Aswan Dam droughts in 1972–73 and 1983–87 that devastated East and West Africa. The High Dam allowed Egypt to reclaim about 2.0 million feddan (840,000 hectares) in the Nile Delta and along the Nile Valley, increasing the country's irrigated area by a third. The increase was brought about both by irrigating what used to be desert and by bringing under cultivation of 385,000 ha that were previously used as flood retention basins. About half a million families were settled on these new lands. In particular the area under rice and sugar cane cultivation increased. In addition, about 1 million feddan (420,000 hectares),
Risks to the Glen Canyon Dam of between 500–700 years. Glen Canyon Dam is a concrete arch dam on the Colorado River in northern Arizona in the United States, just north of Page. The dam was built to provide hydroelectricity and flow regulation from the upper Colorado River Basin to the lower. Its reservoir is called Lake Powell, and is the second largest artificial lake in the country, extending upriver well into Utah. The dam is named for Glen Canyon, a colorful series of gorges, most of which now lies under the reservoir. Construction of Glen Canyon Dam started in 1956 and was not finished until