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How did basin irrigation work in ancient Egypt?

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Side view of the Sphinx with the Great Pyramid of Khufu rising behind it on the Giza Plateau near Cairo, Egypt. — ancient Egypt Side view of the Sphinx with the Great Pyramid of Khufu (Cheops) rising in the background, Giza, Egypt.

Basin irrigation was a traditional agricultural method used in ancient Egypt to harness the predictable annual flooding of the Nile River. The system relied on the natural slope of the land, which allowed water to flow from the riverbanks toward the desert on either side.1

To implement this system, farmers divided the flat floodplain into a series of large basins using earth banks. These basins varied in size, with some covering as much as 50,000 acres. During the annual flood, these basins were inundated, and the water was held on the fields for up to six weeks. This process allowed the soil to become thoroughly saturated and deposited a layer of nutrient-rich Nile silt, which rejuvenated the land for cultivation.12

Once the river level receded, the remaining water was drained away, and farmers sowed autumn and winter crops in the waterlogged, enriched soil. While this method was highly effective, it generally limited farmers to a single crop per year and left them dependent on the annual fluctuations of the flood.1