Transcript
Ecological Impacts of
DamsKamberov, MichaelMincheva, SamuilaVelkov, VelkoSection 10/5
http://users.owt.com/chubbard/gcdam/highres/dam08.jpg
Definition A barrier(wall) builtin a river in order torestrict orchange theflow of the water orto raise the water level in a certain area1
http://nrmsc.usgs.gov/files/norock/research/dam_base_flow_sm.jpg
Usage
Provide reliable water resource and flood control
Hydroelectric dams are used to produce electricity2
Drawbacks
Negative impact on fish life in the area
Loss of sediment in downstream areas
People displacement Disease spread2, 3
Impact on Fish Dams are created
in order to change
the currents of a
river Changing the
current has an
immediate impact on
the ecosystem in the river3,4
http://www.vistapinas.com/images/48.jpg
The dam changes the water qualities to which organisms are used to
Many animal’s life cycles are synced with the annual floods that occur in an area; therefore, those cycles are interrupted when the floods stop because of the dam
The dam basically acts as a barrier stopping fish from going upstream or downstream; thus, lifecycles of migratory fish are deeply damaged, as they cannot go and spawn or interact with others4,5
Soil Erosion Before the
Dam The sediment that the
water carries is blocked
by the dam; as time passes, it slowly builds up,
adding additional pressure to the dam wall In this way, serious accidents can occur: the dams
are only built to withstand a certain amount of water pressure; with the pressure from the sediment in some time the wall either explodes or water is caused to go above the dam, creating a waterfall; in both cases, a lot of organisms, including humans are in great danger4,5
http://www.usbr.gov/pmts/sediment/projects/SavageRapids/images/Sedimentation.jpg
Soil ErosionAfter the Dam
As sediment coming from the upper parts is blocked, the water after the dam is essentially “cleared” of all particles
Once again, that interrupts the ecosystem present The nutrients are blocked along with the
sediment The organisms that used the mud to hide
themselves now have no protection from predators4,5
Disease Spread
When sediment builds up, along with algae and plants start developing; when they die, there is a huge amount of organic material left, which when decomposing, releases gases dangerous for animals and people2,4
The water that is blocked by the dam stays in one place, and, consequently, can get very dirty
It attracts mosquitoes and other disease-carrying insects, which contaminate it
People
in less
developed
countries
have no
access to
clear water,
so they use
the one from
the reservoirs, which results in them being sick
as well2
This photo is taken by Samuila; this is the dam on the Iskar river, creating the Pancharevo lake
People Displacement
When dams are built,
the settlements and habitats
that stand in their way are
generally demolished This way, a lot of people
are left without a home
and a job, which is a big
economical problem2 http://earthobservatory.nasa.gov/images/imagerecords/6000/6574/3gorges_ast
_2006135.jpg
Three Gorges Dam, China
Located on the
Yangtze River The world’s
largest hydropower
dam However, in order
for the project to be
completed, more that 1.2 million people must be
displaced3
http://en.citizendium.org/images/9/9c/Three_gorges_dam_map_2.gif
http://japanfocus.org/data/3gdam.jpg http://i.i.com.com/cnwk.1d/i/ne/p/2007/dam_china001_550x516.jpg
http://www.china-tourism.org/images/stories/articles/three-gorges-dam.jpg
http://4.bp.blogspot.com/_CaoIcsWZxl0/TNzJfdxwQ8I/AAAAAAAARHE/o_n4pJSF6Ms/s1600/three-gorges-dam-d.jpg
A lot of factories will be left under the resulting reservoir, which will seriously pollute the water
On the other hand, the already existing erosion and downstream sediment are cause landslides, which are a serious threat for the area
Scientists have proven that the weight of the water is influencing the seismicity of the area, resulting in more earthquakes than usual
Since the dam’s function is to control flooding, it has already changed the pre-existing natural cycle of the ecosystem in the river3,6
Aswan Dam, Egypt Located on theNile Creates Lake Nasser Actually two dams:
High Dam (1960) Low Dam (1902)
Displaced 60,000people7 http://www.quarryscapes.no/images/Egypt_sites/aswan_loc.
jpg
During the controlled floods, the river goes to the farmlands, and problems are
caused by the soil erosion that follows When water is evaporated from the soil, salt is
left and the ground crystallizes The water is a breeding place for snails carrying theparasite bilharzia, which is the secondworst disease aftermalaria in Egypt7
http://www.mbarron.net/Nile/OWENFALL.JPG
Sources Cited1. “Dam.” The Free Dictionary. Farlex, Inc., n.d. Web. 16 Dec. 2010.
<http://www.thefreedictionary.com/ Dam>.2. Joyce, Stephanie. “Dams - the Advantages and Disadvantages.”
Environment, Health, and Safety Online. EHSO, Inc., n.d. Web. 16 Dec. 2010. <http://www.ehso.com/ ehshome/ energydams.htm>.
3. “Three Gorges Dam.” International Rivers. Creative Commons, n.d. Web. 16 Dec. 2010. <http://www.internationalrivers.org/ china/ three-gorges-dam>.
4. “The Ecology of Dams.” Stream Biology and Ecology. Cristi Cave, n.d. Web. 16 Dec. 2010. <http://chamisa.freeshell.org/ dam.htm>.
5. “Why Are Dams Potentially Harmful to Fish.” WiseGeek. Conjecture Corp., n.d. Web. 16 Dec. 2010. <http://www.wisegeek.com/ why-are-dams-potentially-harmful-to-fish.htm>.
6. “Three Gorges Dam.” Wikipedia. Wikipedia Foundation, Inc., n.d. Web. 16 Dec. 2010. <http://en.wikipedia.org/ wiki/ Three_Gorges_Dam>.
7. “Aswan Dam.” Wikipedia. Wikipedia Foundation, Inc., n.d. Web. 16 Dec. 2010. <http://en.wikipedia.org/ wiki/ Aswan_Dam#Displacement.2C_agriculture_and_health>.
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