The reason why the Guanzhong area is fertile and thousands of miles of agriculture is developed, an important reason is that there are abundant water sources here, with the effective irrigation of the Yellow River, the agriculture here can get rid of the unfavorable situation of relying on the sky to eat, of course, agriculture can get effective irrigation also thanks to the various water conservancy projects built in the past, the Guanzhong Plain starts from Baoji in the west, reaches Tongguan in the east, reaches Beishan in the north, and reaches the Qinling Mountains in the south, covering an area of about 34,000 square kilometers. Because Weishui, the largest tributary of the Yellow River, flows through the whole territory from west to east, it is also called the Weihe Plain. It is formed by loess deposits, the soil layer is deep, fertile and loose, and the frost-free period is long, 180-200 days, which are conducive to the development of agriculture. However, the rainfall is small, with an average of 500-700 mm for many years, and it is mostly concentrated in July, August, and September, which cannot meet the needs of crop growth, especially the needs of spring sowing. In order to develop agriculture in Guanzhong, it is necessary to develop water conservancy, and in the long river of history, people have successively chiseled a number of important irrigation projects here, such as Zhengguo Canal, Bai Canal, and Chengguo Canal.

The first large-scale water conservancy project to be built in Guanzhong was the Zhengguo Canal dug by the Qin State at the end of the Warring States Period. At that time, in addition to the natural conditions mentioned above, another factor was the political and military needs.

During the Warring States period, the history of our country developed in the direction of establishing a unified country, and some powerful vassal states wanted to unify the whole country with themselves as the center. The annexation wars were fierce. Guanzhong was the base of the Qin state, and in order to enhance its economic strength and be invincible in the annexation war, it was very necessary to develop the farmland and water conservancy in Guanzhong to increase the grain production of the Qin state.

Korea is the eastern neighbor of the Qin State. At the end of the Warring States Period, among the seven kingdoms of Qin, Qi, Chu, Yan, Zhao, Wei, and Han, when Qin's national strength was thriving, and when it wanted to have something to do in the East, South Korea bore the brunt. But it is so weak that it is vulnerable, and it may be annexed by Qin at any time. In 246 BC, King Han Huan, in a desperate situation, adopted a very clumsy strategy called "tired Qin". He took Zheng Guo, a famous water conservancy engineer, as a spy and sent him to Qin to persuade Qin to establish a presence in Jingshui and Luoshui (North Luoshui. Weishui tributary), a large irrigation channel was dug through. On the surface, it is said that the agriculture of the Qin State can be developed, but the real purpose is to exhaust the strength of the Qin State.

This year is the first year of King Yingzheng of Qin. The Qin state, which originally wanted to develop water conservancy, quickly adopted this tempting suggestion. He immediately collected a large amount of manpower and material resources and appointed Zheng Guo to preside over the construction of this project. During the construction process, the conspiracy of Korea's "tired Qin" was revealed, and the king of Qin was furious and wanted to kill Zheng Guo. Zheng Guo said: "The first minister is the middle. However, the benefits of the Qucheng are also Qin. The minister is the life of Han Yan for several years, and the merit of Qin Jian for all generations. "Ying Zheng is a very far-sighted politician, thinking that Zheng Guo is very reasonable, and at the same time, Qin Guo's hydraulic technology is still relatively backward, and Zheng Guo is also needed in technology, so as always, it is still reused. After more than 10 years of hard work. The whole canal was completed, and it was called Zhengguo Canal.

Zhengguo Canal is based on Jingshui as the water source. A water conservancy project to irrigate farmland north of Weishui. Its canal head project starts from Zhongshan in the east and reaches the mouth of the 瓠 [hù胡] in the west. Zhongshan and Gukou were later called Zhongshan and Gukou respectively, all of which were in the northwest of Jing County, across Jingshui, looking east and west. It is a dammed water diversion project. The total length is more than 2,300 meters. Among them, 350 meters on the riverbed, the bottom width is still more than 100 meters, the top width is 1-20 meters, and the height is six meters.

About Zheng Guoqu's channel. It is located at the southern foot of Beishan, in the highest position of the secondary terraces of Jingyang, Sanyuan, Fuping, Pucheng, Baishui and other counties, from west to east, the ratio is 0.64/00, and it intersects with Yeyu, Qingyu, Turbidity, Fuqi (now Shichuan River) and other waters along the line. The main canal is arranged on a higher position on the northern edge of the plain, so that it is convenient to dig the branch canal to the south and irrigate a large area of farmland to the south. It can be seen that the design at that time was relatively reasonable, and the level of measurement was already very high. However, Jingshui is a well-known sandy river, in ancient times, there was a saying that "Jingshui is a stone, its mud is a bucket", contemporary measurement, 171 kg/cubic meter, Zhengguo Canal takes the sandy Jingshui as the water source, so the ratio is too small. The specific drop is small, the flow rate is slow, the sediment is easy to deposit, and the channel is easy to be blocked.

After the completion of the canal, the economic and political benefits are significant, with the water of filling the water of the slug (silt), irrigating more than 40,000 hectares of brine land, harvesting all acres for a minute, so Guanzhong is fertile and wild, no murderous year, Qin is rich and strong, and the princes are born, because of the name Zheng Guoqu. "One bell is six stones and four buckets, which is many times higher than the average yield of one and a half stones per mu in the middle reaches of the Yellow River at that time.

Chang'an, the capital of the Western Han Dynasty, and Guanzhong was the main supplier of daily necessities such as Beijing officials, troops, and ordinary people. The Western Han Dynasty attached great importance to the development of the northwest frontier, and Guanzhong was the base for expanding the frontier, shouldering the important task of providing grain and straw. Therefore, in the Western Han Dynasty, especially during the reign of Emperor Wu of the Han Dynasty (140-87 BC), in order to meet the needs of all aspects for grain and straw, in addition to digging canals and transporting grain from the east into the customs, the main thing is to build irrigation projects in Guanzhong to expand the area of irrigated land and increase local grain production. This has formed an unprecedented upsurge in the construction of water conservancy in Guanzhong, and in just a few decades, a large number of farmland water conservancy projects such as the Longshou Canal, the Liufu Canal, the Baiqu Canal, and the Chengguo Canal have been drilled.

The piercing of the irrigation canal in the Guanzhong of the Western Han Dynasty was earlier in the period from Yuanjia to Yuanding (122-111 BC) from Emperor Wu of the Han Dynasty to Yuanding. At that time, there was a man named Zhuang Xiongzhen, who wrote to the emperor, reflecting the requirements of the people of Linjin (now Dali), hoping to open a channel to divert Luo water to irrigate more than 10,000 hectares of saline-alkali land east of Chongquan (now southeast of Pucheng). Emperor Wu adopted this opinion and sent more than 10,000 troops to take up the task of digging ditches. They opened a canal from Zhengxian County (located in the southwest of present-day Chengcheng County) to the south to the foot of Shangyan Mountain (now Tiejiashan). The well canal consists of two parts: an underground channel and a shaft. The former is a water route, and the latter is convenient for personnel to go up and down, excavate and light when digging a ditch. The deepest shaft is more than 40 zhang. Because many fossil bones were dug up during the digging of the ditch and used as keels, it was called the dragon's head ditch. After the channel was dug through, the irrigation effect was not significant because the problem of landslide could not be solved. However, it has created advanced well and canal techniques.

The Liufu Canal was built in the sixth year of Emperor Wu Yuanding (111 BC) and was presided over by Ni Kuan, the history of Zuo Nei. The scale is small, and it is a general term for six auxiliary channels. Later generations believe that it is to divert small water such as Yeyu, Qingyu and Turbidity Valley to irrigate the farmland in the north of the upper reaches of Zhengguo Canal. These farmlands are on higher ground and cannot be irrigated by the Zhengguo Canal. After the completion of the Sixth Auxiliary Canal, in order to better play the role of this project, he stipulated the "Water Order", which was completed in the 16th year after the completion of the Sixth Auxiliary Canal. That is, in the second year of Emperor Wu (95 B.C.), the construction began to dig the white canal. This project was suggested and presided over by Dr. Zhao Zhong Bai Gong. The head of the canal is also at the mouth of the valley, and the channel is in the south of the Zhengguo Canal, flows to the southeast, passes through Chiyang (the seat of governance is in the northwest of present-day Jingyang County), Gaoling, and Liyang (the seat of governance is in the northeast of present-day Lintong County), and injects Weishui. 200 miles long. Irrigate more than 4,500 hectares of farmland beyond the reach of Zheng Guoqu. After the completion of the white canal, Gukou, Chiyang and other counties have become high-yield areas without drought and flood because of the irrigation of Zheng and Bai canals.

Although the irrigated area of the Baiqu is much smaller than that of the Zhengguo Canal, it is far more reasonable than the Zhengguo Canal because of its larger specific drop, so it is not as easy to be blocked by sediment as the Zhengguo Canal, and the Baiqu has played a long-term role in history. "One stone of Jingshui, several buckets of mud." The mud content is high, and it can press the alkali fertilizer field. In the short term, it does work very well. In the long run, after a long period of time, it is easy to silt up the canal and farmland, leading to the field being higher than the canal and the canal being higher than the Jing, which is bound to destroy the entire irrigation system.

Another important farmland water conservancy project in the Guanzhong area that was newly built in the Western Han Dynasty was the Chengguo Canal. When it was built and who presided over the project. It was built during the reign of Emperor Wu. This is a large irrigation canal with Weishui as the water source, located on the north side of Weishui. The head of the canal is in the territory of Yi County, and the Weishui River is to the east, passing through [líli] (the seat of governance is in the southeast of today's Fufeng County), Huaili (the place of governance is in the southeast of today's Xingping County) and other counties, and the end of the canal is connected to the Mengyu Canal of Linyuan. The length of the Chengguo Canal is slightly smaller than that of the White Canal, and the irrigated area is about 10,000 hectares, which is more than double that of the White Canal. Later, it also developed into the main irrigation channel in Guanzhong. Shanglin Yuan is in the west of Xianyang. 300 miles in circumference, across the north and south of Weishui, is the Qin and Han Dynasty emperors hunting and amusement place. Mengyu Canal is a waterway in the royal garden, which is used for watering the garden, rowing boats and other purposes.

In the long history, Guanzhong Water Conservancy has always been composed of three major canal systems. That is, the diversion canal system with Jingshui as the water source, the diversion canal system with Weishui as the water source, and the Luoshui diversion canal system with Luoshui as the water source. It can be said that these three major canal systems have been basically formed in the Western Han Dynasty. In addition to the above-mentioned famous irrigation projects, Emperor Wu also built a number of small irrigation canals in the south of Weishui, such as Lingyi canal and illegal canal. They use the water of mountain streams originating in Nanshan Mountain as a source of water to irrigate the farmland of Weinan.

The construction of these water conservancy projects in the Guanzhong area has greatly promoted the local agricultural production, it can be said that the foundation of the water conservancy facilities in the Guanzhong area is still quite good, and the water conservancy projects in the whole world are the only ones where the water conservancy projects are relatively concentrated, and the Guanzhong area, which has good basic conditions, can realize the revival of agriculture, and the disrepair and successive wars have caused these water conservancy projects to be seriously damaged to varying degrees. Guan Yu inspected these water conservancy projects on the spot, and now these water conservancy projects have been damaged to varying degrees, and the damage is serious, Guan Yu repeatedly considered that if these water conservancy projects are repaired at the same time, not to mention that it is a year or a few years of hard work, after all, all the work in this era has to be manual, so Guan Yu decided to repair the Zheng Guo Canal, which is the hub of many water conservancy projects, as long as the restoration is completed, the benefits will naturally be the greatest, Guan Yu asked Zhang Ji: "How long will it take to repair this project?" ”

Zhang Ji looked at Zheng Guoqu, stroked his beard and said: "The damage is so serious, how can it take half a year to build!" ”

"Half a year? You don't need to restore, you just need to fix it! Guan Yu then reminded.

Zhang Ji looked at the project with a sharp gaze and continued: "I also built some small water conservancy projects when I was in Feng Yi, and in my experience, it takes half a year to repair such a large water conservancy project, which is still fast, and there is no shortage of manpower and equipment!" ”

After Zhang Ji finished speaking, Guan Yu's expression suddenly became solemn, and he then asked: "Is it more money to complete such a project or more money to repair the city defense?" ”

"The cost of such a project is no less than repairing the city defense of Chang'an City! And the repair of this project also needs professional technical personnel to design, you see that now the project is seriously damaged and has injured the main body, so to repair it needs to be re-surveyed, otherwise the project is difficult to play a role! Zhang Ji continued.

Guan Yu nodded after hearing this, and then said as he walked: "I think this is good, no matter what kind of project, let the soldiers under his rule participate in the construction, that is to say, this kind of conscription work is handed over to the soldiers under his command to do, and the soldiers can save a lot of expenses by eating military salaries, which is called 'investing in labor and discounting capital'!" ”

Chen Gong's eyes lit up when he heard this, and he clapped his hands and shouted, "This method is good!" The army is already quick and easy to do its work, and it also saves a lot of labor costs, which is a good idea! ”

"If you want to repair this Zhengguo Canal, it is better to repair the Liufu Canal, Bai Canal, and Chengguo Canal!" Zhang Ji continued.

Guan Yu wondered when he heard this: "How to explain?" ”

Zhang Ji analyzed: "Zhengguo Canal was built in the Qin Dynasty more than 400 years ago, and it has fallen into disrepair for a long time, and it is time-consuming and laborious to repair, and even if it is repaired, it has a very limited effect. And the canal system built later covers the entire Jingshui, Weishui and Luoshui, although the main body is small but has a great effect, it is relatively close to the current era, and it is easy to save time and effort to repair, so it is better to repair these canal systems, and then strengthen and rebuild the Zhengguo Canal when you have time and money in the future! ”

"Brother Tai deserves to be the first among the three assistants in political performance! Feng Yi's Taishou for so many years is really not in vain! The analysis is reasonable! In this regard, I really have to ask my brother for advice. I only think that Zheng Guoqu is more famous and bigger, but I ignore the reality, it seems that what Brother Tai said is reasonable, so I will repair those canal systems according to Brother Tai's wishes, and Zheng Guoqu will be put aside for the time being! Guan Yu decided after the most reluctance. After speaking, Guan Yu and the others actually took a closer look at the canal systems and formulated a repair plan.

After Guan Yu finalized this, he immediately visited Sanfu with Zhang Ji and others, and Guan Yu asked Zhang Ji: "What good talents can be used under Feng Yi's rule for many years?" ”

"Good talent!" Zhang Ji pondered for a moment and said: "There is really a person who is now the commander of Xinzheng County, surnamed Du Mingji, a native of Jingzhao Duling, this person is filial piety, witty, flexible, and good at judging big cases, and he can take on a big responsibility!" ”

"Du Qi?" This name suddenly appeared in Guan Yu's mind, as if this person had been mentioned in the book. Guan Yu had some impression but it was not very clear, it should be a clerical job, Guan Yu then asked: "Tell me his details!" ”

Zhang Ji continued: "Speaking of his family history, it is really brilliant. His ancestors, Du Zhou, Du Yannian, father and son, were big people who once left their names in the "Book of Han". Du Zhou is a cool official and a corrupt official, while Du Yannian is a good official. When the Du family reached Du Ji's father's generation, they were no longer officials, and they were ordinary people. Du Gi's mother died very early. The father remarried, and a fierce stepmother came to the family. It didn't take long for the stepmother to get home. Du Ji's own father also passed away, and the young Du Ji was taken care of by his stepmother alone, not to mention how bitter it was in this day. In other words, Du Ji has been bullied by his stepmother since he was a child, but he survived strongly, and in this harsh environment. has the reputation of a filial son. That is why Du Ji was appointed as Jingzhao Gongcao when he was twenty years old, and his official position is not high, but for young people, it is already very good. The superintendent "Elect the Credit". That is, to investigate, record, and recommend local outstanding figures, which should be very powerful. Later, Du Yi was appointed as the county magistrate of Zheng County, and it was in this position that Du Ji showed his extraordinary political talent for the first time. Zheng County's predecessor was a county magistrate with poor political performance, and there was a backlog of many cases when he was in office, and hundreds of people were imprisoned in prison, and they were locked in prison and suffered. After Du Yi took office, he first dealt with this matter, and he personally went to the prison to try the case, and it only took a short time to conclude all the cases. It is impossible for young people to be thoughtful and fair in handling cases. However, clearing the backlog of cases is a major matter, and Du Yi was able to handle this matter in a very short period of time, which shows that he understands the general situation, takes the overall situation into account, and understands the priorities. However, since then, Du Ji has not been promoted, and he has been working in Zheng County for 6 years. ”

Zhang Ji gave Guan Yu a detailed introduction to Du Ji's situation, and this nuanced introduction made Guan Yu curious: "How does Brother Tai know this Du Ji in such detail?" ”

"Brother Xian doesn't know, I am Feng Yi, Du Yi is too guarded, Du Yi is the county commander of Zheng County, and I have been an official in one place for many years, and I have intersected and interacted with him, to be honest, I appreciate his personality and talent, although his position is lower than mine, but this has not affected our communication, we learn from each other and become close friends, so I know him better!" Zhang explained.

After hearing this, Guan Yu said: "So we will go to Zheng County now, since we are my brother's friend, we are naturally my friend!" After Guan Yu finished speaking, he led this cadre to Zheng County

Guan Yu didn't care about the fatigue of the road, and a group of people came to the territory of Zheng County non-stop, and came to the boundary of Zheng County, and a patchwork of houses came into view from afar, after stepping on this Zheng County, Guan Yu witnessed the unique charm of this small county, although it was devastated by the war, but here you can still experience the style of this small city, the prosperous market here, the orderly layout suddenly attracted Guan Yu's attention, and the bustling crowd added a bit of liveliness. Guan Yu and others walked on the neat streets to feel the warm atmosphere here, you can experience the prosperity here, the shops are lined up, people come and go, the traffic is busy, Guan Yu can't believe that this is a county seat, it seems that the family here really has some ability to govern a small county so wonderfully! (To be continued......)