the nile, egypt river regulation. the nile river river data key concepts –discharge –control of...
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The Nile, Egypt
River Regulation
The Nile River
• River data• Key concepts
– 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
PrecipitationAddis Ababa, Ethiopia (8.98°N 38.79°E) Average Monthly Rainfall
0
50
100
150
200
250
300
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Rai
nfa
ll (
mm
)
Kampala, Uganda (0.32°N 32.60°E) Average Monthly Rainfall
0
50
100
150
200
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
Rai
nfa
ll (
mm
)
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 EgyptUp 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 Constructionpermit 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 Aswanextended area under summer cotton croplevel 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 Networkdriving force was rising water table and need to extend crops into areas closer to sea level
at margins of Delta
~1960: Initial Drainage Pump StationsLate 1960's: Completion of High Dam at Aswan and Large Expansion of Drainage
Pump Stationspermits continuous cropping of entire Nile Deltaup 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