Hongze Lake Irrigation System
2023-12-22 14:56

Sitting in Hongze District, Huai'an City, Jiangsu Province of China, the Hongze Lake Irrigation System lies in the Huai River Basin on the east of the Hongze Lake, the fourth largest freshwater lake in China. With an irrigated area of 32,000 hectares, the System stretches from the Hongze Lake Levee in the west to the Baima Lake in the east, and extends from the sea-entering waterway of the Huai River in the south to the Subei Irrigation Main Canal in the north.

The System underwent three development stages. In A.D. 199, Chen Deng, mayor of Guangling City (currently Yangzhou City), started the construction of the System by using the Pofu Lake as its water source. In A.D. 241, Deng Ai, a local official, built the Baishui Lake to connect the Pofu Lake. In A.D. 1128, the Yellow River, after a flood and dyke break, occupied the course of the Huai River, thus radically altering the size of the System and shifting its function from pure irrigation to flood control and irrigation. Since the Ming Dynasty (A.D. 1368-A.D. 1644), the water source of the System had been extended multiple times. By 1578, the Hongze Lake had taken shape, inundating the Pofu Lake and the Baishui Lake. Since then, the Hongze Lake has been serving as the main water source for the System.

As the water storage project of the System, the Hongze Lake Levee was firstly built in the Eastern Han Dynasty (A.D. 25-A.D. 220), formed in the Ming Dynasty and finalized in the Qing Dynasty (A.D. 1644-A.D. 1912). With the total length of 67.25 km, the Levee was made of more than 2.7 million pieces of stone slabs. In the Ming Dynasty, its storage capacity had exceeded over 1 billion m3. The upright masonry, the gently sloping revetment, the dams and sluices for the purpose of flood discharge and the leak-proof tabia dam surface are all major inventions during the construction of the Levee. Along with numerous engineering heritages, the System also boasts of an exceptionally rich non-engineering heritages with extremely high values, including the operation records of the overflow dams for over 100 years, the observational notes of water level for almost 300 years, imperial edicts, treatises on river engineering, water management techniques, among others.

Nowadays, the System is still playing a comprehensive role in the spheres of irrigation, water supply, ecology and others. Moreover, as a flood control barrier in the lower reach of the Huai River, the Hongze Lake Levee protects the safety of over 2 million hectares of farmland, 26 million people and more than 10 major cities downstream through retaining the water of the Huai River.