In the school of Luxi Academy, Mr. Chen He is teaching the students.

Chen He put down his book and walked slowly with his hands behind his back: "Today we will discuss current affairs. In recent years, the Yellow River has flooded many times and the people have suffered so much. His Majesty the Emperor wants to personally inspect the river and observe the actual situation so that he can formulate a strategy for river control based on this."

"As for this strategy of river management, the officials in the court have been arguing endlessly. Some say that we should follow the methods of our predecessors and clear the silt at the bottom of the river to clear the silt at the bottom of the river, and there are also those who advocated by Pan Shiliang, the Shaoqing of Dali Temple, to build high dams and narrow the river channels. What do you think about these two remarks? This current political discussion is also a must-examination subject in the provincial examination. You don't have to be restrained and speak freely."

A student in the front row immediately stood up: "In history, the Yellow River has been used to build dikes and clear silts. Why did Shaoqing of Dali Temple narrow the river channel? Once the river channel is narrower, the water level will increase. Once the flood season arrives, will the Yellow River collapse more easily? What else is there to say?"

"Have you never heard of water striking sand?" Another person disagreed. "This is the theory proposed by Pan Shaoqing. Although narrowing the river channel, the water level will increase, the water flow will also accelerate. In this way, it can wash away the silt and sand at the bottom of the river and clear the river channel. Isn't it more convenient and quicker than cleaning the silt?"

"Where does it come from the control of the Yellow River once and for all! Of course, it is necessary to clean up regularly and take care of it frequently. Once the river narrows, the flood will come first before the mud and sand are washed away. Then millions of creatures in the middle and lower reaches of the Yellow River will be devastated. What should I do? The ancient book says that Dayu used a dredging strategy to control the flood. He did not follow the laws of his ancestors, but did not lead to any water to attack the sand. Isn't that ridiculous?"

The person was so angry that his face turned red, pointing at the other party and cursing: "Peasy! Times have changed, how can we copy the methods of our predecessors? Building embankments and dams can be carried out at the same time as narrowing the river channel. When the silt and sand at the bottom of the river are washed away, the water level will naturally drop. You said you want to clear it, but the court cleared the Yellow River every year, and has it been improved?"

"Hmph, following the existing practices, the situation will not be worse, not to mention that the last time the Yellow River flooded was eight years ago. As for the flood of water and sand, I have never heard of it before. If it is really implemented, the Yellow River may soon collapse in the spring flood this year!"

"You - unreasonable! I can't explain the truth to you!"

"Okay, OK, it's up to the matter in class discussion. It's normal to argue for a while when different opinions are different. Don't go to heart." Chen He smiled and came out to smooth things over. He turned to see Gu Yunji beside him smiling without saying anything, as if he was confident. He moved his heart and asked, "Do you have any good strategies to manage the river?"

Gu Yunji stood up and said calmly: "Students have three strategies, which can be divided into near, medium and far in terms of time and years."

The hall was in an uproar: "The emperors in the court have only two strategies to fight. As soon as he comes, he says there are three strategies. Could it be that he is talking big..."

Chen He was interested: "Oh? Then tell me."

Gu Yunji said: "The near-term strategy is to clear the silt at the bottom of the river and open up new river channels to divert the Yellow River water. But as I said just now, the silt will be cleared this year, and the silt will be deposited next year, and there will be no end in the cycle. Therefore, this strategy can at most ensure the peace and stability of the Yellow River for five years."

"The central strategy is to narrow the river channel and deepen the riverbed, so that the Yellow River water flow can accelerate, so that the silt at the bottom of the river can be washed away. However, this strategy is also insufficient. Once the flood season occurs, if the silt erosion effect at the bottom of the river does not meet the expectations, it will increase the risk of collapse. What's more, the silt and sand in the Yellow River come from the upper reaches and the downstream is cleaned up, and the problem of silt and sand is not solved, and the flooding of the Yellow River may still exist. This strategy can be maintained for 30 years."

"Yuan Ce is to plant trees and afforestation in Guanzhong area in the middle and upper reaches of the Yellow River. In Guanshan, there are sparse trees, thick and pine soil, and once the wind blows, yellow sand will be everywhere. Every summer, rainwater will be abundant, and the rainwater will wash the ground, and the loess rolls down and eventually flow into the Yellow River. This is the root cause of the silt problem of the Yellow River. If you want to cure the Yellow River, you have to plant trees all over the middle and upper reaches of the Yellow River, grasp the soil layer, so that the rainwater cannot be washed away."

Speaking of this, Gu Yunji paused and said slowly: "This matter cannot be done overnight. It requires the continuous efforts of several generations to see the effect. This strategy can be guaranteed for a hundred years." Suddenly, he increased his pronunciation and his tone became excited, "But if the three strategies are carried out in parallel, the Yellow River can be clear and safe for thousands of years!"

His words opened up the past and present, and proposed a bold and comprehensive theory, which shocked everyone to the point of trembling. Chen He was impressed for a moment and did not speak for a long time.

At this time, a student looked at him disdainfully and said, "You are so sensible. You must have been to Guanzhong area and personally explored the Yellow River?"

"I have never been there, and I have seen the description of Guanzhong in the book." Gu Yunji nodded slightly. The geography class on the Loess Plateau in his previous life included pictures, texts, and even documentaries, which were so detailed that people felt like they saw it in person. It was not comparable to books of this era, but he could only say that.

The man sneered: "Then are you talking about war on paper?" As he said that, he stood up, "I am a Guanzhong person. As far as I have seen with my own eyes, Guanzhong has thousands of miles of fertile fields and lush vegetation. It is not as good as what you said about sparse trees. You are just talking nonsense, and you are talking about nearby strategies, middle strategies and far strategies. It is extremely ridiculous."

Gu Yunji was slow: "The Guanzhong Plain is indeed called the South of the Passjiang River, but further north, it is a plateau area. The mountains are rugged and vertical, the soil is loose, and there are few trees. There are more places like this in the middle and upper reaches of the Yellow River. It is normal that you have lived in the Guanzhong Plain for a long time, and it is not seen before."

"Hmph, it seems like you've seen it?"

"I've seen it." At this moment, a lazy voice came from the corner.

Su Qi yawned and seemed to wake up. He stretched his waist and said carelessly: "I have seen it. I once went to the war with my father, and I have been to the Guanzhong Plain and the plateau in the northern area. Indeed, as he said, large tracts of loess, without dense forests, at most a few bushes of low shrubs. The local people live in caves. When it comes to a strong wind, the yellow sand in the sky makes people unable to open their eyes, and the clothes are filled with sand."

Duke Dingguo was a military general and guarded the border for many years. It was not surprising that as his son, he went to war with the army. Su Qi's words were very credible. As soon as this was said, the students from Guanzhong immediately had nothing to say and sat down reluctantly.

After hearing this, Mr. Chen He looked Gu Yunji and felt more and more extraordinary. His eyes were bright: "When you go back, write your strategy for river management into an article. Remember to be clear and leave it to me next time you go to class."

Gu Yunji nodded and said that.

After school at noon, Gu Yunji returned to the dormitory after lunch. When he saw Su Qi lying on the table fighting crickets, he walked over and said, "Thank you, the prince, for speaking for me in class today."

Su Qi didn't raise his head: "I'm just telling the truth, I don't mean to speak for you." Seeing the cricket in the bamboo tube turn his belly and fall to the ground, he tsk and turned to look at him, "I have seen the land situation in Guanzhong with my own eyes. I think the strategy of river control makes sense. I just said it casually in class, you don't need to thank me."
Chapter completed!