Aswan Low Dam 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. After his field work convinced him of the impracticality of this scheme, and fearing the Caliph's anger, he feigned madness. He was kept under house arrest from 1011 until al-Hakim's death in 1021, during which time he wrote his influential "Book of Optics". Following their 1882 invasion and occupation of Egypt, the British began construction of the first dam across the Nile in 1898. Construction lasted until 1902, and it was opened
Aswan Low Dam 1907–1912 and between 1929–1933, and generation of electricity was added. The first phase was supervised by Sir Benjamin Baker, though much of the detailed work was undertaken by Murdoch MacDonald. With its final raising (designed and supervised by MacDonald's firm, Sir M MacDonald & Partners), the dam is in length, with a crest level above the original riverbed; the dam provides the main route for traffic between the city and the airport. With the construction of the High Dam upstream, the Old Dam's ability to pass the flood's sediments was lost, as was the serviceability provided by the locks. The