Why is the water of the Yellow River yellow?

1. The Yellow River is located in the Loess Plateau, and there are loess areas everywhere. Due to long-term weathering, the soil on the Loess Plateau is soft and the particles are clear, so every time the Yellow River rises and falls, the loess on both sides will be brought into the Yellow River water. At low tide, after air drying, new dust comes and new mounds are formed around, and so on. The Yellow River water will always be yellow.

2. The source of the Yellow River is mountainous, and then the soil in the Loess Plateau is loose. The water source of the Yellow River is not clear water, but muddy silt, which floats to the middle and lower reaches with the flow direction of the river. Because the source is not clean and clear water.

In addition, the bottom of the Yellow River is covered with sediment for a long time, and the waterway is large, so there is no filtering effect. This is also a reason why the Yellow River is yellow.

3. Because it is located in the Loess Plateau, there are mountains but the mountains are not high, so every time there is a strong wind, the sand will be blown into the river and the river bank. In this way, new dust keeps entering the turbid flow, and the river banks are constantly updated and alternated.

Extended data

According to the annual runoff depth contour map, the regional distribution of water resources in the Yellow River Basin is very uneven, with a decreasing trend from south to north. Starting from Mackey in the west, crossing Jishi Mountain, reaching Daxia River and Taohe River, along the main stream of Weihe River, to the south of Fenhe River and Qinhe River watershed. It is a region rich in water resources in the Yellow River Basin, which is dominated by mountainous areas with good vegetation, with an average annual precipitation of over 600 mm and an annual runoff depth of over100 ~ 200 mm..

The northern part of the basin, which passes through Gaolan, Haiyuan, Tongxin and Dingbian to the north of Baotou Line, has a dry climate, with annual precipitation less than 300mm and annual runoff below 10mm, which is the poorest area of water resources in the Yellow River Basin. In the vast loess plateau area between the above two lines, the annual precipitation is generally 400 ~ 500mm, and the annual runoff depth is only 25 ~ 50mm, which is the main source area of the Yellow River sediment.

Due to the influence of monsoon, the seasonal variation of river runoff in the Yellow River basin is great. The river surges in summer and autumn, which is prone to floods. There is little water in winter and spring, and water is scarce. The annual distribution of runoff is very uneven.

During the flood season of 7- 10, the runoff of the main stream and larger tributaries accounts for about 60% of the annual runoff, while the runoff from March to June accounts for only 10% ~ 20% of the annual runoff.

The annual changes of water resources in the Yellow River basin are also very different. The average natural runoff of Huayuankou Station for many years is 580 cubic meters, the maximum annual runoff can reach 93.866 billion cubic meters (July 1964 to June 1965), and the minimum annual runoff is only 27.352 billion cubic meters (July 1928 to June 1965).

The annual variation of runoff in tributaries of the Yellow River is greater than that in the main stream, and the ratio of the maximum annual runoff to the minimum annual runoff is generally 5 ~ 12, even higher than 20 in small and medium tributaries in arid areas.

Baidu Encyclopedia-Yellow River (the second longest river in China)