By Jay Lund, Shumin Liang, and Tingju Zhu
. . .
Every civilization had to organize the management of water across diverse populations and generations. Their histories offer perspective and relevance for water management today and in the future. Achieving human health, wealth, social justice ideals, and ecological sustainability all depend on managing water for drinking, food production, sanitation, flood protection, and sometimes for navigation and defense.
Perhaps the earliest human civilization to manage water intensively over a region was the Liangzhu civilization from 5,100 – 4,300 years before present (3,100 – 2,300 BC), north of Hangzhou, China, in the southern part of the larger Yangtze Delta region. Different from other early water projects in ancient Egypt, Mesopotamia, and the Indus Valley, the Liangzhu system goes beyond river diversions and has a group of water storage dams at its core, with flood control, transportation, and defense purposes as well as water supply to provide more comprehensive basin management.
We (the authors) visited the main Liangzhu site recently. The ancient Liangzhu water project included 11 dams, as well as kilometers of canals and levees, dating from 5100 years before the present. It is one of the earliest dam systems discovered and was listed as a World Heritage Site in 2019. Figure 1 shows the main site for this civilization and its regional water system.
Liangzhu culture was based on extensive rice cultivation and water management, along with extensive jade item manufacturing, but it was a Neolithic society without writing or metals. The main city had a population of 3050 thousand and featured a large centralized granary, with hundreds of thousands of people in the broader cultural area around Lake Taihu on the lower reaches of the Yangtze River. Then, as today, water management (and societies) usually benefit economically from operating at larger scales, but also have growing social challenges with larger scale.
The main Liangzhu water system included a large low-elevation reservoir (50.7 million cubic meters (41 thousand acre-feet) storage capacity) and several higher-elevation reservoirs (totaling 15 million cubic meters (12 thousand acre-ft) storage capacity) formed by several dams and saddle dams on local streams. The dam structure volumes totaled 2.9 million cubic meters. Extensive canals connected these water sources to irrigate rice fields, water and defend cities, support transportation, and drain flood waters. Levees also were built to shunt water away from some areas, sometimes into the lower reservoir. Interestingly, the smaller higher-elevation dams were built before the larger, lower reservoir.
How were these reservoirs operated?
Direct archeological and scholarly insights seem lacking. No contemporary written accounts exist. But it is likely that the reservoirs were operated seasonally to move some water from the wet season to the latter part of the rice growing season, as well as providing some flood buffering. Growth in the drier latter part of the rice growing season could have been supported by flows from the reservoirs, making the area’s crop yields less dependent on rainfall and natural flows and less threatened by early-season floods.
Dam construction for this complex was sophisticated, and the longevity of the original dams attests to the quality of their construction, although there might have been phases of reconstruction. The upper dam heights were 10-20 meters and lower dam heights 2-5 meters. The upper dams, in particular, were systematically constructed with clay cores made of bundles of clay wrapped in grass, which compacted and sealed with construction compaction and time. Coarser outer soil layers strengthened and supported the dams’ clay cores, much like modern earthen dam construction.
The dam’s outlet structures remain a mystery. Lacking metallurgy and evidence of large cut stones, outlet structures might have used natural geologic features as weirs, piled stones, timber frames, perhaps with wood or wicker low-head gates or flashboards.
Social Infrastructure for water management
What was the social basis for water system construction, operation, and maintenance? Hydraulic structures are not built, maintained, or operated without an organizing and motivating social structure and goals. The longevity, scale, and diverse agricultural irrigation, flood control, transportation, sanitation, and defense purposes of the Liangzhu water system implied a need for sophisticated social leadership and broad and substantial social involvement.
Many ancient civilizations managed their hydraulic systems using religious institutions, leadership, and practices, from Bali to Ankor Wat (Scarborough 2017). A religious and governmental center likely mutually reinforced market, production, and social centers. This seems likely to have occurred also in the Liangzhu civilization, which seemed to have had a clear hierarchical social structure and would have needed to systematically organize thousands of workers for infrastructure construction, maintenance, and operation over hundreds of years.
The demise of the Liangzhu civilization seems at least partially explained by increasing extremes of flood and drought in its last centuries, after about 1,000 years of relative prosperity (Zhang et al. 2021). Yet, this civilization pioneered the way for future civilizations and water management in China for millennia to come, through the present day.
Today we now have water use fees and taxes by governmental and private institutions to support and sustain the benefits of water management to societies and individuals, although our water discussions still sometimes reflect religious-like fervor.
About the Authors
The authors are present and past professors and students together who were visiting the ancient Liangzhu water system sites while visiting Professor Zhu. The name of the civilization being a combination of the names of two former students is pure prophetic coincidence.
Jay Lund is an Emeritus Distinguished Professor of Civil and Environmental Engineering at the University of California, Davis.
Shumin Liang is Professor of Agricultural Economics at Chinese Academy of Agricultural Sciences (CAAS).
Tingju Zhu is Professor of Civil Engineering at Zhejiang University.
Further Reading
Chen, M. (2022), China and the World in the Liangzhu Era, Springer and Zhejiang University Press.
Liu, B., et al. (2023), “Earliest hydraulic enterprise in China, 5,100 years ago,” PNAS, Dec. 26, 2017, vol. 114, no. 52, pp. 13637–13642, www.pnas.org/cgi/doi/10.1073/pnas.1710516114
Scarborough, V. (2017), “The hydraulic lift of early states societies,” PNAS, pp. 13600–13601, December 26, vol. 114, no. 52, www.pnas.org/cgi/doi/10.1073/pnas.1719536115
Zhang, H., et al. (2021), “Collapse of the Liangzhu and other Neolithic cultures in the lower Yangtze region in response to climate change,” Sci. Adv. 7 (48), eabi9275. DOI: 10.1126/sciadv.abi9275, https://www.science.org/doi/10.1126/sciadv.abi9275
Zhu, Y. (2022), Eighty Years of Archaeology at Liangzhu, Springer and Zhejiang University Press.
The Great Ancient Ruins: Liangzhu, CGTN. https://www.youtube.com/watch?v=2Bich0hnS7I
Leave a Reply