Why can’t floods in the Yangtze River basin be discharged to the sea in time?

Because the Qingjiang River, Hanjiang River, Dongting Xiangjiang River, Poyang Lake water system and other watersheds downstream of the Three Gorges merge into the Yangtze River and cannot be controlled. Anhui and Jiangxi are mountainous and have high terrain and narrow river surfaces. Recently, all these water systems have rained and merged into the Yangtze River at the same time. Yangtze. In particular, huge amounts of floodwater from across Jiangxi Province poured into the Yangtze River through Hukou, raising the river level, causing the river flow in the Jianghan Plain to slow down, with the inflow greater than the outflow.

The Three Gorges can only regulate the flow in the upper reaches of Yichang. It is powerless to control the Qingjiang River in Western Hubei, Dongting Xiangjiang River, Poyang Lake and other water systems where rainfall has been common recently. The flood situation in Wuhan is mainly caused by downstream floods occupying and raising the river surface, which cannot be discharged. It's clearing up in Jiangxi, but Wuhan is fine.

To solve the problem once and for all, the Poyang Lake water can be introduced into the Shaoguan Pearl River water system through the Ganjiang River, and a large reservoir should be built near the watershed of the Taojiang and Zhenjiang rivers. The water from the Ganjiang River enters the reservoir and opens the Drainage Gate to flow into the Pearl River. During flood conditions, water from the Pearl River is pumped into the reservoir and opens the Taojiang Gate to flow into the Yangtze River through the Ganjiang River. The second option is to build a floodway from Hukou to Nanjing. It can be a park, farmland, lake, or highway in normal times. No residential buildings are allowed. During the flood season, when the upstream warning water level is high, the floodway will begin to flood. Natural flood discharge will be used. Pump, the disadvantage is that it is difficult to build.

This is a worrying question.

As our mother river, the Yangtze River is also the largest and longest river in our country. It has not only given birth to an extremely brilliant civilization in history; it has also provided extremely rich water resources for the Chinese civilization for thousands of years. , is an important source of the South-to-North Water Diversion Project; its thousands of kilometers of rivers are truly golden waterways, connecting my country's most prosperous economic belts.

However, this mother river that has given birth to Chinese civilization for thousands of years has constantly brought us huge disasters, especially the 1998 flood, which has become the most unforgettable memory for all Chinese people.

At present, the increasingly severe floods in the Yangtze River have once again made hundreds of millions of compatriots frightened.

We all know that the direct reason why the Yangtze River floods frequently is that the Yangtze River floods cannot be discharged into the East China Sea in time. The continuous gathering of river water is an important reason for the rising water level of the Yangtze River and seriously threatens people on both sides.

So, why can’t the Yangtze River floods be discharged to the East China Sea in time? Jingye Shi believes that there are the following reasons:

1. The water level difference in the lower reaches of the Yangtze River is too small.

The water level difference in the lower reaches of the Yangtze River is too small, which is the direct cause of repeated flood dangers in the lower reaches of the Yangtze River.

Although the drop in the Yangtze River, which is more than 6,300 kilometers long, is as high as 6,600 meters, with an average drop of 84.4 meters per 100 kilometers, the drop in the upper reaches of more than 3,300 kilometers above Yibin is as high as 6,200 meters, which means that the drop in the Yangtze River is as high as 6,600 meters. The flow of the Yangtze River downstream is extremely gentle.

In fact, the dividing line between the middle and lower reaches of the Yangtze River, namely Hukou County, Jiujiang City, Jiangxi Province, is only 68 meters above sea level, which means that the total height difference in the 938-kilometer-long lower reaches of the Yangtze River is only a few dozen meters!

Such a gentle flow of water can easily lead to flood siltation and sluggish water flow.

2. Too few entrances to the sea

Another important factor in the poor drainage in the lower reaches of the Yangtze River is that there are too few entrances to the sea.

We can see from the Yangtze River Basin map that the width of the basin near the mouth of the Yangtze River is very narrow, which can easily lead to violent siltation of the river water.

In the Yangtze River, which is more than 6,300 kilometers long, there are many tributaries such as the Minjiang River, Jialing River, Hanjiang River, Xiangjiang River, and Ganjiang River. The superimposed effect of the water volume is extremely terrifying.

In fact, rivers such as the Yellow River also have the same problem. The Huaihe River does not even have an entrance to the sea. When all the river water flows into the main stream, the result of the rising water level is self-evident.

In contrast, poor drainage is less likely to occur when many rivers such as the Pearl River enter the sea.

3. The precipitation is too concentrated

When the third brother continued to seek death, many people proposed to cut off the Brahmaputra River to achieve the purpose of defeating the enemy without fighting.

But the problem is that the water volume of the Ganges River, especially during the flood season, mainly comes from precipitation recharge, and the glacier melt water from the upper reaches is negligible to the total runoff.

The same is true for the Yangtze River. The reason why floods occur frequently in the middle and lower reaches of the Yangtze River is due to climate effects.

Due to the seasonal movement of frontal cyclones in eastern my country, widespread precipitation occurs in the Yangtze River Basin from mid-June to mid-July every year, which is the plum rain season. With the slow movement of the frontal cyclone, the tributaries of the middle and lower reaches of the Yangtze River will gradually usher in the flood season, and the Yangtze River will also form concentrated flood disasters in July and August every year.

4. Man-made damage is too serious

In addition to a series of natural factors, the most fundamental reason for the intensification of floods in the middle and lower reaches of the Yangtze River is man-made causes.

The large-scale development of the western region, while bringing economic development to the vast western region, has also caused varying degrees of harm to the ecological environment of the western region. The western region is the source of most of the rivers in our country, which first leads to the intensification of soil erosion.

The direct result of soil erosion in the Yangtze River Basin is a substantial increase in the sediment content of the Yangtze River. When the downstream flow is extremely gentle, the massive accumulation of sediment will inevitably lead to the continuous rise of the river bed and the sudden reduction of the capacity of the river-connecting lakes.

In addition, with the development of the economy, the development intensity of the Yangtze River Basin is becoming more and more intense, and phenomena such as lake reclamation and land reclamation are becoming more and more common. This has resulted in fewer and fewer flood discharge lakes in the Yangtze River Basin. When the flood peak comes, the water level will inevitably continue to rise.

The construction of water conservancy facilities such as the Three Gorges plays a huge role in regulating and storing floods, and the social benefits it creates are also very considerable. Moreover, by blocking the sediment in the Yangtze River, the speed of sedimentation in the lower reaches is also large. for slowing down.

But just like the dilemma of the Brahmaputra River, no matter how powerful the Three Gorges is, its location is still in the middle reaches. Even if it can block the flood peak above the middle reaches, for the downstream areas below the Three Gorges, especially due to continuous precipitation The Three Gorges is doomed to be helpless in the face of floods. After all, water cannot flow backwards.

Although it is an objective fact that the lower reaches of the Yangtze River are densely populated and the relationship between man and land is extremely tense, if we still do not pay attention to the protection of the ecological environment of the Yangtze River, then the floods in the Yangtze River will only become more and more terrible, and we will endure Disasters will also become more and more terrible.

There are many omissions, please correct me.

When there is a flood in the Yangtze River Basin, why can’t it be discharged to the sea in time?

Recently, the main stream of the Yangtze River has surged, causing great flood control pressure on areas along the Yangtze River. Since entering the flood season, the water level and flow of the main stream of the Yangtze River have increased rapidly. On July 3, the high tide water level in the Zhenjiang area reached 7.10 meters, exceeding the warning water level (7.0 meters) for the first time, and the flow rate was 53,000m/s. On July 4, the high tide level rose to 7.34 meters, and the flow rate of Datong reached 58,300 m/s.

To put it simply, the water on the Yangtze River is very anxious and rushes to the sea. If anyone blocks the way, it will flood directly and rush to the sea.

Some friends would like to ask, why can’t the floods of the Yangtze River rush to the sea quickly, posing the threat of huge personal and property losses to people?

I think the main reasons are as follows; 1. The state of the Yangtze River basin is convenient for floods to gather.

The Yangtze River flows from west to east, absorbing water from many tributaries such as the Minjiang River, Chishui River, Tuojiang River, Jialing River, Wujiang River, Hanjiang River, Yalong River, Xiangjiang River, Yuanjiang River, Ganjiang River and Qingjiang River. The north-south tributaries converge into the Yangtze River at the same time. This centralized water system is the most likely to cause floods. 2. Rainfall is concentrated in the Yangtze River Basin, and the Yangtze River’s flood discharge capacity is limited.

The upper reaches of the Yangtze River are affected by both the southwest monsoon and the southeast monsoon, and the rainfall itself is relatively high. The key is that half of the annual rainfall in the Yangtze River is concentrated in July and August. Such a concentrated amount of water has put the main stream of the Yangtze River under tremendous pressure. The dividing point of the upper and middle reaches of the Yangtze River is in Yichang, with an altitude of only 60 to 100 meters. The dividing point of the middle and lower reaches of the Yangtze River is Wuhu, with an altitude of only a dozen meters. On the main stream for thousands of miles, the water level difference is less than 100 meters, and the natural flood discharge capacity is very limited. 3. The Yangtze River Basin is heavily developed and has dense population and industries.

Agricultural development in the Yangtze River Basin began in the Song Dynasty. The original 800-mile Dongting Lake is now almost the Dongting River. The water area of ​​Wuhan, the original city of thousands of lakes, has also been greatly reduced. Poyang Lake has a similar situation. These lakes have a good flood storage function, but they have been filled into cultivated land. Moreover, the plains of the middle and lower reaches of the Yangtze River have the largest urban agglomerations and densely populated areas. It is precisely because of the huge wealth along the Yangtze River that people pay special attention to Yangtze River floods. 4. A large number of maintenance projects such as land reclamation and sedimentation have left floods with nowhere to go.

Frequent human activities have not only caused the loss of a large number of lakes and rivers along the Yangtze River, but also more wetlands have been developed and hardened. The water area of ​​the Yangtze River has been reduced too quickly. In addition, a large amount of sediment is carried upstream, which can easily accumulate and make the river shallower and narrower. Due to the dual effects of natural and man-made disasters, the floods of the Yangtze River have no way to go and can only steal their way away from the heads of humans and cities. 5. The water conservancy construction of the Yangtze River tributaries lags behind and the flood storage capacity is insufficient.

The most direct way to solve the Yangtze River flooding problem is to build water conservancy facilities. If more reservoirs are built on the major tributaries of the Yangtze River to store floods, the flow of the main stream of the Yangtze River may be greatly alleviated, and the safety of the Yangtze River will also be greatly improved. At the same time, soil and water conservation work in the middle and upper reaches of the Yangtze River must also be strengthened. After all, sedimentation is also an important cause of floods.

The Yangtze River is our mother river and our golden waterway. At the same time, the Yangtze River will lose its temper and flood cities and rural areas.

To be kind to the Yangtze River is to be kind to yourself.

The recent floods in the Yangtze River have been affecting the hearts of the people across the country. Due to continuous rainfall in the Yangtze River Basin, especially in the middle and lower reaches, the No. 1 flood of 2020 in the Yangtze River has formed on July 2, in Hubei and Jiangxi. The water levels in the four provinces of Jiangsu, Jiangsu, and Anhui have greatly exceeded the warning level.

(Floods have poured back into Wuhan City)

(Not only Wuhan City, but also Poyang Lake has seen water backflow from the Yangtze River. The water level at Hukou Station is 21.81 meters, exceeding the warning level. The boundary water level is 2.31 meters)

(Dongting Lake has also experienced backflow. On July 11, the Jiangxi Provincial Flood Control and Drought Relief Headquarters raised the flood control level II emergency response to level I. This is also the first time that Jiangxi has launched it since 2010. This response)

The reason why this flood is so violent is because the Yangtze River Basin has been hit by continuous heavy rainfall, which has caused the water level of the Yangtze River to continue to surge.

Let me first introduce to you what is a river basin?

A river basin refers to the catchment area of ​​a river. For example, the Yangtze River basin covers an area of ​​1.8 million square kilometers. All precipitation in this area first flows into the various tributaries of the Yangtze River, and then flows through each tributary into the main channel of the Yangtze River. .

(Map of the Yangtze River Basin. Except for evaporation and capture by plants and animals, all precipitation within this range will be collected into the main trunk road of the Yangtze River, and then discharged from the Yangtze River into the sea)

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Under normal circumstances, the main Yangtze River can smoothly metabolize all precipitation in the basin. However, when heavy rainfall occurs once in ten years, once in fifty years, or once in a hundred years, the width and depth of the main Yangtze River cannot accommodate the excessive rainfall.

(Since July, precipitation has been mainly concentrated in the Yangtze River Basin)

To put it bluntly, the main trunk road of the Yangtze River is just a very thick sewer pipe. You usually pour a basin of water, this drain pipe can drain the water easily.

However, even if this sewer pipe is very thick and has strong drainage capacity, its drainage capacity is ultimately limited. If you pour five basins of water at once, it will exceed its drainage capacity and the water will It will spread out.

Therefore, when there is heavy rainfall, a large amount of precipitation pours into the main channel of the Yangtze River, exceeding the carrying capacity of the Yangtze River, and the river water will overflow the river channel. This is a flood.

(The floods of the Yangtze River overflowed the dams on both sides)

In fact, floods are very common in nature and are a natural phenomenon, but for humans, this is a natural phenomenon. disaster. Because human civilization and cities are basically built along rivers, cities will be submerged when floods occur, threatening human life and property safety.

Floods in the Yangtze River have been continuously managed since the founding of the People's Republic of China. Especially after the completion of the Three Gorges Dam, the probability of floods in the entire Yangtze River basin has been greatly reduced, because the Three Gorges Project can maximize the resolution of floods from the middle and upper reaches of the Yangtze River. Hongfeng.

However, this heavy rainfall was concentrated in the middle and lower reaches of the Yangtze River and was not within the jurisdiction of the Three Gorges Project, thus creating a water supply problem.

Generally speaking, floods are caused by too much and too sudden rainfall. The width and depth of the Yangtze River are fixed and cannot withstand excessive rainfall, causing the river to overflow the levees and cause floods.

First of all, 2020 is really a troubled year. Since July, floods have occurred frequently in various places, especially in the Yangtze River Basin, Sichuan, Chongqing, Hubei, and Jiangxi. There have been continuous heavy rains. This It has been raining for several days. The warning water levels of some rivers or tributaries of the Yangtze River have even exceeded the water levels of the 1998 catastrophic flood. Especially in Hubei and Jiangxi, the first-level flood response alarm was sounded!

Why can’t the water in the Yangtze River Basin be discharged to the sea in time? It’s because the rain is too heavy, lasts for a long time, and there is too much water. The floods continue to flow into the Yangtze River from the various tributaries upstream, and the water It is getting bigger and bigger. The water flowing to the sea cannot outstrip the water flowing into the Yangtze River. Moreover, the terrain of Hubei and Jiangxi is flat. The water rushing from the upper reaches of Sichuan and Chongqing will slow down in Hubei. There is more water in the upper reaches. The Three Gorges Dam We have to open the gate to release water, and we have to ensure the safety of the dam and all people in the upper, middle and lower reaches. We need to give early warning and take safety measures. If we are prepared, we can win the battle!

It also takes a certain amount of time for the river water to flow into the sea. Since the summer of 2020, heavy rainfall has generally occurred in southern my country. It is natural for such a large amount of rainfall to flow into the Yangtze River in a short period of time. question. Moreover, the terrain in the south is complex, with high and low terrain. When encountering long-term heavy rainfall, rainwater can easily gather in low-lying areas, causing rising water.

At the same time, the water flow of the Yangtze River is limited. When the water reaches a certain level, it is likely to overflow the dams and flood farmland and villages. On July 11, a 120-meter-long dike burst in Poyang County, Jiangxi Province, flooding hundreds of thousands of acres of farmland and affecting millions of people.

The two most important lakes in the Yangtze River Basin are Dongting Lake and Poyang Lake, located in Hunan and Jiangxi respectively. These two lakes can also handle a certain amount of water to a certain extent and regulate the middle and lower reaches of the Yangtze River. water level function. However, this year's rainfall has been extremely rapid, and the water level of Poyang Lake has exceeded the warning level, breaking the historical limit in 1998.

The entire length of the Yangtze River is about 6,280 kilometers. The main stream flows through Qinghai Province, Tibet Autonomous Region, Sichuan Province, Yunnan Province, Chongqing City, Hubei Province, Hunan Province, Jiangxi Province, Anhui Province, Jiangsu Province, Shanghai has 11 provincial-level administrative regions (eight provinces, two cities and one district), covering such a large area. When many areas experience heavy rainfall, it is very difficult to rely on the Yangtze River to funnel floods into the sea within a short period of time. .

Because the rainfall exceeds the maximum flow of the Yangtze River. . .

It’s the same as when you suddenly pour a large bucket of water into the wash basin in your bathroom. The drainage pipe of the wash basin is not thick enough, so the wash basin will be filled with a basin of water. Then it slowly flowed down.

1. It is still a long way from the Yangtze River outlet to the East China Sea,

2. The downstream lacks stepped terrain for rapid drainage,

3. The terrain limits the ability to dig canals Entering the sea from the east.

For example, in the early years of the Huangpu River in Shanghai, two straight artificial canals, the Dazhi River and the Chuanyang River, were excavated on the Pudong side of the waist toward the east sea. During the flood season, the sluices can be opened directly to discharge into the East China Sea without passing through the Yangtze River. The Yangtze River is still the Yangtze River. Why can't the water be discharged into the sea? There are five reasons

"The great river goes eastward, and the waves are swept away, and the heroes of the ages". The Yangtze and Yellow Rivers have nurtured the land of China, benefited the Chinese nation for thousands of years, and created the glorious appearance of the Chinese nation today.

The Yangtze River originates from the Tanggula Mountains, known as the "Roof of the World", with a total length of more than 6,300 kilometers, ranking third in the world, and flows into the East China Sea from Chongming Island to the east. The Yangtze River has been formed in ancient times. After about 200 million years of changes, it has formed today's water system structure. It flows through many provinces, cities and autonomous regions in my country, with a drainage area of ​​1.8 million square kilometers. It is one of the most important water components in my country. , known as the "treasure house of water energy".

The Yangtze River has nurtured the Chinese nation, but while promoting the development of the Chinese nation, it has also brought many disasters to the Chinese people, and even swept countless Chinese people into the roaring river. July is now the season of floods from the Yangtze River. Especially since the floods this year, multiple rounds of heavy rainfall have occurred in many places in southern my country, causing the destruction and death of houses in many places in the south, and causing serious flood disasters. According to the forecast of the Yangtze River Water Conservancy Commission, in the next two days, the flood monitoring points at the main control stations of the middle and lower reaches of the Yangtze River will enter the forefront of historical flood peak levels.

The Yangtze River flows into the sea from the east, but the middle and lower reaches of the Yangtze River suffer from floods every year. Even as time goes by, the extent of flooding in the Yangtze River becomes more serious. Since it flows into the sea from the east, there will be floods in the Yangtze River Basin. Why can't it be discharged to the sea in time? 1. Summer heavy rains are concentrated and frequent

The Yangtze River Basin has a subtropical monsoon climate. Affected by the monsoon, there is abundant moisture carried from the eastern ocean, and the amount of precipitation

decreases from southeast to northwest. The Yangtze River Basin, which belongs to the subtropical monsoon climate zone, has extremely obvious monsoon characteristics. It is hot and rainy in summer. Coupled with the influence of continental air masses, southern my country is prone to heavy rains in summer.

According to relevant statistics, the average annual precipitation in the Yangtze River Basin can be as high as 1,100 millimeters. Summer precipitation alone accounts for 85% of the annual precipitation in the war zone. Different regions in the Yangtze River Basin have different precipitation amounts. Heavy rainfall coupled with the numerous and complex branches of the river, which merged into the Yangtze River from different places after the heavy rain, caused the water level of the Yangtze River to rise rapidly. However, the Yangtze River is the third longest river in the world, and the river flows over a long distance, so it takes a certain amount of time to flow into the sea. 2. The vegetation in the middle and upper reaches is seriously damaged, and the river water contains high sediment content

The upper reaches of the Yangtze River mainly flows through plateaus and mountains, and the altitude of China’s first ladder through which it flows is about 3,500-5,000 meters.

< p> The terrain is steep and straight, and the water flow is fast. The source of the Yangtze River is located on the Qinghai-Tibet Plateau. The altitude is high and the temperature is low. The ecological environment is extremely fragile. The high mountainous areas it flows through have weak soil layers. Heavy rains in summer can easily lead to landslides or heavy rains can directly wash away the soil from the slopes into the river, causing the Yangtze River to be sandy. High quantity. The ecological environment in the upstream area, which is already fragile, steep and thin, has become even worse due to damage in recent years, and more sediment has been carried into the river by rainwater. 3. The terrain in the middle and lower reaches is gentle and sedimentary.

The lower reaches of the Yangtze River are mainly hills or plains, with low and gentle terrain. Because the terrain of the Yangtze River is high in the east and low in the west, the drop is very large. The terrain in the upper reaches can be described as "hanging rocks and broken green walls, and the terrain is dangerous and green." The water speed can be said to be "a thousand miles of rivers can be returned in one day"; however, the terrain in the lower reaches is "mountains follow the plains." It can be seen that the water speed difference between the upper and lower reaches of the Yangtze River is very large.

The water velocity difference caused by the disparity in terrain causes most of the sediment carried in the upper reaches of the Yangtze River to settle downstream, causing the downstream river bed and river bottom to rise, which further causes the river water to overflow the river banks and cause flood disasters. The accumulation of sediment downstream will further slow down the flow of river water, causing a vicious cycle of downstream flood disasters. 4. Reduced regulation and storage capacity of lakes

There are actually many lakes in the middle and lower reaches of the Yangtze River, among which Dongting Lake and Poyang Lake have a huge impact.

As an important water resource, lakes can not only meet the functions of industrial water, agricultural water, domestic water and other functions for nearby residents, but also have a regulatory effect on rivers, and their area is directly proportional to the regulation and storage capacity.

However, with the development of the economy, the major lakes in the Yangtze River Basin have suffered serious damage, especially Poyang Lake in the lower reaches of the Yangtze River. Due to the development of economic projects such as lake reclamation and land reclamation, coupled with Due to the accumulation of sediment, the area of ​​Poyang Lake is shrinking at an alarming rate. Poyang Lake connects five rivers to the Yangtze River and is an important "transfer station" for the five rivers to enter the river. However, due to the continuous shrinkage of its area, its water storage capacity has been greatly weakened, and its regulating effect on the Yangtze River has become weaker and weaker. 5. The entrance to the sea becomes narrow

The Yangtze River enters the East China Sea at Chongming Island. Affected by the topography of the island, the entrance to the sea is originally not large. In addition, a large amount of sediment carried from the upstream accumulates at the entrance to the sea, making the entrance to the sea continuously wide. Zoom out.

In summary, although the Yangtze River has an estuary, with the development of social economy, the ecological environment has been seriously damaged, and the uncoordinated contradiction between economic development and ecological environmental protection has become prominent, resulting in the middle and lower reaches of the Yangtze River. The floods are getting worse. When humans take from nature, they should respect nature and pay more attention to protecting nature during economic development. We cannot just blindly ask for survival materials from nature without giving back. Nature will also teach humans a lesson.

Therefore, everyone has the responsibility to protect the ecological environment. We should work together to build an ecological environment where man and nature can live in harmony.

The Hubei section of the Yangtze River Basin is flat and easy to accumulate water. Floodwaters are not discharged in time through the lower reaches of the Yangtze River to Shanghai. Historically, they have been repaired and leaked every year. Is it possible to dig a seasonal river to the north to drain floods? A water storage lake will be built 20 kilometers east of the middle line of the South-to-North Water Diversion Project, passing through Xinyang, Zhumadian, Zhoukou, Kaifeng, Anyang in Henan, Handan, Xingtai, Shijiazhuang, Baoding and Beijing in Hebei.

More than 50 rivers are connected in series along the way, allowing the diversion water to flow eastward naturally. This canal must be wide and deep, and it must be able to carry out tourist shipping. The flow must be large, and the excess Yangtze River water must be stored in the water-deficient Central Plains and North China,