Friday, May 22, 2020
Aswan High Dam Controls the Nile River
Just north of the border between Egypt and Sudan lies the Aswan High Dam, a huge rockfill dam which captures the worlds longest river, the Nile River, in the worlds third-largest reservoir, Lake Nasser. The dam, known as Saad el Aali in Arabic, was completed in 1970 after ten years of work. Egypt has always depended on the water of the Nile River. The two main tributaries of the Nile River are the White Nile and the Blue Nile. The sources of the White Nile are the Sobat River and Bahr al-Jabal (the Mountain Nile), and the Blue Nile begins in the Ethiopian Highlands. The two tributaries converge in Khartoum, the capital of Sudan, where they form the Nile River. The Nile River has a total length of 4,160 miles (6,695 kilometers) from source to sea. Nile Flooding Before the building of a dam at Aswan, Egypt experienced annual floods from the Nile River that deposited four million tons of nutrient-rich sediment which enabled agricultural production. This process began millions of years before Egyptian civilization began in the Nile River valley and continued until the first dam at Aswan was built in 1889. This dam was insufficient to hold back the water of the Nile and was subsequently raised in 1912 and 1933. In 1946, the true danger was revealed when the water in the reservoir peaked near the top of the dam. In 1952, the interim Revolutionary Council government of Egypt decided to build a High Dam at Aswan, about four miles upstream of the old dam. In 1954, Egypt requested loans from the World Bank to help pay for the cost of the dam (which eventually added up to one billion dollars). Initially, the United States agreed to loan Egypt money but then withdrew their offer for unknown reasons. Some speculate that it may have been due to Egyptian and Israeli conflict. The United Kingdom, France, and Israel had invaded Egypt in 1956, soon after Egypt nationalized the Suez Canal to help pay for the dam. The Soviet Union offered to help and Egypt accepted. The Soviet Unions support was not unconditional, however. Along with the money, they also sent military advisers and other workers to help enhance Egyptian-Soviet ties and relations. Building of the Aswan Dam In order to build the Aswan Dam, both people and artifacts had to be moved. Over 90,000 Nubians had to be relocated. Those who had been living in Egypt were moved about 28 miles (45 km) away, but the Sudanese Nubians were relocated 370 miles (600 km) from their homes. The government was also forced to develop one of the largest Abu Simel temples and dig for artifacts before the future lake would drown the land of the Nubians. After years of construction (the material in the dam is the equivalent to 17 of the great pyramids at Giza), the resulting reservoir was named after the former president of Egypt, Gamal Abdel Nasser, who died in 1970. The lake holds 137 million acre-feet of water (169 billion cubic meters). About 17 percent of the lake is in Sudan and the two countries have an agreement for distribution of the water. Aswan Dam Benefits and Problems The Aswan Dam benefits Egypt by controlling the annual floods on the Nile River and prevents the damage which used to occur along the floodplain. The Aswan High Dam provides about half of Egypts power supply and has improved navigation along the river by keeping the water flow consistent. There are several problems associated with the dam as well. Seepage and evaporation account for a loss of about 12-14% of the annual input into the reservoir. The sediments of the Nile River, as with all river and dam systems, has been filling the reservoir and thus decreasing its storage capacity. This has also resulted in problems downstream. Farmers have been forced to use about a million tons of artificial fertilizer as a substitute for the nutrients which no longer fill the floodplain. Further downstream, the Nile delta is having problems due to the lack of sediment as well since there is no additional agglomeration of sediment to keep erosion of the delta at bay, so it slowly shrinks. Even the shrimp catch in the Mediterranean Sea has decreased due to the change in water flow. Poor drainage of the newly irrigated lands has led to saturation and increased salinity. Over one-half of Egypts farmland in now rated medium to poor soils. The parasitic disease schistosomiasis has been associated with the stagnant water of the fields and the reservoir. Some studies indicate that the number of individuals affected has increased since the opening of the Aswan Dam. The Nile River and now the Aswan High Dam are Egypts lifeline. About 95% of Egypts population live within twelve miles from the river. Were it not for the river and its sediment, the grand civilization of ancient Egypt probably would have never existed.