The ingenuity of ancient Egyptian engineers may have been even more ahead of their time than we thought. A new study suggests a currently unexplained ancient structure may have been part of a water purification system feeding a hydraulic lift to raise huge stone blocks to build a pyramid.
From our vantage point thousands of years later, the specific steps of how ancient wonders were built have been lost to time, leaving us with massive, mysterious monuments that we can’t always explain. Aliens are often suggested to have lent a hand, but that explanation doesn’t really give due credit to ancient people, who had much more advanced understandings of engineering and geometry than we might realize. New evidence now suggests that the ancient Egyptians used a unique hydraulic lift system to build their early pyramids.
Built around 2680 BCE, the Step Pyramid of Djoser is the oldest surviving pyramid in Egypt, and it seems to have been a kind of practice run for many of the techniques used in the later, larger structures. A few hundred meters away is a square enclosure called Gisr el-Mudir, the exact purpose of which has been unknown since its rediscovery almost 200 years ago.
In the new study, scientists propose that Gisr el-Mudir was a check dam, designed to trap water and sediment. The area around it shows signs of having been an ancient floodplain, and Gisr el-Mudir seems to have been built right across the long-since-dried Abusir river.
As water flowed from west to east, it would have first come across the structure’s western wall. When it flowed over this wall, the water would have ended up in a large basin, almost 400 m (1,310 ft) wide. On the opposite side, the eastern wall reached a much lower elevation, and the water would have spilled over this wall into another lake, then fed into a series of trenches and tanks around and under the Step Pyramid.
The team proposes that this system would not only have helped protect the structures downstream from floods, but purified the water. A reservoir before the western wall would have captured denser gravel, while the basin formed by Gisr el-Mudir allowed coarse sand to settle to the bottom. Finally, the trenches and tanks are consistent with other ancient water treatment techniques.
But it wasn’t just for drinking and agriculture – the team also found evidence of this water being used for something previously unheard of. The Step Pyramid contains a vertical shaft about 28 m (92 ft) tall, connected by a long pipe to the trenches. It seems like this shaft could be filled and drained on demand, which the team hypothesizes was used to raise and lower a wooden float. Essentially, stone blocks could have been brought in at ground level and placed on the float, the shaft is flooded to raise the platform to the desired height, then workers could remove the block and use it for construction of the pyramid.
After the Step Pyramid had been constructed, this shaft was sealed off and left empty. The trenches meanwhile could have continued to be used for purifying water. It’s an intriguing idea, but one that needs further research to understand better, the team says.
“A collaborative effort between the newly established research institute, Paleotechnic, and several national laboratories (INRAE, University of Orléans) has led to the discovery of a dam, a water treatment facility, and a hydraulic elevator, which would have enabled the construction of the Step Pyramid of Saqqara,” said the authors. “This work opens a new research line for the scientific community: the use of hydraulic power to build the pyramids of Egypt.”
The research was published in the journal PLOS ONE.
