Shuangjin Sluice

Shuangjin Sluice

Shuangjin Sluice is one of the historical and cultural relics in Huai'an City, Jiangsu Province, known as the "Canal Capital of China." It is located in Shuangzha Village, Lingqiao Township, Huaiyin District, Huai'an City. In 2011, it was designated as a Jiangsu Provincial Cultural Relics Protection Unit and is one of the heritage sites of the Grand Canal's application for World Cultural Heritage status.

The earliest Shuangjin Sluice was constructed in the 24th year of the Kangxi reign (1685) due to the Yellow River's backflow into Qingkou. Jin Fu “petitioned to build a large double-gated sluice west of Qinghe County, with an excavated diversion channel ten thousand zhang long downstream to divert and discharge the Yellow River flow into the sea, benefiting the canal route.” Shuangjin Sluice is the abbreviated name for the Double-Gated Great Sluice, with each gate being 1.8 zhang wide, making the total width of both gates 3.6 zhang. Initially, the purpose of the Shuangjin Sluice was to divert and discharge the Yellow River water, which could lower the water level at Qingkou by one or two zhang, facilitating the passage of grain transport boats across the river. In the 26th year of the Kangxi reign (1687), the Middle Canal was opened, with a sluice constructed at Zhongjiazhuang to control the flow, allowing the canal route to bypass the 180-li danger of the Yellow River via the Zhongjiazhuang Sluice. Additionally, “a canal was excavated starting from the northwest of Qinghe County, passing through Andong City,... and extending to Pingwang River, eventually entering the sea via the Chao River (Guancheng River) southeast of Andong, also serving salt transport. It was called the Lower Middle Canal, also known as the Salt Canal.” The Shuangjin Sluice thus became the headworks of the Salt Canal.

In the 24th year of the Kangxi reign (1685), the Director of River Works, Jin Fu, submitted a proposal to construct the Shuangjinmen Sluice and excavate a diversion channel beneath it. Jin Fu stated: “The Hongze Lake spans several hundred li, and the diverted upper-stream Yellow River water is inevitably prone to backflow. Now, a large double-gated sluice will be built west of Qinghe County, along with over ten thousand zhang of diversion channel excavated beneath the sluice. In the event of an extreme rise in the Yellow River, this sluice can be immediately opened to divert and discharge the water into the sea, thereby reducing the Yellow and Huai rivers’ confluence water level by one to two zhang, benefiting the canal route.” Emperor Kangxi approved Jin Fu’s proposal. After the completion of the Shuangjinmen Sluice, in cases of extreme Yellow River rises, the sluice would be opened to divert and discharge the floodwaters into the sea, reducing the water level at the confluence of the Huai and Yellow rivers by one to two zhang. Originally built to discharge Yellow River water, the Shuangjin Sluice was repurposed in the 42nd year of the Kangxi reign (1703), when the canal mouth was moved to Yangzhuang, to exclusively discharge water from the Middle Canal. During winter and spring, the sluice was opened to release water to support the salt canal transportation. The existing Shuangjin Sluice was designed and planned in the 11th year of the Republic of China (1922) by British engineer Lane, hired by the Republican government. Its sluice floor uses pile foundation cement concrete, while the sluice walls are built with cement mortar and stone blocks, with a downstream scour protection base thickness of 1–1.3 meters. The Shuangjin Sluice marks the beginning of using cement as a binding material in hydraulic engineering history. Oriented toward Xingshan, it has a shuttle-head design, with each gate being 7.5 meters wide, sluice walls 8 meters high, 21 layers of stone stacking, and an approximately 60-meter-wide core structure. A stilling basin was built at the outlet to reduce the impact force of the discharged water. Downstream, sheet piles were added and protected with block stones to resist scouring. Steel-frame wooden gates were installed, along with a working bridge and hoisting machinery operated manually. The diversion channel’s upstream clamp dam was reconstructed from fascine work to cement-laid masonry, with a 13.5-meter-wide opening. The Shuangjin Sluice represents the beginning of foreign-designed hydraulic projects, the introduction of Western water conservancy science and technology, and the use of cement, steel gates, and mechanical gate-operating equipment. Its overall structural integrity, strength, and durability were greatly improved, making operation more flexible and reliable. Thanks to the introduction of new technologies and materials, hydraulic engineering advanced significantly. In the 1970s, the Shuangjin Sluice was reconstructed into the Xiajiahu South Power Station. The Shuangjin Sluice holds significant historical, scientific, and artistic value, offering important insights into the Qing Dynasty’s strategies for managing the Yellow and Huai rivers and supporting canal transport, the development of water conservancy during the Republican era, changes in the river course, and the modern socio-economic development of the Huai'an region.

In 2003, the Shuangjin Sluice was designated as a Municipal Cultural Relics Protection Unit by the Huai'an Municipal People's Government. In December 2011, it was listed as part of the seventh batch of Provincial Cultural Relics Protection Units by the Jiangsu Provincial People's Government.

Further Reading:

· Seventh Batch of Jiangsu Provincial Cultural Relics Protection Units