The Nile, Egypt River Regulation

The Nile River River data Key concepts Irrigation Discharge Control of flow Population and crops Irrigation Controlling the river

The Nile River River is longest in world: 6825 km Basin: 3 000 000 km2 Egypt is essentially arid: < 100 mm/yr Nile provides 50  more water than rainfall Flows through 8 countries

Nile River Basin

Discharge

Key Concepts Nile River Q in Egypt, the only major source of surface water in that country, is derived from P in tropical latitudes influenced by the ITCZ (White Nile) and monsoon P in Ethiopia (Blue Nile) All Nile Q is now controlled by storage behind dams (Egypt and Sudan) and used primarily for irrigation Food production in Egypt is not sufficient to meet domestic demand, even with total control of the Nile Source: http://www.ldeo.columbia.edu/edu/dees/U4735/projections/conceptsNile.html

Precipitation Source of the Blue Nile Monsoonal rains can bring a flood (5 months < 50 mm) Source of the White Nile Equatorial consistent rainfall Provides Nile base flow All months over 50 mm

Crop Areas in Egypt

Population

Crop Land Area

Remote Sensing

Irrigation Systems in Egypt Up to early 19th century: Basin Irrigation one crop per year following monsoon flooding (peak flood levels in Aug/Sept) During 19th century: Barrage and Irrigation Canal Construction permit irrigation during low river stage and extend crops to summer months preceding flood - driving force was cotton crop (summer crop) Early 20th century: Storage Dam at Aswan extended area under summer cotton crop level of Dam raised in 1930s and more barrage construction: maximum storage capacity ~2 months of "mean" discharge Mid 20th century: Beginning of Tile Drainage and Drainage Canal Network driving force was rising water table and need to extend crops into areas closer to sea level at margins of Delta ~1960: Initial Drainage Pump Stations Late 1960's: Completion of High Dam at Aswan and Large Expansion of Drainage Pump Stations permits continuous cropping of entire Nile Delta up to 3 crops/year depending on rotation Current: Collection of Drainage Water for Reuse, Especially in Northern Sinai. Future: Sudd Bypass Canal in Sudan

Aswan High Dam Opened 1971: 111 m high, 3820 m long, 980 m thick at base, 40 m thick at top Reservoir (Lake Nasser) surface area: 5000 km2, volume of 164 km3, 270 km long 125 000 people resettled, 22 ancient temples relocated Series of locks control the river height Irrigation canals

Discharge Change

Dam Advantages Power Supply: 64% of Egypt’s electricity Flood and drought protection: regulation Food production: irrigation allowed former desert to be cultivated (doubled area); 3 crops/year means less import; cash crops Transport: locks allow trade and cruise ships Lake Nasser fishing industry: bass, catfish, carp

Dam Disadvantages Water loss: surface area & heat cause huge evaporation Silt: suspended silt held back – 2% of former loads passes – loss of fertilising potential, crop yields reduced; also deposit reduces Lake Nasser capacity – 100 yr to be full Fishing industry: nutrients from silt entering Mediterranean no longer reaches sea – sardine, mackerel, shrimp and lobster industries near mouth are devastated – jobs, economic loss and protein source lost Salinity and waterlogging: from extensive irrigation Brick industry: silt reduction means topsoil must be used Erosion: silt free/clear water erodes riverbed and delta Earthquakes: possible trigger is weight of Lake Nasser water Disease: water-related diseases increased – schistosomiasis, Bilharzia and malaria near irrigation canals – still water promotes mosquitoes breeding

References Kleeman, G (ed.) 2000, A Geography of Global Interactions 1, Reed International Books, Sydney, pp 87-96 http://www.ldeo.columbia.edu/edu/dees/U4735/lectures/06.html http://www.thesykesfamily.net/Images/DSCN0925.JPG http://www.earthkam.ucsd.edu/public/images/graphics/annotated/nile_river.jpg http://www.pbs.org/wgbh/nova/flood/images/nileriver.jpeg http://en.wikipedia.org/wiki/Geography_of_Egypt http://uregina.ca/piwowarj/geog100/images/AswanDam_7_29_02.jpe