My younger brother Zhuge Liang

Chapter 57: The Zhuge family knows a little bit about everything, including water conservancy
Liu Bei took Mi Zhu, Jian Yong and Tian Yu aside to discuss how to bring back the families of his comrades in Youzhou by sea.

Zhuge Jin finally had a chance to catch his breath. He saw that today's important business had been done, and the Song family's independence had been witnessed by everyone.

As for the rest of the official business, we can discuss it anywhere, there is no need to occupy my uncle’s turf.

So he suggested that Song Xin declare the banquet over and send most of the guests away with formalities. There is no need to elaborate on the red tape involved.

After drinking, Zhang Fei didn't care about etiquette and left first. The others who had no excuse to stay also followed him.

But there were still several groups of people left, rushing to talk to Zhuge Jin about things and ask for various instructions.

Zhuge Jin had no choice but to lead the remaining people to another side hall and continue to use the space to entertain the guests.

He saw that Chen Qun was the most prepared and even came to him with a stack of manuscripts, so he wanted to take care of Chen Qun's affairs first.

Unexpectedly, Chen Qun was very perceptive and took the initiative to suggest: "My affairs are slow, sir, please deal with other people's requests first."

This sentence is both a sign of humility and a way of putting some pressure on the people around you: If you also write a lot, then be more self-conscious!
Zhuge Jin looked up and saw that the other people who stayed behind were not Liu Bei's civil or military officials, but representatives of the local gentry in Guangling.

After all, Liu Bei's subordinates wanted to talk to him about official matters, and they had plenty of time at ordinary times, so there was no need to take advantage of the opportunity of treating them to a meal.

For the local gentry, this was a once-in-a-lifetime opportunity. Zhuge Jin was already a 2,000-stone lieutenant, and he was only 21 years old. How could they have the opportunity to meet him normally?

Zhuge Jin had no choice but to apologize to Chen Qun, and then chatted with Bu Long and Wei Hui, two local elders: "I wonder if there is anything I can help you with?"

The two elders did not dare to be arrogant, and said repeatedly: "It is not a matter of teaching. Since I asked my grandson to pay his respects to me last time, I have not had the opportunity to meet you. Today, I have this opportunity to tell you about the recent situation of the captain. My nephew heard that the captain has established a reputation and protected the country and the people. He is also very excited and will return from Wu County soon.

But they have been away from home for a long time, and the local officials have changed frequently. I am afraid that they will not recognize many acquaintances after returning home. I hope the captain will help introduce them to more new friends for the sake of our friendship..."

Bu Long also had to save face, so he didn't dare to ask Zhuge Jin to help him get an official position. He only asked him to introduce some connections and friends to him.

How could Zhuge Jin not understand the subtext?

This kind of thing is normal. Just like a year ago, the two were classmates and fresh graduates looking for jobs.

A year later, one of them became a captain in the imperial court, while the other was still a melon farmer. Of course, the other would go to the captain.

Fortunately, Bu Zhi was knowledgeable and capable, so his recommendation was not based on nepotism, but on merit.

In fact, when Zhuge Jin heard Liu Bei mention Bu Zhi and Yan Jun last time, he knew that Liu Bei had already made up his mind to recruit them.

There was no way, because Liu Bei had heard the rumor that "Bu Zhi and Yan Jun's talents are comparable to Zhuge Jin".

Zhuge Jin is essentially taking advantage of a favor for free, so why not do it?

He also said openly: "Brother Zishan and his men are talented and capable of being a county magistrate or an official. It's just that they are still young and inexperienced, so they need to slowly gain experience. Don't worry."

The people from the Bu and Wei families were immediately overjoyed and thanked Zhuge Jin profusely, little did they know that Zhuge Jin had actually given nothing.

Bu Long's words were evasive, and he also wanted to offer some conditions to please him and show his gratitude, in order to play the long game and catch a big fish.

But Zhuge Jin was too busy with his work, so he evaded the question and did not give him a chance to speak.

……

It took about an incense stick of time to send away those who came to seek official positions.

Zhuge Jin then said sorry to Chen Qun who had been waiting on the other side, and began to sort out his business.

Chen Qun came to discuss the “work-for-relief” issue that we talked about a while ago.

In the past few days, he prepared a lot of materials, read "Guan Zi" carefully, and reviewed the records of Sang Hongyang in "Biographies of Merchants".

So the topic was introduced smoothly. Chen Qun came with ideas, just like the project PPT report in later generations.

Zhuge Jin only needs to listen first and then make a few comments.

Chen Qun reported: "I checked the land documents of each county and visited various places. I found that there is a huge weakness in Guangling's farming. If it can be supplemented, the grain production will be greatly increased."

"What weakness?"

Chen Qun took out a map and pointed at it, saying, "From the map, Guangling County is extremely large, and the entire territory is plains, but its grain production and population are not as good as Xiapi."

Zhuge Jin asked thoughtfully, "Could it be that Sheyang Lake occupies too much area? In fact, is the flat land in Guangling twice as large as that in Xiapi?"

Chen Qun: "When I calculated, I had already deducted Sheyang Lake. Although the big lake covers a large area, it is good for irrigation. Just like Zhenze (Taihu Lake) is good for Wu County, it is not harmful."

Seeing that the other party did not make any stupid mistakes, Zhuge Jin nodded and encouraged: "That's good, keep talking."

Chen Qun: "Later, I made an in-depth investigation and found that although Guangling had a lot of arable land, the grain production was low, mainly due to insufficient irrigation and salty brine in the land.

The Han Canal gave Guangling the benefit of a canal, but it also often caused the sea tide to flow back through the Yangtze River into the canal and Sheyang Lake. Especially during the high tide season, the lake water was slightly salty and bitter.

Zhuge Jin suddenly realized: It turned out to be a problem with the saline-alkali land.

As a gold medal teacher in his previous life, he had a wealth of knowledge in history and geography. He knew that northern Jiangsu had never been a land of plenty in ancient times.

It now seems that the agricultural constraints in northern Jiangsu at different stages in history were actually caused by different reasons:
Before the Song Dynasty, the Guangling tide caused seawater to flow back into the canal from the Yangtze River, forming saline-alkali land.

After the Song Dynasty, although the tide and backflow in Guangling disappeared, the Yellow River changed its course and flowed into the sea from the Huai River during the Southern Song Dynasty, forming Hongze Lake, and the Huai River suffered serious floods. It was not until the construction of the Northern Jiangsu Irrigation Canal after the founding of the People's Republic of China that the floods were alleviated.

It can be said that saline-alkali land and floods have each been responsible for the poverty of the northern Jiangsu Plain for a thousand years.

Zhuge Jin now lives in an era that belongs to the last thousand years. Therefore, as long as the saline-alkali land is solved, the northern Jiangsu plain can be turned into a land of fish and rice.

Thinking of this, he couldn't help but feel excited.

Of course, there are several types of saline-alkali land in Guangling.

Some saline-alkali lands are too close to the sea and the groundwater is very salty. Such lands are hopeless and it would be better to develop the salt-making industry in the future.

What can be saved is only the saline-alkali land caused by the backflow of sea tides.

Chen Qun has done a good job in his homework these days. He has also visited some places and checked the accounts and land registers of previous years.

According to his estimation, the ratio of these two types of saline-alkali land is about 50:50.

Therefore, if the problem of sea tidal backflow can be solved, half of the saline-alkali land problem in Guangling County can be solved.

The area suitable for farming in Guangling County will be greatly increased as a result, and the yield per unit area of many existing fields will also be improved. In the future, it may even be possible to accommodate several times the agricultural population.

……

Chen Qun calculated the expected return for Zhuge Jin, and it was indeed very tempting. But Chen Qun could only do this.

He had 40,000 men and a winter's time.

But Chen Qun was at a loss as to how to utilize this labor force, how to plan, construct and solve this problem.

He is not a water conservancy expert.

Zhuge Jin was not a water conservancy expert, and he had just finished listening to the report, so his mind couldn't think that quickly.

After pondering for about a cup of tea, Zhuge Jin said casually:
"Have you ever considered building a sluice gate between the Hang Canal and the Yangtze River? The sluice gate can be opened for navigation during normal times, and closed during high tides, so that salt water cannot flow into the canal."

Although Zhuge Jin seldom came to Yangzhou in his previous life, he studied and worked in Qiantang for many years. It is also the starting point of the Grand Canal.

He had visited the Canal Museum several times and knew that the kind of locks that could allow navigation between river sections with different water levels did not appear until the Qing Dynasty.

But if it is just a simple gate to isolate the tide and does not take into account navigation due to water level difference, then this technology already existed during the Sui and Tang Dynasties.

To be precise, after Emperor Yang of Sui rebuilt the Grand Canal, the Han Canal sluice gate was built in Yangzhou during the Zhenguan and Yonghui years of the early Tang Dynasty, also to prevent the backflow of sea tides. This led to Yangzhou in the Tang and Song dynasties being much richer than Guangling in the Han Dynasty.

From the Han Dynasty to the Tang Dynasty, this technological gap is not that big. It is possible to overcome it by using your brain and designing some clever ideas.

But Zhuge Jin hasn’t figured out how to overcome it yet.

Of course Chen Qun was shocked when he heard this.

As a Han Dynasty man, he certainly had never heard of sluice gates that blocked rivers:

"Sir, you mean... build a sluice gate that can cut off the entire canal when it is lowered? But the water level of the Han Canal is high at the northern entrance where it connects to the Huai River, and low at the southern entrance where it connects to the Yangtze River.

After the gates are lowered, the water flowing in from the Huaihe River cannot flow out and is stored in the canal. The water levels of the southern section of the river and Sheyang Lake will rise.

The canal is deep enough to avoid overflowing. However, the shore of Sheyang Lake is flat, and the surrounding low-lying areas may be flooded. In the future, the sluice gates can only be opened for navigation at fixed times every day when the water level of the river is almost high due to the tide. "

Chen Qun thought of several disadvantages in one breath.

Sheyangze is a lake in the middle section of the Hang Canal, similar to the Hongze Lake in later generations.

The reason why there is a drop in height at both ends of the Han Canal but the river channel has not dried up is that it relies on the water from Sheyangze for regulation.

When Zhuge Jin heard Chen Qun raise these new questions, he couldn't help but admire his meticulous homework, as these were all good questions.

Zhuge Jin countered the move and asked, "Are there people farming in the low-lying and muddy land around Sheyang Lake? The water level will rise with the tides, right? There shouldn't be good farmland in such a place."

Chen Qun responded immediately: "No, at most some people occasionally plant water chestnuts and lotus roots, but there is no good farmland, and no one settles on the edge of the swamp."

Zhuge Jin had an idea: "That's fine. The rising water level will flood all the rotten land, which no one cultivates anyway. You might as well take advantage of this time to mobilize the people to dredge and rectify the area around Sheyang Lake.

You can estimate how much the water level will rise if the sluice gate is built, and then take half of that as the dividing line. Dig low and raise the weir to form a polder, and then plant reeds on the new lakeshore to consolidate the mud and prevent collapse.

Moreover, with this construction method, the silt you want to dredge is exposed, which is several times more labor-saving than digging silt from the bottom of the water. If you don't do this before the water level is low before the reservoir is filled, when will you do it?
In this way, we can obtain a lot more fertile polder after the project is completed, and the water storage depth of Sheyang Lake can be improved, which is convenient for long-term irrigation, achieving three goals at one stroke. "

Zhuge Jin casually listed a bunch of benefits.

There is actually another one, but he just hasn't thought of it yet.

That is, once the canal has gates and the water level rises, there will be no need to rely on the current special small boats for transportation. Maybe we can directly use the Mi family's large ships instead.

In this way, the labor of loading and unloading dock workers in Huaiyin County and Guangling County can be saved in the future, and there will be no need to switch between river ships and canal ships for loading and unloading.

As for the "30,000 canal workers" who lost their jobs, they could just switch to military settlements. Anyway, there was no shortage of land to farm these days, but what was lacking was population and labor.

Chen Qun was completely shocked by Zhuge Jin's counter-intuitive plan.

I didn't expect Mr. Tzuyu could draw so many benefits from it.

Chen Qun felt his mouth dry and asked, "Sir, do you know how to repair the gate?"

Zhuge Jin: "I don't know for now, but give me a few months and discuss with others, maybe I can figure it out."

Chen Qun was anxious: "But I can't just start the work with a 'maybe'. What have you asked those people who are working in exchange for relief to do in the past two months? The winter farming season doesn't wait for anyone."

Zhuge Jin thought for a while and said, "Didn't I tell you that if we can't repair the sluice gate, we can first dredge Sheyang Lake and build embankments. Once the sluice gate is repaired, the water will flow smoothly."

Chen Qun: "But we don't know how much higher the water level will be than it is now, how high the polder should be, and what the original terrain was like. And if the last step of building the sluice gates cannot be completed, all the manpower invested in the previous steps will be wasted. Isn't that too hasty?"

Zhuge Jin: "It won't be in vain. If it doesn't work this year, it will definitely work next year. Just don't make the laborers who work in exchange for relief too tired and control the speed of food consumption.

Now we have gillnet fishing, and some other subsidies, and Yunchang has also sent troops to Yuzhang for food. The food gap squeezed out is enough to cover the expenses of work-for-relief.

Just say that this is my suggestion, and the envoy will not object."

Zhuge Jin had figured it out: the difficulties that Chen Qun still emphasized were mainly problems related to engineering surveys.
For example, I don’t know how to measure the altitude of various places around Sheyangze, and I don’t know whether the water level is high or low during measurement, so I don’t know how deep to dig or how high to pile.

However, these problems can be easily solved by people in later generations who have a thorough understanding of mathematical thinking.

For example, even if a person does not know trigonometric functions, as long as he understands "light travels in straight lines" and "similar triangles" in fourth grade and knows how to use them, he can measure the altitude simply with ancient tools.

Most people can’t do it, just because they don’t understand it thoroughly enough and don’t think about how to apply it, not because they don’t have enough knowledge.

This is the same principle that applies to the TV series “Drawing Sword” where one can measure how far away the Sakata Regiment is from the mortar by raising one’s thumb.

Zhuge Jin was very confident that if he was given some time he could solve these minor problems.

Even if he doesn't have time to solve it himself, he can let Aliang come and practice.

I believe that with Aliang's flexible thinking and the tutoring I have given him on basic mathematics and basic optics in the past two months, I can help him succeed.

As long as he is given a compass stone that can be used as a level and a few reference poles, Aliang can measure the altitude by using his middle finger.

Before Zhuge Jin was about to go to Yuzhang, he wrote a letter to Aliang, asking Aliang to find a way to get away and meet him in Yuzhang. This would save the brothers the trouble of being separated in two states and doing distance education later.

Zhuge Jin calculated that if Aliang finished learning his first batch of scrolls, his math level would at least be improved to the level of finishing the second year of junior high school, and the only two things he would need to learn before graduating from the third year of junior high school would be "quadratic equations" and "factorization."

Combined with the basic optical knowledge in the physics scroll, this level is enough to handle the canal gates and the planning of the polder after the water level of Sheyang Lake rises.

It also allows Aliang to learn and apply what he has learned immediately, and as soon as he debuts, he will leave a reputation in history books as a "wise minister in flood control."

(End of this chapter)