Water resources management in modern Egypt water management in Egypt begins with the construction of the Old Aswan Dam in 1902 and barrages on the Nile in the 19th and early 20th century. The Old Aswan Dam partially stored the waters of the Nile to allow the growing of multiple crops per year in the Nile Delta, while the barrages raised the water level of the Nile so that water could be diverted into large irrigation channels running in parallel to the river. The water regime of the river was changed fundamentally in 1970 when the Aswan High Dam was completed, eliminating the annual Nile flood.
Aswan Dam mere 460 tons in 1968, but then gradually recovered to 8,590 tons in 1992. A scientific article in the mid-1990s noted that "the mismatch between low primary productivity and relatively high levels of fish production in the region still presents a puzzle to scientists." A concern before the construction of the High Dam had been the potential drop in river-bed level downstream of the Dam as the result of erosion caused by the flow of sediment-free water. Estimates by various national and international experts put this drop at between 2 and 10 meters. However, the actual drop has been measured