With a total length of 5,464 kilometers, the Yellow River is the second longest river in China and the mother river of China. The Yellow River originates from the Bayan Har Mountains on the Qinghai-Tibet Plateau. According to the records of its own documents, the water of the Yellow River is not only the Yellow River but also has a high sand content.

When the Yellow River flows through the Loess Plateau, a large amount of sediment enters the Yellow River due to scouring and erosion, and the river water changes from clear to turbid. . But some people found that the original yellow water of the Yellow River has turned green, and even the Hukou Waterfall of the Yellow River is green. What is going on?

Why is the water of the Yellow River so yellow?

The Yellow River is the most important birthplace of Chinese civilization, so it is called the mother river. It has nine provinces in its basin and has nurtured many Chinese sons and daughters. In people's inherent impression, the water of the Yellow River is particularly yellow, and it is also accompanied by a large amount of yellow mud. The reason why the water of the Yellow River is so yellow and the sand content is so large mainly comes from two aspects.

First of all, the water quality of the Yellow River from the Bayan Har Mountain on the Qinghai-Tibet Plateau is very clear, but it begins to turn yellow in the Loess Plateau. Due to the scarcity of vegetation on the Loess Plateau, it was caused by excessive logging in the past dynasties in history, and the long-term weathering resulted in soft soil and distinct particles. Therefore, when the river flows through the Loess Plateau, it will not only take away a large amount of loess, but also in Every time the Yellow River ebbs and flows, it takes away more loess on both sides of the river.

After the tide of the river ebbs, the loess once again forms new mounds under the action of air drying or sandstorm, but is drawn into the river water under the action of another tidal rise of the Yellow River.

In addition, the turbulent water of the Yellow River and the wide range of water channels often present not a calm river surface, but rolling water, just like the "Yellow River is roaring" described in the lyrics. As a result, a large amount of sediment cannot settle to the bottom of the water, but has been accompanied by the surging of the river in the river.

This has been repeated for thousands of years, so that the water of the Yellow River has always been so yellow, and the sand content in the water has always been so large that it even claims to be the first in the world. Relevant data show that the Yellow River carries 1.6 billion tons of sediment every year, making it the river with the largest sediment content in the world.

In China, there is a saying, "Yellow River water, one catty of water, seven liang of sand". But the Yellow River water, which had been yellow for thousands of years, has undergone different changes in recent years. The river water has turned from yellow to green. What is going on?

Why does the Hukou of the Yellow River turn green?

According to public information, Hukou Waterfall is located at the junction of Shanxi Province and Shaanxi Province in the Yellow River Basin. Due to the very steep terrain, in the basin less than 500 meters, the width of Hukou Waterfall is reduced from 300 meters to less than 30 meters. Formed a waterfall, which is also vividly called Hukou Waterfall of the Yellow River because of its appearance, forming the beauty of "a thousand miles of Yellow River in one pot". The waterfall roars down from a cliff more than 20 meters high with 1,000 cubic meters of river water per second. It is the second largest waterfall in China and a famous 4A-level tourist attraction in China.

Since the summer of 2022, the Hukou Waterfall of the Yellow River, the largest yellow waterfall in the world, has quietly changed from a yellow waterfall to a green waterfall. What makes people wonder is why the Hukou Waterfall of the Yellow River has turned green? Chinese experts gave three reasons.

First, the construction of water conservancy projects in the upper reaches of the Yellow River, according to statistics, can effectively reduce the sediment transport of the Yellow River by 50%, especially with the completion of the Wanjiazhai Water Conservancy Project, a large amount of sediment in the Yellow River water will settle to the bottom of the reservoir. It can also slow down the flow of the Yellow River. Relevant information shows that the flow velocity of the Yellow River during the flood season is 2,700 cubic meters per second, and the usual flow rate is generally only 1,500 cubic meters.

Second, after more than 40 years of efforts in China, the ecological environment of the Yellow River Basin has undergone major changes. The vegetation coverage rate has increased from 33% in 1999 to 60% in 2019. According to statistics, it can directly reduce the content of local rivers. Sand volume was reduced by 78%. In parts of northern Shaanxi, more than 60,000 slope protections and dams have been built, which directly reduced the sediment content of the basin by at least 60% compared with 20 years ago.

Third, there is a special reason this year. The northern region has been severely affected by the subtropical high, resulting in high temperature and drought. There has been no precipitation for several months, resulting in a decrease in the amount of water replenishment in the Yellow River Basin. After the water flow decreases, the sediment in the river can also settle down, and it also helps the growth of some microorganisms and makes the river water green.

Is it good or bad for the water to turn green?

The greening of the river water, some people think it is the reduction of sediment, a precursor to the clear water of the Yellow River; while some people think that this is due to the influence of too much industrialization, which has caused the river water to be affected, which is a typical water quality with severe eutrophication. change. In fact, to see whether the water quality is good or bad after turning green, the key is to look at the impact on the ecology of the Yellow River after the water quality in the Hukou Basin of the Yellow River turns green.

Some remarks said that after the water quality of the basin turned green, it was a good thing for the local fishery and aquaculture. Because the water quality is green, mainly the aquatic plants in the river grow densely, and the algae are also flourishing, which can provide more food for the fish in the river, and at the same time can enrich the dissolved oxygen in the water, further improving the river. Growth and reproduction of various fish.

The above statement is by no means guesswork, but based on relevant local fishery data. The section from Hukou to Sanmenxia is very suitable for the development of fishery resources. There are many indigenous fish surviving in this basin, and indigenous fish are also built there. The spawning base of the language. Take the northern copper fish spawning ground in Shaanxi, and focus on the northern copper fish, which can grow to about 20-30 kilograms and is one of the famous indigenous fish in the Yellow River. It is reported that the period from May to July every year is the peak period for the reproduction of many domestic pig fish.

At the same time, there is no need to worry that the greening of water quality is a serious eutrophication of water quality. Many experts said that the greening of the Yellow River water is a short-lived natural phenomenon. This statement has also been verified. After the end of June every year, with the opening of the high-level open-flow hole and the low-level sand discharge hole of the Xiaolangdi Dam at the same time, most of the soil deposited at the bottom of the reservoir will be brought out. , the water quality in the Hukou Basin of the Yellow River returned to its original yellow color.

If the Yellow River can really completely change the water quality, this will undoubtedly be a great news for China. The good environment is more suitable for the reproduction of many indigenous creatures in the Yellow River, and even some endangered river creatures can be rescued, just like the ban on fishing in the Yangtze River. In that way, with the improvement of the ecological environment, many natives of the Yangtze River who have been missing for decades have reappeared in front of the public.