For example, pharaohs Senusret III and his son Amenemhat III, who ruled Egypt from 1878 BC to 1814 BC, dug a huge canal linking the Nile to the swamps of the Fayum Valley. An intricate system of dams, reservoirs and subsidiary canals diverted some of the Nile waters to Fayum, creating an immense artificial lake holding 13 trillion gallons of water.1 By comparison, Lake Mead, the largest man-made reservoir in the United States (formed by the Hoover Dam), holds at most 9 trillion gallons of water.
