Water resources management in modern Egypt water management in Egypt begins with the construction of the Old Aswan Dam in 1902 and barrages on the Nile in the 19th and early 20th century. The Old Aswan Dam partially stored the waters of the Nile to allow the growing of multiple crops per year in the Nile Delta, while the barrages raised the water level of the Nile so that water could be diverted into large irrigation channels running in parallel to the river. The water regime of the river was changed fundamentally in 1970 when the Aswan High Dam was completed, eliminating the annual Nile flood.
Aswan the summer solstice, a vertical staff cast no shadow. They noted that the sun's disc was reflected in a well at noon. This statement is only approximately correct; at the summer solstice, the shadow was only of the staff, and so could scarcely be discerned, and the northern limb of the Sun's disc would be nearly vertical. However, Eratosthenes used this information together with measurements of the shadow length on the solstice at Alexandria to perform the first known calculation of the circumference of the Earth. The Nile is nearly wide above Aswan. From this frontier town to the northern