Closure to “Hydraulic Principles of the 2,268-Year-Old Dujiangyan Project in China” by Shanghong Zhang, Yujun Yi, Yan Liu, and Xingkui Wang

A critical analysis of the Dujiangyan Irrigation System, a 2,268-year-old UNESCO-listed marvel, reveals that its Baizhang dike and Renzi dike play pivotal roles in flood control and sediment management. Contrary to earlier assumptions, the Fish Mouth does not automatically regulate water diversion; instead, upstream reaches govern flow patterns during floods and dry seasons. The Baizhang dike stabilizes the Min River's bed, preventing flooding while allowing driftwood entry into the Inner River during non-flood periods. Annual maintenance, traditionally performed by farmers in winter, ensures system stability by clearing sediment and adjusting weir structures like Feishayan to balance flood discharge and irrigation demands. Post-1992, maintenance intervals extended to every 10 years due to reduced upstream sediment influx and modern gate installations controlling Inner River flow.

Zhang, S., & Wang, X. (2014). Closure to “Hydraulic Principles of the 2,268-Year-Old Dujiangyan Project in China” by Shanghong Zhang, Yujun Yi, Yan Liu, and Xingkui Wang. Journal of Hydraulic Engineering, 140(5). https://doi.org/10.1061/(asce)hy.1943-7900.0000883