“In 2300 BC, the waterway from the Nile to the natural lake was widened and deepened to make a canal that now is known as the Bahr Yussef. This project was started by Amenemhat III or perhaps by his father Senusret III. This canal fed into the lake. This was meant to serve three purposes: control the flooding of the Nile, regulate the water level of the Nile during dry seasons, and serve the surrounding area with irrigation. There is evidence of ancient Egyptian pharaohs of the twelfth dynasty using the natural lake of Faiyum as a reservoir to store surpluses of water for use during the dry periods.”
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“The immense waterworks undertaken by the ancient Egyptian pharaohs of the twelfth dynasty to transform the lake into a huge water reservoir gave the impression that the lake was an artificial excavation, as reported by geographers and travellers during classical times.[5] The lake was eventually abandoned due to the nearest branch of the Nile shrinking from 230 BC.”
https://en.wikipedia.org/wiki/Lake_Moeris#History