Four thousand years ago, in the central plains of China, a community of about five hundred people built something that has taken us millennia to discover: a network of Longshan period ceramic pipes buried beneath their streets. They are not the oldest pipes in the history of humanity (that honor belongs to the Temple of Bel in Nippur and Eshnunna in Mesopotamia), but they are those of China.
Finding such an ancient and complete drainage network is a milestone from an architectural point of view, but the discovery goes one step further: it demonstrates that preparation for natural disasters is truly something of a lifetime. Because the pipelines at the Pingliangtai oilfield were built monsoon-proof.
The discovery. The paper published in Nature Water describes the results of excavation and a geoarchaeological study of water management infrastructure, which reveal the operation and maintenance of a well-planned and regulated two-level rainwater drainage system. On the first level there were individual domestic ditches that collected water from each home and on the second a network of ceramic pipes buried under the roads and next to the walls, responsible for channeling the water outside the urban center.
The operation is surprisingly modern: each segment of pipe measured between 20 and 30 centimeters in diameter and between 30 and 40 centimeters in length and were assembled together thanks to a recess at one end, so that once joined they allowed water to be transported over long distances.
Why is it important. The relevance of the finding has two dimensions, the technical and the social:
- The Pingliangtai pipe network is the oldest and most complete urban drainage discovered to date in China, making it a reference for understanding Neolithic water engineering in East Asia.
- It calls into question the “hydraulic despotism” theorized by Karl Wittfogel: historically this type of infrastructure has been associated with centralized states with ruling elites capable of undertaking it, but in Pingliangtai there is no evidence of noble palaces or great social inequalities, which suggests that this sewage network was created through community cooperation.
Context. The Longshan period spanned approximately 2600 to 2000 BC About 4,000 years ago, the central plains region of China suffered from an extremely variable monsoon climate: summer monsoons could dump 45 centimeters of rain per month on the region, as evidenced by geological evidence of catastrophic rainfall events. These seasonal floods constituted a threat to permanent settlements, so in that transition period between the late Neolithic and the early Bronze Age, towns began to build defensive walls, not only against enemies, but against water.
Pingliangtai was a perfectly square walled city that housed about 500 people and had protective walls and a moat around it. It is located on the plain of the Upper Huai River, in the vast plain of Huanghuaihai, precisely in that region of China. The drainage system was the technical solution to an existential problem: how to inhabit a flood-prone area without the adobe homes dissolving with each storm.
With “up to date” maintenance. The dating of the pipes indicates that they are between 3,900 and 4,100 years old and the ditches showed signs of various repairs and even reconstructions, which shows that there was maintenance. The quality of the ceramic indicates advanced knowledge in clay firing, essential to guarantee the durability and impermeability of the system.
And be careful, because the research team found the pipe segments in situ, assembled and structurally intact after 4,000 years, quite an achievement. Given that the slope exists, the design is coherent and the tubes still fit, the hydraulic logic is still intact. Bottom line: if water was introduced into those fragments, it would work.
What the discovery reveals about the city and society. What most attracts the attention of the research team from Peking University and the Institute of Archeology at University College London is that the Pingliangtai settlement points to a horizontal and highly organized society. All the houses were uniformly small and not even the cemetery left any clues to social hierarchy, something different from excavations in other nearby cities.
Unlike Mesopotamia or Egypt, where these constructions were commissioned by kings, the design of the houses and the distribution of pipes suggest that decisions were made communally. Thus, water management in Pingliangtai gravitated toward shared collective interest in response to frequent environmental contingencies. Additionally, it displays a long-term prevention and maintenance mindset, as the system required constant cleaning to prevent sediment blockages.
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