The ancient Yellow River irrigation area in Ningxia is one of the four ancient irrigation sites of China. Consistent with the terrain of the Yellow River, it covers a J-shaped strip between Xiaheyan and Shizuishan, two hydrographic stations in the upper reach of the Yellow River, which have irrigated the area for more than 2,000 years. The topography of the Ningxia Plain is higher in the southern part than in the north, thus forming a sloping landform. Taking advantage of the unique geographical conditions, the smart ancient people diverted water from the natural moat into canals, and then the land became fertile due to the exclusive advantages of abundant irrigation, creating a miracle in which “the Yellow River only makes Ningxia rich”. That’s why people often say “the Yellow River does much harm, but makes the Plain rich”.

In early years, the ancient Yellow River irrigation area covered only the southern part of the Yinchuan Plain. Afterwards, the people of many generations and dynasties dredged old canals and dug new ones to continuously expand the irrigation coverage. Up to the prosperous Tang Dynasty in the 7th century, a total of 13 trunk canals were built, irrigating an area of 1 million mu (1 hectare equals 15 mu), and a gravity irrigation system was preliminarily formed in the Yinchuan Plain and the Weining Plain. During the Western Xia Dynasty in the 11th century, its engineering and management systems were further improved, and the irrigation area increased to 1.6 million mu. During the Yuan, Ming and Qing dynasties, the number of trunk and branch canals continued to increase. At the end of the 19th century, more than 20 trunk canals existed, with a total length of more than 1,500 km and a total gravity irrigation area of 2.1 million mu.

Fig.1 The Ancient Yellow River Irrigation Area in Ningxia

The ancient Yellow River irrigation area consists of a canal system, drainage system, gates and other regulating facilities. The ancient Yellow River irrigation mainly features diversion without dams. Starting from the head of each canal, people used stone to build an embankment which was several kilometers long in order to split the river and divert water, which is known as the “water-diverting weir”, and a spillway was built on the weir to guarantee the safety of the canal mouth in case of flooding.

After the Qingtongxia and Shapotou hydraulic engineering projects were built up in 1968 and in 2004 respectively, all the diversion-without-dam projects were replaced by diversion-with-dam ones, and all the canal projects adopted controlling gates, expanding the irrigation area and improving the irrigation dependability through system transformation. The irrigation area currently covers 12,953 km2 and irrigates 8.28 million mu. It consists of 25 trunk canals, with a total length of 2,454 km, a total water diversion capacity of 750 m3/second, and 9,265 control facilities. Today, the Ningxia irrigation site is one of the 12 commodity grain bases in China.