The Yellow River has been diverting water and sand for 20 years, why is it still silting up sediment?Why not vigorously mine sand?
The Yellow River is known as the mother river of the Chinese nation, and its position in the hearts of Chinese cannot be described in words. As the birthplace of Chinese culture, the Yellow River Basin contains a rich and profound historical and cultural heritage.
The Yellow River, a river with a profound history and culture, gave birth to many famous cities such as Luoyang, Chang'an, and Kaifeng, and still attracts the attention of countless people. Every year, the Yellow River carries 1.6 billion tonnes of sediment, 400 million of which ends up downstream, creating a vast alluvial plain that provides an ideal environment for the development of cropping industries.
However, the Yellow River has become a pain for the Chinese, that is, the serious problem of sediment accumulation in the Yellow River. The sediment accumulation problem of the Yellow River is unique in the world.
In order to solve this problem, our country has been carrying out governance for more than twenty years, trying various methods, but it still has not improved, and the situation has even become more serious.
Faced with a dire situation, some experts have proposed a new solution: large-scale sand mining in the Yellow River basin. However, this plan has been opposed by many people.
So why are so many people opposing large-scale sand mining?This is closely related to the overall ecological environment of the Yellow River Basin. 01 The sediment accumulation of the Yellow RiverMost people's impression of the Yellow River is its turbid status and serious soil erosion on both banks.
However, this is only the situation in the lower reaches of the Yellow River Basin, and does not represent the hydrological conditions of the entire Yellow River Basin.
The hydrological characteristics of the Yellow River are mainly manifested in the flow, water level, sediment content and ice period, among which the silt condition is the specific embodiment of the sediment content. The sediment content of different regions of the Yellow River varies significantly, and the upstream area has a large terrain difference, superior environment, high vegetation coverage, small soil erosion, and good water quality, which provides a guarantee for the agricultural development and domestic water supply of Lanzhou, Ningxia Plain and Hetao Plain.
The Hetao Plain and the Ningxia Plain have a pleasant environment and are ideal places for the development of plantation. It has a large population and broad agricultural prospects, and is known as "plugging the south of the Yangtze River".
However, the sediment content of rivers in the middle and lower reaches of the Yellow River has changed significantly, and the sediment content has increased sharply. The main reason is that the Yellow River flows through the Loess Plateau. The Loess Plateau is the plateau with the lowest vegetation coverage among the four major plateaus in China, with serious soil erosion.
When the Yellow River flows through the Loess Plateau, it carries a large amount of sediment into the river, causing the sediment content of the Yellow River to rise sharply.
However, the problem does not end there. The topography of the North China Plain is an important reason for the high sediment content in the lower reaches of the Yellow River. The low sediment content in the upper reaches of the Yellow River is due to its high vegetation coverage on the one hand, and the large terrain difference and fast water flow rate on the other hand, which allows less sediment to be deposited and continue to flow to the middle and lower reaches.
However, in the lower reaches of the river, the topography has changed, not only has the amount of sediment increased dramatically, but the North China Plain has become flat, resulting in a decrease in the flow rate of the Yellow River and a consequent reduction in its ability to carry sediment.
A large amount of sediment has accumulated in the middle and lower reaches of the Yellow River, and even in the Kaifeng area of the middle and lower reaches of the Yellow River, a peculiar above-ground hanging river landscape has been formed.
Although the sediment deposits of the Yellow River provide fertile soil for the downstream areas, they also pose many problems. The most serious of these is flooding. The middle and lower reaches of the Yellow River are low-lying and have poor drainage capacity, and the Yellow River flows relatively slowly, making flooding in northern China during the rainy season.
In addition, the problem of overhanging rivers is also very serious, and the dikes need to be strengthened every year to prevent the river from reaching water levels** and causing flooding caused by levee breaking. In addition, due to the high sediment content of the Yellow River, the complex conditions of the river bottom, and the large number of reefs, although the Yellow River is the second longest river in China, its navigation conditions are relatively poor.
The Yellow River has a huge water flow, but it is not fully utilized because its shipping value is far inferior to that of the Yangtze River, Pearl River and other rivers. Therefore, it is very important to control the sediment of the Yellow River, which has been continuously controlled since ancient times.
In the lower reaches of the Yellow River, the riverbed has risen due to the severe siltation of sediment, and more than 20 diversions of the Yellow River have been recorded in history, each of which has brought devastating disasters to the people of the lower reaches of the Yellow River.
Therefore, it is urgent to control the Yellow River, and even in modern times, it is necessary to invest a lot of manpower and material resources in the sediment control of the Yellow River.
In September 2019, the ecological protection and high-quality development of the Yellow River Basin was designated as a national strategy, which made a fine division of the governance of the Yellow River and formulated different strategies for the development and governance of the upper, middle and lower reaches.
In the upper reaches, areas such as the Sanjiangyuan, Qilian Mountains, and the upper reaches of the Yellow River in Gannan will be the focus of the region, and we will promote the implementation of a series of major ecological protection and restoration projects to improve water conservation capacity.
In the midstream, we will pay special attention to soil and water conservation and pollution control;Downstream, we will protect river ecosystems and promote biodiversity to ensure the health of river ecosystems.
Important projects in the control of the Yellow River: South-to-North Water Diversion and Water and Sand Transfer. In the lower reaches of the Yellow River, there is less water and more sediment, and the relationship between water and sediment is not coordinated, which is the main problem of the Yellow River governance.
In order to solve this problem, since 2000, we have begun to carry out multi-dimensional and large-scale joint management in the middle and lower reaches of the Yellow River, including the use of reservoirs such as Xiaolangdi and Sanmenxia, and the drainage and sediment discharge experiments that have lasted for many years are also underway.
For a long time, the problems in the Yellow River basin have not been effectively solved, and the problems are still serious. In recent years, with the economic development of North China and Northwest China and the large-scale transfer of industries in the east, the water demand along the Yellow River has been rising, resulting in more prominent water and sediment problems in the Yellow River Basin.
The Yellow River basin alone could no longer solve the problem completely, so the South-to-North Water Diversion Project was added to the desertification control project. The South-to-North Water Diversion Project is divided into three routes: eastern, central and western, of which the solution to the sediment problem in the Yellow River Basin mainly depends on the western route.
Through the south-to-north water diversion, the flow of the Yellow River will be increased, so as to adjust the proportion of water and sediment in the Yellow River basin.
Despite the implementation of large-scale flood discharge projects such as the South-to-North Water Diversion Project and the Xiaolangdi Reservoir, the sediment problem in the lower reaches of the Yellow River has not been fundamentally solved. This is due to the low-lying terrain of the lower reaches of the Yellow River, which makes it impossible to effectively discharge sediment even if the amount of water increases.
In addition, the amount of sediment and silt in the lower reaches of the Yellow River is large, and it is difficult to completely solve it for a while. Although the amount of sediment transported in the entire Yellow River basin has been reduced, the actual effect is not obvious.
The main problem is that the amount of sediment reduced is negligible for the total amount. The decrease is mainly due to the increase in vegetation coverage in the middle and upper reaches of the Yellow River, and the reduction of sediment in the Yellow River basin due to large-scale afforestation and ecological restoration.
In recent years, a lot of manpower and material resources have been invested in the ecological management of the Loess Plateau, and remarkable results have been achieved. Some experts have proposed large-scale sand mining to reduce sediment accumulation in the Yellow River Basin, but this proposal has met with widespread opposition, mainly because sand mining has a negative impact on the Yellow River basin's ecological environment.
Sediment in the Yellow River Basin is an important building material, which can be mixed with traditional construction sand to enrich the aggregate gradation of concrete, improve the strength of concrete, and save the amount of cement.
The fine sediment and lime, cement and other miscellaneous materials in the Yellow River Basin have a wide range of uses, such as bricklaying, whitewashed walls, etc., and the economic benefits are significant. But in the last century, large-scale sand mining flourished in the Yellow River basin and was subsequently banned and penalties for illegal sand mining increased.
So why is sand mining having such a serious impact on the ecological environment of the Yellow River Basin?First of all, the sand mining ship will produce a large amount of waste in the process of work, and a large amount of wastewater will be discharged into the Yellow River, causing environmental pollution.
In addition, the sand mining industry used to be very chaotic, with illegal sand mining vessels rampant and undisciplined sand mining, resulting in serious damage throughout the river.
Disorderly sand mining has had a serious impact on the ecological and economic development of the Yellow River Basin. It will destroy the morphology of the riverbed, lead to the subsidence and collapse of the beach on both banks, and pose a safety hazard to the transportation facilities and bridge projects on both sides.
In addition, sand mining can also damage the ecological environment at the bottom of the river, leading to a decline in biodiversity. Large-scale disorderly sand mining will also lead to traceable erosion, which will reduce the amount of sediment in the estuary of the Yellow River, and cause the coastline at the estuary of the Yellow River to retreat.
At the same time, irrational sand mining will lead to a large loss of sediment in the entire Yellow River Basin, reduce the scale of the alluvial plain in North China, and further exacerbate environmental damage.
Therefore, it is not feasible to strictly prohibit illegal sand mining, or to rely solely on large-scale sand mining to deal with sediment accumulation. Although the control effect of water and sediment diversion is not obvious and the progress is slow, it is relatively more in line with ecological laws and causes less damage, which is more conducive to the long-term development of the Yellow River Basin.
In the management of the Yellow River Basin, we should not only consider economic factors, but also take into account the ecological environment to ensure the simultaneous development of ecology and economy.
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