Hundreds of ship-type schooners carrying 15,000 kilograms were led by two thousand cattle, and under the protection of five thousand soldiers, they slowly advanced north along the Tao River.

This was the reinforcements and supply convoy led by Li Su himself, transporting supplies to Guan Yu who was already besieging Jincheng.

When you encounter a shoal where the water is slow, you push the convoy ashore and then pull it by the cattle. When the water level is slightly appropriate and the flow rate is enough to save labor, you slowly pull the car down the river and flow for dozens of miles. The livestock will scatter along the river, saving animal strength. Without the drag of heavy caravans, the cattle can walk by nearly half, which is easy.

Li Su sat in a specially made, most massive and sturdy caravan, looking at the scenery on both sides of the strait, and her heart was also full of strength.

The caravan he personally took was eight feet wide and more than three feet long. The cabin next to it was six feet high. The wooden board of the whole car was three inches thick, which was twice as thick as other cars. So according to the size of this car, the weight alone was close to six thousand kilograms, which was a waste of load. Other cars only had just over two thousand kilograms.

Because of the huge car, Li Su's theoretical displacement of the car is as high as fifteen tons, which is 120,000 kilograms, but in fact Li Su would not let the car carry more than 30,000 kilograms of goods. He would rather have a lot of drainage allowance to ensure that the ship is not easy to sink and is absolutely safe, and he cannot shoot through the crossbow, and even the catapult cannot smash it with gravel. Because the car is heavy, his car needs to be dragged by eight cows or twelve horses.

Even so, the 30,000 kilograms of load on the car would not be used to transport the rough stuff. They were all his own daily necessities, dietary supplies, or family maids, and the car weighed less than 40,000 kilograms in total.

Some people may think: Is it too unscrupulous to lead women in the army? When Li Suyuan led his troops to fight, he would not be so arrogant even if he didn't come to the front line in person. Why did this change? He actually brought his wife to him.

Even his wife Cai Yan felt it was incredible. Although the child was over half a year old and could be weaned, it was quite strange to take his wife to the commander to see him.

Cai Yan and other concubines in the family were in late spring. Li Su settled down in Lintao before he was taken to the northwest to live with his husband. After all, Li Su rarely returned to Chengdu for a long time in his official position. He took his family to Lintao first, so it would be easier to go directly to Chang'an in the future.

"Husband, although I am not afraid, will the lieutenant general think you are frivolous and detrimental to morale?" Cai Yan asked in a general way. On the first day after leaving Lintao, she was even embarrassed to look out to enjoy the scenery.

Li Su said arrogantly: "What's the frivolous thing? I never regard my wife as an ordinary woman. The wife is a great man who will study the Han Ji and the Book of the Later Han in the future. Even outsiders can call her wife a gentleman.

The reason why I didn't take you in previous years was that some wars were too difficult and you were young. Secondly, it was to kill rebels, which was not worth mentioning. Although we were the first battle to attack Han Sui, after we defeated Han Sui, we would immediately face the Qiang King who was rebelling by Guo Si and the tribes. This was a great cause to re-expand the border for the Han Dynasty.

When the great general Dou Xian defeated the Huns, he continued to pursue the northwest from Juyanhai. He followed the army to the guard Ban Gu, and ordered him to write the "Inscription on the Mount Yanran". Ban Gu cultivated the "Book of Han" and recorded the merits. Gu Wenxiong was a lifetime ago. Now his father-in-law has no son, and he is not like Ban Biao who has a son Ban Gu, so Ban Chao had to blame his wife for being affected, and he was in charge of being a charity. Chao and Zhaozhi were responsible."

Speaking of the last two sentences, Li Su changed his initial proud tone and became a little tender. It can be seen that he also has a sense of heroism that is creating a glorious history of the nation.

Although this Western Expedition would definitely not be as far away as Yanran Mountain, and the country did not have the financial resources. But one day, Li Su would also want to win the stones in the Western Regions to remember the merits.

Cai Yan finally understood completely: My husband made an exception this time, not asking her to come and have fun, but asked her to help leave behind famous works throughout the ages and praise merits.

This is the benefit of having a great writer around you who is strong enough to be famous in history.

Thinking about this, Cai Yan's eyes also changed a little, becoming complicated and excited.

This is not frivolous or risky, and she knows that her husband has always paid great attention to safety, so what else can she be afraid of?

Cai Yan leaned on the side of the caravan with slender hands. This height was just between her mouth and nose. Cai Yan was about six feet, six or seven inches tall, eight inches shorter than her husband, so she could just comfortably see the view outside the car tent. If she was not relaxed and comfortable enough, she could also move a few packs of food to sit down and watch.

She was never so eager to collect writing materials from beginning to end.

The most obvious sight to drive on the Tao River is the intermittent rammed earth ruins on the top of the hillside on the east bank of the river.

Some other women may not realize anything when they see these broken walls, but Cai Yan is a talented woman who is well-read in poetry and books. When she thinks about it briefly, she feels a little excited:

"The First Emperor built the Great Wall, starting from Lintao in the west and ending in Liaodong in the east. We set out from Lintao the day before yesterday, and what we see now should be the extreme west of the Qin Great Wall, right?"

According to their itinerary, you can arrive at Didao today and arrive in Jincheng four days later.

A hint of pleasure had passed through the corner of Li Su's mouth, and she sighed proudly: "Yes, this is the extreme western section of Qin Shihuang's Great Wall, east of Tao River, even the Han area during the Qin Dynasty. To the west of Tao River, it has been the Qiang area since ancient times. However, during the hundreds of years of the Han Dynasty, our source of the river, the end of Huang, and the plateau. The source of the Yellow River and the Huangshui Valley were also the territory of our Han Dynasty, but it was gradually lost since the reign of Emperor Huan.

I thought seven years ago, I followed the king to pacify Zhang Chun in Liaodong, and went to Xigaima, Xuantu County, Anping and other counties. At that time, I also saw the ruins at the easternmost end of the Great Wall. For seven years, we have fought from the easternmost end of the Great Wall to the westernmost end."

These are actually nothing to Li Su. He even went deep into the southern middle and went deep into the barren area. It is not only the westernmost part of the Han area, but also the southwest corner. These memories are very touching when thinking about it, making people unable to help but sing "The Rolling Yangtze River Flows East".

Cai Yan's heart was shaken, and the maids who held the piano and polished ink for her were even more admiring the master.

Before the battle was fought, Cai Yan felt that he should write a poem first.

After thinking for a while, she picked up her pen and wrote a few big words "Fu of the West" on a piece of paper.

The article "Fu of the West" was later written in history. It was written by Pan An, a writer in the Western Jin Dynasty (the Pan An who most people only know that he is very handsome). However, since Cai Yan wants to write it first, let Pan An change his name in the future, if there is still Pan An in this world.

Pan An's "Fu of the West" obviously also imitates Ban Biao's "Fu of the North" and Ban Zhao's "Fu of the East". Now it's Cai Yan's turn to write it, so of course it's more high-level.

"At the beginning of Jian'an, I followed my husband to the west; in midsummer, I was so cruel and fierce, and I was so brave that I went up to the Tao. Seeing the West of the First Emperor, I only found the ruins; I admire the virtues of the Emperor and the heavens, and sighed that human achievements will not last forever.

After seeing Di Dao, I was surrounded by the majestic steepness of Gaolan. Looking at the vast soup of Hehuang, I felt the labor and leisure of the garrison. I lifted the chariots and boats to help the dragon soar to be vigorous and vigorous; only the power of the same unity can be used to drift forever..."

Cai Yan wrote seven or eight couplets first. He was so happy that he threw the pen and asked the maid to pour her two glasses of wine. After drinking it, he pressed the piano and played it casually to find some inspiration.

Li Su couldn't see the mystery for a while. He knew that it was just a draft, so he didn't comment. He just hugged his wife from behind and encouraged his creative confidence with body language.

...

After the convoy arrived north along the Tao River and reached Didao, the next day, it began to turn west. The convoy's route also parted ways with the ruins of the Great Wall for the first time-

The Tao River is blocked by Gaolan Mountain here, and it must turn northwest, travel another 150 miles, and then flow into the Yellow River in Liujia Gorge. After converging with the Yellow River, it will wind up to the north and east for 130 miles before reaching Jincheng.

The ruins of the Qin Shihuang Great Wall are not to be done with this matter. They continue to go north from the turning point, cross the steep place on Gaolan Mountain, and directly connect to Jincheng 90 miles north.

Therefore, the route to cross Gaolan Mountain is saving nearly 200 miles than sailing along the Tao River and the Yellow River. However, because the cost of walking on a water route is twenty times higher than the unit mileage of climbing Gaolan Mountain, normal people still take the water route.

Cai Yan was not familiar with the local terrain. He originally thought that Jincheng could go straight to the north of Lintao. He was blocked by Gaolan Mountain, so he curiously observed the surrounding terrain carefully.

"No wonder the land of Jincheng is Longxi and Hehuang. There is a Gaolan Mountain in the north and south of this city, and the city is located in the valley. The four rivers of Tao, He, Huang and Lang are all blocked by high mountains. They are just dozens of miles away from Liujia Gorge at the entrance of the valley and flow into one.

So whether it is from Tao River to Lintao, Dazhong, or from Huangshui to Xiping (now Xining, the capital of Qinghai Province), or Linqiang; or along Langshui to Wuwei Lingzhi, Guzang, or even down the Yellow River, they have to pass through Jincheng."

Li Sulai had seen the map before, but it was the first time he had arrived at this place. Only after observing the terrain with his own eyes could he have a deeper understanding.

When he was studying in his previous life, he knew that there was a famous Liujiaxia Hydropower Station in the upper reaches of Lanzhou, which was blocked at the mouth of the Lanzhou River Valley, and built a dam to form a large reservoir, which stored the Hehuang Tao River.

Now that he has come here in person, he has verified an idea that he had laid before the Western Expedition - in the future, he will plant cotton widely in the northwest and develop cotton spinning, so that the Western Qiang people can gradually transform from "pardoning but not travel" into a nation that is completely farming-oriented. The key point is to build water conservancy in Liujiaxia.

Of course, the water conservancy construction here will be more complicated than the Leshan Imperial Palace in Dujiangyan. You may have to find relatively low-lying and closed areas upstream of the gorge that are suitable for water storage, blocking the Tao River to build dams, diversion and breaking, forming a dam when it flows into the Yellow River, and digging supporting diversion and discharge channels, which can be covered with water trucks on both sides.

Li Su's purpose of building a water storage lake is of course not to generate electricity. He just wants to "distribute peaks and valleys" to ensure that the runoff and water flow impact kinetic energy of each season are relatively controllable. When there is less water, the water in the water storage lake will be released. When it is almost empty, it will store water when it encounters a season with more water.

In this way, it can at least solve the problem of "water truck machinery that cannot be used due to the large gap in water flow speed and water level in each season", so that the water truck that could only be effectively operated for three or four months a year can be operated for eight or even ten months (it is impossible to boil water trucks for twelve months a year, as like Dujiangyan, because the dry water period in the upper reaches of the Yellow River is too drought)

By the way, we can also optimize the irrigation conditions near the basin, and also ensure that ships can be driven during dry periods.

At that time, the Tao River Basin in Longnan, the source of the Yellow River in the Qinghai-Tibet Plateau, the Huangshui River Basin in Qinghai, the Langshui River in Xiliang, and the cotton in the Ruoshui River Basin can all be distributed here to spin cotton yarn and weave cotton cloth, making Lanzhou the capital of cotton cloth and allowing the northwest nation to get rid of its dependence on sheepskin coats.

From then on, the vast areas of Qinghai-Tibet, Xinjiang and Gansu in later generations can be said to be of great merit from the perspective of long-term stability (the area of ​​Huangshui River Valley only accounts for 2% of Xinjiang Province, but the industrial and agricultural output in later generations accounts for more than 60% of the entire Qinghai Province. The essence is here, because only the Huangshui River Basin can connect with the Yellow River, and the others are rotten land on the plateau).

Moreover, history has already reported the answer to Li Su. In the entire northwest, only Liujiaxia can engage in hydropower industry. The water volume in the upper reaches of the Yellow River is too small, and it is not easy to construct. If Liujiaxia goes further down, the water volume of the Yellow River suddenly becomes several times larger because the four rivers converge, which is inconvenient to intercept it. Unlike at the mouth of Liujiaxia, which can be "divided and treated and defeated each one."

At the same time, once you pass the Gaolan Mountain Canyon, the drop of the Yellow River is not that big. Once the water flow rate is slow, the water energy resources that can be developed will be much less efficient. The location of Liujiaxia is the result of the exploration summary of geological and water conservancy experts in later generations. Of course, Li Su has to directly listen to the answers reported by smart people in later generations.

Of course, there will definitely be many new problems during the specific construction. When Zhuge Jin should solve it, he will find Zhuge Jin. After all, in the experience accumulated in the construction of Dujiangyan Leshanyan, he has never done such a scattered operation as "damstorm lake, reservoir". Even if it does not generate electricity and does not require a full dam body, the technical difficulties in engineering design are still not something Li Su can handle.

Still the same thing, Li Su can only serve as Party A to request, but he is an excellent Party A, with specific needs and clearly knowing what he wants.

Even considering that they are preparing to build the "Liujiaxia Flood Release Area" in the future, if Li Su plans to completely kill Han Sui's best friends in Jincheng this time, he can store water at the mouth of Liujiaxia in advance. Then, after the water flow of the Yellow River Tao River and Huangshui River is accumulated too much, he will rush down and flood the entire Jincheng.

However, he felt that Jincheng City was not all ten-year-old thieves who were unforgivable. After all, there were still people. Even if the number of people might not be as large as that of old thieves, and it would take more time to flood the city, it would be better to let Guan Yu think of other ways. After all, Guo Si and those hard-working Qiang Kings are the main enemies this year. Han Sui is just an appetizer and cannot be delayed for too long.

After the convoy passed through Liujia Gorge, it sailed for two more days, especially the Tao River and the two points where the Huangshui River flowed into the Yellow River. The water flow was turbulent. Li Su asked the caravan team to go ashore and dragged it for twenty miles with a cow. When the water flow was slightly regular, it could continue to drive down the river. Li Su was also recorded on the map of each point that was not conducive to the navigation of the caravan. After the pacification in the future, it would be necessary to farm and rectify it.

On May 27th, Li Su finally completed the entire survey, and his convoy also arrived at the mouth of the Yellow River-Langshui River west of Jincheng, where Guan Yu's camp was stationed.
Chapter completed!