Chapter 11 Section 5 Canal Engineering in the Tang Dynasty

The canal construction in the Tang Dynasty was mainly to repair and improve the large canal system established in the Sui Dynasty.At the same time, in order to better play the role of the canal, important reforms were made to the old water transport system. The Guangtong Canal dug by Emperor Wen of the Sui Dynasty was originally the main grain road in Chang'an.When Emperor Yang of the Sui Dynasty moved the political center from Chang'an to Luoyang, the Guangtong Canal fell into disrepair and gradually silted up.Chang'an was the capital of the Tang Dynasty. At the beginning, due to the relatively economical use of the country, the amount of grain transported from east to west was not large, about hundreds of thousands of stones per year, and Weishui River could still barely undertake the task of transporting grain.Later, the grain consumption of the capital continued to increase, and it was so serious that the emperor had to lead hundreds of officials and troops east to Luoyang for food because the supply was in short supply.Especially during Wu Zetian's reign, almost all government affairs were handled in Luoyang.Therefore, in the first year of Tianbao (742 A.D.), the project of Guangtong Canal was reopened.The new waterway is called Caoqu, presided over by Wei Jian.At that time, Xingcheng weir was built on the Weishui river bed near Xianyang, and Weishui was diverted as the main water source of the new canal.At the same time, Fengshui and Chanshui from Nanshan were also blocked into the canal as a supplementary water source.The Cao Canal is more than 300 miles long from the east to the Yongfeng warehouse in the west of Tongguan and meets the Weishui River.Caoqu has a large shipping capacity. In the year when the canal was established (the second year of Kaiyuan), that is, "Caoshan East (east of Xiaoshan) millet four million stones".

To transport corn from Shandong into the Customs by water, it is necessary to improve the shipping conditions of another waterway, that is, to solve the threat of the three pillars in the Yellow River canal to grain ships.The water in this section of the river is turbulent, and going westward along the river, it often takes hundreds of people to pull a boat of grain; moreover, there are hidden reefs everywhere, and nearly half of the passing ships hit the rocks and are wrecked.In order to avoid this difficult and dangerous waterway, at about the same time as the re-opening of the canal between Chang'an and Weikou, Li Qiwu, the prefect of Shan County (where the government is located in today's Xijiu Shan County, Sanmenxia City), organized forces to attack the waterway on the north side of Sanmen Mountain. Construction was carried out on the rock to prepare a new channel to replace the old channel.After about a year of hard work, although a waterway named Kaiyuanxin River was dug out, due to the hard local rock, the depth of the riverbed was not dug enough. It can only be navigated when the Yellow River is flooded, and it does not work normally.The problem of the three dangerous roads is far from being resolved.

Tongji Canal and Yongji Canal are the two most important waterways built in the Sui Dynasty.In order to play the role of these two canals, the Tang Dynasty also made some modifications and expansions to them.The Tongji Canal in the Sui Dynasty was called the Bian River in the Tang Dynasty.Tang dug a waterway in the east of Bianzhou (now Kaifeng City), named Zhan Canal, which was connected to another waterway, Baimagou, and Baimagou was connected to Jishui. In this way, Jishui was incorporated into the Bianhe system, making The rent and transfer of most counties and counties in the Qi and Lu areas can also be transported westward along the Bian River.Tang's transformation of Yongji Canal mainly included the following two projects.The first is to expand the southern section with large traffic volume, widen the channel to 17 feet, and deepen it to 24 feet to make the channel more smooth.The second is to dig a batch of new branch canals on both sides of the Yongji Canal, such as the Zhangjia River in Qinghe County and the Wudi River in Cangzhou, so as to go deep into the grain area and give full play to the role of the Yongji Canal.

For the government of the Tang Dynasty, the main function of the Grand Canal was to transport food and silk from various places to Beijing.In order to play this function, a major reform was made to the water transportation system in the late Tang Dynasty.In the early Tang Dynasty, local wealthy households were in charge of rent transfers in the south, and they were sent directly to Luokou along the river and canal, and then the government transferred them to Beijing from Luokou.This kind of water transportation system has many problems because the wealthy households try to escape in many ways, there is no necessary protection along the way, and it is difficult for each boat to adapt to the different water conditions of the Jiang and Bian (generally referring to the canal).If the transportation period is long, it will take up to nine months from Yangzhou to Luokou.Another example is that there are many accidents and large losses. Every year, a large number of boats sink, and the loss of food is as high as about 20%, and so on.After the Anshi Rebellion, these problems became more prominent.Therefore, starting from the first year of Guangde (763 A.D.), Liu Yan reformed the water transportation system, replacing direct transportation with segmented transportation.Regulations: River boats do not enter Bian, and their transportation accumulates in Yangzhou; Bian boats do not enter the river, and their transportation accumulates in Heyin (northwest of Zhengzhou City); river boats do not enter Wei, and their transportation accumulates at Weikou; Weichuan It was shipped to Taicang.The transportation work is also hired and organized, with 10 ships as one outline, and troops are sent to escort them along the way.The efficiency is greatly improved by segmented transportation. It can reach from Yangzhou to Chang'an in 40 days, and the loss is also greatly reduced.

In addition to water transport, rent and transfer, the Grand Canal has also greatly promoted the prosperity of many commercial cities along the route.For example, Yangzhou at the southern end of the Yangchu Canal (that is, Shanyangdu in the Sui Dynasty) and Chuzhou at the northern end (Shanyang County where the government is located, now Huai'an City), Bianzhou (now Kaifeng City) and Songzhou (now Shangqiu) on the Bian River City), Zhuo County on the Yongji Canal, etc.Because Yangzhou is located at the confluence of the Yangchu Canal and the Yangtze River, public and private boats and boats, going from south to north, have to pass here.It is "Ten Li Changjie Jingshilian" and ranks first among the prefecture-level cities in the country, surpassing Chengdu and Guangzhou. It is called "Yang Yi Yi Er".Bianzhou is located in the north section of Bianhe River, passing through Jishui River, connecting Qilu in the east; passing through Yongji Canal, connecting with Youji in the north; passing through the Yellow River, reaching Qin and Jin Dynasties, and rapidly developing into a metropolis in the middle and lower reaches of the Yellow River.Later, the Liang, Jin, Han, Zhou, and Northern Song Dynasties all established their capitals here. The main reason is that it is a prosperous city with convenient water transportation.