2011 10 5 dams.ppt


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2011 10 5 dams.ppt

  1. 1. Ecological Impacts of Dams Kamberov, Michael Mincheva, Samuila Velkov, Velko Section 10/5 http://users.owt.com/chubbard/gcdam/highres/dam08.jpg
  2. 2. Definition <ul><li>A barrier </li></ul><ul><li>(wall) built </li></ul><ul><li>in a river </li></ul><ul><li>in order to </li></ul><ul><li>restrict or </li></ul><ul><li>change the </li></ul><ul><li>flow of </li></ul><ul><li>the water or </li></ul><ul><li>to raise the water level in a certain area 1 </li></ul>http :// nrmsc . usgs . gov / files / norock / research / dam _ base _ flow _ sm . jpg
  3. 3. <ul><li>Usage </li></ul><ul><li>Provide reliable water resource and flood control </li></ul><ul><li>Hydroelectric dams are used to produce electricity 2 </li></ul><ul><li>Drawbacks </li></ul><ul><li>Negative impact on fish life in the area </li></ul><ul><li>Loss of sediment in downstream areas </li></ul><ul><li>People displacement </li></ul><ul><li>Disease spread 2, 3 </li></ul>
  4. 4. Impact on Fish <ul><li>Dams are created </li></ul><ul><li>in order to change </li></ul><ul><li>the currents of a </li></ul><ul><li>river </li></ul><ul><li>Changing the </li></ul><ul><li>current has an </li></ul><ul><li>immediate impact on </li></ul><ul><li>the ecosystem in the river 3,4 </li></ul>http://www.vistapinas.com/images/48.jpg
  5. 5. <ul><li>The dam changes the water qualities to which organisms are used to </li></ul><ul><li>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 </li></ul><ul><li>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 others 4,5 </li></ul>
  6. 6. Soil Erosion Before the Dam <ul><li>The sediment that the </li></ul><ul><li>water carries is blocked </li></ul><ul><li>by the dam; as time passes, it slowly builds up, </li></ul><ul><li>adding additional pressure to the dam wall </li></ul><ul><li>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 danger 4,5 </li></ul>http :// www . usbr . gov / pmts / sediment / projects / SavageRapids / images / Sedimentation . jpg
  7. 7. Soil Erosion After the Dam <ul><li>As sediment coming from the upper parts is blocked, the water after the dam is essentially “cleared” of all particles </li></ul><ul><li>Once again, that interrupts the ecosystem present </li></ul><ul><ul><li>The nutrients are blocked along with the sediment </li></ul></ul><ul><ul><li>The organisms that used the mud to hide themselves now have no protection from predators 4,5 </li></ul></ul>
  8. 8. Disease Spread <ul><li>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 people 2,4 </li></ul><ul><li>The water that is blocked by the dam stays in one place, and, consequently, can get very dirty </li></ul><ul><li>It attracts mosquitoes and other disease-carrying insects, which contaminate it </li></ul>
  9. 9. <ul><li>People </li></ul><ul><li>in less </li></ul><ul><li>developed </li></ul><ul><li>countries </li></ul><ul><li>have no </li></ul><ul><li>access to </li></ul><ul><li>clear water, </li></ul><ul><li>so they use </li></ul><ul><li>the one from </li></ul><ul><li>the reservoirs, which results in them being sick </li></ul><ul><li>as well 2 </li></ul>This photo is taken by Samuila; this is the dam on the Iskar river, creating the Pancharevo lake
  10. 10. People Displacement <ul><li>When dams are built, </li></ul><ul><li>the settlements and habitats </li></ul><ul><li>that stand in their way are </li></ul><ul><li>generally demolished </li></ul><ul><li>This way, a lot of people </li></ul><ul><li>are left without a home </li></ul><ul><li>and a job, which is a big </li></ul><ul><li>economical problem 2 </li></ul>http :// earthobservatory . nasa . gov / images / imagerecords /6000/6574/3gorges_ ast _2006135. jpg
  11. 11. Three Gorges Dam, China <ul><li>Located on the </li></ul><ul><li>Yangtze River </li></ul><ul><li>The world’s </li></ul><ul><li>largest hydropower </li></ul><ul><li>dam </li></ul><ul><li>However, in order </li></ul><ul><li>for the project to be </li></ul><ul><li>completed, more that 1.2 million people must be </li></ul><ul><li>displaced 3 </li></ul>http :// en . citizendium . org / images /9/9c/ Three _ gorges _ dam _ map _2. gif
  12. 12. 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
  13. 13. <ul><li>A lot of factories will be left under the resulting reservoir, which will seriously pollute the water </li></ul><ul><li>On the other hand, the already existing erosion and downstream sediment are cause landslides, which are a serious threat for the area </li></ul><ul><li>Scientists have proven that the weight of the water is influencing the seismicity of the area, resulting in more earthquakes than usual </li></ul><ul><li>Since the dam’s function is to control flooding, it has already changed the pre-existing natural cycle of the ecosystem in the river 3,6 </li></ul>
  14. 14. Aswan Dam, Egypt <ul><li>Located on the </li></ul><ul><li>Nile </li></ul><ul><li>Creates Lake </li></ul><ul><li>Nasser </li></ul><ul><li>Actually two dams: </li></ul><ul><ul><li>High Dam (1960) </li></ul></ul><ul><ul><li>Low Dam (1902) </li></ul></ul><ul><li>Displaced 60,000 </li></ul><ul><li>people 7 </li></ul>http :// www . quarryscapes . no / images / Egypt _ sites / aswan _ loc . jpg
  15. 15. <ul><li>During the controlled floods, the river goes to the farmlands, and problems are </li></ul><ul><li>caused by the soil erosion that follows </li></ul><ul><li>When water is evaporated from the soil, salt is left and the ground crystallizes </li></ul><ul><li>The water is a breeding place for snails </li></ul><ul><li>carrying the </li></ul><ul><li>parasite bilharzia, </li></ul><ul><li>which is the second </li></ul><ul><li>worst disease after </li></ul><ul><li>malaria in Egypt 7 </li></ul>http :// www . mbarron . net / Nile /OWENFALL.JPG
  16. 16. Sources Cited <ul><li>1. “Dam.” The Free Dictionary . Farlex, Inc., n.d. Web. 16 Dec. 2010. <http://www.thefreedictionary.com/‌Dam>. </li></ul><ul><li>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>. </li></ul><ul><li>3. “Three Gorges Dam.” International Rivers . Creative Commons, n.d. Web. 16 Dec. 2010. <http://www.internationalrivers.org/‌china/‌three-gorges-dam>. </li></ul><ul><li>4. “The Ecology of Dams.” Stream Biology and Ecology . Cristi Cave, n.d. Web. 16 Dec. 2010. <http://chamisa.freeshell.org/‌dam.htm>. </li></ul><ul><li>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>. </li></ul><ul><li>6. “Three Gorges Dam.” Wikipedia . Wikipedia Foundation, Inc., n.d. Web. 16 Dec. 2010. <http://en.wikipedia.org/‌wiki/‌Three_Gorges_Dam>. </li></ul><ul><li>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>. </li></ul>