Shengtian Aqueduct

Shengtian Aqueduct

Shengtian Aqueduct is a cultural relic protection unit of Sichuan Province.

Shengtian Aqueduct, also known as "Sanxi Aqueduct," is located in Sanxi Town, about 17 kilometers northeast of Wusheng County. Constructed in the 1950s, the Sanxi Aqueduct is a key part of the right canal of the Wupai Drainage Reservoir, which has a water storage capacity of 52 million cubic meters. Built in the early 1970s, it stretches across valleys and gullies over several miles, resembling a rainbow and winding like a dragon. With its grand scale and majestic presence, it stands as an extraordinary marvel in China’s agricultural water conservancy projects.

The original plan for the right main canal of the Wupai Drainage Reservoir did not include the Shengtian Aqueduct. The canal was designed largely along foothills and mid-slopes, requiring crossings over three streams and multiple landslide-prone zones. This not only posed high construction challenges but also left many hidden risks for future irrigation management. To solve this issue, after more than a month of field surveys, three options were proposed. After thorough analysis, comparative study, and repeated evaluations by technical experts and local residents, it was ultimately decided to replace the surface canal with the Sanxi Aqueduct.

Construction of the aqueduct began in 1972 and was hailed as a "model of using local materials and traditional methods." Since the area had naturally occurring high-quality sandstone — abundant and easy to quarry — suitable for on-site building material sourcing, the entire aqueduct was built by stacking rectangular stone blocks. At the time, during the late Cultural Revolution, funding, materials, and technology were all extremely scarce, so the project was carried out entirely manually. When probing foundation stability, workers used steel drills to test the ground. By listening to the sound and observing the slurry color, they judged the hardness and integrity of the bedrock. For the arch ring construction, they relied on formwork and mortar

The Shengtian Aqueduct stretches from south to north in an arched structure. The main body of the Shengtian Aqueduct comprises 10 stone arches spanning nine gullies, ten ridges, and one river, traversing the town of Sanxi. Both the trough and supporting structures are built from blocks of strip-shaped square stones, with a total length of 4,060 meters, a width of 3.4 meters, and a depth of 1.8 meters. There are 153 main arches and 270 spandrel arches, with the largest arch span reaching 20 meters, the highest single arch at 34.5 meters, and the longest arch section extending 600 meters. The spans of the stone arches come in three sizes: 10 meters, 15 meters, and 20 meters. This span design not only allows the arch formwork to be repurposed for constructing other bridge arches, eliminating the need for layout and mold-making, but also helps save on materials. From a distance, it resembles a giant dragon lying across the vast plains, with the bridge arches beneath appearing like rainbows embedded between heaven and earth or silver hooks hanging in the distant sky, exuding grandeur and majesty. The water flow rate reaches 6 cubic meters per second. The aqueduct is equipped with the Shengtian Sluice, Shengtian Tunnel, and a spillway with a total length of 15 kilometers.

Between two large arches, four smaller arches are constructed, with additional holes carved within the small arches, forming arches within arches. This not only reduces the pressure exerted by the trough and the various arches on the piers but also saves on stone material, while enhancing the aesthetic beauty and making the aqueduct even more spectacular. The cross-section of the trough is rectangular, measuring 2.2 meters in width and 1.8 meters in depth, with a water delivery capacity of up to 5.4 m³/s. The stone walls of the trough feature a water-lotus arch design, which from afar looks like evenly undulating curves, while close up resembles ripples spreading toward the trough. Every 10 meters, there is a trough chain made of reinforced concrete, firmly securing the stone walls on both sides of the arch trough. As a result, the trough not only functions as a longitudinal beam but also adds visual variety and reduces the overall weight of the aqueduct.

The Shengtian Aqueduct is built from locally sourced high-quality natural sandstone with a compressive strength of 400 kg/cm³. It is not only uniquely designed and magnificently imposing but also exceptionally sturdy in structure. Since its completion decades ago, it has withstood the test of time, standing firmly on the land of Sanxi. It has endured the tremors of major earthquakes such as the Tangshan and Songpan earthquakes, and even the rare and violent shaking caused by the Wenchuan Earthquake. Yet, it remains unmoved, defiantly standing against each onslaught from the depths of the earth. Today, it is well-preserved, with no cracks, folds, or damages in the thousands of meters of its main structure. Even under the severe corrosion of acid rain today, the rocks rooted in the aqueduct show no signs of weathering, instead being covered with lush green moss. This speaks volumes about the extraordinary precision and dedication of the builders in selecting materials, excavating foundations, preventing pier displacement, and resetting arch rings.

The Shengtian Aqueduct creatively applies the design and manufacturing principles of ancient Chinese stone arch bridges, and the entire project was completed while constructing and designing simultaneously. The project involved excavating 143,000 cubic meters of earth and stone, laying over 40,000 cubic meters of stones, mobilizing 210,000 laborers, and costing 2.5 million yuan. In 1977, the fifth issue of China Report featured a significant spread showcasing panoramic photos of the Sanxi Aqueduct along with related reports, attracting tens of thousands of visitors from within and outside the province to study and learn from Sanxi.

The Shengtian Aqueduct in Sanxi is a masterpiece and iconic representation of China’s farmland water conservancy construction during the 1960s and 1970s. It fully demonstrates the wisdom and strength of the people and is a concentrated embodiment of Mao Zedong’s belief that “man can conquer nature.” It not only plays a vital role in agricultural irrigation but also symbolizes the spirit, faith, and determination of the Chinese nation during that particular period. It bears witness to the history, politics, economy, culture, and art of that era, holding significant historical importance for studying the living conditions, spiritual outlook, ideologies, and value orientations of the nation during those extraordinary times.

As the sun sets and its afterglow bathes the scene, the aqueduct appears even more majestic and splendid, with its rows of arches stretching across the vast fields, sometimes mirroring the colorful rainbows above. The towering aqueduct stands like a monument shimmering with national spirit and the essence of the times, guiding people to forever remember that era, to remember those who toiled without complaint, braved dangers, united closely, fought strenuously, found joy in hardship while building the aqueduct, and to remember the enduring spirit and soul of the Chinese nation that has allowed it to thrive through the ages.

Nowadays, some of the irrigation channels of the Shengtian Aqueduct have fallen into disrepair due to age, leading to a gradual decline in irrigation capacity. Many rural pumping stations have outdated and aging equipment, facing issues such as severe siltation in canals, partial collapses of main channels, and leakage.

Protected area: The aqueduct structure extends 5 meters outward on both sides, and the Shengtian Sluice extends 3 meters outward.

Construction control zone: An additional 5 meters beyond the protected area.

Further reading:

· Eighth Batch of Sichuan Provincial Cultural Relics Protection Units