Irrigation and drainage make it possible to develop cultivated land, as we have seen. In addition, the transport of bulk matter (especially grains) relies mainly on canals. Therefore it is typical to find dense networks of irrigation canals branching out from main transport canals during the major kingdoms. The following text of Sima Qian gives us an idea of the scale:
“Sometimes later (up to this point the text speaks of the works of Yu the Great) the Hong Canal was constructed, leading off from the lower reaches of the Yellow River at Xingyang, passing through the states of Song, Zheng, Chen, Cai, Cao, and Wey, and joining up with the Ji, Ru, Huai, and Si rivers. In Chu two canals were built, one in the west from the Han River through the plains of Yunneng, and one in the east to connect the Yangzhe and Huai rivers. In Wu a canal was dug to connect the three mouths of the Yangzhe and the Five Lakes, and in Qi one between the Zi and Ji rivers. (…)
“All of these canals were navigable by boat, and whenever there was an overflow of water it was used for irrigation purposes, so that the people gained great benefit from them. In addition, there were literally millions of smaller canals which led off from the larger ones at numerous points along their courses and were employed to irrigate an increasingly large area of land…. u
Let us look more closely at one of these projects. The most impressive transport canal in this period is the Hong canal, or canal of the wild geese. This is in fact a system of canals linking the Yellow River, from a city called Xingyang (or Jungyang) near the present-day Kaifeng, to the Ji River that flows to the north of the Shandong mountains but whose origin is quite near, and to the tributaries of the north bank of the Huai river. The canal has two main branches (Figure 8.3). The north branch (or Bian canal), the one most used for transport, probably follows the course of the ancient Bian (or Pien) river, which rejoins the Si and the Huai. This is a watercourse some 900 km long, surely artificial along a portion of its course. The south branch (the Langtanqu canal) links the Ying, Sui and Kuo rivers at their origins. It is some 400 km long, and constitutes a second fluvial passage between the Yellow River and the Huai,[395] through the Ying River which is navigable. The lengths of these canals are impressive, even though the originally swampy terrain is practically flat between the Yellow River and the Huai. At the beginning, the Hong canal may have simply been a collection of irrigation canals for the north basin of the Huai.
The date of construction of the Hong canal is uncertain. As we have seen, when Sima Qian cites this canal as the very first in his list, he describes the regions linked by this pathway using names that refer to the period of springs and autumns. Moreover, Joseph Needham indicates that the Hong canal is mentioned around 330 BC in the account of a diplomat in his discussions of the boundaries between states. So, should we follow those who suppose that the canal dates from the 6th or 5th century BC? The construction of a work of such scale implies a strong central power and an economic motivation for exchanges between the basins of the two rivers. The coexistence of these factors would seem problematic in the troubled period from the 5th to the 3rd centuries BC.
The Hong canal is destined to be well maintained, and remains in use in its original course up until 600 AD. Another important project in Sima Qian’s list is the Han canal, linking the Huai and the Yangtze. The king of the southern state of Wu has it built in 486 BC to supply his troops who were on a campaign against his northern neighbors.
