What did the Aswan High Dam give Egypt, and what did it take away?

The Aswan High Dam gave Egypt control of the Nile, and it took away the river's yearly gift of mud. Built between 1960 and 1970, the dam created the Lake Nasser reservoir. Egypt, with Soviet help, built it to control flooding, store water for irrigation and generate hydroelectricity.

Control mattered because the Nile's flood was unreliable. Its yearly floods brought nutrients and minerals that enriched the soil of the floodplain and delta, which had made the valley ideal for farming since ancient times. But the floods varied: high-water years could destroy a whole crop, and low-water years could bring drought and famine. The smaller Low Dam of 1902 let most water pass, so floods and droughts continued.

With the High Dam's greatly increased storage, floods could be controlled and water stored for later release over multiple years. The dam has brought protection from floods and droughts, more agricultural production, electricity and improved navigation.

The price came with the mud. The rich silt the Nile traditionally carried now settles in the dam's lake. Without silt deposits at the river's mouth, the delta coast has a serious erosion problem. Egypt's Mediterranean catch fell from 35,000-40,000 tons a year to 20,000 or less, largely because the loss of silt-fed plankton eliminated the sardines. The dam is also blamed for coastline erosion, soil salinity and health problems. And Lake Nasser flooded much of lower Nubia, so 100,000 to 120,000 people were resettled in Sudan and Egypt.