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
Hydropower policy in the United States of 90% efficiency. More importantly, Francis's mathematical and graphical calculation methods advanced turbine design and engineering and allowed confident design of high efficiency turbines to exactly match a site's flow conditions. In the 1870s and deriving from uses in the mining industry, the high efficiency Pelton wheel impulse turbine was developed to use hydropower under very different flow and pressure conditions. Advances in dam design also progressed, with the completion of Old Aswan Dam being considered a milestone of engineering over nature. At the time of its construction, nothing of such scale had ever been attempted: it also became one