Sustainable development not only means meeting the needs of several generations, but also means not damaging the ability of future generations to meet their needs. Principle:
1, the principle of fairness refers to the equality of opportunity choice, which has three meanings: one refers to intergenerational fairness, and the other refers to horizontal fairness among the same generation. Sustainable development should not only achieve fairness among contemporary people, but also achieve fairness between contemporary people and future generations. Third, it refers to the fairness between man and nature and other creatures. This is one of the fundamental differences with traditional development. Intergenerational equity requires that no generation can be in a dominant position, that is, all generations have equal opportunities to choose.
2. The principle of sustainability. Refers to the ability of an ecosystem to maintain its productivity when disturbed. The sustainable utilization of resources and the sustainable development of ecosystem are the primary conditions for the sustainable development of human society. Sustainable development requires people to adjust their lifestyles according to the conditions of sustainable development. Determine your own consumption standards within the scope of ecological possibility.
3. The principle of harmony. The strategy of sustainable development is to promote harmony between people and between people and nature. If we can act in good faith according to the principle of harmony, then human beings and nature can maintain a mutually beneficial relationship, and only in this way can we achieve sustainable development.
4. The principle of demand. People's needs are determined by social and cultural conditions and the result of the interaction between subjective and objective factors. It has something to do with people's values and motives. Sustainable development develops people on the basis of people's needs, emphasizing people's needs rather than market commodities, so as to meet everyone's basic needs and provide everyone with opportunities to realize their good wishes.
5, the principle of high efficiency, the principle of high efficiency is not only measured according to its economic productivity, but more importantly, according to the degree to which people's basic needs are met. It is the synthesis of the overall development and efficiency of human beings.
6. Step principle. With the passage of time and the continuous development of society, the content and level of human needs will continue to increase and improve, so sustainable development itself implies a gradual process from a lower level to a higher level.
Advantages and disadvantages of Aswan Dam
Aswan Dam consists of three parts: main dam, spillway and power station. The total length of the main dam is 3,600 meters, the width of the dam foundation is 980 meters, the width of the dam crest is 40 meters, the dam height is 1 1 meter, and the building materials used are about 43 million cubic meters, which is equivalent to 17 times of the Great Pyramid in the western suburbs of Cairo. It is one of the seven largest dams in the world. The project started on 1960 and was completed on 197 1, ranking first among dams in the world. Dam is a comprehensive utilization project integrating flood control, irrigation, shipping and power generation.
The Aswan Dam, built with modern science and technology, has irrigated more than 90% of Egypt's cultivated land, greatly improving the multiple cropping index and agricultural output of Egypt's farmland. Aswan Dam not only increased the irrigation area of Egypt by 6.5438+300,000 ~ 2 million hectares, but also turned the annual crop area of 700,000 hectares into a multi-season crop area with permanent irrigation, which increased the irrigation amount of Egypt by 25%~30%. Aswan Dam has increased cotton production by 50% and cultivated land by 2 million hectares. More importantly, due to the huge and cheap power generation of Aswan Dam Power Station, 4,000 villages in Egypt have been electrified one after another. The dam generates 8 billion kWh of electricity every year, providing 70% of the total electricity consumption in the country, making it a power base in Egypt. At the same time, the Aswan Dam prevents the Nile from flooding every year, thus defusing the threat of the Nile flood to Egypt.
For decades, Egypt has mainly relied on Nile water to irrigate its land, which can be said to be the main artery of agricultural development in Egypt. Although Aswan Dam has played a positive role in promoting the development of Egypt's industrial and agricultural production, it has also caused some changes in the ecological environment, especially in recent years, the water volume of the Nile has decreased obviously year after year, posing a great threat to Egypt's industrial, agricultural and electric power industries.
Due to the shortage of water resources, the water level of Aswan Dam is 3 meters lower than the original design height of 60 meters in 1987, which seriously affects the production of Egypt's power industry. With the development of electric power, the electricity sector has also been affected. Therefore, from 65438 to 0988, the Egyptian government had to take measures to allocate water and electricity.
Due to the drought, industrial water use has also been affected. Under normal circumstances, industrial water needs about 2.7 billion cubic meters per year, of which 265.438+0.3 billion cubic meters is used for power generation and cooling in power stations. Due to the repeated reduction of the Nile flood season, the power generation of the dam is correspondingly insufficient. The Egyptian Ministry of Industry also decided to adjust the industrial electricity consumption, limit the hours of electricity consumption, adjust the technological process, and reduce the lighting and administrative electricity consumption to minimize the power grid load.
The practice of water distribution in Egypt shows that Aswan Dam has not finally solved the problem of water use in Egypt, but has also produced side effects.
Nile water carries sediment, reaching 654.38 billion tons every year. Mud contains a lot of humus, which provides abundant natural fertilizer for Egyptian agriculture. However, after the completion of the Aswan Dam, these fertile silt were blocked and could no longer go down the Nile. Egypt had to import a large number of chemical fertilizers from abroad, which increased foreign exchange expenditure and agricultural costs, and also reduced the fertility of the land, which brought many adverse effects on agricultural production in Egypt. Silt was stopped in the upper section of the dam, and it could not flow to the Mediterranean with the river, which also seriously affected the Nile Delta.
The increasing leakage rate and evaporation rate of Aswan dam and reservoir are also a serious problem. According to the statistics of Egypt's Ministry of Water Resources, Aswan Dam has a "vertical" leakage of 6 billion cubic meters, a "parallel" leakage of 65.438 billion cubic meters, an annual leakage of 7 billion cubic meters and an evaporation loss of 65.438 billion cubic meters. In addition, the strong wind in Egypt may increase the evaporation rate of water by 40%, that is, 4 billion cubic meters, and the above two items will lose 265.438+0 billion cubic meters of water.
Aswan Dam also faces the problems of waterlogging and salinity. About 35% of agricultural farmland around the dam is affected by salinization, and the salinization rate increases by 10% every year. In addition, 95% of the existing farmland in Egypt was affected by floods because it could not be drained and irrigated in time, but the drainage project has not kept up at present. The shortcomings of Aswan Dam have greatly damaged the agricultural production in Egypt. In recent years, Egypt's grain output has been unable to meet the demand, and now 50% of its grain is imported.