How did ancient Egyptians use basin irrigation from the Nile?

Ancient Egyptians utilized basin irrigation to harness the Nile River's predictable annual flood for agriculture. This traditional method involved the following process:

• Land Preparation: Farmers divided the flat floodplain into a series of large basins using earth banks. These basins varied in size, sometimes reaching up to 50,000 acres.1
• Inundation: During the annual flood, the basins were filled with water, which was allowed to remain on the fields for up to six weeks.1
• Deposition and Planting: As the river level fell, the water was drained away, leaving behind a thin, nutrient-rich layer of silt. Farmers then sowed autumn and winter crops into the waterlogged, enriched soil.12

This system required significant social organization and engineering to manage the dikes and embankments. While effective, it limited farmers to one crop per year and left them vulnerable to annual fluctuations in flood size. Consequently, this method has been largely replaced by perennial irrigation systems.21