Lost branch of the Nile was used to build Giza pyramids

An international team of scientists from France, China, and Egypt has recently found evidence that the Khufu branch of the Nile River once ran so close to Giza that it could have been used to carry the enormous blocks of stones needed to construct the massive pyramids which constitute one of the world’s most iconic cultural artefacts.

The researchers collected core sediment samples from several sites in and around Giza and analyzed the fossilized pollen grains trapped in them for millennia. The investigation revealed that the pollen grain fossils were mostly from flowering grasses similar to the ones that line the Nile River today. In addition, they found evidence of a few marsh plants which typically grow on the edges of lakes, indicating that the Khufu branch remained at high levels for an extended period of time.

Together with the results from previous studies of the rock layers surrounding the pyramids, these findings helped them reconstruct the history of the Khufu branch as it flowed and ebb in the area over the past 8,000 years. The analysis showed that its levels were most likely high enough that it reached nearly all the way to Giza – now located seven kilometers from the Nile – during the times when three of the major pyramids (Menkaure, Khafre, and Khufu) were constructed. 

“The Khufu branch remained at a high-water level (∼40 precent of its Holocene maximum) during the reigns of Khufu, Khafre, and Menkaure, facilitating the transportation of construction materials to the Giza Pyramid Complex,” the study author reported.

“From the third to the fifth dynasties, the Khufu branch clearly offered an environment conducive to the emergence and development of the pyramid construction site, helping builders to plan the transport of stone and materials by boat.” 

Not long after the reign of King Tutankhamun though, the levels of the Khufu branch began to drop, leading to a much more arid environment – a fundamental change that other studies of oxygen levels in the bones and teeth from the mummies of that time period has also confirmed, suggesting a period of low water access and consumption. By the time Alexander the Great conquered Egypt (332 BCE), the Khufu branch remained just a small channel.

These techniques could be used in further studies to better understand how changing river flow impacted other ancient civilizations, and thus shed new light on the role of natural factors in the development of humanity.

The study is published in the journal Proceedings of the Royal Academy of Sciences. 

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By Andrei Ionescu, Earth.com Staff Writer