Water resources management in modern Egypt about 3.5 BCM/year of municipal wastewater was being discharged into the Nile and the sea in 2002, out of which only 1.6 BCM/year (about 45%) were treated. Industrial effluents contribute to about 1.3 BCM/yr of wastewater being discharged to surface waters, only some of which is being treated. Hydropower. An important use of water in Egypt is for the production of hydropower. This use is non-consumptive and is thus available for other uses further downstream. Hydropower plants exist at the Aswan High Dam (2100 MW), the old Aswan Dam (270 MW)and power plants at the Esna (90 MW) and Naga
Aswan Low Dam granite. When constructed, the Old Aswan Dam was the largest masonry dam in the world. The design also included a navigation lock of similar construction on the western bank, which allowed shipping to pass upstream as far as the second cataract, whereas a portage overland was previously required. At the time of its construction, nothing of such scale had ever been attempted. Despite initial limitations imposed on its height, due to concern for the Philae Temple, the initial construction was soon found to be inadequate for development needs, and the height of the dam was raised in two phases, between