河渠書

The Book of Xia says: Yu labored to tame the great floods for thirteen years, passing his own door without entering. On land he traveled by cart, on water by boat, through mud on sledges, and over mountains by bridge. He delineated the Nine Provinces, followed the mountains to dredge the rivers, and assessed the soils for tribute. He opened nine routes, diked nine marshes, and measured nine mountain ranges. Yet the Yellow River's flooding and overflows caused the greatest harm to the Central States. This was his primary concern. He therefore channeled the Yellow River from Jishi through Dragon Gate, south to Huayin, east down past Dizhu to Mengjin, Luorui, and on to Dapi. Yu judged that since the river's headwaters were at a great height, the current was swift and violent, making it hard to control on flat terrain and causing repeated destruction. He therefore cut two diversionary channels. The water was carried northward onto high ground, past the Jiang River, to the Great Marshes, where it split into nine rivers that merged into the Retrograde River and entered the Bohai Sea. When the nine rivers were dredged and the nine marshes drained, the various Xia states found peace, and the benefits endured through the Three Dynasties.

After this, below Xingyang the river was diverted southeast to create the Hong Canal, connecting Song, Zheng, Chen, Cai, Cao, and Wey, and linking with the Ji, Ru, Huai, and Si rivers. In Chu, canals connected westward to the Han River and the Yunmeng marshlands, and eastward linked the Yangtze and Huai basins. In Wu, canals connected the Three Rivers and Five Lakes. In Qi, they linked the Zi and Ji rivers. In Shu, Governor Bing cut through the Lidui outcrop to avert the Mo River's flooding and channeled two rivers through the center of Chengdu. All these canals could accommodate boats, and surplus water was used for irrigation — the people enjoyed great benefit. At every place they passed, smaller channels branched off for irrigating farmland, beyond any possibility of counting.

Ximen Bao channeled the Zhang River to irrigate Ye, enriching the Henei region of Wei.

Han heard that Qin was fond of great works and sought to exhaust it, preventing Qin from invading eastward. So Han sent the hydraulic engineer Zheng Guo to Qin as a covert agent, to persuade Qin to dig a canal from the Jing River starting at Zhongshan west to Hukou, running along the northern mountains east to the Luo River for over 300 li, supposedly to irrigate farmland. Midway through construction, the deception was discovered and Qin wanted to execute Zheng Guo. Zheng Guo said: "I began as a spy, but when the canal is completed it will also benefit Qin." Qin agreed and let him finish the canal. Once completed, it channeled sediment-laden water to irrigate over 40,000 qing of saline and alkaline land, yielding one zhong per mu. From then on, the Guanzhong plain became fertile land with no years of famine. Qin grew rich and strong and ultimately conquered all the feudal lords. The canal was named the Zhengguo Canal.

Thirty-nine years after the founding of the Han dynasty, during Emperor Wen's reign, the Yellow River broke through at Suanzao and burst eastward through the Jin Dike. The Dong Commandery mobilized a large force of conscripts to close the breach.

More than forty years later, during the Yuanguang era of the present Emperor, the river broke through at Huzi, flooding southeast into the Great Wild Marsh and connecting with the Huai and Si rivers. The Emperor sent Ji An and Zheng Dangshi with a labor force to close the breach, but it repeatedly broke again. At that time, the Marquis of Wuan, Tian Fen, was chancellor, and his revenue fief was at Shu. Shu was on the north bank of the river — if the river broke southward, Shu would suffer no flooding and harvests would be plentiful. Tian Fen told the Emperor: "When the great rivers break through, it is an act of Heaven. It is not easy to force them closed with human strength, and closing them may not accord with Heaven's will." The cloud-watchers and numerologists agreed. As a result, the Emperor for a long time did nothing about closing the breach.

At that time Zheng Dangshi was Grand Minister of Agriculture. He proposed: "Previously, grain transported from east of the passes came up the Wei River, taking six months for the round trip, over a waterway of more than 900 li with frequent hazards. If we draw from the Wei and cut a canal starting at Chang'an, running along the foot of the southern mountains to the Yellow River — just over 300 li, a straight route, easy for transport — the round trip could be completed in three months. Moreover, the land below the canal, over 10,000 qing of farmland, could be irrigated. This would reduce transport costs, save conscript labor, and further enrich the Guanzhong land with grain." The Emperor agreed and ordered the Qi hydraulic engineer Xu Bo to survey the route. A force of tens of thousands of conscripts was mobilized to dig the transport canal. It was completed in three years. Once open, it greatly facilitated grain transport. Afterward, transport volumes gradually increased, and the people farming below the canal gained considerably from irrigation.

Later, Fan Xi, Governor of Hedong, proposed: "Grain transported from Shandong westward amounts to over a million shi annually. Passing the Dizhu gorge, losses from wrecks are enormous, and the expense is burdensome. If we dig canals to draw the Fen River to irrigate Pishi and below Fenyin, and draw the Yellow River to irrigate below Fenyin and Puban, we could gain 5,000 qing. These 5,000 qing are currently abandoned riverside land where people merely cut reeds and graze animals. If irrigated, I estimate they would yield over two million shi of grain. Grain transported up the Wei would be no different from Guanzhong grain, and we could eliminate transport east of Dizhu entirely." The Emperor agreed and dispatched tens of thousands of conscripts to build canal-fed fields. After several years, the river shifted course, the canals became useless, and the farmers could not even recover their seed costs. Eventually, the Hedong canal-fields were abandoned and given to Yue settlers, with the Minor Treasury collecting a modest income.

Later, someone submitted a memorial proposing to open the Bao-Xie route for transport. It was referred to the Imperial Secretary Zhang Tang. Tang investigated and reported: "The old road to Shu has many hills and is roundabout. The Bao-Xie road has fewer hills and is 400 li shorter. The Bao River connects to the Mian, and the Xie River to the Wei — both navigable. Grain could be transported from Nanyang up the Mian into the Bao, then transferred by cart over the 100-plus li gap to the Xie, and floated down to the Wei. This would bring Hanzhong grain to the capital, with unlimited supply from Shandong via the Mian — far more convenient than the Dizhu route. The Bao-Xie valley is also rich in timber and bamboo, rivaling Ba and Shu." The Emperor agreed, appointed Tang's son Ang as Governor of Hanzhong, and mobilized tens of thousands of workers to build the Bao-Xie road for over 500 li. The road was indeed shorter and more convenient, but the water was too rapid and rocky for boat transport.

Afterward, Zhuang Xiongpi proposed: "The people of Linjin wish to channel the Luo River to irrigate over 10,000 qing of formerly saline land east of Chongquan. If properly watered, each mu could yield ten shi." Over 10,000 conscripts were mobilized to dig the canal, drawing the Luo from Zheng to the base of Shangyan Mountain. The banks were prone to collapse, so they drilled wells — the deepest over forty zhang — at regular intervals, connecting them underground to carry the water. The water flowed through these well-tunnels, crossing under Shangyan Mountain for over ten li. The invention of the well-canal (qanat) system originated from this project. During the digging, dragon bones were found, so it was named the Dragon Head Canal. After more than ten years of work, the canal was largely functional, though it had not yet produced the expected abundance.

More than twenty years after the Yellow River broke through at Huzi, harvests failed year after year, and the Liang and Chu regions suffered the worst. The Emperor had completed the Feng and Shan sacrifices and toured the sacred mountains and rivers. The following year brought drought, with little rain after the Feng ceremony. The Emperor then sent Ji Ren and Guo Chang with tens of thousands of conscripts to close the Huzi breach. After performing rites at Wanli Sha, the Emperor returned and personally supervised the river closure. He sank a white horse and jade discs into the river, and ordered all officials and attendants from generals on down to carry firewood on their backs and fill the breach. At that time a fire in Dong Commandery had consumed the grasslands, making firewood scarce, so bamboo from the Qi Gardens was cut down to make pilings.

The Emperor, present at the breach and grieving that the work might not succeed, composed a song: "The Huzi breach — what shall we do? White and dazzling, the settlements are swallowed by the river! Swallowed by the river, the land finds no peace; the work has no end as my mountains are leveled. My mountains leveled, the Great Wild overflows; fish seethe and steam through the winter days. The road stretches slack, torn from its normal course; dragons sport as they range far abroad. Return to the old channel — how divine and magnificent! Without the Feng and Shan, how would we know the world beyond? Tell the River Lord for me: why so merciless? The flooding never stops, tormenting my people. Mulberries gnawed and floating, the Huai and Si brim; long unreturning, only slow waters remain." A second version reads: "The river surges vast, rapids splashing! To cross northward through the mire, to dredge the flow — how hard! We pull the long reeds and sink fine jade; the River Lord agrees, but firewood runs out. Firewood runs out — the fault of the Wey men! The land burned bare — alas, what can hold back the water? Felling forest bamboo, piling stones — the Xuanfang is sealed and ten thousand blessings come!" The breach was at last closed. A palace was built atop the site, named Xuanfang Palace. The river was redirected northward into two channels, restoring the ancient course of Yu, and the Liang and Chu regions found peace again, free of flood.

Thereafter, officials in charge of waterworks competed to advocate irrigation projects. In Shuofang, Xihe, Hexi, and Jiuquan, the Yellow River and mountain streams were channeled for irrigation. In Guanzhong, the Fu Canal and Ling-Zhi drew the Du River. In Runan and Jiujiang, the Huai was drawn. At Donghai, the Juding River. Below Mount Tai, the Wen River. All had canals dug for irrigation, each covering over 10,000 qing. Smaller canals cutting through mountains and opening routes were beyond counting. But the most notable achievement was Xuanfang.

The Grand Historian remarks: I climbed Mount Lu in the south and observed where Yu dredged the Nine Rivers, then traveled to the Great Lake at Kuaiji, ascended Gusu, and gazed over the Five Lakes. In the east I looked down into the Luorui and Dapi, met the Yellow River, and traveled the canals of the Huai, Si, Ji, Luo, and Ta. In the west I viewed the Min Mountains and Lidui in Shu. In the north I went from Dragon Gate to Shuofang. I say: how immense are the benefits and harms that water can bring! I personally carried firewood to help seal Xuanfang, and, moved by the Huzi poem, I composed the Treatise on Rivers and Canals.