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),
Aswan Dam soil surface over the years. Since most of the farmland did not have proper subsurface drainage to lower the groundwater table, salinization gradually affected crop yields. Drainage through sub-surface drains and drainage channels is essential to prevent a deterioration of crop yields from soil salinization and waterlogging. By 2003, more than 2.0 million have been equipped with a subsurface drainage system at a cost from 1973 to 2002 of about $3.1 billion. Contrary to many predictions made prior to the Aswan High Dam construction and publications that followed, that the prevalence of schistosomiasis (bilharzia) would increase, it did not. This