Discovery helps solve ancient water mystery

In the latest round of studies from 2019, archaeologists revealed they found an artificial ridge to the northeast of the city, which stretched across the valley of the tributaries of the Chenghe River. It measures about 260 meters in length from north to south, and is 39 meters at its widest point from east to west. Its maximum visible height is 6.5 meters.

Based on explorations, archaeologists speculate that this ridge was a dam built by people of the Qujialing Culture, dating back about 5,000 years. "It was used to intercept water from the tributaries, raising the water level and creating a reservoir. Then, water could enter the city through artificial channels built through the hillock," says Peng.

Smaller dams have also been found in moats around the city to store water, he adds.

An artificial ridge belonging to the early period of Qujialing Culture in the west of the site is inferred to be part of a wall to prevent flooding.

"The discoveries enhance our understanding of ancient people's control over water. In the early period, they built a wall to intercept water, and later they built dams to make use of water. That reflects the changes in their ideas of water management," says Peng.

Zhang Chi, an archaeology professor at Peking University, says the Chenghe site's system of water management is not rare in sites located in the middle reaches of the Yangtze River, but the one in Chenghe is the most complete ever found.

According to Liu Jianguo, a researcher at the Institute of Archaeology, CASS, the people of Chenghe built dams to intercept natural river channels, preventing droughts and draining floods, which was a reasonable way of managing and allocating water resources, and is an outstanding example of prehistoric water management in the Jianghan Plain in Hubei.

"For agricultural settlements in the middle and lower reaches of the Yangtze River, the need to plant rice required people to control water. …Controlling water was an important driving force for the development of Chinese civilization there," says Liu.

More than 300 tombs have been found in the Wangjiabang cemetery to the north of the city ruins, where painted pottery, lacquerware and jade yue axes have been unearthed.

According to Peng, the site is the largest and most well-preserved Qujialing Culture cemetery discovered to date. Two other cemeteries have also been found in the neighboring area, suggesting there was a tomb area to the north of the city.

Various types of tombs provide clues to understanding the funeral rituals of the Chenghe people. For example, in the early period there was a type of tomb in which there was a large shared pit, within which there were two or more smaller pits, arranged in parallel, in which a number of people were buried. In the later period, there were tombs that only belonged to one person.

"It shows differences in funeral rituals of the Qujialing Culture people. … It reflects the complexity of the social structure and the phenomenon of social differentiation in the Qujialing Culture, and provides new evidence for exploring the process of Neolithic civilization in the middle reaches of the Yangtze River," says Peng.