Why is the most peculiar appearance of the Yangtze River at its source?

Branches and roads

Beaches

The longest river in Asia

The world's largest river with hydropower

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Source of the Yangtze River

When you stand in front of this river, you are likely to forget the countless titles given to it by humans and indulge in the casual creation that nature has given to the river.

Originating from the Qinghai-Tibet Plateau and flowing into the East China Sea east of Chongming Island, this river runs almost across the entire China.

"The mountains end with the plains, and the river flows into the wilderness." Needless to say, it is the Yangtze River.

When discussing the twists and turns of the Yangtze River, people often mention its braided water system - a magnificent weaving of water, sandbanks and living things.

Water from the source

Image source: Xinhuanet

The river at the source of the Yangtze River is the freest. The braided water system in the source area of ​​the Yangtze River is only distributed in the hinterland of the Qinghai-Tibet Plateau, with an average altitude of more than 4,500 meters. Here, multiple forked river channels meander through countless sandbanks of all sizes, splitting and merging, intertwined like a huge fishing net.

Looking down from the sky, due to the mixture of mud and sand in the water, the dark red tributaries look like the blood vessels of the earth or like a girl's long braids, which makes people marvel at the magic of nature.

Why was the source of the Yangtze River formed?

Such a special braided water system?

Photography: Li Shaofeng

First, the riverbed should be easy to scour, and there should be no obvious constraints on both sides, so that the riverbed can become wider and shallower horizontally, forming a large number of side beaches and central beaches to disperse the water flow. Therefore, the places that can form braided water systems are generally relatively flat.

Secondly, the degree of sediment transport must be large, and the exchange of suspended sediment in the river water and riverbed sediment causes the riverbed to be constantly scour and silt adjusted.

During the flood period when the glaciers melt rapidly, the flood brings a large amount of sediment from the upstream due to the erosion and transportation of the water. When the flood flows out of the mountain pass or the wide river channel, the terrain becomes flat, the river valley is relatively open, the river flow slows down, and the sediment carried accumulates, forming underwater shoals.

In the dry season after the flood peak, many shallows emerge from the water and become sand islands, with multiple river channels between them. Due to the scattered distribution of sand islands, the river channels are divided and combined, interwoven like braids.

After each flood, the old channels and sand islands are completely changed and the braided water system presents a new look.

Finally, the mainstream must change its course frequently, causing the riverbed to change and the river flow to be very unstable in order to form a complete braided water system.

The weaving of life

A corner of the Chumar River (above) and the Tuotuo River (below)

Image source: Xinhua News Agency

The braided river system weaves together not only glaciers and silt, but also the fate of many wild creatures.

The Chumar River flows through the Hoh Xil region, which has the least rainfall on the Qinghai-Tibet Plateau. The soil there is poor, the vegetation is sparse, and due to severe soil erosion, the water is red and yellow, and the entire river is like a blood vessel exposed on the earth.

Image source: China Green Times

The braided water system occupies 80% of the entire Chumar River, and it is also the favorite habitat of the Tibetan antelope.

In addition to Tibetan antelopes, the braided water system also has special significance for birds living on the Qinghai-Tibet Plateau.

The Demoiselle Crane is a bird that can fly across the Himalayas.

Their whole body is blue-gray, with black eyes, head sides, throat and front neck, and a white ear tuft behind the eyes, which is very eye-catching. When seen from a distance, they can stand out from many migratory birds. The feathers on both sides of their bodies are white and long, like a straw raincoat draped over their bodies.

Every year, thousands of demigod cranes use the braided river system as a stopover to rest and forage on the river beach. The grass beach provides the cranes with abundant food to replenish their physical energy consumed by the long journey.

Photography: Zhao Chao

And every year when the Demoiselle Cranes migrate, the mating season for the White-lipped Deer also arrives.

With their large hooves and excellent swimming skills, white-lipped deer freely roam in the wide braided river channels, and occasionally you can encounter herds of dozens of deer. They forage on the grassy beaches or sandbars on the shore, and once there is movement, they quickly cross the river, cross one sandbar after another, and wade through one waterway after another.

In the fall, braided rivers become a battleground for white-lipped deer to compete for mates, court, and breed.

Image source: State Forestry and Grassland Administration

The braided river channel with many shoals and shallow water is a passage for animals to wade through, a station for birds to stop and rest, and a ferry crossing on ancient commercial roads. The famous Seven Ferry Crossings on the Tang-Tibet Ancient Road is located in such a river section.

The channel of each Han River is not wide, the water volume is not large, and the current is gentle. Loaded yaks and horses can easily wade across a stream, go to a sandbar, rest for a while, and then cross the next stream. Many sandbars have become "safe islands" on the Tongtian River.

Source: Wetland Science and Management

Producer: Ma Lian

Editor: Wu Nan

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