"The maps show the River Nile at low water, high flood and also the protection of the downstream rock surface prior to heightening work. Built between 1898 and 1902, the Aswan Dam was designed to better control the massive annual Nile floods for irrigation as well as providing the possibility of hydro-electric power for industry. After the dam was completed, it became clear that its height and the size of the reservoir behind it were insufficient. As a result, the dam's height was further raised in 1907-1912 and again in 1929-1934. Even after this the dam ultimately proved inadequate for its purpose, leading to the building of the much larger Aswan High Dam between 1960 and 1970."
© Science Museum / Science & Society Picture Library