What impact does the South-to-North Water Transfer Project have on the ecological environment of the transfer-out area and the transfer-in area?

The distribution of soil and water resources in China is very uneven, and the runoff of the Yangtze River and its southern basin accounts for the whole country! "# above, the cultivated land area is less than the national $" #. The Yellow River, Huaihe River, Haihe River and Northwest China account for% # of the national area, cultivated land accounts for $% #, and population accounts for only () # of the total water resources in China. Northwest China and North China are rich in natural resources such as land and minerals, which are the production bases of energy, grain, cotton and oil in China, and have an important strategic position in the national economy, especially in the Yellow River, Huaihe River, maritime plain and Jiaodong Peninsula, with dense population, high cultivated land rate and developed economy. However, the shortage of water resources has become one of the main constraints of regional economic development and has caused the deterioration of the ecological environment, which is urgently needed. The South-to-North Water Diversion Project introduced the concept of "South-to-North Water Diversion Project" in "Century%". After decades of research, the overall layout of the South-to-North Water Diversion Project has been formed, namely, the west route project, the middle route project and the east route project of the South-to-North Water Diversion Project, which transfers water from the upper, middle and lower reaches of the Yangtze River to meet the development needs of northwest and north China. The maximum annual adjustable water volume of a river is about) ""billion+&; Transfer water from the upper reaches of the Yangtze River to Tianhe ("100 million+&; Water transfer from Yalong River, a tributary of the Yangtze River, is about% "billion+&; Transfer water from Dadu River% "billion+&; Initially, the water supply scope is Qinghai, Gansu, Ningxia, Shaanxi, Inner Mongolia and Shanxi provinces; There are two ways of water diversion: gravity flow and water lifting. No matter which water diversion method is adopted, it is necessary to build a high dam with a height of about "+"and excavate a long tunnel with a height exceeding "+". The Yalong River diversion line will build a hub near Changxu of Yalong River, and the water will be diverted to the tributaries of the Yellow River by gravity. The dam height of the hub is (-%+), and the lines are all tunnels. (,+.(* *) Tongtianhe Water Diversion Line This scheme is jointly developed with Yalong River Water Diversion Project, that is, the second phase of Yalong River Water Diversion Project under the condition of early development. Tongtianhe built a hub near Tong Jia to introduce water into the Yalong River, and then the Yalong River introduced water into the tributaries of the Yellow River. The & height of the hub is just right & "+,all lines are tunnels, full length)! . +,of which the same is added to Yalong River (%! +,Yalong River to the Yellow River (&; (,+.(*(* & amp； The Dadu River diversion line builds a hub near the Zumuzu River in the upper reaches of the Dadu River, and pumps water to Jiaqu, a tributary of the Yellow River. The dam height of the hub and the total length of the line are&1000 m; ",+,in which the tunnel is long)! *%,+.Pump head $%! +,annual electricity consumption-(billion,/? 0. The West Line Project is located on the Qinghai-Tibet Plateau, with an altitude of&""1%"+,which is one of the most complicated geological structures in China, and the earthquake intensity is mostly! # degree，local $ "%degree。 Buildings in this high mountain area &; (The height from left to right+and the depth of the tunnel is several hundred meters, and the length can reach) * (The above tunnel engineering technology is complex and the construction environment is difficult. Therefore, it is necessary to deepen the preliminary work and actively carry out scientific research and technical research to solve these difficulties. )+&; The Middle Route of South-to-North Water Transfer Project recently diverted water from Danjiangkou Reservoir, a tributary of the Yangtze River, along Funiu Mountain and the piedmont plain of Taihang Mountain, ending in Beijing. In the long run, it is considered to transfer water from the Three Gorges Reservoir or the main stream of the Yangtze River below to increase the amount of water transferred to the north. The middle route project has the advantages of good water quality, large coverage and self-flowing water delivery, and is a major infrastructure to solve the water crisis in North China. After Danjiangkou Reservoir is completed in the later period, the water level will be normal. & After properly completing the annual development level and partial compensation projects in the middle and lower reaches of the Hanjiang River to ensure the development of industry and agriculture, shipping and the transfer of environmental water, the average annual adjustable water volume of the middle line project is)+) billion (-), and the average annual adjustable water volume in dry season is #. /)) One billion (-. The water supply scope of the middle route project is mainly in the central and western parts of Tangbaihe Plain and Huanghuaihai Plain, with a total water supply area. Due to the limited amount of water drawn from the Han River, it can not meet the requirements of the planned water supply area, and can only be mainly used for urban life and industry in the Beijing-Tianjin-Hebei-Henan-Hubei area, and some areas give consideration to agriculture and other water use. The mid-line project can alleviate the water crisis in North China, especially in Beijing and Tianjin, and increase urban life and industrial water supply along Beijing, Tianjin and Hebei! The increase of agricultural water supply will greatly improve the ecological environment and investment conditions in water-using areas and promote the economic development in the central region. The heightening of Danjiangkou reservoir dam will improve the flood control standard in the middle and lower reaches of the Han River and ensure the safety of Hanbei Plain and Wuhan. )+-The East Route Project of South-to-North Water Transfer takes water from the lower reaches of the Yangtze River, basically pumping water to the north along the Beijing-Hangzhou Grand Canal and supplying water to the eastern part of the Huang-Huai-Hai Plain, with Tianjin as the destination. The lower reaches of the Yangtze River are rich in water resources. 1 100 million (-,even in particularly dry years! The east route project takes water from the lower reaches of the Yangtze River, which is rich in water resources, and the water regulation depends on the scale of the water transfer project. The planning considers the reasonable final scale of the East Line Project, and uses &; & The planned scale for the development level in 2000 and the planned scale for & year; The scale of the first phase of South-to-North Water Transfer Project in the 21st century. See the table below for the corresponding water regulation in each period. The water supply scope of the Eastern Route Project involves five provinces and cities, namely, the lower Huaihe River plain in northern Jiangsu except for Lixia abdomen and its eastern and northern highlands, the banks of the Huaihe River below Bengbu in Anhui, the banks of the new Bianhe River to the east of Huaibei City and some areas of Tianchang County. Around Nansi Lake in Shandong Province, banks of Hanzhuang Canal and Ji Liang Canal, some cities in Jiaodong area, non-Yellow River diversion irrigation area in Lubei, Yundong area in Heilonggang, Hebei Province, Tianjin and its suburbs. Cheng Kewei, Jiangsu, Anhui, Shandong, Hebei and Tianjin have increased their water supply by-100 million (-), including domestic, industrial and shipping water! +.！ Billion (-,agricultural water #! +#! After the implementation of the 100 million (-) East Route Project, the water shortage problem in Tianjin, the eastern part of Heilonggang, Hebei Province, Lubei, Southwest Shandong and some cities in Jiaodong can be basically solved, and the conditions for supplying water to Beijing will be met, which will promote the economic development in the Bohai Rim region and the eastern part of the Huang-Huai-Hai Plain, improve the environment deteriorated by water shortage, ensure the perennial navigable water source of the Jining-Xuzhou section of the Beijing-Hangzhou Grand Canal, and consolidate the development of the two major commodity grain bases in western Shandong and northern Jiangsu. The East Route of South-to-North Water Diversion Project "Ecological and Environmental Impact of Water Diversion Projects with Different Scales and Grades"; +) Ecological analysis of water balance of water transfer project Generally speaking, the quantity of water transfer is determined by the calculation of supply and demand of water resources. However, from the environmental and ecological point of view, the scale of water transfer to the region must be appropriate, and the water shortage area is not the more water, the better. There is a close relationship between ecological balance and water balance. As we all know, for a region, water balance factors (such as precipitation, evaporation, surface water and groundwater, etc. ) is an important eco-physical factor. Inter-basin water transfer project will cause the change of water balance factors and their comparative relationship, which will eventually lead to the change of ecosystem. How to control the suitability of water balance elements and their comparative relationship changes? This problem can be solved by putting forward indicators from a geographical perspective. The contrast between the elements of water balance constitutes the structure of water balance. The theoretical study of the law of natural zonality shows that the division of natural zones can adopt radiation drying index! " #$%(! " Net solar radiation (USD is latent heat of evaporation and% is precipitation) as an indicator. In fact! # $% is the ratio of evaporation to precipitation, because in the heat balance equation,! "# $ stands for the upper limit of evaporation%&; That is%&; (!" # $ ()) Because the conditions of surface runoff change with the geographical conditions such as topography and soil, in order to eliminate this difference, surface runoff is subtracted from the precipitation factor% in the radiation drying index! ), you can get the expression *+of regional wettability, which can be found in doudingwenke/p-378137569.html and Baidu library.