Dongfeng weir is located in the Jiajiang county of Sichuan Province in south-west China in the lower reaches of Qingyijiang River, a tier 3 tributary of Yangtze River, where the river enters this county. Dongfeng Weir, built during the early time of Qing Dynasty in 1662 is a masterpiece of historic irrigation development and the greatest work of diversion irrigation without storage. It is an outstanding example of sustainable operation and management, great contribution to ecological conservation and development in its command for a period of more than 350 years.
The design and construction of the weir exemplifies the Chinese ancient philosophy of harmony with the nature. Dongfeng weir, as the water inlet, at that time was made of local material bamboo baskets filled with cobbles and earth-rock available from local mountains. The project consists of a group of the 12km main diversion canal, two secondary canals diverting into 4 by-canals, one tunnel, 11 aqueducts, 21 water-gates and other supporting facilities. The main diversion canal is connecting 10 previous micro canal systems the net of canals goes through Jiajiang county.
Before the construction of Dongfeng Weir and Canal system, Jiajiang County was drought prone. The Dongfeng weir and canal substantially promote the development of irrigation and economic along Qingyijiang River. Since the completion of works in 1662, sufficient irrigation water supply has ensured the agriculture stabilization and the social development with irrigated area has expanding by more than 10 times from 467 hectares to 5113 hectares, covering over 4 towns and 48 villages. The local multiple cropping index has increased to 2.68, and the cultivated area to 13367 hectares. The project has remained in use continuously for more than 350 years and underwent reconditioning twice to achieve increased and sufficient water supply. In 2006, when the once-in-a-century drought attacked Sichuan Province and led to severe water shortage in many places, thanks to Dongfeng Weir, Jiajiang County was not affected by this disaster and achieved a bumper harvest. The water reserve of Dongfeng Weir apart from playing a critical role in the fight against drought also replenishes groundwater sources and improves the ecological environment.
Two sub-canals through the county create a scenic and comfortable living environment for the residents. The sufficient water supply takes a chance in reducing the county pollution. The several changes of the site of the water intake ensured that not only the surface water of Qingyijiang River got diverted with reduced sediment load, but also helped maintain the ecological and water-soil conservation as well. Overall, the weir and canal system has made great contribution to irrigation farming, ecological conservation, and economy.
As a public infrastructure, the Dongfeng Weir with its water distribution system was originally built by local government of Qing Dynasty in 1662. The local people took charge of annual repair outlay, labor expenditure, and construction supervision the management mechanism which continued until 1949. Nowadays, Dongfeng Weir is managed by the local government and the residents. The local government take charge of the maintenance of the general canals and branch canals, meanwhile the water user association, in the village as a unit, is responsible for the sub-lateral canals. The project is providing sufficient, reliable and sustainable irrigation water supply, is now discharging combined function of irrigation, drainage, urban flood control, and catering to environmental needs.
Nowadays, Dongfeng Weir is managed jointly by the local government as well as the beneficiaries. The local administration is in charge of the maintenance of the general canals and branch canals, while the water user association is responsible for the sub-lateral canals.