At the beginning of the new millennium, the themes of "World Water Day" and "China Water Week" are "Sanitary Water Use" and "Strengthening Conservation and Protection to Realize Sustainable Utilization of Water Resources" respectively. Looking at such a theme, we can't help thinking of the famous aphorism:
If we don't cherish the precious water resources, then the last drop of water on the earth is probably our tears!
Water resources, a "crisis" facing human society.
Water is one of the important resources for human survival and development, and it is an indispensable and irreplaceable special resource. Without water, there would be no life, no civilization progress, no economic development and no social stability. The water resources in the world are limited, so the economic and social development must adapt to the water supply, and the water cannot be used indefinitely or exceed the carrying capacity of water resources. In today's world, with the continuous growth of population and economic development, the demand for fresh water resources is increasing day by day; At the same time, due to unreasonable utilization, the shortage of fresh water resources is increasingly tense.
China has been short of water for a long time. Historically, China is a country with frequent droughts, known as "nine droughts in ten years". In the historical documents of more than 2200 years, there have been 1300 droughts. China's per capita water resources are only about 2,300 cubic meters, which is about a quarter of the world's per capita water. Water resources in China are not only less per capita, but also unevenly distributed. The basin area north of the Yangtze River accounts for 63.5% of the land area, while water resources account for 19% of the whole country. With the development of society and economy, the gap of water resources is getting bigger and bigger. At present, China's agricultural irrigation lacks more than 30 billion cubic meters of water every year on average, and there are still more than 30 million people in rural areas who have difficulty drinking water. There are more than 400 cities in China that are short of water, and there are more than 1 10 cities that are seriously short of water. The daily water shortage in Chinese cities is160,000 cubic meters, which affects the industrial output value by more than 200 billion yuan every year, and the urban population is about 40 million.
In addition to China, there are many countries and regions in the world with serious water shortage problems.
The United Nations Water Conference pointed out: "We are entering a new era of water shortage". The increasingly serious global water crisis has aroused great concern of the international community. 1972 United Nations Conference on Human Environment and 1977 United Nations Water Conference warned the world: "Water will soon become a serious social crisis, and the next crisis after the oil crisis is water." Countries all over the world have begun to pay unprecedented attention to water problems, and gradually formed a * * * understanding of water crisis. 1In August, 1995, the World Bank survey report announced that 26 countries, accounting for 40% of the world's population, were facing water crisis, and their agriculture, industry and people's health were seriously threatened; About 654.38 billion people in developing countries do not have access to clean water, 654.38 billion people do not have good sanitation facilities, 80% of diseases are caused by drinking unclean water, and 25 million people die every year. 1999 World Water Day, the United Nations warned that with the development of human production and the improvement of living standards, the world water consumption is increasing at an annual rate of 5%, and the total water consumption will double every 15 years. Unless governments take effective measures, before 2025, more than half of the population on earth will face the crisis of fresh water resources, and more than one third of the population will not be clean. The shortage of water resources has become the main restricting factor of global social and economic development. Rational utilization of water resources is an urgent task for sustainable development of human beings, and water saving is the key to rational utilization of water resources, and it is also one of the fastest, most feasible and most extensive ways to maintain sustainable utilization of water resources.
Saving water is an inevitable choice for sustainable development.
1992 170 heads of state and government put forward the strategy of sustainable development in the "2 1 Agenda Declaration" adopted at the Rio Conference on Environment and Development, pointing out that "water is not only necessary to maintain all life on earth, but also of vital significance to all social and economic sectors." China took the lead in formulating "China 2 1 Century Agenda", and explicitly included sustainable development as a national development strategy in the Ninth Five-Year Plan and the 20 10 development plan of national economy and society. Among them, water-saving work, as an important strategic decision of the CPC Central Committee and the State Council, has been included in the agenda of governments at all levels, and the concept of water-saving has been deeply rooted in people's hearts step by step.
Saving water is an action to improve water utilization efficiency, reduce waste and coordinate the relationship between water resources and society, economy and environment. Therefore, in the process of water saving, we should proceed from China's water saving status, national conditions and water conditions. First, it is necessary to deeply analyze the current water-saving level and the water-saving effect produced by the current water-saving measures, analyze the existing problems, causes and difficulties in the work, and analyze the potential and breakthrough points of water-saving. On this basis, according to the needs and specific conditions of national economic and social development, regions, departments, industries and types are divided. Focusing on improving water use efficiency, this paper analyzes and puts forward the water-saving level that should be achieved in different stages and the engineering and non-engineering water-saving measures that should be taken, so as to realize the optimal matching and efficient utilization of water resources with water saving as the core, paying special attention to the comprehensive balance between water saving and open source, water saving and society, economy and environment, and ensuring the sustainable development of water resources and society, economy and environment.
The sustainable utilization of water resources is directly related to the implementation of China's sustainable development strategy. At present, there are some problems that can't be ignored in the process of shortage and unreasonable utilization of water resources in China: the interruption of northern rivers, represented by the lower reaches of the Yellow River, has intensified, resulting in the decline of river flood discharge capacity, the loss of industrial and agricultural production, the difficulty of drinking water for urban and rural residents, the serious destruction of ecological balance and the deterioration of ecological environment in estuary areas. Overexploitation of groundwater in some areas has affected urban and rural water supply, urban construction and people's survival. Due to the over-exploitation of groundwater in China, the funnel area has reached 87,000 square kilometers, and the water level in some funnel centers has reached 60-80 meters. The rapid growth of sewage and wastewater discharge has seriously damaged the comprehensive function of limited water bodies. Nearly 46.5% of major rivers and more than 90% of urban waters in China are polluted, of which 10% is seriously polluted, which has basically lost its use value and aggravated the shortage of water resources. In addition, there are 58 million poor people in China, mainly distributed in arid and water-deficient areas, who have long endured the threat of water shortage to their survival. 199 1 ~ 1996, there were 66,000 water disputes nationwide, and in the two years of 1997 and 1998, * * mediated water disputes 17400.
The demand for water in the economic development of northern China shows an upward curve in the future development chart, and the implementation of the strategy of developing the western region is even more indispensable. It has become an inevitable choice for China's economic development to develop water resources rationally and save water.
It can be said that through years of efforts, China has made great progress in water conservation, but compared with some developed countries, we still have a long way to go.
Agriculture is a big water user and a great waste of water resources. At present, the agricultural irrigation mode of "soil canal water conveyance plus flood irrigation" is still widely used in China. Half of the irrigation water is lost in the water conveyance, and the irrigation water utilization coefficient is mostly only 0.4, which is less than half of that of some developed countries. After irrigation with water per square meter, the grain yield in China increased by 0.5 kg, and that in developed countries could reach 2 kg. Industry, due to the backward technology of existing water facilities, the current water consumption per 10,000 yuan of industrial output value in China is 103 cubic meters, 8 cubic meters in the United States and only 6 cubic meters in Japan, which is 10 ~ 20 times that of developed countries; The reuse rate of industrial water in China is only about 40%, while the average level in developed countries is 75% ~ 85%. The phenomenon that urban residents don't talk about saving and waste domestic water is very serious, and water-saving education has a long way to go. Beijing alone leaks 360,000 tons of water every year. In Israel, which is also short of water, there are not only two sets of pipes for residents to flush toilets and wash their hands, but also two buttons for defecation. It was the Israelis with a strong sense of water crisis who invented the agricultural drip irrigation technology.
From now until the middle of the next century, China will fully realize the grand goal of socialist modernization. With population growth and socio-economic development, water consumption will increase substantially, and the contradiction between supply and demand of water resources will become more acute. It is predicted that the total water demand in 20 10 will be 698.8 billion cubic meters, in 2030 it will be 800 billion cubic meters, and in 2050 it will be at least 850 billion cubic meters, which will increase by 1995 respectively, so as to achieve a general balance between supply and demand of water resources in moderately dry years. It can be seen that the gap in water use is still quite large. Only by adhering to the principle of combining open source with throttling, putting throttling in the first place, further strengthening water conservation, realizing optimal allocation and efficient utilization of water resources centered on water conservation, and striving to achieve a basic balance between supply and demand, can the long-term economic development goal be successfully achieved.
Saving water and ensuring the sustainable utilization of water resources are our common cause and our common responsibility!