<P> The assessment of the costs and benefits of the dam remains controversial decades after its completion . According to one estimate, the annual economic benefit of the High Dam immediately after its completion was E £ 255 million, $587 million using the exchange rate in 1970 of $2.30 per E £ 1): £ 140 million from agricultural production, £ 100 million from hydroelectric generation, £ 10 million from flood protection, and £ 5 million from improved navigation . At the time of its construction, total cost, including unspecified "subsidiary projects" and the extension of electric power lines, amounted to £ 450 million . Not taking into account the negative environmental and social effects of the dam, its costs are thus estimated to have been recovered within only two years . One observer notes: "The impacts of the Aswan High Dam (...) have been overwhelmingly positive . Although the Dam has contributed to some environmental problems, these have proved to be significantly less severe than was generally expected, or currently believed by many people ." Another observer disagreed and he recommended that the dam should be torn down . Tearing it down would cost only a fraction of the funds required for "continually combating the dam's consequential damage" and 500,000 hectares of fertile land could be reclaimed from the layers of mud on the bed of the drained reservoir . </P> <P> Periodic floods and droughts have affected Egypt since ancient times . The dam mitigated the effects of floods, such as those in 1964, 1973, and 1988 . Navigation along the river has been improved, both upstream and downstream of the dam . Sailing along the Nile is a favorite tourism activity, which is mainly done during the winter when the natural flow of the Nile would have been too low to allow navigation of cruise ships . A new fishing industry has been created around Lake Nasser, though it is struggling due to its distance from any significant markets . The annual production was about 35 000 tons in the mid-1990s . Factories for the fishing industry and packaging have been set up near the Lake . </P> <P> The dams also protected Egypt from the 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), mostly in Upper Egypt, were converted from flood irrigation with only one crop per year to perennial irrigation allowing two or more crops per year . On other previously irrigated land, yields increased because water could be made available at critical low - flow periods . For example, wheat yields in Egypt tripled between 1952 and 1991 and better availability of water contributed to this increase . Most of the 32 km of freshwater, or almost 40 percent of the average flow of the Nile that were previously lost to the sea every year could be put to beneficial use . While about 10 km of the water saved is lost due to evaporation in Lake Nasser, the amount of water available for irrigation still increased by 22 km . Other estimates put evaporation from Lake Nasser at between 10 and 16 cubic km per year . </P> <P> The dam powers twelve generators each rated at 175 megawatts (235,000 hp), with a total of 2.1 gigawatts (2,800,000 hp). Power generation began in 1967 . When the High Dam first reached peak output it produced around half of Egypt's production of electric power (about 15 percent by 1998), and it gave most Egyptian villages the use of electricity for the first time . The High Dam has also improved the efficiency and the extension of the Old Aswan Hydropower stations by regulating upstream flows . </P>

Consequences of the aswan high dam in egypt include