Dongfeng Weir

Dongfeng Weir

Dongfeng Weir, a World Heritage Irrigation Structure located in Jiajiang County, Leshan City, Sichuan Province, is the first such heritage site in Sichuan.

Dongfeng Weir is located on the left bank of the Jiajiang section of the Qingyi River, a third-order tributary of the Yangtze River. It is a water conservancy project in Jiajiang County primarily used for agricultural irrigation, while also providing urban flood control, power generation, as well as water supply for urban and rural industries and daily life, along with urban environmental protection functions. The project was initially built in the first year of the Kangxi reign during the Qing Dynasty (1662), and has been in continuous use for over 350 years. Dongfeng Weir is now the second-largest water conservancy project in Leshan City and a key infrastructure project in Jiajiang County. The irrigation area is co-managed by both government and local communities, featuring a well-developed and rationally distributed canal system that enables gravity-fed irrigation. Currently, Dongfeng Weir draws water without a dam from the Wulidu Qianfoyan Hydropower Station reservoir area in the Jiajiang section of the Qingyi River, with a diversion flow rate of 50 m³/s. The irrigation zone covers 48 villages across four towns in Jiajiang County—Yancheng, Huangtu, Ganlin, and Ganjiang—providing agricultural irrigation for over 70,000 mu of farmland.

The Qingyi River originates from Jiajin Mountain in Baoxing County, Sichuan Province, stretching 289 kilometers in length with a drainage area of 12,928 square kilometers. It boasts abundant water resources, and the Jiajiang section has an average annual flow of 515 m³/s. This consistent and plentiful water supply has made both riverbanks highly suitable for irrigated agriculture. During the Yuan and Ming dynasties, numerous small-scale weirs such as Baxiao Weir and Shijie Weir were gradually developed. In the first year of the Kangxi reign (1662), amid water shortages in the Qingyi River, Wang Shikui, then the magistrate of Jiajiang County, constructed a bamboo cage dam in the river, dug canals to divert water for irrigation, and incorporated downstream irrigation channels such as Baxiao and Shijie into the system. The weir's intake was located outside Pilu Temple and was thus named Pilu Weir. In 1900 (the 26th year of the Guangxu reign), it was renamed Longtou Weir. In 1930, due to riverbed erosion and resulting difficulties in water diversion, Hu Jiangrong, then the magistrate of Jiajiang County, relocated the intake from Longnaotuo to Yingjiang Shigu Slope upstream. In 1967, it was renamed Dongfeng Weir. In 1975, the intake was moved again from Shigu Slope further upstream to Wulidu in Qunxing Village, Yingjiang. Having been in use for over 350 years, Dongfeng Weir stands as a model of traditional dam-less water diversion irrigation in the Qingyi River basin.

Over the past 350 years, the ancient weir’s intake has been moved multiple times to counteract the continuous downcutting of the Qingyi River’s riverbed, thereby ensuring the sustainable use of the irrigation area. The irrigated area has expanded from the original 467 hectares to 5,113 hectares—an increase of more than tenfold. The crop rotation index within the irrigation zone has risen from 2.34 to 2.68, and the planted area has increased from 175,300 mu to 200,500 mu. Through the reclamation of medium- and low-yield fields, the annual added output value reaches 15.8768 million yuan. Based on a comprehensive water conservancy benefit allocation coefficient, this translates to an annual added output value of 4.4455 million yuan.

Dongfeng Weir flows past the Qianfoyan Rock Carvings, a national key cultural relics protection unit, together forming a culturally and historically dynamic corridor along the Qingyi River that balances motion and tranquility. The water management steles coexist with the grotto carvings, spreading the heritage of irrigation civilization and enriching its cultural significance. In addition, the East and West Main Canals of Dongfeng Weir run through the urban area of Jiajiang, enhancing the city’s water supply and drainage systems while beautifying the urban environment.

For centuries, Dongfeng Weir has made significant contributions to Jiajiang County’s agricultural development, increased crop yields, farmers’ incomes, improvement of the urban living environment, and the beautification of tourist attractions, demonstrating notable economic, social, and ecological benefits. Owing to its advanced engineering techniques and management practices at the time, it stands as an outstanding example of sustainable river-based irrigation engineering in southwestern China. Through traditional dam-less water diversion methods, it achieves gravity-fed irrigation, boosting local agricultural growth. Collaborative management by local government experts and rural water user associations has ensured the project’s continuous operation for over 350 years. Moreover, the project has preserved numerous historical and cultural sites along its route, such as Qianfoyan, which bear witness to the important role of irrigation works in regional history and culture. This project exemplifies the sustainable use of traditional water infrastructure and the integration of water conservancy with local culture, serving as a microcosm of the vanishing river irrigation agriculture in East Asia.

Further Reading:

· World Heritage Irrigation Structures