China's water environment is facing various pressures such as water pollution, water shortage and floods. Water pollution intensifies the shortage of water resources, and the destruction of water ecological environment promotes frequent floods. According to the 1999 Bulletin on Environmental Status of China, the groundwater in seven major water systems, major lakes, coastal waters and some areas in China has been polluted to varying degrees. Rivers are dominated by organic pollution, and the main pollutants are ammonia nitrogen, biochemical oxygen demand, permanganate index and volatile phenol. The lake is characterized by eutrophication, and the main pollution indexes are total phosphorus, total nitrogen, chemical oxygen demand and permanganate index. The main pollution indexes in coastal waters are inorganic nitrogen, active phosphate and heavy metals. These factors constitute a wide range of water environmental problems, serious harm, and difficult to control. There are many reasons for the water environment problems in China, but they are mainly influenced by human subjective factors. For a long time, China's economic growth mode is extensive, and enterprises simply pursue economic benefits, ignoring environmental benefits and ecological benefits. In industrial development, water consumption is large and utilization rate is low. Not only the sewage discharge per unit output value is large, but also the water consumption per 1, yuan output value varies greatly among provinces. In 1998, the national average water consumption per 1, yuan GDP was more than 683m3. Among them, Beijing is 161m3, Tianjin is 21m3 and Shanghai is 3m3. However, Heilongjiang, Inner Mongolia, Jiangxi, Guangxi, Guizhou, Qinghai, Gansu and other provinces and regions are mostly above 1m3. Ningxia and Xinjiang are about 4m3. 1m3 irrigation water in Beijing can produce 2kg grain, while Ningxia can produce less than 1kg. At the same time, under the traditional planned economy system, the extensive economic growth mode makes enterprises lack the motivation to save energy and reduce consumption. The technological transformation of enterprises often aims at expanding reproduction, with backward production technology and slow upgrading. With the deepening of economic system reform, the transformation of economic growth mode and the rapid improvement of scientific and technological level, the rational development and utilization of water resources will gradually embark on the track of scientific management. However, this transformation needs a long historical process. Another important reason for the serious water environment problem is the deviation of national policy orientation. For a long time, national economic and social development has focused on economic growth rate, output of major products, income growth of urban residents and other indicators, but failed to include resource consumption and environmental costs in the economic accounting system. So far, urban environmental infrastructure construction is still regarded as "unproductive welfare undertakings". Urban sewage treatment and garbage disposal are undertaken by the government, which makes the government overwhelmed, so that it can't afford to build environmental infrastructure, and even build pollution treatment facilities, which is difficult to operate normally because of the unresolved source of funds. Under the planned economy system, some economic development policies are contrary to environmental protection. Small enterprises in the Tenth Five-Year Plan, which once blossomed everywhere in China, are scattered in layout, uneconomical in scale and backward in production technology, causing serious environmental pollution and ecological damage.
the incompatibility between regional economic development and regional environmental capacity is also an important cause of water environmental pollution. In the past, when determining the direction of regional industrial development and the layout of regional productivity, the regional environmental capacity was often ignored. The serious river basin water pollution in China's major rivers is directly related to the unreasonable industrial structure and layout of the river basin. Since the early 198s, the four provinces in Huaihe River Basin have made great efforts to develop small-scale industries such as chemical industry, paper making, leather making, thermal power and food with high water consumption by using local resources, and the discharge of pollutants has exceeded the carrying capacity of Huaihe River, which has caused the water quality in Huaihe River Basin to deteriorate sharply. Due to the lack of scientific certification and management, some water-deficient areas blindly develop high-water consumption industries, resulting in the decline of groundwater level; In some resource-rich areas, a single resource-based industry is developed, and the matching processing industry is not developed. The industrial structure is similar, resulting in serious structural pollution.
the influence of natural factors has aggravated the deterioration of water environment problems to a certain extent, and increased the difficulty of water pollution prevention and control. In recent years, due to climate change, the distribution of global temperature, humidity and precipitation has changed, which has caused frequent disasters in some countries and regions. The climate in northern China is also obviously warming, and the average winter temperature in North China is 2.1℃ higher in the 199s than in the 195s. As the temperature rises, surface runoff decreases, evaporation increases, and the chances of drought increase. In 1997, affected by El Nino phenomenon, the precipitation in northern China was unusually low and the temperature was high, and the sea and river water resources were only 4% of the average for many years. The water resources of the Yellow River are 61% of the average for many years. Due to the decrease of river runoff, the self-purification ability of water body decreases, which aggravates the deterioration of water environment. In 1998, due to the El Ni? o phenomenon, the precipitation in the middle and lower reaches of the Yangtze River, Nenjiang River and Songhua River basins was too high, which led to the occurrence of catastrophic floods.
the regional distribution of water resources in China is uneven, with more in the south and less in the north, which is very different, and the distribution of water resources is extremely uncoordinated with the layout of population, economy and social development. The Yellow River, Huaihe River, Haihe River, Songliao River and inland rivers in the north account for about 47% of the country's total population, more than 65% of the cultivated land and more than 45% of the country's GDP, while water resources only account for 19% of the country's total water resources, and the per capita possession is only one third of that in the south. These factors are also important aspects that lead to outstanding water environment problems.
2. Main problems in water pollution prevention and control in key river basins
Since the Ninth Five-Year Plan, the prevention and control of water pollution in key river basins in China has been guided by the Huaihe River, and Taihu Lake, Chaohu Lake, Dianchi Lake, Haihe River and Liaohe River have started one after another. By adopting a series of measures, such as terminal treatment of industrial pollution sources, and banning, closing and eliminating enterprises with backward production technology, outdated equipment and serious pollution in industrial structure adjustment and compression of excess productivity, the treatment work has achieved certain results. Some water areas are close to achieving the first stage of pollution prevention and control objectives. As the first large-scale river basin water pollution prevention in China's history, the ninth five-year plan has accumulated a lot of valuable experience, which has long-term strategic significance for opening up China's environment and development road. However, on the whole, the progress of water pollution prevention and control in key river basins is still relatively slow, and the achievements are very fragile. Some problems exposed in practice fully show that the prevention and control of river basin water pollution in China is still facing serious challenges at present and in the future.
2.1 Water environment problems in the Yellow River and Yangtze River basins need to be solved urgently
The control of "three rivers and three lakes" during the Ninth Five-Year Plan period only opened the prelude to water pollution prevention and control in China. While treating "three rivers and three lakes" on a large scale, it must be noted that the pollution problems of the Yellow River and the Yangtze River have reached the point where they must be treated. The Yellow River, the cradle of the Chinese nation, has nurtured mankind and brought disasters to mankind countless times. Nowadays, due to the action of human activities, the environmental problems of the Yellow River are becoming more and more serious. In 1999, on the 114 key monitoring sections of the Yellow River Basin, the water bodies of Class V and worse than Class V were 7% and 56.2% respectively, and the pollution of the main tributaries of the Yellow River was more serious, and the pollution of the Yellow River mainly came from tributaries. At present, the Yellow River has little water, weak self-purification ability, and the water environment is in crisis. In the western development, the economic development of the Yellow River Basin will enter a period of rapid growth. The water pollution of the Yellow River will inevitably make the shortage of water resources along the coast "worse".
With the rapid development of economy and society and the acceleration of urbanization in the coastal areas of the upper reaches of the Yangtze River, the pollutant discharge in this area has increased rapidly, and the pollution problem has been aggravated, especially the water quality in the Three Gorges reservoir area and its upper reaches has been deteriorating. If effective measures are not taken, it is estimated that by 21, the wastewater discharge in key areas in the upper reaches of the Yangtze River will increase at an average annual rate of 4.1%; The amount of domestic garbage from towns along the Yangtze River will increase from about 2 million tons in 1995 to 4.67 million tons in 21. The self-purification capacity of water in the Three Gorges reservoir area will be greatly reduced. After the Three Gorges reservoir area is completed and impounded in 29, the reservoir area will be transformed from a river with fast flow rate and large discharge into an artificial lake with slow flow rate, long detention time and large backwater area. The dilution and self-purification ability of water body decreases, and water pollution will inevitably increase. According to the forecast, after the completion of the Three Gorges Project, the concentration of main pollutants in the pollution zone on the upstream bank of the lake area will increase by 2-1 times compared with that before the dam is built, and it will become a heavily polluted area.
2.2 Urban domestic sewage is increasing year by year, and the construction of sewage treatment facilities is seriously lagging behind
Urban infrastructure is the carrier of industrial construction, which restricts the scale and development speed of industrial construction. For a long time, China's urban construction has inappropriately reduced the carrier status of infrastructure construction to the general subsidiary status of industry, and the development of infrastructure is not in harmony with population, resources, environment and industrial construction, resulting in long-term overload of infrastructure. In particular, the urban environmental protection infrastructure has only started to be built in recent years. The sewage treatment capacity of most cities in China is far from meeting the actual needs.
with the rapid increase of population and the improvement of people's living standards, the amount of domestic sewage has increased greatly. In recent years, the proportion of urban domestic sewage and industrial wastewater discharge has been close to the same. However, the construction of urban sewage treatment plants is far from meeting the needs of economic and social development. Under normal circumstances, the construction period of urban sewage treatment plants is 3 years. Judging from the current construction progress, it will take quite a long time to realize the national requirement of building centralized sewage treatment devices in cities with a population of 5, during the Ninth Five-Year Plan period. Taking the Huaihe River as an example, according to the plan, by 2, the four provinces in the Huaihe River Basin need to build 52 urban sewage treatment plants with a total investment of 6.8 billion yuan, forming a sewage treatment capacity of 3.52 million L/d. By June 1999, only three sewage treatment plants had been built, and the sewage treatment capacity was only 44, L/d.. The reason for the slow construction of centralized sewage treatment facilities is not only the shortage of funds, but also the constraints of the current management and operation mechanism, which also makes the construction and operation of urban sewage treatment plants in trouble. Because the policy of "polluter pays" is not really implemented, the local finance is unable to pay the sewage treatment fee, which often makes the sewage treatment plant after completion unable to operate normally, and the investment in environmental protection cannot effectively play the environmental benefits.
2.3 A large number of non-point source pollution problems have not been solved
At present, industrial pollution in China has been effectively controlled. By the end of 2, all industrial pollution sources in China will meet the discharge standards. Urban sewage treatment is gradually accelerating. However, the pollution of pesticides, fertilizers and livestock breeding brought by rural economic development is extensive and difficult to control. From 195s to 199s, China's pesticide consumption increased by nearly 1 times, making it the largest country in the world. The number of people poisoned by pesticides in China accounts for 5% of the number of people poisoned by similar accidents in the world every year. Moreover, due to the large loss of pesticides, serious water pollution has been caused. The use of chemical fertilizers in the country is also increasing exponentially. 1995 was four times that of 1978. At present, the imbalance of nitrogen, phosphorus and potassium is more serious because of the partial application of chemical nitrogen fertilizer. Moreover, the utilization rate of chemical fertilizer is only about 3%, and a large number of chemical fertilizers are lost and enter rivers, oceans and lakes, becoming the main source of non-point source pollution of water bodies. At the same time, due to the use of a large number of chemical fertilizers, the agricultural utilization of livestock manure in rural areas has decreased, and the intensification of livestock industry has increased, which has aggravated the disconnection between aquaculture and planting. The rate of returning livestock manure to the field is only over 3%, and most of it is not used. In 1998, the output of livestock manure in China was 3.4 times that of industrial solid waste in that year. Most of these animal wastes are directly discharged into rivers, lakes and seas without treatment. At the same time, as an important part of rural economy, the development of township enterprises has always been a major problem that puzzles the rural environment. According to two national surveys on pollution sources of township industries in 1991 and 1997, the emissions of sulfur dioxide, soot, chemical oxygen consumption and solid waste in township industries increased by 22.6%, 56.5%, 246.6% and 552% respectively. While the total discharge of major industrial pollutants in China has been controlled, the discharge of pollutants from township enterprises is increasing, which will pose a serious threat to the water environment.
2.4 The economic policies are not matched, and the funds for pollution control are seriously short
Under the planned economy system, the funds for pollution control in China are mainly from the national budget. With the establishment of the market economy system, it is no longer effective to manage the environment entirely by administrative means. However, because the environmental and economic policy system under the market economy has not yet been established, it is difficult to form a diversified environmental protection investment system. As an important economic means to promote pollution prevention and control, the sewage charge system is still far from perfect. The main problem is that the sewage charges are too low to stimulate pollution prevention and control. As the main part of sewage charge, the charge for excessive discharge of sewage is less than half of the operating cost of pollution treatment facilities; The maximum sewage discharge fee shall not exceed .5 yuan/L; The sewage charges are not complete, and the main targets are large and medium-sized enterprises and some institutions. Urban sewage treatment fees are only levied in a few cities, and the charging standards are low, so the principle of "polluter pays" is not fully reflected; The transfer payment mechanism of sewage charges has not yet been established, there is a lack of interest compensation policy between upstream and downstream in the basin, and the development, utilization and protection of water resources are not coordinated, resulting in the waste of water resources.
During the Ninth Five-Year Plan period, China's investment in environmental protection has been greatly improved. In particular, the state has adopted a proactive fiscal policy and made environmental protection a key investment field in expanding domestic demand. Some key projects for water pollution prevention and control have been supported by national debt funds. However, due to the narrow channels of environmental protection funds and small investment, the shortage of pollution control funds is still very prominent. According to the plan, the water pollution prevention and control of "Three Rivers and Three Lakes" needs about 126 billion yuan, but the funds already implemented are far from the demand. In 1998, the state issued additional financial bonds and bank loan funds for infrastructure construction, and allocated 1 billion yuan of financial bonds to the Huaihe River Basin for the construction of urban sewage treatment plants. However, these funds only account for 16.5% of the total investment of Huaihe urban sewage treatment plant, and there are 34 investment projects. Due to the lack of local matching funds, many projects have started, but due to the lack of funds, the construction progress is slow, and many projects have not yet been invested.
3. Policy suggestions on water pollution prevention and control
China has achieved rapid economic development under the condition of relatively backward economy and technology. With a large population base and few per capita resources, the prevention and control of environmental pollution and ecological destruction will be a long-term strategic task. In particular, the solution to the problem of water environmental pollution cannot be achieved overnight, and it needs a hard process of governance. Therefore, we must conscientiously sum up the experience and lessons of water pollution prevention and control during the Ninth Five-Year Plan period, learn from all successful experiences in the world, and combine the specific conditions of our country, constantly strengthen policy innovation, system innovation and technological innovation, and gradually embark on a road of water pollution prevention and control with China characteristics.
3.1 Control the emergence of new water environmental problems in decision-making
When determining the speed of economic development, formulating national economic and social development plans, resource development plans and regional development plans, and formulating economic and technological policies, and making major economic decisions, national and local governments should make a scientific evaluation of the possible environmental impacts arising from the implementation of these decisions, and the evaluation conclusions should serve as the basis for decision-making at all levels. In decision-making, environmental, economic and social factors should be considered comprehensively, so as to minimize the impact of development on the environment. Establish a scientific evaluation index system, set up a special evaluation and deliberation institution, legalize this system, and gradually establish an operational mechanism for decision-making according to law. <