Built in the Yuan Dynasty (A.D.1271-A.D.1368), Zhidanyuan Sluice boasts of a history of 700 years. This ancient sluice came to light by means of archaeological excavation, standing as one of the best-preserved ancient water projects in China so far. The sluice lies at the junction of Zhidan Road and Yanchang West Road in the Shanghai's Putuo District.
The Layout of Zhidanyuan Sluice
In the Qin (B.C.211-B.C.207) and Tang (A.D.618-A.D.907) Dynasties, the Dongjiang River, the Songjiang River and the Loujiang River acted as the main waterways for the Taihu Lake to empty itself into the sea. However, due to the daily tidal waves, these three river courses were easily choked by the sea silts. In the Northern Song Dynasty (A.D.960-A.D.1127), the Wusong River (the Songjiang River) was the only existing waterway that still connected the Taihu Lake and the sea, but it also became increasingly silts-clogged. Just as the history recorded "two rivers (the Dongjiang River and the Loujiang River) have been clogged, and only the Wusong River (the Songjiang River) remains". Apparently, the siltation of the Wusong River became more serious in the Yuan Dynasty after experiencing natural siltation, artificial dredging and river course shifting. Thus, Zhidanyuan Sluice, a man-made dredging project, was built up as a tailor-made solution to defy the natural siltation of the Wusong River.
The Map of the Shanghai's Water System in the Yuan Dynasty
Zhidanyuan Sluice was one of the numerous projects built in the Yuan Dynasty to tackle the siltation of the Wusong River. These diverse projects consisted of stone and wooden sluices, whose main roles were to block and clean up tidal sands and silts.
The Cross Section of Zhidanyuan Sluice
With a width of 6.8 meters and a total area of 1,500 m2, the sluice is composed of gates, walls, bottom stones, rammed earth, etc. Moreover, it features in the sphere of the rigorous layout, elaborate construction method, high-quality materials and outstanding workmanship.
The first step of construction was to select the sluice location. Once the bottom trench was dug, about 10,000 pine piles with a length of 4-6m each were staked down to reinforce the soil base. Every pile was numbered to enable each engineering detail to be well recorded. This approach not only shows a monitoring method of the construction process, but also embodies the essence of Zhidanyuan Sluice.
Pine Piles
Secondly, the gaps among the piles were filled with gravels and further compacted. Afterwards, place wooden beams on the piles, and lay down stone-lined wooden boards. On top of that, bluestone slabs were placed, serving as bottom stones. Then, approximately 400 iron ingots were deployed to hold these stone slabs together.
Consequently, set up gate walls and then erect gate stone columns. The foundation of gate walls were made of large stones and built on stone-lined wooden boards. Then, multi-layer stone bars were placed on top of those boards. The gate stone columns were sandwiched between these stone walls.
Finally, outside the stone walls, bricks were lined, and then waste rocks were piled up and filled with lime-soils.
In accordance with archaeological findings, Zhiduanyuan Sluice pursues excellence in the sphere of design, construction, function, workmanship and even gaps among rocks. The quality of construction 700 years ago was not inferior to today's level.
Bottom Stones
Zhidanyuan Sluice serves as a rare real-world exhibit that sheds light on the history of water engineering in the Wusong River, the Taihu Lake Basin and China as well as the economic strength of Shanghai during the Yuan Dynasty. It is also an invaluable material to research the evolution history of Shanghai from town to metropolis. Hence, this facility plays an extremely pivotal role in the history of water engineering and urban development in China.
