Aswan Dam the water saved is lost due to evaporation in Lake Nasser, the amount of water available for irrigation still increased by 22 km. Other estimates put evaporation from Lake Nasser at between 10 and 16 cubic km per year. The dam powers twelve generators each rated at , with a total of . Power generation began in 1967. When the High Dam first reached peak output it produced around half of Egypt's production of electric power (about 15 percent by 1998), and it gave most Egyptian villages the use of electricity for the first time. The High Dam has also
Aswan Low Dam in the lower Nile. The dam, originally limited in height by conservation concerns, worked as designed, but provided inadequate storage capacity for planned development and was raised twice, between 1907 and 1912 and again in 1929–1933. These heightenings still did not meet irrigation demands and in 1946 it was nearly over-topped in an effort to maximize pool elevation. This led to the investigation and construction of the Aswan High Dam upstream. The earliest recorded attempt to build a dam near Aswan was in the 11th century, when the Arab polymath and engineer Ibn al-Haytham (known as "Alhazen" in the West)