Aswan Dam dam near Aswan was in the 11th century, when the Arab polymath and engineer Ibn al-Haytham (known as "Alhazen" in the West) was summoned to Egypt by the Fatimid Caliph, Al-Hakim bi-Amr Allah, to regulate the flooding of the Nile, a task requiring an early attempt at an Aswan Dam. His field work convinced him of the impracticality of this scheme. The British began construction of the first dam across the Nile in 1898. Construction lasted until 1902, and the dam was opened on 10 December 1902. The project was designed by Sir William Willcocks and involved several eminent engineers,
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