Scientific and engineering highlights of an 1171-year-old weir in Eastern China

In Chinese history, Tuoshan Weir, located in Ning County of Ningbo, Zhejiang Province, Eastern China, is ranked as one of the four most outstanding hydrological projects ever undertaken. Since the weir was originally constructed during the Tang Dynasty in 833 a.d., it has succeeded for 1171 years in playing a distinctive role in preventing saline water of the East Sea from backing up, conserving freshwater, ensuring safety of people from flooding hazards and irrigating farmlands in the Ningxi Plain. From eight highlights in planning, design and construction of the hydrological project, this paper reveals the ancient knowledge involved in using hydraulic principles, such as distributed flows and mechanics, such as engineering infrastructures.