Egypt -The Aswan Dam Environmental Impact New

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Egypt: The Aswan

High DamThe Environmental Impact of the dam


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Background The Aswan Dam is an embankment dam situated

across the Nile River in Aswan, Egypt. ince the!"#$s, the name commonly re%ers to the &igh Dam,

which is larger and newer than the Aswan 'ow Dam,which was (rst completed in !"$). *ollowing Egypt+sindependence %rom the nited -ingdom, the &ighDam was constructed between !"$ and !"/$. 0taimed to increase economic production by %urther

regulating the annual river 1ooding and providingstorage o% water %or agriculture, and later, to generatehydroelectricity. The dam has had a signi(cant impacton the economy and culture o% Egypt.


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Be%ore the dams were built, the Nile River 1oodedeach year during late summer, as water 1owed downthe valley %rom its East A%rican drainage basin. These

1oods brought high water and natural nutrients andminerals that annually enriched the %ertile soil alongthe 1oodplain and delta2 this made the Nile valleyideal %or %arming since ancient times. Because 1oodsvary, in high3water years, the whole crop might be

wiped out, while in low3water years widespreaddrought and %amine occasionally occurred. As Egypt+spopulation grew and conditions changed, both a desireand ability developed to control the 1oods, and thusboth protect and support %armland and theeconomically important cotton crop. 4ith the reservoirstorage provided by these dams, the 1oods could belessened, and the water could be stored %or laterrelease.


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*eatures and 5b6ectives o% &AD

The main aims o% the construction o% the &igh Aswan Dam can besummari7ed as %ollows8

%ull control o% the Nile 1ow at Aswan in the %ar south o% Egypt2

regulation o% the discharge downstream o% the dam to match theactual water

needs %or di9erent re:uirements2

protection o% the Nile ;alley and Delta %rom high 1oods anddrought ha7ards

that could persist %or several consecutive years2

generation o% cheap and clean hydroelectric power2

reali7ation o% hori7ontal land e, toperennial

irrigation =two or more crops per year>2

e


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Advantages o% &igh Aswan Dam

Water


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*ew ?ore..

Increase in Rice and Sugar-cane Areas


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EnvironmentalImpact


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Resettlement o% @eople'ake Nasser 1ooded much o% lower Nubia and

!$$,$$$ to !)$,$$$ people were resettled inudan and Egypt. The ma6ority o% the #$,$$$Nubians resettled in Egypt were resettledthree to ten kilometers %rom the Nile near -om5mbo # kilometers downstream %rom Aswanin what was called New Nubia. &ousing and%acilities were built %or / village units whoserelationship to each other appro


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The Aswan &igh Dam, when it was buildcreated 'ake Nasser, 'ake Nasser trechesback )/$ kilometres %rom the Dam. The 'akehas also created a lot more land %or people to%arm on. This is because a lot o% water isstored in the lake, and in turn this water canbe used to irrigate land around the lake. 'akeNasser has also created a big (shing industry,which produces )#,$$$ tons o% (sh a year, the(shing industry is aiming to produce !$$,$$$tons by the year )$$$.


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n%ortunately this dam has caused a big change tothe lives o% %armers downstream %rom the dam.sually when the river 1ooded once a year be%ore the

dam was built. 0t deposited %ertile soil %rom upstreamon its banks downstream. This washed up soil wase


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The Aswan &igh Dam is also used to

create hydro3electricity %or Egypt,0n the !"$+s this dam was providing hal% o% Egypt+s

Electricity, but by the !""$+s this had %allen as energydemands increased. The electric power capacity o% the

Aswan &igh Dam is8 ).! gigawatts =F4>. 0t consists o%!) &ydro3Fenerators each rated at !/# ?4. Egyptcurrently has a total installed generating capacity o%!. gigawatts =F4> compared to G. F4 in !"/, thusthe percentage contribution by the &igh dam has

decreased %rom over hal% the total electricitygeneration to less than !GH. This percentage willcontinue to decrease as more thermal power plants areadded. Total capacity e


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4aterlogging and increase in soilsalinity

Be%ore the construction o% the &igh Dam, groundwaterlevels in the Nile ;alley 1uctuated 3"m per year withthe water level o% the Nile. During summer whenevaporation was highest, the groundwater level wastoo deep to allow salts dissolved in the water to be

pulled to the sur%ace through capillary action. 4ithheavy year3round irrigation, groundwater levelsremained high with little 1uctuation leading towaterlogging. oil salinity also increased because thedistance between the sur%ace and the groundwater

table was small enough =!I) m depending on soilconditions and temperature> to allow water to bepulled up by evaporation so that the relatively smallconcentrations o% salt in the groundwater accumulatedon the soil sur%ace over the years.


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'osses due to salini7ation

ince most o% the %armland did not haveproper subsur%ace drainage to lower thegroundwater table, salini7ation graduallya9ected crop yields.J!K A total o% ).! millionhectares thus re:uired subsur%ace drainage ata cost that e


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Coastal Erosion The &igh Dam has accelerated erosion o% coastlines

=due to lack o% sediment, which was once broughtby the Nile> in Egypt and, according to some

sources even all along the eastern ?editerranean.Coastal erosion occurred and e9orts to control itwere made even be%ore the construction o% the &ighDam. This erosion may to some e


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&ealth 0mpact The standing water in irrigation canals is a breeding

ground %or snails carrying the parasite bilhar7ia. Theincidence o% bilhar7ia increased due to the Aswan

&igh Dam inhibiting the natural 1uctuations in waterheight. 0mportant %actors contributing to theprevalence o% schistosomiasis were poor sanitationand limited awareness o% how the disease wastransmitted. @rovision o% clean water, sanitation,health education and rural clinics has reduced theoverall prevalences o% schistosomiasis %rom morethan $ per cent during the pre3dam period to !$per cent in !""# and only )H in )$$).


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Reservoir sedimentationReservoir sedimentation. ediment deposited in the

reservoir is lowering the water storage capacity o% 'ake

Nasser. The reservoir storage capacity is !) kmG,including G! kmG dead storage at the bottom o% the lakebelow !/m above sea level, "$ kmG live storage, and! kmG o% storage %or high 1ood waters above !/#m

above sea level. The annual sediment load o% the Nile isabout !G million tons. This means that the deadstorage volume would be (lled up a%ter G$$I#$$ years i%the sediment accumulated at the same rate throughoutthe area o% the lake. 5bviously sediment accumulates

much %aster at the upper reaches o% the 'ake wheresedimentation has already a9ected the live storage7one.J)$K 0t would take about another "$$ years until thelive storage 7one would be completely sedimented andoperation o% the dam would become impossible sometime be%ore that.


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Reservoir evaporation; Aquaticweeds; ollution from fertili!ers

Evaporation %rom 'ake Nasser is estimated at !$ kmG peryear, varying mainly as a %unction o% the lake area. 4hile theabsolute amount o% water lost to evaporation is enormous, itis only !!H o% the average volume stored in the 'ake and!H o% Egypt+s share o% the annual 1ow o% the Nile.

Be%ore the dam was built, the #$,$$$ km o% irrigation anddrainage canals in Egypt had to be dredged regularly toremove sediments. A%ter construction o% the dam, a:uaticweeds grew much %aster in the clearer water, helped by%ertili7er residues. The total length o% the in%ested waterways

was about )/,$$$ km in the mid3"$s. 4eeds have beengradually brought under control by manual, mechanical andbiological methods.

The increased use o% arti(cial %ertili7ers has caused chemicalpollution which the traditional river sediment did not do.

http://var/www/apps/conversion/tmp/scratch_1/Negative%20impacts.pptxhttp://var/www/apps/conversion/tmp/scratch_1/Negative%20impacts.pptx


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*ishery in the Delta and the ?editerranean

?editerranean (shing and brackish water lake (sherydeclined a%ter the dam was (nished because nutrientsthat used to 1ow down the Nile to the ?editerraneanwere trapped behind the dam. *or e


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Algae FrowthBecause o% the lower turbidity o% the water

sunlight penetrates deeper in the Nile water.Because o% this and the increased presence o%nutrients %rom %ertili7ers in the water, morealgae grow in the Nile. This in turn increasesthe costs o% drinking water treatment.Apparently %ew e


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Irrigated

"armland in

Egypt


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Dam peci(cations The Aswan &igh Dam is G,G$ metres long, "$

metres wide at the base, $ metres wide at thecrest and !!! metres tall. 0t contains G million

cubic metres o% material. At ma


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A @anoramic ;iew 'ake Nasser


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Dam


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http://var/www/apps/conversion/tmp/scratch_1/Negative%20impacts.pptx

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Egypt -The Aswan Dam Environmental Impact New

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