Why is China short of water resources?

China's total water resources are 2.8 trillion cubic meters. According to the 1997 population statistics, the per capita water resources are 2,22 cubic meters. It is predicted that when the population increases to 1.6 billion in 23, the per capita water resources will drop to 1,76 cubic meters. According to the internationally recognized standards, the per capita water resources are less than 1,7 cubic meters ...

The total water resources in China are 2.8 trillion cubic meters. According to the 1997 population statistics, the per capita water resources are 2,22 cubic meters. It is predicted that when the population increases to 1.6 billion in 23, the per capita water resources will drop to 1,76 cubic meters. According to internationally recognized standards, countries with per capita water resources less than 1,7 cubic meters are water-stressed countries. Therefore, the future situation of water resources in China is grim. In the 5 years since the founding of New China, the total water consumption in China has increased from more than 1 billion cubic meters in 1949 to 556.6 billion cubic meters in 1997, of which agricultural water accounts for 75.3%, industrial water accounts for 2.2%, urban life accounts for 4.5%, and the per capita comprehensive water consumption has increased from less than 2m3 cubic meters to 458m3 cubic meters. The shortage of water resources and the waste of water coexist; Over-exploitation of water and soil resources causes damage to the ecological environment; The deterioration of water environment and the rapid development of water pollution have reached an extremely serious level. After the research, it is considered that by building water-saving and efficient modern agriculture, China can basically base itself on the existing scale of cultivated land and irrigation water consumption to meet the needs of agricultural products of the future 1.6 billion people. It is predicted that China's water consumption will peak around 23, with a total water consumption of 7-8 billion m3/ year and a comprehensive water consumption of 4-5 m3 per capita. According to the analysis, the actual possible water resources in China are about 8-95 billion m3, and the water demand is close to the limit of possible water utilization. Therefore, we must strictly control the continued population growth and strengthen the water demand management, so that after the population reaches zero growth, the water demand will gradually reach zero growth. The overall strategy of China's water resources: we must support the sustainable development of China's social economy with the sustainable utilization of water resources. It is suggested to carry out strategic transformation from eight aspects: 1. Flood control and disaster reduction-from disorderly and uncontrolled competition with floods to orderly and sustainable coordination with floods. Therefore, it is necessary to change from the strategy of building a flood control engineering system to building a comprehensive flood control and disaster reduction system on the basis of the flood control engineering system. 2. Agricultural water use-it is necessary to change from the traditional extensive irrigation agriculture and rain-fed agriculture in dry land to an agricultural water use strategy aimed at building water-saving and efficient modern irrigation agriculture and modern dry land agriculture. 3. Urban and industrial water use-we should change from not paying attention to water saving, pollution control and developing non-traditional water resources to a sustainable utilization strategy of urban water resources with priority on throttling, pollution control as the foundation and multiple channels and open sources. 4. Pollution prevention and disaster reduction-a comprehensive pollution control strategy should be changed from terminal control to source control. 5. Eco-environmental construction-we should change from not paying attention to eco-environmental water use to a water resource allocation strategy to ensure eco-environmental water use. 6. Balance of supply and demand of water resources-from simply determining supply according to demand to a strategy of balance of supply and demand of water resources based on strengthening water demand management. 7. The problem of water resources in the north-from over-exploitation of groundwater and the use of untreated sewage to maintaining economic growth: on the basis of vigorously saving water and pollution control and rational use of local water resources, the strategic measures of transferring water from South to North are adopted to ensure the sustainable social and economic growth in the north. 8. The problem of water resources in the western region-it is necessary to change from low-level development without ecological environment awareness to a strategy of water resources development and utilization coordinated with ecological environment construction. In order to realize the above strategic transformation, three reforms must be carried out: 1. The reform of water resources management system; 2. Reform of water resources investment mechanism; 3. Reform of water price policy. * This paper is a comprehensive report of the consulting project "Strategic Research on Sustainable Development of Water Resources in China in the 21st Century" organized by China Academy of Engineering. The consultation project was presided over by Qian Zhengying and Zhang Guangdou, attended by 43 academicians of the two academies and nearly 3 experts from outside the hospital. After more than a year of intense work, it was reported to the State Council and relevant ministries and commissions on July 11, 2. The project is divided into seven research groups, and nine special reports are put forward. On this basis, this comprehensive report is completed through repeated discussion and revision by the project comprehensive group. The list of project comprehensive groups is attached. It is said that water resources are basic natural resources and one of the controlling factors of ecological environment. At the same time, it is a strategic economic resource and an organic part of a country's comprehensive national strength. Looking ahead, water resources are increasingly affecting the global environment and development, and may even lead to conflicts between countries. To explore the national strategy of water resources in the 21st century and its related scientific issues is one of the key topics of global concern and governments at the turn of the century. In the historical development, the Chinese people are struggling with frequent floods and droughts. After the founding of New China, large-scale water conservancy construction has been carried out, and great achievements have been made. Our country has supported food and clothing and economic development with renewable water resources accounting for about 6% of the world and cultivated land accounting for 9% of the world's population. However, in the process of water resources development and utilization, some more complicated new situations and new problems have emerged. The floods in the Yangtze River and Nenjiang River in 1998, the cut-off of the Yellow River since the early 199s, the increasingly serious sandstorms in the northern region, and the water pollution in rivers, lakes and seas have attracted the attention of people all over the country and even the world. Facing the strategic goal of China's development in the 21st century, can our water resources support the food supply of 1.6 billion people in the future? Can it support the sustainable development of social economy? How to solve the flood, water shortage and water pollution in China? In response to these problems, people from all walks of life have made suggestions. To this end, under the leadership of the State Council and the strong support of relevant ministries and commissions, China Academy of Engineering has organized 43 academicians of the two academies and nearly 3 experts from outside the academy covering geography, geology, meteorology, hydrology, agriculture, forestry, water conservancy, land, soil and water conservation, ecological environment, urban construction, environmental engineering, social economy and other related disciplines, with "Strategic Research on Sustainable Development of Water Resources in China in the 21st Century" as the general project, according to the 23. After more than a year of intense work, Nine special reports were put forward: 1. Study on flood control and disaster reduction countermeasures in China; 2. Evaluation of water resources in China and analysis of development trend of supply and demand; 3. Agricultural water demand and water-saving and efficient agricultural construction in China; 4. Sustainable utilization and protection of urban water resources in China; 5. Countermeasures for pollution prevention and disaster reduction in rivers, lakes and seas in China; 6. Rational allocation of water resources in northern China and South-to-North Water Diversion Project; 7. Development and utilization of water resources in northwest China; 9. Development and utilization of water resources in southwest China; China's ecology. Environmental Construction and Water Resources Protection and Utilization Based on the above special reports, the comprehensive report "Strategic Research on Sustainable Development of Water Resources in China" was put forward after repeated discussions and key investigations by the project comprehensive team. I. Status and Problems of Water Resources in China 1. Natural Status of Water Resources The recharge source of water resources is mainly atmospheric precipitation, and the forms of occurrence are surface water, groundwater and soil water, which can be updated year by year through water cycle. (1) Total water resources and per capita water resources According to the evaluation of national water resources conducted by the Ministry of Water Resources in the early 198s, the average annual precipitation in China is 6.2 trillion cubic meters, and the average annual water resources of surface water and groundwater that can be renewed through water circulation are 2.8 trillion cubic meters, except that soil water is directly used in natural ecosystems and artificial ecosystems. According to the 1997 population statistics, China's per capita water resources are 2,22 cubic meters. It is predicted that by 23, when China's population increases to 1.6 billion, the per capita water resources will drop to 1,76 cubic meters. According to the internationally recognized standards, a country with a per capita water resource of less than 1,7 cubic meters is short of water. Therefore, the future situation of water resources in China is grim. (2) The time distribution of water resources is extremely uneven. In addition to the shortage of water resources per capita, the time distribution of water resources in China is very uneven. Due to the influence of monsoon climate, precipitation mainly occurs in summer. The same period of rain and heat is a favorable condition for agricultural development, which enables China to develop irrigated agriculture and dry land agriculture at the same time. However, due to the excessive concentration of precipitation season, the precipitation for four consecutive months in flood season accounts for 6% ~ 8% of the whole year in most areas, which is not only prone to spring drought and summer waterlogging, but also about 2/3 of the water resources is flood runoff, resulting in floods in flood season and low water in non-flood season. However, the drastic change of precipitation between years has caused serious floods and low water in rivers, and even continuous flood years and continuous low water years have occurred. (3) The spatial distribution of water resources is also extremely uneven. The annual precipitation in China is the highest in the southeast coastal areas and gradually decreases to the northwest inland areas. From Huma, Heilongjiang Province to the southeastern border of Tibet, this northeast-southwest diagonal line is generally consistent with the rainstorm isoline ③ with an average annual precipitation of 4mm and an average annual maximum precipitation of 5mm for 24 hours, which is the dividing line between the humid and semi-humid areas in the southeast and the arid and semi-arid areas in the northwest. The humid and semi-humid areas in the southeast are also frequent areas of rainstorm and flood. The spatial distribution of water resources does not match the distribution of land resources in China. The Yellow River, Huaihe River and Haihe River basins account for 13.4% of the country's land area, 39% of cultivated land, 35% of population and 32% of GDP, while water resources only account for 7.7%, with a per capita of about 5 cubic meters and cultivated land less than 4 cubic meters, which is the most tense area in China. The inland river basin in northwest China accounts for 35% of the country's land area, 5.6% of cultivated land, 2.1% of population, 1.8% of GDP and 4.8% of water resources. Although this area is an arid area, the per capita water resources are about 5,2 cubic meters and the per mu of cultivated land is about 1,6 cubic meters because of the sparse population. If the water and soil resources are rationally developed and utilized under the guidance of science, and the appropriate economic structure and arrangement are made. (4) The high sediment content in rivers is a prominent problem in China's water resources. The western part of China is the birthplace of the Yangtze River, the Yellow River, the Pearl River and many international rivers. There are large areas of loess plateau and karst mountains. Natural factors and long-term man-made destruction have caused serious soil erosion in many areas, which has caused serious harm to local land resources and ecological environment, and also caused many rivers to carry a lot of sediment. The high sediment content of the Yellow River is the highest in the world. These problems increase the complexity of river management and the urgency of ecological environment construction in China. From a historical point of view, river sediments have created and continued to develop vast alluvial plains and intermountain basins with a total area of 1.85 million square meters in the eastern and central regions. These places, with flat terrain and fertile soil, have become important bases for the survival and development of the Chinese nation, but due to improper development and utilization, they have also brought a series of floods and droughts and environmental problems. (5) Impact of Climate Change on China's Water Resources According to the analysis of precipitation and temperature data in the past 5 years from 195 to 1997, China has experienced drought in the north and waterlogging in the south in the past 2 years. In 198s, the drought in North China continued, and the ten-year average precipitation in Beijing-Tianjin area, Hailuan River basin and Shandong Peninsula was 1% ~ 15% less. In 199s, the eight-year average precipitation in the middle and upper reaches of the Yellow River, Hanjiang River basin, upper reaches of Huaihe River and Sichuan Basin was about 5% ~ 1% less, and the natural inflow at Huayuankou of the Yellow River was estimated to be about 2% less, and the annual runoff of Hailuan River and Huaihe River was also obviously less. In the inland areas of northwest China, the precipitation decreased slightly (2.5%) in 198s and increased slightly (8.9%) in 199s. Due to the multi-year regulation of glacial meltwater in alpine areas, the multi-year average flow of rivers out of the mountain pass is basically the same. A few rivers, such as Aksu River in Xinjiang, have a slight increase in runoff, while some rivers, such as Shiyang River in Hexi Corridor, have less runoff. From a national perspective, it is estimated that adding the data of the last 18 years on the basis of the original 24-year evaluation series will have little impact on the total water resources in the country. However, the emergence of continuous dry years in the water-deficient areas in the north, and the influence of unfavorable factors such as the dry years of the Yellow River, Huaihe River, Haihe River and Hanjiang River at the same time have aggravated the contradiction between supply and demand of water resources in the north. According to international research, the global annual average temperature may rise in the next 5 years due to the greenhouse effect caused by human activities, but the predicted values are quite different. The increase of temperature will increase the surface evaporation and reduce the water resources accordingly. Specific to China's major river basins, the degree of impact remains to be discussed. 2. Achievements in the past 5 years and current problems. In the 5 years since the founding of New China, the Party and the government have led the broad masses of people to carry out unprecedented water conservancy construction. The country has built a total of 25, km of reinforced dikes and built more than 8, large, medium and small reservoirs, initially controlling the frequent floods of major rivers, forming an annual water supply capacity of more than 56 billion cubic meters, and expanding the irrigation area from 16 million hectares to nearly 53.33 million hectares (including agriculture, forestry and animal husbandry). The national water consumption increased from more than 1 billion cubic meters in 1949 to 556.6 billion cubic meters in 1997, of which agriculture accounted for 75.3%, industry accounted for 2.2%, urban life accounted for 4.5%, and the per capita comprehensive water consumption increased from less than 2 cubic meters to 458 cubic meters. These great achievements have created conditions for ensuring China's rapid economic development and long-term social stability. However, due to various reasons, the model of water conservancy development basically belongs to extensive type. Many projects have low safety standards, poor construction quality, incomplete supporting facilities, weak management, great waste of water and serious water pollution, and so far a benign operation mechanism has not been established. In the rapid development of the national economy, some new contradictions have also emerged. To sum up, the main problems are as follows: (1) Flood control safety is still lacking. The flood control engineering system of rivers in China has not yet reached the approved planning standards. The Jingjiang reach of the Yangtze River and the main dikes of the Yellow River, after the completion of the Three Gorges and Xiaolangdi water control projects and corresponding supporting projects, can reach the standard of preventing floods with a return period of more than 1 years; The Huaihe River, Haihe River, Liaohe River, Songhua River, Pearl River and other rivers, except for a few key cities, most dikes can only defend against the frequent floods that occur once every 2 years or so. Even if the flood control capacity of the above rivers reaches the planning standard, according to the laws of meteorology and hydrology in China, there is still the possibility of over-standard floods that cannot be solved by the project. However, due to the lack of unified planning and management, all localities are competing to build flood control projects and improve flood control capacity, and the length of dikes in the country has increased from 11, km in the 197s and 16, km in the 198s to 25, km at present. The dike line is getting longer and longer, the dike is getting higher and higher, and the space for flood storage and discharge is getting smaller and smaller, resulting in the continuous rise of flood levels in many rivers under the same flow, resulting in a vicious circle of heightening and repairing dikes and raising flood levels. Due to the continuous heightening of dikes, the burden and risk of flood control are also increasing, which will cause even more devastating disasters if the dikes break. (2) The shortage of water resources and the waste of water coexist. According to the analysis and estimation, according to the current normal needs of the whole country,