According to Xia Dynasty writings, Da Yu took thirteen years to control the floods, during which he didn't even return home. He traveled by carriage, boat, and on foot, building bridges as needed. He divided the country into nine regions, cleared rivers following the mountain terrain, and mobilized local resources effectively. He dredged nine waterways, controlled nine marshes, and crossed nine mountains. However, the Yellow River was a disaster, especially for the Central Plains—it had to be tamed. The Yellow River flowed from Jishi Mountain, through Longmen and Huayin, to Mengjin, Luoyang, and finally Dapei. Da Yu found that the upper reaches of the Yellow River flowed too fast and often breached its banks, so he dug two diversion channels to redirect the water. He diverted water to higher ground, lowering the water level and creating nine channels that eventually flowed into the Bohai Sea. With the nine rivers dredged and the nine marshes controlled, peace and prosperity followed, and Da Yu became a legendary hero.
Since Da Yu's flood control efforts, many irrigation projects spread throughout the land. For example, below Xingyang, people diverted the Yellow River southeast, dug the Honggou canal, connecting the Song, Zheng, Chen, Cai, Cao, and Wei states, and linking with the Ji, Ru, Huai, and Si rivers. In the state of Chu, canals linked the Hanshui River and Yunmeng Marsh to the west and the Jiang and Huai rivers to the east. In the state of Wu, irrigation projects connected the Sanjiang River and the Five Lakes. In the state of Qi, canals linked the Zishui and Ji rivers. In Shu, the governor of Shu County used ice to break up a blockage in the river, eliminating the threat of foam water, and dug two rivers in Chengdu. These channels were navigable, and excess water could be used for irrigation, benefiting the people.
Xi Men Bao's irrigation project enriched the Henan region of Wei.
Han Zhaohou heard that the Qin State liked to undertake large projects and wanted to stop the Qin king's eastward expansion. He sent the irrigation engineer Zheng Guo to convince the Qin king to build a canal in the Jing River, flowing north through present-day Shanxi province and into the Luo River for over three hundred miles, with the purpose of irrigating farmland. When the project was halfway through, the King of Qin discovered Zheng Guo's identity as a spy and wanted to kill him. Zheng Guo said, "I was indeed sent by the King of Han at the beginning, but this canal will also benefit the Qin State!" The Qin king saw his point and ultimately allowed him to continue the project. After the completion of the canal, it was used to irrigate saline-alkali land, covering an area of over forty thousand hectares with a yield of one stone (approximately 150 kg) per mu. As a result, the Guanzhong plain flourished, never experiencing famine again. The Qin State became prosperous and eventually unified the six states, naming the canal the Zhengguo Canal.
Thirty-nine years into the Han Dynasty, during the reign of Emperor Xiaowen, the Yellow River breached the Jin dike in Suanzao, flooding the Dongjun area severely. The Dongjun sent troops to build dams to block the breach.
Forty years later, during the reign of Emperor Wu of the Han Dynasty, the Yellow River breached the Huzi dike, flowing southeast into the Juye marsh and connecting to the Huai River and the Si River. The emperor then sent Ji An and Zheng Dang to block the breach, but the repairs were constantly undone. At that time, Wu'an Marquis Tian Fei was the prime minister, with his fiefdom in Shu County. Although Shu County lay north of the Yellow River, and the river flooded south, Shu County did not suffer from water disasters and had a good harvest. Tian Fei said to the emperor, "The Yellow River's breach was an act of God, and it is difficult to forcibly block it with human power. Even if blocked, it may not necessarily be in accordance with fate." Astrologers and diviners also said the same. Therefore, the emperor did not order the blocking of the Yellow River for a long time after that.
At that time, Zheng was serving as the top agricultural official. He suggested, "Currently, transporting grain from the region east of the Guanzhong area upstream along the Wei River would take six months to complete. The transportation canal is over 900 miles long, fraught with difficulties. If we dig a canal from Chang'an, along the foothills of the Nan Mountains, all the way to the Yellow River, it would only be over 300 miles long, making transportation more convenient. It is estimated that it would only take three months to complete. Additionally, this canal could irrigate tens of thousands of hectares of land along the way, significantly increasing grain production. This would reduce the manpower needed for transportation and make the Guanzhong region more prosperous." The Emperor found his suggestion good and ordered Xu Bobiao, a water conservancy expert from the Qi State, to employ a massive workforce to dig the canal. Three years later, the canal was finally completed. With the canal open, it was much more convenient, and the amount of grain transported also increased. Locals along the canal could now irrigate their fields.
Later, Fan Xi, the Prefect of Hedong Commandery, made another suggestion: "Currently, transporting grain from the western part of Shandong, totaling over a million bushels annually, must pass through the perilous Dizhushan pass, where accidents often occur, resulting in significant losses and being time-consuming and labor-intensive. If we dig a canal to divert the water of the Fen River to irrigate the areas of Pishi and Fenyin, and the water of the Yellow River to irrigate the areas of Fenyin and Puban, this would irrigate around five thousand hectares of land. These five thousand hectares are abandoned land along the banks of the Yellow River, where people could only graze their livestock. If used for irrigation, it is estimated that it could increase grain production by over two million bushels annually. Grain transport from the Wei River would be just as easy as in the Guanzhong region, and there would be no need for transportation east of Dizhushan." The Emperor also found this idea good and sent tens of thousands of laborers to dig canals and cultivate farmland. Several years later, the Yellow River shifted course, rendering the canals useless, and the local farmers who cultivated the land could not even recover their investment. After a long time, the canals and farmland in Hedong were abandoned. They were given to the Yue people, and a small amount of tax was collected by the treasury.
It is said that later someone submitted a memorial to the emperor, suggesting the repair of the Baixie Road to facilitate grain transport. This memorial was handed over to Chief Imperial Censor Zhang Tang. After understanding the situation, Zhang Tang analyzed to the emperor: "Currently, the route to Shu is the old road, with many mountainous and winding paths, making the journey long. If the Baixie Road is repaired, there will be fewer mountainous paths, shortening the distance by four hundred miles; furthermore, the Ba River can connect to the Mian River, and the Xie River can connect to the Wei River, allowing for the transportation of goods. Grain transport can start from Nanyang, go through the Mian River to the Ba River, and the distance between the Ba River and the Xie River is just over a hundred miles. This section of the journey can be done by carts, then continue down the Xie River to reach the Wei River. This way, grain from the Hanzhong area can be transported, and the Shandong area can receive an infinite supply of goods from the Mian River, making transport near Dizhu easier. Furthermore, the resources such as wood, bamboo, and arrows in the Baixie area can be compared to those in Bashu." The emperor agreed with Zhang Tang, so he appointed Zhang Tang's son, Zhang Yang, as the Prefect of Hanzhong, mobilized tens of thousands of workers, and built a Baixie Road of over five hundred miles. This road was indeed convenient and fast, but the river's rapids and rocky bed made it impassable.
Following that, someone named Zhuāng Xióngpí proposed: "The common people in Linjin hope to excavate the Luo River to irrigate more than ten thousand hectares of salt flats east of Chongquan. If water can be brought in, the yield per acre can be increased to ten shi (approximately 100 kg)." Therefore, the emperor mobilized over ten thousand people to dig a canal, bringing water from the Luo River to the foot of Shangyanshan. However, the river banks often collapsed, so they had to dig wells, with the deepest well being over forty zhang. They dug many wells, connecting the bottoms of the wells to let the water flow through. The water flowed around Shangyanshan, eastward to the mountains about ten miles away. This marked the beginning of well-irrigation techniques. Because dragon bones were found during the excavation of the canal, the canal was called Longshou Canal. Despite over a decade of work, the canal yielded disappointing results.
Since the Yellow River's breach at Huzi, more than twenty years have passed, and there have been crop failures year after year, especially in the Liangchu area. The emperor performed a Fengshan sacrifice for the mountains and rivers, and the following year, Qianfeng barely saw any rain. The emperor then sent Ji Ren and Guo Chang with an army of tens of thousands to block the breach at Huzi. He personally inspected the breach and even tossed a white horse and a jade *bi* into the river, ordering all officials from generals to the lowliest official to carry firewood to block the breach. At that time, Dongjun was clearing fields by fire, so there was a shortage of firewood, and bamboo from Qiyuan was cut down for support.
The story goes that the emperor personally visited the breach at Huzi, looking at the unfinished water conservancy project, feeling very sad, and composed a song, singing: "The breach at Huzi, what can we do? Day and night toil, the people all work hard to control the river! The people exhaust their energy to control the river, the land is not peaceful. When the project is not completed, my mountain tomb is flat. My mountain tomb is flat, Juye is flooded, fish are churning like boiling water, cypress trees are submerged in the winter flood. The river changes course, deviating from the original riverbed, the dragon plays freely in the distance. Return to the original riverbed, may heaven bless! No need for any Fengshan sacrificial ritual, just know the situation outside! I want to ask the River God, why are you so unkind, flooding endlessly and causing suffering to the people? Mulberry trees are submerged, the Huai River and the Si River are all full, the flood does not recede for a long time, and the river flows slowly." He continued, "The river surged, churning up waves; the northern ferry was awash in sewage, and dredging the river was a nightmare! Harvesting long water caltrop, heavy jade also sinks into the water. River God, you promised us but did not provide firewood. Without firewood, the people of Weiguo are guilty; the scorched trees stood stark and bare. Alas, what will resist the flood! Cutting down forests, blocking the river, building embankments—God help us!"
Finally, the breach at Huzi was blocked, and a palace named Xuanfang Palace was built on top of it. At the same time, two channels were dug on the north side of the river, bringing back Dayu's old ways of controlling the floods. The borders between the states of Liang and Chu returned to peace, and there were no more floods.
Since then, those in power have attached great importance to water conservancy projects. Shuofang, Xihe, Hexi, and Jiuquan all diverted river or valley water for irrigation; Guanzhong built auxiliary canals, and Lingzi diverted water for irrigation. Runan and Jiujian used the Huai River, Donghai the Juding River, and at the foot of Mount Tai, the Wenshui River—all irrigating tens of thousands of acres. These places have all dug channels to irrigate fields, benefiting numerous hectares of land. There are countless other small water channels crossing mountains and ridges. However, the most famous is still the water control project at Xuanfang Palace.
Historian Sima Qian (the renowned historian Sima Qian) said: I once climbed Mount Lu in the south, inspected Dayu's project of dredging the Jiujian River, and walked all the way to Taihuang in Kuaiji, climbed Mount Gusu, and looked out over the Five Lakes; I looked east towards Luoyang and Dapei, where I saw the Yellow River; I traveled along the Huai, Si, Ji, and Luo Rivers; I looked west to the Minshan Mountains and Lidui in Shu; and I looked north from Longmen all the way to Shuofang. I truly marveled at how great the benefits and drawbacks of water are! Having helped block the breach at Xuanfang myself, and moved by the lament for Huzi, I wrote this *Book of Rivers and Canals*.
