Linear Structures Found Near The Red Pyramid Hint At How Ancient Egyptians Built These Colossal Monuments Over 4,500 Years Ago

But a new archeological discovery near Cairo is helping to reaffirm one prominent theory, that water played a star role in this ancient construction process.

The Red Pyramid

The breakthrough comes from the Red Pyramid, the largest pyramid located at the Dahshur necropolis on the west bank of the Nile Valley on the outskirts of Cairo. Along with its massive size, it's known for its rusty appearance thanks to the presence of iron oxide in its limestone blocks.

Built during the 4th Dynasty under the reign of pharaoh Sneferu around 2590 to 2575 BCE, it’s believed to be one of the first "true" smooth-sided pyramids built by the ancient Egyptians.

Old theories kicked out

In the 19th century, archaeologists unearthed two linear structures just southwest of this pyramid. Later research argued they were two causeways, or perhaps even a ramp, used to transport materials from local quarries towards the construction site.

However, a stream of recent research has shown that the Nile Valley landscape has changed significantly since the pyramids were constructed.

Over 30 pyramids are situated along a vertical strip between Giza and Lisht along the edge of the barren desert, including the Great Pyramid of Giza and the Red Pyramid, leading researchers to believe they might have once sat along a long-lost branch of the river system.

In light of this idea, team behind this latest study were curious to see how the mysterious structures near the Red Pyramid might have fitted into this narrative.

The new study

Scientists from Paleotechnic, a private research institute based in Paris, combined satellite imagery with watershed mapping to conclude that the two long structures were probably not transport ramps after all. 

Instead, they argue they were dams designed to control the flow of a lost watercourse known as Wadi Dahshur.

According to the study, the dams would have stretched between 600 and 700 metres (1,970 to 2,300 feet), taming the river’s flash floods while diverting water towards the Red Pyramid.

“The eastern structure likely served as the main water-retention dam, whereas the western structure, equipped with a duckbill weir, may have acted as a check dam, trapping sediment and regulating flow into the diversion channel,” the study authors write.

“Taken together, the two structures may therefore have operated as a coupled hydraulic system, regulating episodic runoff, buffering flood peaks, and managing sediment fluxes before water was delivered to the upstream diversion channel or released in the downstream Wadi Dahshur,” they added.

Before you build a pyramid, you must build a dam

The researchers go on to suggest this hydraulic system may have done more than simply control flash flooding. By maintaining navigable waterways leading towards the construction site, it could have allowed workers, limestone blocks, timber, food, and other supplies to be transported by boat.

As such, the team suspects many other dam-like structures are likely to be out there, buried somewhere in the sands of the Nile Valley. 

“These results reinforce the view that water management, including flood regulation and controlled surface -water exploitation beyond the Nile floodplain, may have played a more significant role in Old Kingdom engineering strategies than traditionally assumed,” the paper reads. 

“Other hydraulic structures are most probably lost in the desert, waiting to be identified.”

Long-lost river systems, dams, and canals might explain how materials reached the construction site, but many questions remain about how exactly the pyramids were built, like how millions of stone blocks, some weighing several tons, were stacked on top of each other in near-perfect formation.

Nevertheless, Egyptologists and archaeologists are slowly but steadily piecing together the story.

The new study was published in the journal npj Heritage Science.