Hydraulics, a new solution to a 4000-year-old mystery

For years, Egyptologists have been arguing over how the massive pyramids of ancient Egypt were built more than 4,000 years ago. Now, a team of engineers and geologists has come up with a new theory – a hydraulic lift that could have lifted heavy blocks of stone up the middle of Egypt’s oldest pyramid using the power of water.

The ancient Egyptians built the Step Pyramid for Pharaoh Djoser in the 27th century BC, and it was the tallest structure at the time, standing at around 62 metres (200 feet). But how exactly was this pyramid built, with some of its stones weighing up to 300 kilograms (660 pounds)? Scientists have now provided a surprising answer to a centuries-old mystery, according to research published in the journal PLOS One.

Dr Xavier Landreau, Executive Director of the Paleotechnic Institute and lead author of the study, said that the step pyramid located at the Saqqara cemetery, located on a limestone plateau on the west bank of the Nile, may have been built using a clever hydraulic lift system.

The study authors suggest that the system involved water flowing into two shafts located inside the pyramid, allowing pontoons to be raised and lowered to lift the large stone blocks used to build the structure.

By analyzing available data, including paleoclimatology, paleoclimate studies, and archaeological data, the team hypothesized that water from ancient streams flowed from the western Saqqara plateau into a system of deep gullies and tunnels surrounding the step pyramid.

Water will also flow into the Gisr el-Mudir, a giant rectangular limestone structure measuring 650 by 350 meters that will act as a check dam. The dam will control and store water from major floods, as well as filter out sediment and dirt so it doesn't clog the waterways.

"Through this hydraulic network, water would be directed to a central well beneath the pyramid and, through cycles of filling and draining, a buoy carrying the stones would be raised," said Dr. Landreau. "The Pyramid of Djoser would have been built like a volcano, with building materials pouring into its central axis."

The Sahara was once a steppe with high rainfall.

According to the PLOS One article, the Step Pyramid of Djoser was built below a basin and likely had access to a significant water supply at the time. The authors also point to previous research suggesting that the Sahara Desert had more regular rainfall thousands of years ago than it does today. And the landscape would have been more like a savanna, which could support a wider variety of plants than arid desert conditions.

Dr Judith Bunbury, a geoarchaeologist at the University of Cambridge in London, said there may have been enough water to support a system like a hydraulic lift. She pointed to previous research that found rain gutters were built and used in the Old Kingdom (dating from 2686 to 2181 BC), as well as previous research that looked at the diet of birds during that time, which included wetland species like frogs.

"I think there's a fairly widespread belief that the Old Kingdom was wetter, particularly in the early Old Kingdom, when the step pyramid was being built," Ms Bunbury added.

Accordingly, continuous rainfall could have filled structures that supported hydraulic lifts, such as the "Dry Moat," a giant channel surrounding the step pyramid and nearby structures, which the authors believe accumulated water that helped power the lifts when in use.

Of course, more research is needed to confirm the hydrostatic hypothesis, but Dr. Landreau says this is a possible explanation because “Ancient Egypt was a ‘hydraulic civilization’ skilled in managing irrigation canals and transporting heavy stones over long distances.”

“Hydraulic lift systems could hold the key to unlocking the mystery of how the largest monoliths, found in pyramids like Khufu or Kephren, were lifted,” said Dr. Landreau. “These monoliths weigh tens of tons, making them seemingly impossible to lift by human power alone. In contrast, a medium-sized hydraulic lift could lift 50 to 100 tons. Exploring hidden shafts inside these pyramids could be a promising research direction.”

Quang Anh (according to Newsweek, CNN)