In September 2025, Jianjiang Weir was added to the World Heritage Irrigation Structures list. The result was annouced by the International Commission on Irrigation and Drainage, raising the number of such Chinese facilities to 42.

Located in Pengzhou, Sichuan province, Jianjiang Weir was first constructed around 141 BC during the Western Han Dynasty. It is the oldest and most well-preserved gravity irrigation project still in operation on the Western Sichuan Plain.

Jianjiang Weir takes advantage of the supplement of both surface and ground water sources. By utilizing the geographical advantage of higher northwest and lower southeast areas, a water network by diverting water from Jianjiang River into several channels has been constructed. This addresses the problem of  uneven seasonal flow of the Jianjiang River, which frequently resulted in droughts in spring and floods in summer. More than 300 artesian spring ponds have been excavated, replenishing unstable surface water sources by shallow groundwater. At the same time, pebble arch construction technology has been adopted to channel water below while cultivating fields above.

In 2022, amid the severe drought in Sichuan, Jianjiang Weir effectively guaranteed the bumper harvest of 160 thousand mu (more than 10 thousand hectares) of farmland in the irrigation area through its capacity for water supplementation from springs/ponds and precisely regulated flow by the canal system, consolidating Pengzhou’s status as a national key commercial vegetable production base. In the same year, the irrigation area underwent a modernization upgrade centered on intelligent perception and remote control. In addition, initiatives such as establishing a scientific research base for water heritage have breathed new vitality into this 2,166-year-old weir.

Source: INTCE