Information: World Water Resources

Water is an important component of natural resources and is the main material basis for the structural composition and life activities of all living things. Globally, water is the link between all ecosystems, and natural ecosystems control the flow of water as well as continuously contribute to its purification and repeated cycles. Therefore, water is of decisive significance for the survival of living creatures and human beings in the natural environment.

The Earth's water resources, in the broadest sense, refers to the totality of the amount of water in the hydrosphere.

Sea water is brackish and cannot be utilized directly, so the water resources usually referred to are mainly freshwater resources on land, such as river water, freshwater, lake water, groundwater and glaciers. Land-based freshwater resources account for only 2.53% of the total amount of water on Earth, most of which (nearly 70%) is solid glaciers, that is, distributed in the polar regions and the middle and lower latitudes of the mountain glaciers, it is also very difficult to utilize. At present, human beings can easily utilize freshwater resources, mainly river water, freshwater lake water, and shallow groundwater, accounting for about 0.3% of the total global freshwater reserves, accounting for only seven hundred thousandths of the total global water reserves. According to research, from the point of view of the water cycle, the world's real effective use of freshwater resources about 9,000 thousand cubic meters per year. Saving water resources is something we all have to do!

Nature and Characteristics of Water Resources

Water and water bodies are two different concepts. While pure water is composed of H2O molecules, water bodies contain a variety of substances, including suspended matter, aquatic organisms, and substrates. A water body is actually a natural complex of water-covered sections of the earth's surface, including rivers, lakes, swamps, reservoirs, glaciers, groundwater, and oceans. Water resources and human beings have a very close relationship, human beings take water as a source of life-sustaining, human beings in the historical development has always been to the place where there is water to gather, and carry out economic activities. With the development of society and technological progress, the degree of human dependence on water is growing.

Water resources is the world's most widely distributed, the largest number of resources. Water covers more than 70% of the earth's surface area, totaling 1.5 billion cubic kilometers; is also the world's most exploited resources. Now the annual human consumption of water resources is far more than any other resources, the world's water consumption amounted to 3 trillion tons.

The distribution of water resources on Earth is very uneven, and precipitation and runoff vary greatly from place to place. About one-third of the world's land is dry with little rain, while other areas are prone to flooding during the rainy season. For example, in China, the Yangtze River Basin and its south, water resources accounted for more than 82% of the country, 36% of the arable land, more water, less; north of the Yangtze River, 64% of the arable land, water resources less than 18%, more water, *** in the Huanghuaihai Basin of the greatest potential for food production of the arable land accounted for 41.8% of the country, and less than 5.7% of water resources.

The utilization of water resources

Although the total amount of water resources in China is relatively large, but the per capita amount is not rich. Water resources are characterized by uneven regional distribution, unbalanced combination of soil and water resources; intra-year distribution of concentrated, large inter-annual variations; even the abundance of dry years is more prominent; river sedimentation is serious. These characteristics cause our country is prone to drought and water disasters, water supply and demand to produce a contradiction, which also determines our country on the development and utilization of water resources, river training is a very arduous task.

1. Utilization of water resources and the contradiction between supply and demand

China's average annual runoff of surface water is about 2.7 trillion cubic meters, equivalent to 5.5% of the total global land runoff, accounting for the world's fifth, lower than Brazil, the former Soviet Union, Canada and the United States. China also has an average annual meltwater volume of nearly 50 billion cubic meters of glaciers, about 800 billion cubic meters of groundwater and nearly 5 million cubic kilometers of offshore seawater. At present, China's available water year about 1.1 trillion cubic meters, while in 1980 China's actual total water consumption has reached 507.5 billion cubic meters, accounting for 46% of the available water resources.

Since the founding of the country, in the development and utilization of water resources, river regulation and prevention of water hazards have done a lot of work, and made greater achievements.

In the urban water supply, more than 300 cities across the country have built a water supply system, the daily water supply capacity of 40 million tons of tap water, the annual water supply of more than 10 billion cubic meters; urban industrial and mining enterprises, institutions, self-supplied water supply capacity of more than 60 million tons of daily water supply capacity, the annual water supply of 17 billion cubic meters; more than 7,400 towns and towns in the 28% of the establishment of the water supply equipment, the daily water supply capacity of about 8 million tons, the daily water supply capacity of about 8 million tons, and the water supply of more than 7,400 towns, the water supply equipment is established.

Irrigation of farmland, the country's existing irrigated farmland area of nearly 720 million mu, woodland orchards and pasture irrigated area of about 0.3 billion mu of irrigated farmland with irrigation facilities accounted for 48% of the country's arable land area, but it produces food accounted for 74% of the country's total grain production.

Flood control, the existing embankment more than 200,000 kilometers, protecting 500 million mu of arable land and large and medium-sized cities more than 100. There are more than 80,000 large, medium and small reservoirs with a total capacity of more than 440 billion cubic meters, controlling a watershed area of about 1.5 million square kilometers.

Hydroelectric power generation, China's hydropower installed capacity of nearly 30 million kilowatts, the proportion of the total installed capacity in the power of about 29%, the proportion of power generation in about 20%.

However, with the rapid development of industry and urbanization, the demand for water continues to increase, and there is a tight water supply situation. According to the 1984 statistics of 196 water-scarce cities, the daily water shortage amounted to a total of 14 million cubic meters, the degree of assurance of water resources has become a major constraint on the economic development of certain areas.

The contradiction between the supply and demand of water resources, both by the quantity and quality of water resources, the distribution of the law and its development conditions and other natural factors, but also by the various sectors of the demand for water resources of the socio-economic factors of constraints.

China's total water resources is not small, but the per capita possession of water resources is very poor, only the world's average value of 1/4 (China's per capita possession of surface water resources of about 2700 cubic meters, ranking 88th in the world). Comparison of water resources per capita, Canada for our country 48 times, Brazil for 16 times, Indonesia for 9 times, the former Soviet Union for 7 times, the United States for 5 times, and also lower than Japan, Mexico, France, the former Yugoslavia, Australia and other countries.

China's water resources in the south and north of less, the regional distribution of great differences. The annual runoff of the Yellow River Basin accounts for only about 2% of the total annual runoff of the country, and about 6% of the water volume of the Yangtze River. In the country's total annual runoff, Huai, Haihe, Luanhe and Liaohe three basins only about 2%, 1% and 0.6% respectively. The per capita volume of water in the four basins of the Yellow River, Huaihe River, Hailuan River and Liaohe River is only 26%, 15%, 11.5% and 21% of the per capita value of our country respectively.

With the growth of population, the continuous development of industrial and agricultural production, resulting in the increasing contradiction between supply and demand of water resources. Since the beginning of this century, to the mid-1970s, the world's agricultural water consumption increased by 7 times, industrial water consumption increased by 21 times. China's water consumption also grew rapidly, and by the end of the 1970s the total water consumption of the country was 470 billion cubic meters, 4.7 times that of the early years of the founding of the country. Among them, urban water consumption increased 8 times, while industrial water consumption (including thermal power) increased 22 times. Beijing in the late 70's urban water consumption and industrial water consumption, are more than 40 times the early years of the founding of the country, Hebei, Henan, Shandong, Anhui and other provinces of urban water consumption in the late 70's than the early years of the founding of the country have increased dozens of times, and some even more than 100 times. As a result, the contradiction between supply and demand of water resources is exceptionally prominent.

As the contradiction between supply and demand of water resources has become increasingly acute, there are many adverse effects. First of all, the impact on industrial and agricultural production is very large, for example, in 1981, the city of Dalian due to water shortages caused by the loss of industrial output value of 600 million yuan. Of the 1.5 billion mu of arable land in China, there are still 830 million mu of arid land without irrigation facilities, and another 1.4 billion mu of water-scarce pasture. Every year, 300 million mu of farmland in the country are affected by drought. In the northwestern agricultural and pastoral areas, 40 million people and 30 million head of livestock still have difficulty in drinking water. Secondly, it causes inconvenience to people's life and work; some cities have insufficient water supply to buildings or often cut off water, and some water-scarce cities have to take regular and limited water supply, which makes people's life difficult. Thirdly, the over-exploitation of groundwater has caused a continuous decline in the groundwater level and the depletion of water resources, with 24 out of 27 major cities experiencing groundwater descent funnels.

2. Water conservancy construction and floods

Due to its geographical location and climate, China is a country where water and drought disasters occur frequently, especially floods have long plagued the development of the economy. According to statistics, from 206 BC to 1949, 2155 years, *** occurred 1062 times larger floods, an average of two years that is one. The Yellow River in more than 2,000 years, an average of three years, two breaks, a century a diversion, only in 1887 a flood death of 930,000 people, the country in 1931 in the great flood killed 3.7 million people. After the founding of the country, floods still occur constantly, causing great losses. Therefore, the construction of water conservancy, river training, prevention and control of water damage for the country's a major plan of governance, but also a very important strategic task.

Over the past 40 years in China, **** refurbishment of river embankments more than 20 million kilometers, to protect 500 million mu of arable land. Built more than 80,000 reservoirs of various types, supporting 2.63 million electromechanical wells, with more than 66 million kilowatts of irrigation and drainage machinery. The area of electromechanical drainage and irrigation is 460 million mu, the area of flood control is about 290 million mu, the area of saline and alkaline land is 0.72 billion mu, and the area of soil erosion control is 510,000 square kilometers. The construction of these water conservancy projects not only provides 500 billion cubic meters of water annually for agriculture, industry and urban life, but also solves the drinking water difficulties of 123 million people and 73 million livestock in mountainous and pastoral areas. And it has played a huge role in the defense of floods and disasters.

With the sharp increase in population and irrational use of water and soil resources, leading to the deterioration of the water environment, exacerbating the occurrence of floods. In particular, since the beginning of summer in 1991, in China's Jianghuai, Taihu Lake area, as well as other areas of the Yangtze River Basin continuous heavy rainfall or torrential rainfall, some areas of the rare floods in the last hundred years. As of August 1, the victimized population reached 220 million, with more than 50,000 casualties, 2.91 million collapsed houses, 6.05 million damaged houses, and the affected area of crops was about 315 million mu, with a disaster-affected area of 195 million mu, and the direct economic loss was as high as 68.5 billion yuan. In front of this large area of severe flooding, should further improve the understanding of the serious threat of floods facing our country, summarize the lessons learned and look for prevention and control measures.

In addition to natural factors, the main causes of flooding are:

(1) irrational use of natural resources. In particular, deforestation, destruction of water and soil balance, ecological environment deterioration. As mentioned earlier, China's soil erosion is serious, since the founding of the country has been managed 510,000 square kilometers, but the current area of soil erosion has reached 1.6 million square kilometers, the annual loss of 5 billion tons of sediment, the river takes away about 3.5 billion tons of sediment, of which siltation in the river, reservoirs, lakes in the sediment up to 1.2 billion tons. Lakes unreasonable reclamation, the area is shrinking, so that its flood control capacity decline. According to the Chinese academy of sciences, nanjing institute of geography and lakes investigation, in the late 70's, China's area of 1 square kilometer above the lake about 2300 more than a total area of 71,000 square kilometers, accounting for the total area of the country's 0.8%, the water resources of the lakes 707.7 billion cubic meters, of which 225 billion cubic meters of freshwater, accounting for the total amount of China's land water resources of 8 percent. Over the past 30 years since the founding of the People's Republic of China, China's lakes have been reduced by more than 500, shrinking in area by about 18,600 square kilometers, accounting for 26.3% of the area of existing lakes, and the water storage capacity of lakes has been reduced by 51.3 billion cubic meters. The water system and natural water surface of the middle and lower reaches of the Yangtze River have been reduced, and the water surface of the lakes in Hubei, Anhui, Jiangsu, and Dongting and Poyang has been reduced by about 12,000 square kilometers since 1954 due to the encirclement of the lakes for the purpose of making farmland, etc., which has greatly weakened the ability to prevent floods and fight against floods. On the other hand, the river channel is silted and encroached, the flooding capacity is reduced, and the river bed of many rivers is elevated due to a large amount of sediment siltation in the river channel, which reduces the flooding capacity and increases the chance of flooding. For example, the flooding capacity of the main stream of the Huaihe River has decreased by 3,000 cubic meters per second. In addition, the river is crowded, narrowing the water cross section, also reduces the flooding, flood control capacity, increasing the degree of flood damage.

(2) water conservancy project flood control standards are low. China's large rivers and flood control standards are generally low, at present, in addition to the lower reaches of the Yellow River can be prevented 60 years of flooding, the rest of the Yangtze River, the Huaihe River and other six rivers can only be prevented 10 to 20 years of flood standards. Many large and medium-sized cities have poor flood prevention and drainage facilities and are often under the threat of general flooding. The vast middle and lower reaches of the rivers are under the threat of flooding in an area of 738,000 square kilometers, accounting for 7.7% of the total land area of the country, of which there are 500 million mu of arable land and a population of 420 million people, which accounted for more than 1/3 of the total number of people in the country, and the total output value of industry and agriculture accounted for 60% of the total value of the country. In addition, the rivers in the middle and lower reaches of the vast rural areas discharge standard is even lower, with the development of the rural economy, far from being able to meet the current requirements of flood control and drainage.

(3) population growth and economic development to deepen the degree of disaster. On the one hand, the ability to resist flooding is weakened, on the other hand, due to socio-economic development but the extent of the disaster has increased significantly. The population has more than doubled since the founding of the PRC, especially in the eastern part of the country, where the population density in the Yangtze River Delta is 10 times the national average density. The country's total industrial and agricultural output value was only 46.6 billion yuan in 1949, but by 1988 it had reached 240.89 billion yuan, an increase of 51 times. In the past 10 years, township and village enterprises have been developing rapidly, and the output value of township and village enterprises in the eastern and central regions accounts for 98% of the total output value of the country's township and village enterprises, and because of the continuous development of the economy, the various kinds of losses caused by floods of the same frequency have multiplied. For example, in 1991, the May-July rainfall in the Taihu Lake basin area was 600-900 millimeters, less than one in 50 years, and did not exceed the 1954 flood, but the disasters and economic losses caused were much more serious than in 1954. In addition, the middle and lower reaches of the rivers are generally agriculturally developed, with a large number of commercial grain, cotton and oil production base, once the disaster, agricultural losses are also quite serious.

3. Water pollution and its hazards

Water is the most important natural solvent, so it is very easy to pollute. Common water pollution has the following categories.

(1) water eutrophication Water eutrophication is a type of organic pollution, due to excessive nitrogen, phosphorus and other nutrients into the natural water body and deteriorate water quality. Fertilizer applied to farmland, generally about half of the nitrogen fertilizer is not used, into the groundwater or ponds and lakes, a large number of domestic sewage often make the water body over-fertilized. Excessive nutrients to promote phytoplankton in the waters, such as cyanobacteria, diatoms, as well as the proliferation of water plants, sometimes the entire water surface is covered with algae and the formation of "splash", algae die and then deposited on the bottom of the water, microbial decomposition of a large number of dissolved oxygen consumption, resulting in the lack of oxygen and the death of a large number of fish. Eutrophication of the water body will accelerate the decline of the lake, so that the development of swamp.

Marine near-shore sea area, the phenomenon of eutrophication, so that the waist flagellate algae (such as bare ditch algae and glow-in-the-dark worms, etc.) and other mass reproduction, dense together, so that the seawater was pink or reddish-brown, known as the red tide, the fishery is very harmful. In recent years, the northern Bohai Sea and the South China Sea has occurred many times.

(2) Pollution of toxic substances Toxic substances include two major categories: one refers to mercury, cadmium, aluminum, copper, lead, zinc and other heavy metals; the other is organochlorine, organophosphorus, polychlorinated biphenyls (PCBs), aromatic amino compounds and other chemical products. Many enzymes depend on the complexation of proteins and metal ions in order to function, and thus require certain trace elements (e.g., manganese, boron, zinc, copper, molybdenum, cobalt, etc.); however, unsuitable metals, such as mercury and lead, or even excessive amounts of essential trace elements, such as zinc and copper, can disrupt this protein-metal-ion equilibrium, thereby weakening or terminating the activity of certain proteins. Mercury and lead, for example, have a strong tendency to bind to certain enzymes of the central nervous system, thus predisposing to neurological disorders such as insanity, mental retardation, coma and even death. In addition, mercury and a protein that interacts with the genetic material DNA form a specialized binding, which is why mercury poisoning often causes severe birth defects.

The binding of these heavy metals to proteins not only leads to poisoning, but also to bioaccumulation. Once the heavy metal atoms are bound to proteins, they cannot be excreted and gradually accumulate from low doses to higher concentrations, thus causing harm. A typical example is the once mentioned Minamata disease in Japan. Upon investigation, it was found that the metallic form of mercury is not very toxic, and that most of it passes through the digestive tract without being absorbed. However, the bacteria in the water sediment absorbed the mercury, so that the mercury chemical reaction, the reaction of mercury and methyl groups combined to produce methylmercury (Hg-CH3) organic compounds, which is different from the mercury itself, methylmercury absorption rate is almost equal to 100%, the toxicity of its almost 100 times greater than the metal mercury, and it is not easy to excrete away.

Organic chlorine (or chlorinated hydrocarbons) is an organic compound in which one or several hydrogen atoms are replaced by chlorine atoms, and this compound is widely used in plastics, electrical insulators, pesticides, fire extinguishers, wood preservatives, and other products. Organochlorines have two characteristics that make them particularly susceptible to bioaccumulation, namely extreme chemical stability and high fat solubility and low water solubility. Chemical stability means that they are neither easily decomposed in the environment nor metabolized by organisms. High lipid solubility indicates that it is easy to be absorbed by the organism, and once it enters, it cannot be excreted, because excretion requires water solubility, which results in bioaccumulation and the formation of toxicity. Typical organochlorine pesticides such as DDT, six six six, etc., because they cause serious harm to organisms and humans have been banned by many countries.

(3) thermal pollution Many industrial production processes produce waste heat emitted into the environment, the environmental temperature will be raised to the degree of undesirable or biological maladaptation, known as thermal pollution. For example, the heat released by the power plant fuel 2 / 3 in the vapor recondensation process scattered into the surrounding environment, dissipate waste heat the most commonly used method is to pump up the water in the rivers and lakes by the water pump, drenched in the cooling pipe, and then the heated water back to the natural body of water. The water passing through the cooling system is itself hot enough to kill most organisms. And experiments have shown that small changes in the temperature of a body of water have a profound effect on the ecosystem.

(4) Marine pollution With the population explosion and the development of production, China's marine environment has been subject to varying degrees of pollution and damage.

A survey in 1980 showed that the country's annual direct discharge into the sea of industrial and domestic sewage of 6.65 billion tons, each year with these sewage discharged into the toxic and harmful substances for petroleum, mercury, cadmium, lead, arsenic, aluminum, cyanide and so on. The amount of pesticides applied in the coastal counties of the country each year, about a quarter of the flow into the sea, about more than 50,000 tons. These pollutants are very harmful to a wide range of the Yangtze River estuary, Hangzhou Bay, pollution is becoming increasingly serious, and began to jeopardize China's largest fishing ground Zhoushan Islands.

Marine pollution in some areas of the sea fish deaths, biological species to reduce the increase in toxic residues in aquatic products, the fishing ground outside, many beach farms abandoned. For example, in Jiaozhou Bay, there were 171 species of marine organisms in the intertidal zone of the bay from 1963 to 1964; the number dropped to 30 from 1974 to 1975; and there were only 17 species in the early 1980s. In the Bailang River mouth of Laizhou Bay, the highest annual production of silverfish was 300,000 kilograms; in 1963, there were about 100,000 kilograms, and now it is basically extinct.

Protection and Rational Utilization of Water Resources

[Editorial]

1. Strengthening Water Resource Management and Establishing a Water-Saving Economy

The key to alleviating China's water scarcity lies in improving water-use efficiency and establishing a water-saving economy. The main symbols of water-saving economy should be to develop industries with good quality, high output value, less water consumption and less sewage discharge, and to form a reasonable industrial structure; industrial layout should be adapted to the conditions of water resources; to improve the efficiency of water use in agriculture, and to develop crops with less water consumption; to make the water consumption quota of industrial and agricultural products and the water discharge quota to reach the domestic and international advanced level; to popularize the advanced domestic water-saving equipments; to strengthen the multiple reuse of water and to develop Sewage resource utilization and so on. Improve industrial water conservation, both reduce the amount of new water intake, naturally also reduces the amount of industrial wastewater. Industrial water conservation indicators are usually expressed in terms of water reuse rate, and our industrial water reuse rate is low. In the early 1980s, the national average was only about 20%, and only a few cities reached 40%. China's agricultural water accounted for 88% of the national water intake, and the United States 49%, 59% of the former Soviet Union, Japan 46%, France 47% compared to the gap is very large, which with the modernization of the national economic development requirements are extremely disproportionate. In the future, we should improve the efficiency of irrigation water, the development of organic sewage water quality standards in line with the agricultural irrigation, cultivation and promotion of drought-resistant crops in order to obtain stable and high yields.

2. Establishment of sewage treatment system

Establishment of sewage treatment system, so that the sewage resources with the governance and control of industrial waste, heavy metal pollution of water bodies will tend to slow down, and the management of organic sewage is becoming more and more prominent in the city is more important.

The use of sewage treatment plants is the main way to manage organic sewage in industrialized countries. The United States, Britain, France, Germany, etc., an average of every 1 to 1.5 million people have a sewage treatment plant. But these plants can only solve the biodegradable organic matter, and can not remove nitrogen, phosphorus and non-biodegradable organic matter. In recent years, more and more countries are turning to the development of old land treatment and biological ponds (oxidation ponds) and other natural purification methods, the use of ecosystems for organic sewage purification and treatment. Such as the United States of America, Michigan, Markisgen ecological engineering is composed of storage ponds, aeration ponds and irrigated fields, Australia, Victoria, Werribee Ranch is the use of oxidation ponds, farmland and pastures composed of the treatment system. Through the environmental ecological engineering to make sewage resources to obtain renewable water for the expansion of water supply, to a certain extent, can alleviate the local water scarcity of the state.

3. Development and use of water resources in the sky

Sky water (i.e., the water content of the air) is only 28 trillion tons, accounting for only 0.002% of the total global water, but plays an important role in weather changes. Sky water, 95% for the water vapor, clouds and precipitation clouds accounted for only 5%. The total amount of water in the sky is small, but its cycle is very fast, the cycle is only 8.7 days, while the underground and surface water cycle for 400 years, that is to say, a year in the sky water can be recycled 42 times a year, the amount of water in the sky will be 1176 trillion tons, far more than the total amount of surface water.

The development and utilization of water resources in the sky is firstly to investigate and study the situation of water resources in the sky in the region, including the sky water vapor, clouds and rain and snow spatial and temporal distribution, climate characteristics and variability, the availability of water resources in the sky and so on. Secondly, it is to carry out artificial precipitation in water-scarce areas, and the experimental results of countries around the world over the past 40 years have shown that, under suitable cloud conditions and with the correct catalytic methods, the artificial increase in precipitation can generally reach an average of 10 to 30%. China from 1958 also conducted a number of tests, Fujian Gutian Reservoir 1975-1986 12-year test results, an average increase in precipitation for 23.8%, only to generate a calculation of the investment benefit ratio of 1:50.

4. The main countermeasures to prevent and mitigate floods

Floods are a natural and social phenomena, the causes of which are both natural factors, but also man-made influences. Man-made influences. As a natural disaster can not be completely avoided, but with the advancement of science and technology and economic strength, human understanding of the laws of disaster, the evolution of the process will continue to improve and deepen, through the pre-disaster forecasting, early warning and take preventive and control measures can be reduced to a certain extent to reduce the losses caused by the disaster. To this end, the prevention and control of floods as the central task of national land management and socio-economic development planning an important part of the country's long-term flood management master plan, and through legislation to be implemented. At the same time, it is necessary to formulate flood control regulations, implement the rule of law for water, and emphasize the implementation of unified management. Accelerate research on flood prediction and forecasting, alarming and disaster assessment. Industrial layout should be adapted to the changes in the water environment, and the water environment should be transformed in a favorable direction through various measures, such as maintaining soil and water, building water storage projects, constructing dykes, dredging rivers, irrigation and drainage, and setting up stagnant flood storage zones, in order to obtain obvious ecological and social benefits. China's Three Gorges Project is a major project focusing on flood control and power generation, which, if successfully constructed, will have a great effect on flood control and disaster mitigation as well as economic construction.

China's water conservation status

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China is a country with water scarcity, the total amount of water resources in the world's sixth, measured by the per capita amount of water resources, per capita possession of 2,500 cubic meters, for the world's average per capita water quantity of 1/4, the world ranked 110th, by the United Nations as one of the 13 water-poor countries. At present, the country's 668 cities, more than 400 cities are water shortages, annual water shortages of more than 6 billion cubic meters. For a long time, under the influence of the traditional value of "inexhaustible water resources", water resources have been utilized without compensation for a long time, resulting in people's low awareness of water conservation, which has led to a huge waste of water resources and non-sustainable development and utilization of water resources. Increasing shortage of water resources, rational development, utilization of water resources, protection of the ecological environment, maintaining harmony between man and nature has become the twenty-first century mankind **** the same mission.

The water crisis will lead to further deterioration of the ecological environment. In order to obtain enough water supply society, will certainly increase the development of water resources. Over-exploitation of water resources may lead to a series of ecological problems. The seriousness of water pollution, both the results of water resources overdevelopment, but also to further increase the development of water resources, the two affect each other, the formation of a vicious circle. It is usually believed that when the runoff utilization rate exceeds 20% it will have a great impact on the water environment, and when it exceeds 50% it will have a serious impact. At present, China's water resources development and utilization rate has reached 19%, close to three times the world's average level, and higher in individual areas. For example, in 1995, the utilization rate of the Songhua River, the Hai River, the Yellow River and the Huai River had reached more than 50%, of which the Huai River basin reached 98%. In addition, over-exploitation of groundwater can cause ground subsidence, seawater intrusion, seawater back-up and other environmental problems.

I, China's water conservation status

In the life of water conservation, at present all cities and the vast majority of municipalities, basically do the installation of metered water meter charges, basically canceled the residents of the domestic water package fee system.

In terms of industrial water conservation, the current national water reuse rate is generally more than 40% higher than in the early 1980s, the water consumption of 10,000 yuan of output value than in the 1980s reduced by 50 percent, the cumulative amount of water saved from 1983 to 1995 of nearly 20 billion cubic meters, reducing the amount of sewage discharged of nearly 15 billion cubic meters of sea water used in coastal cities of nearly 6.5 billion cubic meters.

In terms of agricultural water use, in recent years, the construction of 300 key counties in the country to save water and increase production, 209 high-standard water-saving efficiency demonstration areas, and 99 large-scale irrigation districts and 40 medium-sized irrigation districts to carry out water-saving irrigation as the center of the continuation of the matching and renewal of the reconstruction of a number of national water-saving demonstration zones, at the end of 1998, the country's water-saving irrigation project area of 228.5 million mu, of which sprinkler, drip and micro-sprinkler irrigation projects, the area of 228.5 million mu. The area of water-saving irrigation projects nationwide amounted to 228.5 million mu at the end of 1998, of which 26 million mu were under sprinkler, drip and micro-sprinkler irrigation, 78 million mu were under pipeline irrigation, and 130 million mu were under channel seepage control water-saving irrigation. In addition, the promotion of non-engineering measures to save water 224 million mu.

Two, China's water conservation problems

1, insufficient understanding. Water conservation is a wide range of social and regional work, water conservation needs social understanding and support, especially through water conservation to alleviate the North China and the lower reaches of the Yellow River to cut off the flow of this kind of regional water shortages and water environment problems, but also the need for the whole region (or the whole river basin) members of the community and the various regions, departments, industries **** the same efforts may be effective. And our people's awareness of water conservation is generally not high, water conservation often stays only on the verbal.

2, insufficient investment. Water conservation work wide, large, complex and diverse situations, requiring large amounts of investment and certain advanced technologies, such as industrial water, generally can be divided into cooling water, boiler water, water, washing water, process water, etc., which saves the cooling water is relatively easy, while saving water, washing water, water, process water is relatively difficult. But no matter which kind of industrial water to save, all need to update and reform the water equipment, some even need to update and reform the process equipment. This requires a large amount of investment. With the increase in the amount of water saving, water reuse rate increases, the single party water saving investment will be more and more large, the technical requirements are also more and more high. At present, China's industrial water conservation from top to bottom there is no fixed investment channels, water-saving projects are generally to fight for a on one. Agricultural water conservation investment has been strengthened in recent years, but the efforts are not enough, insufficient investment and technological backwardness of China's industrial and agricultural water use level and the international gap widened.

3, the mechanism is not strong. Currently there is no set of water conservation work to adapt to the market economy mode of operation. The price of water is too low is the main reason, many of the direct economic benefits of water conservation projects are limited, more reflected in the social and ecological benefits, alleviate the contradiction between supply and demand for water resources, and the lack of preferential development policies. The existence of these reasons, resulting in many water users water saving enthusiasm is not high, water saving has not really become a business, farmers spontaneous action, water saving work in a passive state.

4, the legal system is not strong. Water conservation involves all walks of life, thousands of households, relying solely on government behavior, no market promotion, water conservation is bound to be insufficient power; relying solely on the market to promote, no government guidance, water conservation is bound to be difficult to see results. Grasp the water conservation must take full account of the characteristics of water conservation work, both by the market to promote, but also to strengthen the government's behavior. Strong government to promote and effective combination of active and conscious action of the vast number of water users, it is possible to promote China's water conservation work jumped to a new level.