Yellow river basin information?

The length is 5464 kilometers.

The source is 4800 meters above sea level.

The average flow rate is1774.5m3/s.

The basin covers an area of 752,443 square kilometers.

From Qinghai province

Inject into Bohai sea

The cut-off point of the middle and lower reaches: Old Jin Meng Estuary.

Nickname: insert Jiangnan

Origin: the northern foot of Bayan Kara Mountains in Qinghai Province.

Natural characteristics

The Yellow River, the second longest river in China, originated in Bayan Kara, Qinghai. Its main stream runs through nine provinces and regions, and flows through Qinghai, Sichuan, Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi, Henan and Shandong, with a total length of 5,464 kilometers, a drainage area of 750,000 square kilometers, an annual runoff of 57.4 billion cubic meters and an average runoff depth of 79 meters. But the amount of water is not as big as that of the Pearl River. There are 35 main tributaries along the way, with Huangshui River and Taohe River in the upper reaches, Qingshui River, Fenhe River, Weihe River and Qinhe River in the middle reaches, and Yihe River and Luohe River in the lower reaches. There are no lakes on both sides of the river, and the lower reaches of the Yellow River are very small, and few rivers flow into the Yellow River. The estuary of the Yellow River is1500m wide, generally 500m, the narrower part is only 300m, and the water depth is generally 2.5m.. In some places, the depth is only 1.2 ~ 1.3 meters.

geographical environment

The mountainous and grassland plateaus from Heyuan to Guide belong to the Qinghai-Tibet Plateau. The peaks are all above 3000 meters above sea level; The upper valley is over 4200 meters above sea level. The terrain on both sides of the upper valley is gentle and the drainage is not smooth; Causing large areas of swamps and many lakes. Guide's reach from Jinmeng River is the Loess Plateau, with Xibe and Weihe valleys in Lvliang in the south, Ordos Plateau in the north and Lanzhou Valley in the west. The elevation of the Loess Plateau is generally 1, 000- 1, 300m, with uneven landform and steep slope. The gully ground slope is 1.5-20 degrees, the gully area accounts for 40-50%, the gully density is 3-5km/km2, and the cutting depth exceeds/kloc-0. Below Jin Meng, it enters the low-lying North China Plain, with an altitude of no more than 50 meters. After entering the downstream, the river channel is flat, and the average gradient is only 0. 12%. The water flow slows down and a lot of sediment is deposited, which is 4-5 meters above the ground. Due to the repeated diversion of the Yellow River, the fan-shaped ancient riverbed and ancient natural dike have become inclined plains with alternating gentle hills and depressions, and the depressions are relatively open and flat.

River basin survey

The Yellow River reaches Hekou Town, Tuoketuo County, Inner Mongolia Autonomous Region, with a total length of 3,472 kilometers. The middle reaches are from Hekou Town to Taohuayu, Zhengzhou, Henan Province, with a river length of 1206 km. Below Taohuayu is the downstream, with a river length of 786 kilometers. There are many opinions on the division of the upper, middle and lower reaches of the Yellow River, and the division scheme of the Yellow River Water Resources Commission is adopted here. The Yellow River runs across China from east to west, with a length of 1.900 km from east to west and a width of1.654,38+0.000 km from north to south, with a total area of 752,443 square kilometers.

The Yellow River, like a lion with his head held high, crosses the mountains of Qinghai and Gansu provinces from the Qinghai-Tibet Plateau. Hetao Plain across Ningxia and Inner Mongolia; Pentium in the ravine between Shanxi and Shaanxi; Break through the "Longmen", turn around at the foot of Huashan Mountain in Xiyue, cross the North China Plain, and head for the coast of Bohai Sea. It flows through 9 provinces and autonomous regions and gathers more than 40 main tributaries and 1000 streams and rivers, with a journey of 5,464 kilometers and a drainage area of more than 750,000 square kilometers, making it the second largest river in China. The average annual precipitation in the whole basin is about 400 mm, while the average annual runoff of the Yellow River is only 57.4 billion cubic meters, ranking eighth among Chinese rivers. There are more than 200 million mu of cultivated land in the basin, plus the lower reaches of Henan and Luyan rivers, with a population of about 654.38 billion.

The average natural runoff of the whole Yellow River for many years is 58 billion cubic meters, the average annual runoff depth of the basin is 77 mm, the per capita water volume of the basin is 593 cubic meters, and the cultivated land is 324 cubic meters.

The middle reaches of the Yellow River flow through the Loess Plateau, and tributaries bring a lot of sediment, making the Yellow River the largest river with sediment concentration in the world. The annual maximum sediment discharge is 3965438+ 1 100 million tons (1933), and the maximum sediment concentration is 920kg/m3( 1977). The average sediment discharge of Sanmenxia Station for many years is about 65.438+0.6 billion tons, and the average sediment concentration is 35 kg/m3.

branch

The main tributaries of the Yellow River are Baihe, Heihe, Huangshui, Zuli, Qingshui, Dahei, Kuye, Wuding, Fenhe, Weihe, Luohe, Qinhe and Dawenhe.

Major lakes

There are Zhaling Lake, Eling Lake, Wuliangsuhai Lake and Dongping Lake.

Mainstream canyon

There are 30 canyons in the main stream of the Yellow River, 28 in the upper reaches and 2 in the middle reaches. The lower reaches flow through the North China Plain without canyons. The canyon section of the main stream is 1707 km long, accounting for 3 1.2% of the total length of the main stream.

Biological resources

There are 98 species of pure freshwater fish in the main stream of the Yellow River, accounting for 78.4% of the total. The main economic fish are naked spotted carp, flat-edged swallowtail, thick-lipped naked heavy-lipped fish, yellow river naked-lipped fish, yarrow, northern Tongyu, carp, crucian carp and so on. There are only 16 species of fish in the upper reaches of the Yellow River, and the composition is relatively simple. Among Cyprinidae and Misgurnus, there are only Schizothorax, Pulsatilla, yarrow and Misgurnus. Fish in the middle and lower reaches are generally similar, mainly CYPRINIDAE. There are 7/kloc-0 species of fish in the middle reaches, and there are no typical plain fish such as silver carp, bighead carp, bream and bream. There are Schizothorax and Misgurnus anguillicaudatus in the upper reaches of the middle reaches, and 78 species of fish in the lower reaches, including a variety of fish crossing estuaries and brackish water. According to the survey data of tributaries of the Yellow River, according to the fish statistics of Taohe River in Gansu, Weihe River in Shaanxi and Jinghe River, there are 30 species in Weihe River, followed by Taohe River 1 1 species, and only 4 species in Jinghe River. Most of the tributaries in the middle and upper reaches are small fishes of CYPRINIDAE and Misgurnus, a few are Tasmanian fishes and catfish, and the economic fishes are carp, crucian carp, yarrow fish and catfish.

Fishery production

The main catch species of the Yellow River have also changed. The fish in the main stream has the highest yield ever, and the "Yellow River Carp" is famous all over the country. Now the yield has dropped significantly. Before the 1960s, carp in the middle reaches of Shanxi and Shaanxi accounted for 60-70% of the catch, ranking first in the catch composition. According to the investigation of catches at the Yellow River port in Shaanxi Province in August1-82, the catches only accounted for 2 1%, and catfish replaced the main position, accounting for 4 1. 1%. Followed by Pelteobagrus fulvidraco, accounting for 26.3%. From 65438 to 0983, the catch of the Yellow River in Pinglu County, Shanxi Province was investigated. Among them, only 20% of carp and 60% of catfish are the main catches. In the early 1950s, carp accounted for 50-70% of the total output in the lower reaches of Shandong Province, but it dropped to 15% in the 1960s and only 7. 1% in 1982. The situation of fishery labor force in the eight provinces where the Yellow River mainly flows is as follows: except for Qinghai province, the fishery professional labor force in Gansu, Ningxia, Inner Mongolia, Shanxi, Shaanxi, Henan and Shandong provinces was 26,964 in 1980, and decreased to 1 1320 in 1983. Part-time fishing labor force 1980 was 24,843, and it increased to 25,873 in 1983, accounting for 8.9% and 5.7% of the total similar labor force in China respectively. In the past 30 years, the resources of carp, the main economic fish in the Yellow River, have been greatly reduced, and the composition of its catch groups has also changed accordingly. In the early 1980s, most of the carp caught in Tongguan port section of the Yellow River were third instars, with an average of 0.7 kg per carp accounting for 44.7%, followed by fourth instars with an average of 1.5 kg accounting for 28.4%.

Fishing method: fishing method, the fishing gear used in fishery production in the main stream of the Yellow River, the gill net is the main fishing gear in the middle and upper reaches, and there are also beach seines. The gill net is divided into single layer and three layers, and the three layers gill net is more efficient. In addition, there are many kinds of roll fishing, including hooks and clips, only four or five in the middle reaches.

Characteristics of fishing area: upstream: 8 species of Schizothorax subfamily and Fish subfamily; Middle reaches: carp, crucian carp and catfish; Downstream: Coilia ectenes, Carp, Grass Carp and Catfish.

Upstream: From Heyuan to Guide, there are mountainous and grassland plateaus on both sides, with an altitude of over 3,000m and a peak of over 4,000m m.. The river course is S-shaped, and the river course twists and turns within 400 kilometers of the headwaters. There are many lakes, grasslands and swamps on both sides of the strait, and the clear water flow of rivers is stable, with less water consumption and large water production. There are many lakes, and the largest lakes, Xingsuhai and Eling Lake, have a cold plateau climate. Fish resources have not been exploited for a long time.

Mid-stream: Jin Meng tour guide, mostly passing through high mountains and canyons, with fast current and steep slope. The Liujiaxia Valley is extremely deep, with a river width of 50-70 meters, a narrowest point of less than 15 meters and a valley depth of 100-500 meters. The current is swift, narrow and steep, and it is rich in hydraulic resources. A large reservoir was built on the canyon. The Yellow River flows through Hekou Town, turns south, passes through Qin Jin Canyon, and reaches Longmen with a total length of only 7 18km, a drop of 6 1 1m, and a steep slope. From Longmen to Tongguan, the river reaches 130km, and the water flows in Nafen, Weihe, Zhu Jing and Luozhu rivers, with a large increase in water volume, serious sediment deposition and unstable river course.

Downstream: The section from Jinmeng to North China Plain is the downstream, with a total length of 874 kilometers. The river is wide and flat, with slow water flow and siltation. The riverbed is 4-5 meters above the ground on average. It is an aboveground river with the richest fish resources, including estuarine migratory fish, river fish, settled fish, brackish water fish and aquatic fish.

historical changes

"Yellow River, you are the cradle of the Chinese nation, and 5,000 years of ancient culture originated from you ..." This is the lyrics of the famous song Ode to the Yellow River. Whenever people sing this song, they will be immersed in infinite memories of the Yellow River. The Yellow River is the mother river of the Chinese nation. As the birthplace of Chinese civilization, it maintains the blood of the descendants of the Yellow Emperor and is a symbol of the national spirit and feelings of the Chinese nation.

As early as 800,000 years ago in the Paleolithic Age, the ancestors of the Chinese nation lived a life of hunting and gathering in the Yellow River Basin. More than 2,000 primitive village sites have been found in the Yellow River Basin, indicating that in the Neolithic Age, ancestors settled in this vast land and engaged in primitive agricultural production.

In the middle Neolithic period, the Huangdi tribe scattered on the loess plateau in the middle reaches of the Yellow River. At that time, Chiyou tribe and Yan Di tribe were the three major tribes in ancient China. They live a nomadic life of uncertain migration. Later, Emperor Yan and Huangdi joined forces to attack and kill Chiyou. Soon, Yan Di people and Huangdi people gradually merged and settled in Shaanxi, Gansu and Shanxi to jointly develop the middle and lower reaches of the Yellow River.

Xia, Shang and Zhou dynasties, which entered the slave society more than 3,500 years ago, are all descendants of the Chinese people. They call themselves "Hua" or "Xia". Chinese is the predecessor of the Han nationality, so the Han people regard the Yellow Emperor as their ancestors and call themselves descendants of the Yellow Emperor. At that time, China people lived in the Central Plains and were considered to be among the four directions, so they were also called "China". Later, Chinese culture spread all over the country, and the word "China" became the name of China.

In Shang Dynasty, Pan Geng moved its capital to Yin Ruins (now Anyang County, Henan Province), and its sphere of influence has reached the North China Plain between Taihang Mountain and Taishan Mountain, which is called Yin Empire. The culture of the Yin Dynasty was quite developed, and it was called the three ancient empires with Egypt and Babylon at that time, and it was the three major cultural centers of the ancient world. In Yin Ruins, exquisite Oracle Bone Inscriptions and exquisite bronze vessels are still preserved. However, outside the three ancient empires, most human beings still live a primitive life. It can be seen that our motherland is one of the ancient civilizations in the world, and the ancient culture originated from the embrace of the Yellow River.

From Yin Dynasty to Northern Song Dynasty, the Yellow River Basin has been the political, economic and cultural center of China for nearly 2,500 years. Xi 'an (known as Chang 'an in ancient times), from the Western Han Dynasty to the Sui and Tang Dynasties, had 1 1 dynasties as its capital, which lasted for more than1/00 years. It not only made an important contribution to the economic and cultural development in ancient China, but also left an immortal chapter for international economic and cultural exchanges. Luoyang, which has been the capital of nine dynasties for nearly a thousand years, is called "the ancient capital of nine dynasties". Historians, scientists and writers gathered in Luoyang, leaving immortal works for China and the world cultural treasure house.

For thousands of years, the Yellow River valley was the center of feudal rule, and the struggle of the broad masses of working people against oppression was also continuous. Chen Sheng and Guangwu in the late Qin Dynasty, Red Eyebrows, Bronze Horses and Yellow Scarves in the Han Dynasty, Wagang Army in the late Sui Dynasty, Huang Chao and Wang Xianzhi in the Tang Dynasty and Li Zicheng and Zhang in the late Ming Dynasty all staged magnificent historical dramas in this land of the Yellow River Basin. During War of Resistance against Japanese Aggression and the War of Liberation, the Shaanxi-Gansu-Ningxia Border Region was a reliable revolutionary base for the people of China until the great People's Republic of China (PRC) was founded.

The source of the yellow river

The Yellow River originated at the northern foot of Bayan Kara, Qinghai Province, and the real source is still controversial. Historically, people's understanding of the source of the Yellow River has a process.

"Shangshu Gong Yu" once recorded that "the stone is accumulated by drawing water from the river, but as for Longmen", and "the stone is accumulated" is located in Qingshan, Anima, near Xunhua Salar Autonomous County, Qinghai Province, which is still far from the source of the Yellow River. It is recorded in Shan Hai Jing and Er Ya that the river flows from Kunlun. After Zhang Qian went to the Western Regions in the Western Han Dynasty, it was said that the Yellow River originated in Khotan, flowed to Yanze in the east, then flowed underground, and flowed to the source of the river in the south (see Biography of Dawan in Historical Records). These statements are not accurate, but they continued until the Sui and Tang Dynasties.

After the Sui and Tang Dynasties, people gradually established a correct understanding of the source of the Yellow River. In the fifth year of Yang Di the Great (609), Tuguhun was destroyed and later moved to Heyuan County, which is now part of Golog Tibetan Autonomous Prefecture in Qinghai and Hainan Tibetan Autonomous Prefecture, indicating that people know that the Yellow River originated here. In the ninth year of Emperor Taizong's Zhenguan reign (635), in order to quell the Tuguhun rebellion, Li Jing, Hou, Li Daozong and other generals once led troops to the area around the Star Sea. The Book of the New Tang Dynasty contains them "visiting the stars, Suzhou, Dabahai, Jishishan and Heyuan." . Xinghai has been called the source of the Yellow River since the Tang and Song Dynasties.

In the Yuan Dynasty, people began to make field trips to the source of the Yellow River. In the 17th year of Yuan Dynasty (1280), Kublai Khan of Yuan Shizu sent Du Shi and others to explore the source of the Yellow River and made a detailed investigation of the area around Xingsuhai. 13 15, Pan Anxiao wrote a book "Heyuan Zhi" based on his investigation in Du Fu's poems, clearly pointing out that the Yellow River originated in the southwest of the Star Sea, where "there are more than 100 wells with water gushing from the ground".

In the 43rd year of Qing Emperor Kangxi (1704), Emperor Kangxi ordered Laxi and Lan Shu to explore the source of the Yellow River. When they arrived in Xinghai, they found that there were three rivers in the upper reaches of Xinghai, but they didn't catch up with the source. After Lacey and Lan Shu returned to Beijing, they drew a map of Heyuan, and Lan Shu also wrote a record of Heyuan. At the end of Kangxi, a nationwide topographic survey was organized. In the fifty-sixth year of Kangxi (17 17), Lama Chu Er Qin Zangbo, Lamu Zhanba and the president of the hospital were sent to Heyuan area for investigation. This trip "crosses the source of the river and involves Wan Li". After returning to Beijing, the survey results are drawn into the imperial map. This mapping also explored and mapped the source of the river above Xinghai.

In the forty-seventh year of Qianlong in Qing Dynasty (1782), Amitabha, the bodyguard of Mingmen in Qianlong, paid tribute to Heyuan. Amitabha arrived 300 miles west of Xinghai and made a field survey of three rivers in the upper reaches of Xinghai. It is determined that Allerstam Guole River (now Kaliqu) in the southwest of Xinghai is the upstream source of the Yellow River.

After the establishment of People's Republic of China (PRC), the source of the Yellow River has been inspected many times. From 65438 to 0952, organized by the Yellow River Conservancy Commission and led by Xiang Lizhi and Dong Zaihua, the source of the Yellow River was explored for several months. Heyuan exploration team determined that Yuegu Zonglequ is the main source of the Yellow River, and Yahe Lada Heze Mountain is its source, with Ering Lake above and Zhaling Lake below. This result is not consistent with the previous investigation results, which has caused controversy in academic circles, but the statement that the Yellow River originated from Zonglie Canal in Yuegu is widely circulated. During the period of 1978, Qinghai Province invited relevant scientific research professionals from the central and local governments to make another field trip to the headwaters of the Yellow River and the two lakes of Zhaling Lake and Eling Lake, and confirmed that Kaliqu was the main source of the Yellow River, with Zhaling Lake above and Eling Lake below. From 198 1 to 1982, scholar Yang traveled all over the Yellow River on foot. He believes that the longest source of the Yellow River is Lalang Love Song, which starts from the ridge of Bayan Kara Mountains, and is 30.5 kilometers longer than that of Guzong Liesong and1/0.9 kilometers longer than that of Kari Song. From 65438 to 0985, the Yellow River Conservancy Committee confirmed Maqu as the main source of the Yellow River according to historical traditions and opinions of various factions, and set up a sign of the source of the Yellow River in Maqu Fruit Tree in the southwest corner of the Yogu Zonglie Basin.

The three tributaries of Xinghai Shangyuan are Zhaqu, Yuegu Zonglie and Kariqu. Zhaqu, located in the northernmost part, originated in Cha Hasila Mountain. This river is 70 kilometers long and narrow, with few tributaries and limited water, and it is cut off for most of the year. Yoguliequ is located in the west of Xinghai, among the three upstream sources, and originated in the southwest corner of Yoguliezong Basin, with an altitude of 4,750 meters. The water volume is very small, and it is a stream with a width of 1.0- 1.5 meters and a depth of 0. 1-0.2 meters. Kaliqu, a tributary in the south, originated at the northern foot of Geziya Mountain, a branch of bayan har, with an altitude of 4,800 meters. Five springs gushed out of the valley and merged into a small river with a width of about 3 meters, a depth of 0.3-0.5 meters and a flow rate of about 3 meters per second. This river has water all the year round. Yueguzong Liequ and Kariqu merged at the source of the Yellow River to form the original river Maqu, which was then injected into Xinghai. According to the aerial survey of1:100000, the length of Kazqu is 25 kilometers longer than that of Beyogul Zongqu. Kariqu basin covers an area of 3 126 square kilometers, and Yuegu Zonglequ basin covers an area of 2,372 square kilometers. Near the intersection of Kariqu and Guzong Liequ, the measured flow of Kariqu is 6.3 m3/s, and that of Yogu Liequ is 2.5m3/s. Through the investigation of the source of 1978 Yellow River, it is determined that Kariqu is the main source of the Yellow River.

There have been many stories about the source of the Yellow River in history. As early as the first half of the 7th century, it was suggested that Kariqu was the source of the Yellow River, but it was not recognized. Du Fu's poems in Yuan Dynasty in A.D. 1280 and Laxi in Qing Dynasty in A.D. 1704 arrived in Xinghai to find the source of the river. Therefore, the saying that Xinghai is Heyuan has been circulating for many years. After the founding of New China, the Yellow River Conservancy Commission organized an expedition to the source of the Yellow River in August 1952, with Yuegu Zonglie as the main source of the Yellow River. For more than 20 years, although mistakes have been made, many people have raised questions. Until the summer of 1978, the Heyuan investigation team was organized again and went into the Heyuan area for on-the-spot investigation. In the west of Heyuan area, there are three rivers flowing into Su Xinghai. They are Zhaqu River, Yuegu Zonglie River and Kariqu River. Zhaqu has the shortest flow and smaller water volume, which can only be regarded as a tributary of Yuegu Zongle Qu. Compared with Kariqu, Yuegu Zonglie Qu is nearly 30 kilometers long, with a drainage area of 700 square kilometers and more than twice as much water. Therefore, the basis for determining Kariqu as the positive source of the Yellow River is sufficient. Kariqu originated in Geziya Mountain at the northern foot of Bayan Kara at an altitude of 4,800 meters. The clear water overflowed from several springs at the foot of the mountain is the initial flow of the Yellow River, which "roars Wan Li and moves Longmen".

River flood season

The Yellow River has two flood seasons every year. The flood season is summer, and the incoming water is mainly the upstream rainstorm. The flood season may last for 3-4 months. The small flood season is from March to April in spring, and the incoming water is mainly the melting of ice and snow in the upper reaches, which lasts for a short time. Because peach blossoms are in full bloom every year, it is also called peach blossom flood season.

According to "History of Song Dynasty", the speaker named the phenology water potential because the Yellow River fluctuates at any time. Since the beginning of spring, the east wind has thawed and the river is waiting for water. At the beginning, it reached an inch, and it reached a foot in summer and autumn, which was quite reliable, so it was called "believing in water". In February and March, when the peach blossoms first opened, the ice piled up, the rivers gathered and the waves were rough, which was called "Peach Blossom Water". Turnip blooms in late spring, which is called "vegetable water". At the end of April, wheat has beautiful ridges and discolored awns, which is called "wheat yellow water", and in May, melon seeds spread, which is called "melon vine water". Wild land, deep mountains and poor valleys, solid yin and cold, hard ice and late flooding, caught in midsummer, let go, and rock shaking, fishy water, flowing in the river, so it was called "alum scene" after mid-June. The bean show in July is called "Bean Flower Water". The chaos in China in August is called "Miao Shui Miao". In September, the Double Ninth Festival is called "Climbing Water". In October, the water falls and flows safely, and it returns to its old way, which is called "re-watering". 1 1,1February, when it is cold, it is called "surging Lingshui". The water credit is unchanged, and the rate shall prevail; The untimely expansion is called "guest water".

River division

There are different opinions about the boundary between the upper, middle and lower reaches of the Yellow River. The Yellow River Conservancy Commission divides Hekou Town and Taohuayu into upper, middle and lower reaches. Traditional middle school textbooks divide Hekou Town and Jin Meng into upper, middle and lower reaches. Scholar Yang thinks Qingtongxia and Harmony are more suitable. Scholar Xu advocated Jiayingguan in Wuzhi County, Jiaozuo City, Henan Province as the dividing line between the middle and lower reaches of the Yellow River. The following is the division plan of the Yellow River Water Conservancy Commission.

Upstream

The upper reaches of the Yellow River are above Hekou Town, Tuoketuo County, Inner Mongolia. The total length of the upper reaches is 3,472 kilometers, and the basin area is 386,000 square kilometers, accounting for 5 1.3% of the total Yellow River. The total upstream drop is 3496m, with an average gradient of10 ‰; There are 43 large tributaries (basin area 1000 square kilometers or more), and the runoff accounts for 54% of the whole river; The upper reaches of the Yellow River only account for 8% of the annual sediment discharge of the whole river, with more water and less sediment, which is the clear water source of the Yellow River. The upper reaches of the river are controlled by Qingshan Mountain, Xiqiao Mountain and Nanshan Mountain in Anima, Qinghai, with an S-shaped bend. According to the different characteristics of rivers, the upper reaches of the Yellow River can be divided into three parts: source section, canyon section and alluvial plain section.

The upper part of Qinghai Kariqu to Qinghai Guide Longyangxia is the Heyuan section. Heyuan section starts from Kariqu, passes through Xingsuhai, Zhaling Lake and Eling Lake to Maduo, bypasses Qingshan and Xiqingshan in Anima, and reaches Guide in Qinghai via Longyangxia. Most of the rivers in this section flow through the plateau of three or four kilometers, and the rivers are tortuous, with lakes, swamps and grass beaches on both sides. The water quality is clear, the water flow is stable and the water yield is large. There are Zhaling Lake and Eling Lake in the reach, both above 4260 meters above sea level, with storage capacity of 4.7 billion cubic meters and 654.38+0.08 billion cubic meters respectively, which are the largest plateau freshwater lakes in China. The Yellow River runs from Maduo, Qinghai Province to Maqu, Gansu Province, and flows through the ancient basin and low hills between Bayankala and Animaqing Mountain. Most river sections have wide valleys, and occasionally there are canyons. The Yellow River runs from Maqu, Gansu Province to Longyangxia, Guide, Qinghai Province, and flows through high mountains and canyons, with fast-flowing water and abundant hydraulic resources. Baihe and Heihe rivers, tributaries originating in Minshan, Sichuan, join the Yellow River in this section.

The section from Longyangxia in Qinghai to Qingtongxia in Ningxia is a canyon section. This section of the river flows through mountainous hills. Due to different rock properties, river valleys and wide valleys appear alternately: river valleys are formed in hard gneiss, granite and Nanshan metamorphic rocks, while wide valleys are formed in loose sand shale and red rock series. There are 20 canyons in this section, including Longyang Gorge, Jishi Gorge, Liujiaxia Gorge, Bapan Gorge and Qingtongxia. There are cliffs on both sides of the canyon, with narrow riverbed, steep river slope and rapid water flow. From Guide to Lanzhou, this section is one of the concentrated reaches of the three major tributaries of the Yellow River, and the inflow of important tributaries such as Taohe River and Huangshui River has greatly increased the water volume of the Yellow River. The reach from Longyangxia to Xiaheyan River in Ningxia is a "mine-rich" area of the Yellow River and one of the important hydropower bases in China.

Qingtongxia in Ningxia to Hekou Town in Tuoketuo County, Inner Mongolia is an alluvial plain. After leaving Qingtongxia, the Yellow River flows northeast along the northwest boundary of Ordos Plateau, and then reaches Hekou Town eastward. Most of the areas along the river are deserts and desert grasslands, and there is basically no tributary injection. The river bed of the main stream is gentle and the water flow is slow. On both sides are large alluvial plains, namely the famous Yinchuan Plain and Hetao Plain. There are floods and ice disasters in the plain along the Yangtze River to varying degrees. Hetao Plain starts from Xiaheyan in Ningxia in the west and reaches Hekou Town in Inner Mongolia in the east, with a length of 900 kilometers and a width of 30-50 kilometers. It is a famous irrigation area for diverting water from the Yellow River with a long irrigation history. Since ancient times, there has been a saying that "the Yellow River is full of disasters and there is only one set of wealth".

middle reaches

The reach of the Yellow River between Hekou Town, Tuoketuo County, Inner Mongolia and Taohuayu, Zhengzhou, Henan Province is the middle reaches of the Yellow River, with a total length of 1.206 km and a drainage area of 344,000 square kilometers, accounting for 45.7% of the total drainage area. The total drop in the middle reaches is 890 meters, with an average gradient of 0.74 ‰; This river has 30 major tributaries; The increased water volume accounts for 42.5% of the Yellow River water volume, and the increased sediment volume accounts for 92% of the whole Yellow River sediment volume, which is the main source of the Yellow River sediment.

Hekou Town to Yumenkou is the longest continuous canyon on the main stream of the Yellow River-Shanxi Canyon. Most tributaries in the reach flow through the loess hilly and gully region, which is the main source of coarse sediment in the Yellow River, and the annual average sediment transport of the whole river is 900 million tons from this region. This reach is the second largest hydropower base of the Yellow River with large gradient and abundant hydraulic resources. There is a famous Hukou Waterfall in the lower part of the canyon, with a deep trough width of only 30-50 meters and a low water level drop of about 18 meters, which is magnificent.

From Yumenkou to Sanmenxia, the Yellow River flows through the Wei Fen Plain, the valley widens and the water flows slowly. On both sides of the reach are Weibei and Jinnan loess tablelands, which are important agricultural areas in Shaanxi and Shanxi provinces. This reach has accepted Fenhe River, Luohe River, Jinghe River, Weihe River, Luo Yi River, Qinhe River and other important tributaries, and is one of the main sources of sediment in the lower reaches of the Yellow River, with an average annual output of 550 million tons. The reach is located in the channel from Yumenkou to Tongguan (that is, the small north main stream of the Yellow River) 132.5km, with drastic changes in erosion and deposition, and the channel is very unstable from side to side. Constrained by the mountains near Tongguan, the valley suddenly narrows, forming a natural bayonet with a width of only 1000 meters. The level of Tongguan river bed is closely related to the changes of erosion and deposition in the Xiaobei main stream of the Yellow River and the lower reaches of the Weihe River, so the hydrological term "Tongguan elevation" is used.

Sanmenxia to Taohuayu section is divided into two parts from Xiaolangdi: above Xiaolangdi, the river is between Zhongtiao Mountain and hill, which is the last canyon on the main stream of the Yellow River; The valley below Xiaolangdi gradually widens, which is the transition section of the Yellow River from mountainous area to plain.

lower reaches

The Yellow River below Taohuayu in Zhengzhou, Henan Province is the lower reaches of the Yellow River, with a total length of 786 kilometers and a drainage area of only 23,000 square kilometers, accounting for 3% of the total drainage area. The total downstream drop is 93.6m, with an average gradient of 0.1.2 ‰; The increased water volume in the interval accounts for 3.5% of the water volume of the Yellow River. Due to the large amount of sediment in the Yellow River, the downstream reaches have been silted for a long time to form a world-famous "aboveground river", and the Yellow River has become a watershed between the Haihe River Basin and the Huaihe River Basin. Except for the Dawen River flowing from Dongping Lake, there are no big tributaries in this section.

Except for the low hills between Dongping Lake on the south bank and Jinan, the lower reaches depend on dikes, with a total length of 1.400 km. Historically, the lower reaches of the Yangtze River often burst, which brought heavy disasters to the Chinese nation. Because the lower reaches of the Yellow River flow from southwest to northeast, the north of the Yellow River freezes first in winter, forming ice flood. Ice dams are easily blocked by the overflow of ice, which leads to the overflow of dikes and poses a serious threat.

Below the downstream Lijin is the Yellow River estuary. Due to sediment deposition, the mouth of the Yellow River keeps extending and swinging. At present, the Yellow River estuary is located at the intersection of Bohai Bay and Laizhou Bay, which is a new channel formed by the siltation of Qingshuigou after the artificial diversion of 1976. In recent 40 years, the average sediment transported by the Yellow River to the estuary area is about 654.38+100 million tons/year, with an average annual net land of 25 to 30 square kilometers.