Aswan Dam have been flooded by Lake Nasser. Before the construction of the High Dam, the Nile deposited sediments of various particle size – consisting of fine sand, silt and clay – on fields in Upper Egypt through its annual flood, contributing to soil fertility. However, the nutrient value of the sediment has often been overestimated. 88 percent of the sediment was carried to the sea before the construction of the High Dam. The nutrient value added to the land by the sediment was only 6,000 tons of potash, 7,000 tons of phosphorus pentoxide and 17,000 tons of nitrogen. These amounts are
Aswan average relative humidity of only 26%, with a maximum mean of 42% during winter and a minimum mean of 16% during summer. The weather of Aswan is extremely clear, bright and sunny year-round, in all seasons, with a low seasonal variation, with almost 4,000 hours of annual sunshine, very close to the maximum theoretical sunshine duration. Aswan is one of the sunniest places on Earth. The highest record temperature was on July 4, 1918, and the lowest record temperature was on January 6, 1989. In 1999, South Valley University was inaugurated and it has three branches; Aswan, Qena and Hurghada.