Ancient Egyptians May Have Used Hydraulic Lift to Build Pyramid

Standing as much as hundreds of feet tall and made of stones weighing up to 100 tons, Egypt’s pyramids are a remarkable feat of ancient engineering. To this day, scientists aren’t entirely sure how they were constructed.

In a study published Monday in the journal PLOS One, researchers propose that ancient people may have relied on water to build the Step Pyramid of Djoser in Saqqara, Egypt. They suspect a hydraulic system may have helped lift stones from the center of the pyramid.

“This is a watershed discovery,” Xavier Landreau, first author of the new study and CEO of the private research institute Paleotechnic in France, tells Live Science’s Jennifer Nalewicki. “Our research could completely change the status quo [of how the pyramid was built].”

Some other researchers are not yet convinced by the argument.

Judith Bunbury, a geoarchaeologist at the University of Cambridge in the U.K. who did not contribute to the findings, tells Ars Technica’s Jennifer Ouellette that while there is evidence of Egyptians using other hydraulic technologies at the time, there isn’t evidence of a hydraulic lift system.

“While information from this period is sparse, it is not absent, and it is surprising when so many other details of daily life and technologies are recorded in the Old Kingdom tomb scenes and texts like the Red Sea Scrolls, that this type of device is omitted if it were in use,” she says to the publication.

The Step Pyramid of Djoser was built around 4,700 years ago as a burial complex for King Djoser. It’s the oldest important stone building in Egypt, according to Encyclopedia Britannica. The Step Pyramid was the first design to use a pyramid shape for the pharaoh's grave and was innovative in how it raised and precisely stacked stones that had been shaped in a particular fashion, per the new paper.

The stones used for the pyramid weighed more than 650 pounds, and the building stretched to about 200 feet high. Later pyramids would grow to taller heights and were made of even larger stones.

Researchers have proposed many techniques that ancient Egyptians may have used to raise stones to the heights needed to construct the pyramids, including ramps, cranes, hoists and pivots. But “no generally accepted wholistic model for pyramid construction exists yet,” the study authors write.

For the new study, the researchers propose that a massive enclosure to the west of the pyramid could have served as a dam that trapped sediment and water. Water could have then flowed east into a floodplain that was possibly once a lake, and from there into the Dry Moat surrounding the pyramid.

The researchers argue that compartments in the moat could have acted as a water treatment facility, purifying water and regulating its flow.

Finally, the water in the moat may have been used to elevate stones. Water entering a vertical shaft could have allowed a pulley system to raise a float and lower a platform, writes Science News’ Bruce Bower. Then people could have placed rocks on the platform and drained the shaft, lowering the float and raising the platform, per Science News.

Researchers have previously found evidence that ancient Egyptians used hydraulics for other purposes, such as delivering materials, building ports and locks and constructing irrigation systems, the study authors write.

Bunbury tells CNN’s Taylor Nicioli there may have been enough water to support a hydraulic lift. On the other hand, Oren Siegel, an archaeologist at the University of Toronto who was not involved in the research, tells Science News that the proposed dam could not have held enough water from occasional rain to maintain a hydraulic system.

“My biggest concerns about the study are that no Egyptologists or archaeologists were directly involved and that the authors actually question the use of the Djoser Pyramid as a burial site,” Julia Budka, an archaeologist at Ludwig Maximilian University of Munich who did not contribute to the findings, wrote to Live Science in an email, after reading a pre-print version of the paper. "Scientifically, their hypothesis is not proven at all.”

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Will Sullivan is a science writer based in Washington, D.C. His work has appeared in Inside Science and NOVA Next.