Analysis:

The Yangtze River is the largest river in China, with a total length of 6,397 kilometers (based on Tuotuo), commonly known as 6,300 kilometers. The total area of the river basin is1800,000 square kilometers, and the annual water inflow into the sea is about 960 billion cubic meters. In terms of the length of the main stream and the amount of water entering the sea, the Yangtze River ranks third in the world.

Tuotuo River, the upstream source of the Yangtze River, originated from the Gladin Winter Snow Mountain in Tanggula Mountain on the southwest border of Qinghai Province, and was called Tongtian River after meeting with the south source of the Yangtze River. From Batang estuary in Yushu county to Yibin city in Sichuan province, it is called Jinsha River. Yibin is called the Yangtze River and Yangzhou is called the Yangtze River. The Yangtze River flows through * * *, Sichuan, Chongqing, Yunnan, Hubei, Hunan, Jiangxi, Anhui, Jiangsu and other provinces and cities, and joins the East China Sea in Shanghai. There are tributaries such as Yalong River, Minjiang River, Tuojiang River, Jialing River, Wujiang River, Xiangjiang River, Hanjiang River, Ganjiang River, Qingyi River and Huangpu River. It intersects with the Beijing-Hangzhou Grand Canal in Zhenjiang City, Jiangsu Province.

The upper reaches of the Yangtze River are above Yichang City, Hubei Province, with many rapids. Yichang to Hukou in Jiangxi is the middle reaches, with meandering development and numerous lakes (Poyang Lake and Dongting Lake are the largest). Below the mouth of the lake is the downstream, the river is wide, and Chongming Island is alluvial at the mouth of the river. The Yangtze River is rich in water resources. During the flood season, 10,000-ton ships can reach Wuhan, and boats can trace back to Yichang.

The Yangtze River valley is a densely populated and prosperous area in China, and Chongqing, Wuhan, Nanjing and Shanghai are important cities along the Yangtze River.

The Yangtze River is the most abundant river in China, with a total hydropower capacity of 200 million kilowatts. The main stream of the Yangtze River has a navigation mileage of more than 2,800 kilometers and is known as the "golden waterway".

The Yangtze River is a steep Three Gorges (Qutang Gorge, Wuxia Gorge and Xiling Gorge) in Duan Xiongwei from Fengjie in Chongqing to Yichang in Hubei. The Three Gorges Project, the largest water conservancy project in the world, is located in Sandouping in the middle of Xiling Gorge.

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The Yangtze River is the largest river in China and one of the largest rivers in the world, with a total length of more than 6,300 kilometers. It originated in the southwest of the main peak of Tanggula in Qinghai-Tibet Plateau-Geladan Winter Snow Mountain (33 28 ′ north latitude, 965 438+0 08 ′ east longitude). The main stream flows through Qinghai, Tibet, Sichuan, Yunnan, Hubei, Hunan, Jiangxi, Anhui, Jiangsu, Shanghai and other provinces, municipalities and autonomous regions 10 and flows into the East China Sea. The total length is about 6,300 kilometers (if Dangqu is the source, the total length of the Yangtze River should be 6,403 kilometers), ranking third in the world. The basin is located between 24 30 ′ and 35 45 ′ north latitude and 90 33 ′ and 65 438+065 438+02 25 ′ east longitude, with an area of 65 438+800,000 square kilometers (excluding Huaihe River Basin), accounting for about 65 438+0 of the total land area of China. The average annual water inflow into the sea reaches 1 trillion cubic meters, ranking third in the world. In ancient times, it was called Jiang for short, and it was called Dajiang and Changjiang only after the Six Dynasties.

General situation of the main stream The name of the main stream of the Yangtze River is different: the source to Dangqukou (called "Qu" River in Tibetan) is Tuotuo, which is the main source of the Yangtze River, with a total length of 358 kilometers; From Dangqukou to Batang Estuary in Yushu County, Qinghai Province, it is called Tongtianhe, with a length of 8 13 km; Batangkou to Minjiang Estuary in Yibin, Sichuan, known as Jinsha River in ancient times, is 2308 kilometers long; Yibin's Minjiang River estuary is about 2800 kilometers away from the Yangtze River estuary, commonly known as the Yangtze River. Yibin and Yichang in Hubei Province are called "Chuanjiang" (the Three Gorges section from Fengjie to Yichang is also called "Xiajiang"), Zhicheng in Hubei Province is called Jingjiang, and Yangzhou and Zhenjiang in Jiangsu Province are also called Yangtze River below. Plateau and mountainous areas account for 65.6% of the basin area; Hills account for 24%; Plains and lowlands account for 10.4%.

There are 48 tributaries of the Yangtze River, covering an area of 6.5438+0 million square kilometers; More than 50,000 square kilometers are Yalong River and Minjiang River and their tributaries, including Dadu River, Jialing River, Wujiang River, Yuanjiang River, Xiangjiang River, Hanjiang River and Ganjiang River. Among them, the Yalong River, Minjiang River, Jialing River and Hanjiang River are more than 65,438+10,000 square kilometers, and the Jialing River basin has the largest area, about160,000 square kilometers.

Most of the freshwater lakes in China are distributed in the middle and lower reaches of the Yangtze River, with Poyang Lake, Dongting Lake, Taihu Lake and Chaohu Lake in larger areas.

The Yangtze River originates from the Qinghai-Tibet Plateau between Bayan Kara and Tanggula Mountain, on the southwest side of Gladin, the main peak of Tanggula Mountain. Glaciers are widely distributed here, and meltwater from snow and ice is the source of the Yangtze River. From Jiangyuan to Haikou, it can be divided into three sections. Above Yibin, Sichuan, it is upstream; Yibin, Hubei to Yichang is the middle reaches; Below Yichang is the downstream. The upper reaches are about 3,500 kilometers long, and the Chumar River is the northern source of the Yangtze River. Muluwusu River is the southern source of the Yangtze River, with long water flow and large water volume. According to the principle that the source of the Yangtze River is only far away, Tuotuo River, its longest tributary, should be the positive source of the Yangtze River. The section from the mouth of Dangqu River to Yushu in Qinghai is called Tongtianhe, which is 8 13 kilometers long. The river is wide and the water is slow. From Yushu to Yibin, it is called Jinsha River, which was called Lishui in ancient times. From north to south, it crosses the Hengduan Mountains, turns northeast near Shigu in Yunnan, enters the Sichuan Basin, and joins the Minjiang River in Yibin, with a total length of 2,300 kilometers. Known as the Yangtze River after Yibin. The middle reaches are about 1000 km long. Because they flow through the Sichuan Basin, they are often called Chuanjiang. From Yibin to Chongqing, the river is quite tortuous. This river runs from Baiti Mountain in Fengjie to Nanjinguan in Yichang, passing through the Grand Canyon in the mountainous area at the junction of Sichuan and Hubei. From west to east, there are Qutang Gorge, Wuxia Gorge and Xiling Gorge, collectively known as the Three Gorges, with a total length of 204 kilometers. There are rapids everywhere on the beach, and the river gap is very large. It has been called the natural barrier of the Yangtze River since ancient times. The downstream section is about1850km long, with small river drop, slow water flow and wide river surface, generally more than 2km, and the narrowest part is 650m. The river course is very tortuous, especially the section from Zhijiang, Hubei Province to Chenglingji, Hunan Province, which was called Jingjiang in ancient times and is known as the "nine-bend ileum". Due to the slow flow rate and excessive sediment deposition, whenever the flood season comes, it is easy to cause flood disasters. Since ancient times, there has been a saying that "a long river travels a thousand miles, and the danger lies in Jingjiang". From Yichang to Wuhu, there are many lakes on both sides of the strait, among which Dongting Lake and Poyang Lake are the largest. Dongting Lake is the natural reservoir of the Yangtze River. After the river entered Jiangsu, it bypassed Ningzhen Mountain to the northeast because of mountain resistance. Turn from Zhenjiang below to southern Sichuan and enter the delta region. The terrain is flat, the lakes are dotted, and the waterways are intertwined like a net, which is a scene of water towns and villages. The mouth of the river is 80 kilometers wide, showing a spectacular view of the river and the sea. There are many famous osawa on both sides of the Yangtze River, with beautiful scenery and many tourist attractions. Because of the long process, wide river basin, fertile land and convenient irrigation, there is a "land of abundance" in the middle reaches and a "land of plenty" in the lower reaches, which is rich in products. Although the cradle of the Chinese nation is in the Yellow River Basin, according to historical records, after the Yin Dynasty was destroyed, the territory reached the Yangtze River Basin in the south, and then the Yellow River and the Yangtze River Basin became the focus of China's historical and cultural development. There are many famous cities along the river, such as Chongqing, Yichang, Wuchang, Nanjing and Shanghai. Shanghai is the largest industrial and commercial city in China. There are many places of interest on both sides of the Taiwan Strait, which are valuable materials for understanding the history of China, and there are also many myths and legends, which are valuable heritages of China literature. Since ancient times, the trunk and tributaries of the Yangtze River have been the main artery of water traffic in southern China, crossing east and west, running through north and south, with a total length of more than 80 thousand kilometers. Ten thousand-ton ships can reach Nanjing, 3000-ton ships can reach Hankou, 1000-ton ships can reach Chongqing, and 500-ton ships can reach Yibin.

■ Plain in the Middle and Lower Reaches of the Yangtze River

The banded plain in the middle and lower reaches east of the Three Gorges of the Yangtze River in China. Huaiyang Mountain and Huanghuai Plain are in the north, and Jiangnan hills and Zhejiang and Fujian hills are in the south. It is alluvial from the Yangtze River and its tributaries. It covers an area of about 200,000 square kilometers. The terrain is low and flat, and the altitude is mostly about 50 meters. The middle reaches include Jianghan Plain in Hubei, Dongting Lake Plain in Hunan and Poyang Lake Plain in Jiangxi. The downstream plains include the plain along the Yangtze River and Chaohu Lake in Anhui Province (the central plain of Anhui Province), and the Yangtze River Delta between Jiangsu, Zhejiang and Shanghai. Most of the climate belongs to the north subtropical zone, and a small part belongs to the northern edge of the middle subtropical zone. The annual average temperature is 14 ~ 18℃, the most Leng Yue average temperature is 0 ~ 5.5℃, the absolute minimum temperature is-10 ~-20℃, the hottest month average temperature is 27 ~ 28℃, and the frost-free period is 2 10 ~ 270 days. For agricultural crops, the annual precipitation is 1000 ~ 1400 mm, which is concentrated in spring and summer. Zonal soil is only found in low hills and gentle hills, mainly yellow brown soil or yellow cinnamon soil. The southern margin is red soil, and most of the plains are paddy soil. With developed agriculture and high land reclamation index (62. 1% in Shanghai and 45.6% in Jiangsu), it is an important grain, cotton and oil production base. Rich in rice, wheat, cotton, rape, silkworm, ramie, jute and so on. Rivers and branches crisscross, and lakes are dotted. The lake covers an area of 20,000 square kilometers, equivalent to 10% of the plain area. There are more than 1300 large lakes, including small lakes, on the two-lake plain, totaling more than 10000, with an area of 12000 square kilometers, accounting for more than 20% of the area of the two-lake plain, which is the place with the largest number of lakes in China. There are many freshwater lakes such as Poyang Lake, Dongting Lake, Taihu Lake, Hongze Lake and Chaohu Lake, which are connected with the Yangtze River and have the functions of regulating water volume and reducing flood peak. They produce fish, shrimp, crab, lotus, water chestnut and reed, as well as world treasures such as Chinese sturgeon, Chinese alligator and baiji. Aquatic products occupy an important position in China and are known as the land of plenty. It is one of the most economically developed regions, including Shanghai, Nanjing, Wuhan, Nanchang, Suzhou, Wuxi, Changzhou, Nantong, Wuhu and Changsha. The main industries are steel, machinery, electricity, textiles and chemistry, and it is an important industrial base. The plain is located in the hub of China's north-south and east-west transportation networks, with developed land and water transportation. The Yangtze River runs through the middle and becomes an east-west waterway artery, and its many tributaries form a huge waterway network.

■ Yangtze River Delta

China Yangtze River and Qiantang River are alluvial deltas where they enter the sea. Include Jiangsu province, southeastern Shanghai and northeastern Zhejiang. It is a part of the middle and lower reaches of the Yangtze River. It covers an area of about 50,000 square kilometers. The apex of the delta is in Zhenjiang and Yangzhou, and the north reaches Xiaoyangkou. South bank of Hangzhou Bay. The elevation is mostly below10m, and the low hills (such as Huishan, Tianpingshan, Yushan and Langshan) are scattered, with an elevation of 200-300m. The annual sediment discharge of the Yangtze River is 400-900 million tons. In general, 28% of the sediment is deposited in the Yangtze River, and in some years it is as high as 78%. The delta continues to extend to the sea. The ancient sand mouths in Changzhou, Changshu, Taicang, Jinshan and other counties south of the Yangtze River are mostly 4 ~ 6 meters above sea level; The ancient sand mouth in Yangzhou, Taizhou, Taixing and Rugao, north of the Yangtze River, is 7-8 meters above sea level. The ancient sand mouths in Jiangnan and Jiangbei developed gradually after the highest sea level stabilized in the late glacial period. By about 2000, the north bank sand mouth extended to Liaojiaozui, and the south bank sand mouth extended to the southeast with the mainstream of the Yangtze River and connected with the mouth sand mouth of Qiantang River. Sediment continues to accumulate, advancing annually 1958 ~ 1973. It belongs to the northern subtropical monsoon climate, with abundant rainfall, criss-crossing waterways and dotted lakes, and is known as a water town and a country. The land is fertile, and agriculture mainly produces rice, cotton, wheat, rape, peanuts, silk, fish and shrimp. It is one of the most densely populated areas in China. There are many important towns in the lower reaches of the Yangtze River and on both sides of the Shanghai-Nanjing line, such as Shanghai, Suzhou, Changzhou, Wuxi, Zhenjiang, Yangzhou, Taizhou and Nantong. Among them, Shanghai is the largest industrial and commercial city in China and a world-famous foreign trade port, while Suzhou and Wuxi are scenic spots and emerging industrial cities.

■ Yangtze River hydropower resources

The Yangtze River is the largest river in China, second only to the Nile and Amazon rivers in length, and the amount of water flowing into the sea is second only to the Amazon and Congo rivers, ranking third in the world. The Yangtze River basin covers an area of 6,543,807,000 square kilometers. The upper reaches mostly flow through high mountains and canyons, with steep slopes and rapid flows, with a drop of 5360 meters. The total reserves of hydropower resources in the main and tributaries are about 268 million kilowatts, of which 65.438+0.97 billion kilowatts can be developed and the annual power generation is about 654.38+0 trillion kWh. By the end of 1990, the installed capacity of hydropower stations built or under construction in the whole basin exceeded110.7 million kilowatts, of which Gezhouba hydropower station has an installed capacity of 2710.5 million kilowatts, making it the largest hydropower station in China. The installed capacity of the proposed Three Gorges Hydropower Station is 6.5438+0.768 million kilowatts. Other large hydropower stations available for development include Xiangjiaba in Jinsha River (4.6 million kilowatts), Jinping in Yalong River (3 million kilowatts) and Pubugou in Dadu River (2.8 million kilowatts).