Lingqu was dug in the thirty-third year of Qin Shihuang (2 14 BC), so it is also called Qin ditch. After Qin Shihuang unified China, he set out to explore Lingnan area and appointed Wei Tusui to lead the troops south. In order to transport the army's food and grass, he ordered Jian Lu to lead the troops to dig a canal in Xing 'an, Guangxi, connecting the Lijiang River and the Pearl River in Hunan.
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The main projects of Lingqu include Huazui, Taiping, Nanqu and Beiqu. Huazui is a dam. It looks like a plough share in Dayang River, a tributary of Xiangjiang River. It is made of stone, and the corner refers to the opposite direction of river flow, which divides the Dayang River into two parts, one of which flows into the South Canal and the other into the North Canal. The balance is a stone barrage located at the end of the shovel mouth, with a herringbone bank and a height slightly lower than that of the river bank. Close to the east bank of the river is Taiping, which is connected with the mouth of the North Canal.
The section near the west bank of the river is called Xiao Taiping, which is connected with the mouth of the South Canal. The function of Taiping is to raise the water level of Gao Xiang River, prevent the river from storing water, and intercept all the river water into the canal for water transportation in dry season. In flood season, the flood peak overflows the top of Tian Ping Dam and flows into the old channel of Haiyang River, reducing the water potential. As a result, the flowing water in the canal rises without overflowing, dries up and is inexhaustible, and always maintains a safe flow.
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