Live broadcast: Ancient people accompany me to make up lessons

At night, at the same time as yesterday, people who have finished their work for the day return home, and they still have their eyes open when they usually fall asleep, waiting for any changes in the white curtain in the sky.

Finally, at eight o'clock, the familiar anchor and her study began to appear.

["Good evening, everyone."

Xiaoxiao picked up several color pictures of materials printed in the afternoon and waved them at the camera.

"We agreed to watch the animation together, but before showing it, I will first fill in the answers I owed a lucky viewer and talk about floods and droughts."

She remembered this matter. She checked the information on her own in her free time, and also asked her father, who was in the civil engineering and construction industry, to collect information in detail.

As for the lucky viewer Zhu Houcong, when he checked the list in the afternoon, he didn’t know who it was. He was shocked when he called up the system information. He looked at the time and was pressed by the system to do some science. At this time, Jiajing had not become an immortal cultivator. It was a serious system. , the hosts are chosen to be in a world where they can make a difference, which can be regarded as reducing the difficulty for novice hosts.

Xiaoxiao: ...Don't say that. Is it difficult for me to live broadcast to these ancients from parallel time and space for four hours a day? Will there be other tasks that can be superimposed on it in the future? Isn’t it enough for us to earn enough points to pay off the debt? 】

Zhu Houcong, who has always remembered this incident: My mood that was made boring by the chemical experiment suddenly felt relieved, so I said that the anchor would never forget it. It felt so good to hold a special show for me alone at night!

I didn’t quite remember the lucky viewer at first, but when I heard the anchor was going to talk about floods and droughts, the people who were waiting for entertainment before going to bed became less sleepy. Those who had the conditions to light up their lamps and burn ink were ready to remember, and those in the villages without the conditions would do the same. All the men and women in the village came out together to listen together to prevent anyone from not remembering it.

Not to mention the emperor's officials who were not bastards, whether they had rested in the evening or were continuing to work, they all hurriedly moved their desks outside to ensure that they would not be delayed in attending classes.

["Let's talk about the flood first, let's take a look at its causes."

Xiaoxiao picked up a color satellite map and said, "my country's most important Yangtze and Yellow Rivers originate in the Qinghai-Tibet Plateau. The source of the Yellow River is the Bayan Har Mountains, and the source of the Yangtze River is the Tanggula Mountains. The two rivers have many tributaries and a wide drainage area."

Pick up a red pen and draw three arrows on the East China Sea toward the land.

"Let's talk about the Yangtze River first. During the summer flood season, the southeast monsoon prevails in the Yangtze River Basin. The emergence of storm surges at this time will cause seawater intrusion, further hindering the rapid flow of Yangtze River water into the sea. At the same time, summer is also the season of large-scale heavy rains in the Yangtze River Basin..."

Change to the next picture, and the main tributaries of the Yangtze River are covered with a heavy rain pattern with floating water.

"Floods in the upper main stream and midstream tributaries will break out at the same time, resulting in catastrophic floods in the middle and lower reaches. The midstream area is low and flat, the water flow is slow, sedimentation leads to poor drainage, and there is a lack of adequate flood control and flood detention sites."

Pick up a red pen and circle a certain channel in the middle of the river.

"The Jingjiang River is winding and winding. During floods, the river water does not drain smoothly and the water level rises, which aggravates the outbreak of floods in the Yangtze River. The root cause of the Yangtze River floods is that the middle and lower reaches of the plains are low and flat and have poor drainage."]

The residents around the Jingjiang River nodded. Every time summer comes, the water in their area is indeed rising.

In fact, flood disasters were mainly caused by certain dynasties in the Yellow River: let’s talk about the Yangtze River first, and then we will definitely talk about the Yellow River, right!

People living in the Gobi Desert, which is full of loess, look at satellite images and are envious of the green color that fills the screen; many professional water control professionals look at satellite images and their own maps and feel that their own water maps can also be modified, as shown above That way of drawing is quite good, more intuitive and clear.

[Change to another picture of the Yangtze River. Several lakes are particularly conspicuous.

"In the past, there were many lakes in the middle and lower reaches of the Yangtze River, and these lakes played a role in regulating the water volume. They shared the Yangtze River's floods during the flood season and fed back the Yangtze River's water volume during the dry season.

With the increase in population and frequent human activities, lake land has been continuously occupied, resulting in the shrinkage of lakes and weakening the ability to regulate flood peaks. Deforestation has destroyed a large amount of vegetation and aggravated soil erosion. Forests conserve water sources, regulate runoff, and cut peaks. The effect of drying up is reduced, and a large amount of sediment flows into the river, silting up the river bed, and further reducing the river's flood discharge capacity. ”]

Su Shi understood very well. After dealing with local hydrology, he would also order people to plant trees to stabilize the land.

In later generations, he became famous as a scholar, but he also did a good job as a local official and was an expert in flood control. He built Limin Lake in Shaanxi, built embankments to fight floods in Xuzhou, and dredged the West Lake in Hangzhou. He also designed the earliest tap water project in Guangzhou, built two bridges and one embankment in Huizhou, and dug double springs and Dongpo wells in Danzhou, Hainan.

"It's a disaster for people, but for nature, it's just a normal climate phenomenon." Su Shi shook his head and sighed: "But if you don't live by water, people can't even survive."

At this time, the benefits of high-yield crops are reflected. Not only can they feed a large population, they can also be planted in areas where disasters are bound to occur.

He remembered the satellite image in the map on the anchor's mobile phone. The anchor Nancheng was also near the water. After shrinking, many of the gray houses were close to the blue water, so there must be ways to control the water in future generations.

[“For the management of the Yangtze River, we are now advocating returning farmland to forests and lakes; we have also set up the Jingzhou Flood Diversion Project in the Jingzhou River.”

For many people, eating is already the most important thing. Xiaoxiao did not focus on the issue of returning farmland. Instead, he picked up new data and focused on the latter.

“The Jingzhou Flood Diversion Project is the first Yangtze River management project established in New China.

The project is located in Gong'an County, Hubei Province and was built at the turn of the late spring and early summer of 1952. 30 soldiers and civilians participated in the construction of the project, and completed the first phase of the Jingjiang flood diversion project at an astonishing speed of 75 days, including the Hudu River Taipingkou flood gate 15km upstream opposite Shashi on the right bank, the control gate at the east foot of Huangshan Head and the southern line of the flood diversion area Main projects such as levees.

The safe flood discharge capacity of the Jingjiang River has thus been significantly improved, alleviating the incompatibility with the huge and frequent floods in the upper reaches. ”]

Such a large piece of good land is all used for flood diversion?

In theory, even ordinary people can see from the map that such a large flood discharge area is necessary, but it would still be a pity for people to abandon fertile farmland by the water like this.

Others saw some hidden things.

"30 people, built so much in 75 days..." Officials who have done water conservancy work are all amazed.

Take Zheng Guo Canal as an example. At its peak, there were as many as 100,000 people building it, and it took about ten years to build it. Zheng Guo’s design of the canal was not only about recruiting corvees, but also how to manage distribution, how to plan and arrange, and Make sure the results you spend a lot of money on are actually useful.

That so many people were able to build the first phase of the project in 75 days shows the scheduling ability of later generations of the court.

["The Jingjiang Levee Water Conservancy Project was built in 1945 to directly protect the low-lying Hanjiang Plain." There is a flood discharge area on the left of the Jingjiang River and the Jingjiang Levee on the right.

"In addition, we have built a large number of hydropower facilities on the main stream and main tributaries of the Yangtze River. The Three Gorges Project here is a key project to solve the serious flood threat in the middle and lower reaches of the Yangtze River."

Xiao Xiao dug out an aerial video of the Three Gorges. Under the blue sky and white clouds, a huge and wide gray-white embankment lay on the ground, and the gushing water splashed white waves.

"The Three Gorges Project, whose full name is 'Yangtze Three Gorges Water Conservancy Project', is located in Yichang City, Hubei Province. It consists of a hub project, a power transmission and transformation project, and an immigration project.

On December 1992, 12, the Three Gorges Project officially started construction. By November 14, the Three Gorges Project completed the overall completion acceptance.

The hub project is located in Sandouping Town, Yichang City, Hubei Province, in the middle section of Xiling Gorge on the upper reaches of the Yangtze River. It consists of a barrage dam, a post-dam hydropower station and an underground power station, a double-line five-level ship lock and a vertical ship lift.

The Three Gorges Dam is the largest concrete gravity dam in the world. The cross slope of the dam is similar to that of the vocational education system. The total length of the dam axis is 2309 meters. The dam crest elevation is 185 meters. The maximum dam height is 181 meters. The maximum dam crest width is 22 meters. The maximum width at the bottom is 126 meters. "

The aerial footage is already facing the Three Gorges Dam from above, slowly approaching.

"The Three Gorges Dam has a total of 89 holes through which the Yangtze River water flows to the lower reaches of the Yangtze River. There are 45 holes in the spillway dam section, as well as holes connecting the turbine generators of the hydropower station, flood discharge and drift holes, and sand drainage holes.

The Three Gorges Dam's designed maximum flow rate exceeds 10 cubic meters per second, ranking first in the world. It is like a large valve that can regulate floods in the Yangtze River, significantly improving the flood control and disaster reduction capabilities of the Yangtze River Basin, and raising the flood control standard of the downstream Jingjiang River section from a once-in-ten-year occurrence to a once-in-a-century event. During the Yangtze River flood season in 2010 and 2012, It has withstood the test of flood peaks exceeding cubic meters per second. ”]

According to the above system's thoughtful display, one meter is equal to three feet. This dam is 185 meters equal to 555 feet, which is about fifty feet long...

People from Sandouping Town in the past: From here? Won’t all the people in our town be dragged into building dams in the future?

Such a high embankment requires a lot of people's energy, and some people have begun to want to scold the court for building it.

It’s not that they are ignorant, hypocritical, or ignorant of the sufferings of the people, but they are actually fed up with the exploitation of some officials.

The money allocated by the court is one thing, but it is another thing to get it into the hands of embankment workers. Most of the time, they are recruiting corvees. It is thankful to God that they can come back safely after going to the corvee, and then they can return it in a few years. I need to repair it again.

If something goes wrong in a dam as high as the Three Gorges, how many people will be needed to fill the hole?

Even people living by the waterside know that the dams need to be repaired, but they have to shoulder the pain of building the dams themselves.

Some of the people who had been drafted into the dam repair industry looked at the bigger and taller dams and thought about the hard times, and they could only feel grateful that they came back alive.

["The maximum height of the dam is 185 meters, the normal water storage level is 175 meters, the lowest ebb and flow level in the dry season is 155 meters, and the flood control limit water level is 145 meters. Before the flood season, if the water level of the dam exceeds 145 meters, the middle section of the spillway dam will be opened for Flood discharge. Flood discharge is to have enough storage capacity to meet the subsequent rainfall during the flood season.

The flood control method of the Three Gorges Dam is not to store floods for a long time, but to block water for a period of time. The key role in flood control is peak shifting and peak shaving. "

Click on the favorites, find the animation of the Three Gorges Dam water storage and flood release operation that you have collected, and show it to them.

"When upstream floods come, the Three Gorges Dam reduces the outflow, stores floods, and reduces the flood control pressure on the downstream reaches; the water level in the downstream drops. To alleviate floods, the Three Gorges Dam must increase flood discharge to free up storage capacity for the next flood peak. This achieves peak shifting and peak clipping effects.

Floods in the upper reaches of the Yangtze River are the main source of floods in the middle and lower reaches. Therefore, controlling floods in the upper reaches is crucial to flood control in the middle and lower reaches. The Three Gorges Dam is located at the throat where floods from the upper reaches of the Yangtze River enter the plains in the middle and lower reaches, and can effectively control and regulate floods in the upper reaches. Through the storage of the Three Gorges Reservoir, the flood peaks in the upper and middle reaches are staggered to avoid superposition of floods and ensure the safety of flood control in the middle and lower reaches. ”]

Flood discharge at staggered peaks is not a forced stop. If you think about it carefully, you can understand the rationality of this. The question is how on earth did you build this dam, and how can you store and release water at any time?

The eyes of the Mohist disciples who gathered together to discuss calculating the load-bearing capacity of the dam lit up: "During the day, the anchor said that the houses they build are made of cement and reinforced concrete. This dam is also a concrete gravity dam, so the materials used to build the dam, The anchor has already told us!”

The senior brother shook his head: "The materials used to build a house are definitely not the same as those used to build a dam. It is no joke if something goes wrong in such an important project."

"It doesn't matter, senior brother!" The young disciple next to him said with bright eyes: "Then we can adjust it ourselves and we will always make the same good material!"

The Mo family was having an excited discussion here, and the public losers over there were listening to lectures and having a meeting at the same time.

Looking at the drawings he quickly copied in his hand and pointing to the blank area next to the flood discharge area, one person said: "This Three Gorges Dam must have more than just this purpose, and many anchors haven't mentioned it."

"There are also power transmission and transformation projects and immigration projects. The anchor should only be part of the hub project."

The Three Gorges Dam gave them some inspiration, and their skills can be combined with such a large project to improve people's livelihood.

Thinking about the Mo family who had definitely entered Xianyang, the descendants of Gongshu looked at each other and made up their minds to study something before going to Xianyang.

Liu Che, who suffered a serious setback on the Yellow River three years ago: Not only did he not say how the dam was built, he said that the water must be stored and released based on the drainage conditions of downstream rivers and lakes. Timely communication is a big trouble. Moreover, this is the Yangtze River of later generations a thousand years later, not the Yellow River. You can write down the method and see if it can be used in the future.

Until the Northern Song Dynasty, the economic center moved south mainly in the Yellow River Basin. Compared with the Yangtze River, the Yellow River suffered more and more frequent floods. They were also looking forward to future water control plans for the Yellow River.

Some people who have traveled to many places recall the land of the Yangtze River in the south, and they don't quite understand why the Yangtze River has become so fierce in later generations. It is obvious that there were heavy rains in the Yangtze River at this time, and the water would disappear after a while.

Residents around the Yellow River hope to know from the anchor what will happen to the Yellow River thousands of years from now. Will there be so many water conservancy projects like the Yangtze River?