Commenting on the past, current situation and prospect of China s water environment planning, as wel

China's water resources are facing three major problems:

First, floods are frequent and pose a great threat to economic development and social stability. Since the 90s, there have been five major floods in several major rivers in China. In particular, the devastating floods in the Yangtze River, Nenjiang River, and Songhua River valleys in 1998 fully demonstrated that flood disasters are still a problem for our hearts.

Second, drought and water shortage are becoming increasingly serious. Water scarcity is widespread in agriculture, industry and in cities. The drying up of rivers in the north is becoming more and more serious.

Third, the water ecological environment has deteriorated. In recent years, the water quality of water bodies in China has generally shown a deteriorating trend. Of the country's approximately 100,000 kilometers of river lengths, polluted rivers account for the total. More than 90% of the country's urban waters are polluted to varying degrees, and the problem of water shortage is serious.

The source of the problem:

The spatial and temporal distribution of water resources in China is extremely uneven. There are more in the south and less in the north, and more in the east and less in the west, which is extremely mismatched with the distribution of resources such as population, cultivated land, and minerals. The north of the Yangtze River accounts for only 19% of the country's land area.

The inland region of the northwest accounts for the total land area of the country, and only accounts for the amount of water resources. Due to the influence of the monsoon climate, the rainfall is very unevenly distributed throughout the year, and the precipitation in most areas accounts for about 70% of the annual total for four consecutive months during the flood season.

Brief introduction. Water is an important resource for the survival of all life, including inorganic compounds, and is also the most important component of living organisms.

Water is one of the most common substances on Earth, with 71% of the Earth's surface covered by water. Although water is present in small amounts in the air, it is an important component of the air.

Pure water is a very weak electrolyte with very weak electrical conductivity. Water in daily life has more anions and cations due to the dissolution of other electrolytes, so it has more obvious conductivity.

China's water environment is facing three major problems.

First, the discharge of major pollutants far exceeds the capacity of the water environment.

Second, rivers and lakes are generally polluted.

Third, there is a shortage of ecological water, and the deterioration of the water environment is intensifying.

The above causes are the large amount of wastewater discharged by industry, in fact, the most important thing is that the development of China's environmental protection industry is slow, and many technologies are not up to standard.

Floods, droughts and water shortages, and deterioration of the water environment are the three major water problems facing China in the new century. Among them, the deterioration of the water environment is particularly prominent.

The rational development and utilization of water resources and the realization of the optimal allocation of water resources are the fundamental guarantees for China to implement the strategy of sustainable development. The optimal allocation of water resources is a large-scale system problem of multi-objective decision-making, and the ideas of large-scale system theory must be applied for analysis and research. The traditional allocation of water resources has not paid enough attention to environmental protection, emphasizing water conservation and ignoring high efficiency, focusing on the optimal allocation of water resources in water-scarce areas and ignoring the improvement of water efficiency in areas with sufficient water resources, highlighting the distribution efficiency of water resources and ignoring the rationality of water use within the industry, which has affected the development of regional economy and the sustainable use of water resources. The dynamic relationship between the economy and the ecological environment ensures the sustainable development of society, economy, environment and resources.

1. The impact of water conservancy projects on the ecological environment of rivers.

Water conservancy projects are usually built on the basis of natural river channels, so the construction of water conservancy projects will have a certain impact on the natural ecological environment formed by the evolution of rivers for a long time, and the result may cause local discontinuity and homogenization of rivers, so that under the long-term effect of rivers, the diversity and environment of the original rivers have changed. Some large reservoirs are built on top of rivers, and the unique nature of the building materials of the reservoir can affect both water temperature and quality. Under the strong irradiation of the sun, the water temperature will increase a lot, so that the water quality will be affected, and the life and reproduction of aquatic organisms in the water will be affected.

Such a river is no longer in its original state. The construction of water conservancy projects will also reduce the flow rate of the original river water, so that the contact exchange rate between the water surface and the air will be reduced, and the self-purification capacity of the water will also be reduced.

2. The impact of water conservancy project construction on the ecological environment near the river.

The impact of water conservancy project construction on the ecological environment near the river is mainly reflected in the important impact on the vegetation around the river. Due to the construction of water conservancy projects, it has a serious impact on the terrestrial biological environment around the river, and the change of the natural and chemical properties of the river has gradually deteriorated the biological survival and living environment on the bank of Muwang. In this way, most of the organisms living around the river will be forced to migrate due to the deterioration of the environment, so that the ecosystem in the construction area will lose its original balance, and if there are no reasonable protection measures, it is likely to cause the danger of extinction of species.