Chatan Weir, a major ancient water project in China, is located on the Niuhou River, a tributary of Ganjiang River, in Taihe County, Ji’an City, Jiangxi Province. Initially constructed in AD 937 during the Southern Tang Dynasty, this water facility has been in operation for over a thousand years. It currently irrigates an area of about 3,300 hectares of farmlands in approximately 200 villages. In 2016, Chatan Weir was successfully inscribed on the World Heritage Irrigation Structures List.
Historical records indicate that Chatan Weir was built under the direction of Zhou Ju, an Investigating Censor of the Southern Tang Dynasty. Witnessing the hardships locals faced due to droughts, Zhou Ju was determined to build a water project. After years of site selection and investigation, he led villagers in building a weir--using wooden piles, bamboo, and stones to impede the river flow on the Niuhou River, and to dig canals to divert water. This project helped create the fertile fields of the Jitai Basin in later centuries, transforming large arid areas into a “land of milk and honey”.
Chatan Weir consists of a main weir, an auxiliary weir, diversion channels, a raft passage, sand discharge sluices, flood embankments, and a main intake gate. The main weir is 105 meters long and 4 meters high. The auxiliary weir is 177 meters long and 4.1 meters high, and the top and the bottom are 7 meters and 18 meters wide, respectively. Both weirs are equipped with a sand-flushing sluice. The system works by impounding river flow and diverting it laterally. To regulate water volume and prevent flooding, Zhou Ju had a smaller flood-mitigation weir named “Diaoshi” built about 3.5 kilometers downstream, forming a coordinated system between the two weirs.
Chatan Weir has remained effective for over a millennium due to its intelligent engineering design. It was constructed on a river bend where the flow is naturally slower. The crest height was carefully designed to be submerged during floods, allowing overflow, and to impound water for irrigation during dry seasons, thus serving both irrigation and flood control purposes.
In addition, the project embodies managerial wisdom and a public-spirited philosophy ahead of its time. From its inception, Zhou Ju established a family rule clarifying that the weir was a public irrigation facility and “should not be monopolized by the Zhou Clan Family.” His descendants later engraved this rule on a stele in the ancestral hall to ensure future generations would uphold it. To guarantee long-term maintenance, Zhou Ju also purchased mountain land, using the income generated to fund weir repairs, achieving a self-sustaining operation model.
By the Yuan Dynasty, collaborative efforts between officials and the local community led to the famous “Five-Virtue Covenant” (a rotational management agreement). This system involved five major clans taking annual turns to oversee the weir's management and maintenance, making Chatan Weir a common-pool resource truly shared and managed by the community.
During the Ming Dynasty, Chatan Weir underwent multiple repairs and reinforcements. Its irrigation network expanded, steadily increasing its benefits. The project embodies the water management philosophy of “following the nature terrain and adapting to the times,” showcasing the ancient Chinese approach of harmonizing with nature to turn flood damage into water benefits.
Today, following modern renovations and protection efforts, Chatan Weir continues to perform its irrigation function. The Chatan weir irrigation system has also been designated as a National Water Scenic Area, becoming an important site for showcasing China’s enduring water culture.