460mm, while the year with the least precipitation was only 200mm, which is undoubtedly the main natural factor that caused the shortage of water resources in North China.

The rapid growth of population and the rapid development of industry and agriculture have aggravated the shortage of water resources. Northern China has been one of the areas with concentrated population distribution since ancient times. After the founding of New China, the population growth in this area is particularly rapid. 1952, the total population of five provinces (cities) in North China accounted for 19.6% of the whole country, but it rose to 24. L in 196. The population density of Beijing, Tianjin, Shandong, Hebei, Henan and other provinces (cities) ranks in the forefront of China, and Beijing, Tianjin, Shijiazhuang, Tangshan and Qingdao in this area have become the most tense cities in China. Since the early days of the founding of New China, China has carried out large-scale harnessing of the Haihe River and the Yellow River basins, as well as the transformation of saline-alkali land in the North China Plain, which has continuously increased the crop planting area, irrigation area and agricultural water consumption. Especially through decades of construction, Beijing-Tianjin-Tangshan Industrial Zone has become the largest comprehensive industrial base in northern China. The establishment of a large number of large, super-large and water-consuming industrial enterprises, such as Capital Iron and Steel, Yanshan Petrochemical and Tianjin Chemical, has made the supply of fresh water more tense.

3. The comprehensive utilization rate of water resources is low, and the waste and pollution are serious. Water conservancy projects in North China, especially agricultural irrigation projects, are not well matched, and leakage-proof and seepage-proof facilities are not perfect. There are different degrees of water leakage in agricultural irrigation, and the effective utilization rate of water resources is only about 50%; The loss rate of urban water supply is as high as 10% (including pipeline leakage). At the same time, a large number of industrial wastewater is continuously discharged into rivers, which makes the water quality polluted to varying degrees, especially in Haihe River, and the downstream river water can no longer be directly used as production and domestic water.

4. The ecological environment deteriorated and the frequency of drought increased. Due to the long-term influence of natural and human factors, the forest coverage rate in North China is only 3.5%, of which the forest coverage rate in Loess Plateau is only 1%. Low forest coverage rate not only leads to low water conservation capacity, serious soil erosion on the surface, and reduced groundwater volume, but also reduces air humidity and increases drought frequency. For example, during the period of 2000 190- 10, there was a continuous dry weather in North China for seven years. On the other hand, in order to meet the needs of production and domestic water, a large number of groundwater exploitation methods have been used in North China Plain for many years, which has greatly reduced the groundwater level and formed the largest groundwater funnel area in the world.

Second, the main way to solve the problem of water shortage in North China

1. Strengthening the comprehensive management of water resources, improving the utilization efficiency of water resources, saving water and preventing water pollution are the most effective ways to solve the shortage of water resources in North China at present, and the main reasons for the waste and pollution of water resources in North China are poor management and people's lack of awareness of protecting water resources. Therefore, on the one hand, the government and relevant functional departments should strengthen the law enforcement and publicity of water resources management, raise people's awareness of protecting water resources, make cherishing and protecting water resources become people's conscious behavior, and take measures to improve the utilization efficiency of water resources. If the loss rate of urban water supply can be reduced by 5%, the amount of water lost in agricultural water due to seepage, leakage and unreasonable irrigation will be reduced by 15%, which is equivalent to increasing the water resources of the whole North China every year. In the past, due to the lack of unified and comprehensive management of water resources, Haihe River. There is competition for water resources in the Yellow River basin. For example, since 1992, the lower reaches of the Yellow River have been cut off almost every year. From the winter of 1998 to the early summer of 1999, the lower Yellow River has been cut off for 227 days. The main reason for this phenomenon is not only the climatic factors, but also the excessive use of Yellow River water in the middle and upper reaches of the Yellow River. 1999 since the winter, the state has carried out comprehensive management and unified allocation of water resources in the Yellow River. Although there was a rare dry weather in northern China from the winter of 1999 to the early summer of this year, there was no water cut in the lower reaches of the Yellow River, which shows that it is necessary to strengthen the comprehensive management of water resources and implement macro-control.

2. Strengthening the construction of water conservancy projects and ecological projects First of all, the inter-basin water transfer project is the fundamental way to solve the water shortage in northern China. After the founding of People's Republic of China (PRC), China has successfully built inter-basin water transfer projects in North China, such as diverting Luanhe River into Tianjin, diverting Luanhe River into Tang, etc., which has alleviated the water shortage in large industrial cities such as Tianjin and Qingdao to some extent. However, the water shortage in North China accounts for 72% of the total water shortage in China, so it is not enough to transfer water only within the region. The "South-to-North Water Diversion Project" that the country is planning and about to implement is to transfer water from the Yangtze River basin to northwest and north China. Once the project is completed and implemented, it will fundamentally change the situation of water shortage in northern China. Secondly, building reservoirs is the main measure to solve the seasonal variation of precipitation. Precipitation in North China is mainly concentrated in July and August, which is easy to cause floods. Therefore, we should vigorously build reservoirs in the middle and upper reaches of rivers in North China, and at the same time increase the flood storage capacity of the original water conservancy projects through reconstruction or expansion, so that the water resources in the dry season can be supplemented to some extent and the utilization rate of water resources can be improved. The third is to strengthen the construction of ecological engineering and improve the coverage rate of surface vegetation. For example, in the loess plateau area, combined with small watershed management, trees and grass are vigorously planted to conserve water, so that the soil does not go downhill, green mountains are always there, and clear water often flows. It is estimated that if the forest coverage rate of the Loess Plateau and North China Plain is increased from the current 3.5% to about 10%, the total amount of hidden water resources is equivalent to building a water conservancy project with a total storage capacity of1500 million cubic meters, and because forests can increase air humidity, 6 billion cubic meters of water and steam can be transported to the arid areas in northwest China through atmospheric circulation every year.

3. Vigorously developing water-saving agriculture is not only highly dependent on water, but also the production department with the largest water consumption. In the past, in order to increase grain production, the irrigation area in North China was blindly expanded, coupled with improper irrigation methods and aging irrigation facilities, the effective utilization rate of water resources was only 50%, and the repeated utilization rate was even lower, at around 20%. Therefore, water-saving agriculture should be vigorously developed in North China where water resources are scarce. The main ways include actively promoting drought-tolerant crops; Reforming irrigation technology, such as pipeline water delivery, sprinkler irrigation and drip irrigation, saves water 1/2 to 2/3 than flooding irrigation.