Ecological impacts of dams


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Ecological impacts of dams

  1. 1. Ecological Impacts of Dams Lora Stoyanova Viara Tzvetkova Goran Georgiev 10/3
  2. 2. Impact on Fishes <ul><li>Dams obstruct fish movement, </li></ul><ul><li>especially their migration. </li></ul><ul><li>This can have a great influence </li></ul><ul><li>on the fish population in the area. </li></ul><ul><li>Very bad ecological impact for species such as bears (1) </li></ul>
  3. 3. Water Quality <ul><li>Water becomes still </li></ul><ul><li>with little to no flow of new </li></ul><ul><li>water – gather of pollution. </li></ul><ul><li>Alters water’s natural seasonal temperatures – affects oxygen levels and chemical reactions. </li></ul><ul><li>Huge amounts of water evaporates.(2) </li></ul><ul><li>Release of pesticides which contaminate water. </li></ul>
  4. 4. Water Quality - Carbon <ul><li>Still water stores and releases a lot of carbon. </li></ul><ul><li>Vegetation starts to rot also releasing a lot of carbon as well as other greenhouse gases such as methane. </li></ul><ul><li>Carbon is both an air and water polluting agent. </li></ul><ul><li>Stored carbon forms organic pesticides which start killing the river’s species (5) </li></ul>
  5. 5. Loss of Sediment <ul><li>Water flow stops making the sediment sink to the bottom of the reservoir (4) </li></ul><ul><li>Overtime the sediment builds up, which rises water levels and puts pressure on dam walls. </li></ul><ul><li>The dam might not be able to hold up and can eventually bursts with the water flooding towns and killing people. </li></ul><ul><li>There is no way of removing this sediment. (1) </li></ul>
  6. 6. Impact on People <ul><li>Dam bursts because of sediment can lead to hundreds of death and destruction. (1) </li></ul><ul><li>The side of the dam with less water, famers struggle to keep their crops, etc. alive. </li></ul><ul><li>Fisherman suffer the reduction of fish greatly and must fish next to the dam or simply move out (3). </li></ul>
  7. 7. Three Reasons for Dams <ul><li>Agriculture, irrigation, and water supply </li></ul><ul><li>Energy </li></ul><ul><li>Flood management </li></ul><ul><ul><li>Water can be saved, not wasted </li></ul></ul><ul><ul><li>Better irrigation systems (40% of the food is gotten from 17 % of irrigated land) </li></ul></ul><ul><ul><li>Better water harvesting techniques </li></ul></ul><ul><ul><li>Better energy efficiency </li></ul></ul><ul><ul><li>Renewable sources of energy (wind, sun, etc) </li></ul></ul><ul><li>IRBM- Integrated river basin management  </li></ul><ul><ul><li>Managing, developing, and conserving the use of water and land within a river basin </li></ul></ul><ul><ul><li>S ustainable use of freshwater resources </li></ul></ul><ul><ul><li>P reventing disastrous floods (12) </li></ul></ul>
  8. 8. Changed Environmental Requirements <ul><li>Aerial photography and photogrammetry </li></ul><ul><li>Streamflow measurement and yield estimation </li></ul><ul><li>Flood hydrology </li></ul><ul><li>Spillway, diversion and outlet hydraulics </li></ul><ul><li>Geotechnical investigations </li></ul><ul><li>Site selection </li></ul><ul><li>Selection of dam type and layout (13) </li></ul>
  9. 9. Dam Risk Assessment <ul><li>Identification of potential hazards </li></ul><ul><li>Assessment of risk by assigning probabilities to failure modes </li></ul><ul><li>Dam break modelling (1 and 2 dimensional) </li></ul><ul><li>Identification of unacceptable risks </li></ul><ul><li>Investigation of appropriate risk reduction measures (13) </li></ul>
  10. 10. Examples <ul><li>Aral Sea </li></ul><ul><li>Three Gorges Dam </li></ul>
  11. 11. Aral Sea <ul><li>Location: between Kazakhstan and Uzbekistan </li></ul><ul><li>Since 1960- shrank a lot </li></ul><ul><li>Impact </li></ul><ul><ul><li>in depth- more than two times less in 20 years </li></ul></ul><ul><ul><li>in width- a tiny water basin in the western part (11) </li></ul></ul> <ul><li>Socio-economic and Ecological Impact </li></ul><ul><ul><ul><ul><ul><li>- A former fishing zone is now dry => many fishermen lost their jobs </li></ul></ul></ul></ul></ul><ul><ul><li>- Different crops are now grown (cotton and rice) </li></ul></ul><ul><ul><li>- The remaining of the Aral sea- very polluted from drainage water </li></ul></ul><ul><ul><li>- Increased salinity => only one of the 20 living species in the Aral sea survived (8) </li></ul></ul>
  12. 12. Reason and Solution <ul><li>Reason- rivers flowing into the Aral Sea were diverted by the Soviet Union </li></ul><ul><ul><li>Result- water supply to the Aral sea: cut off (10) </li></ul></ul><ul><li>Improvement </li></ul><ul><ul><li>a dam created </li></ul></ul><ul><ul><li>for 2 years- level increased with 12 meter (9) </li></ul></ul>
  13. 13. Three Gorges Dam <ul><li>Location: Eastern China </li></ul><ul><li>World’s largest electricity- generating plant </li></ul><ul><li>Reasons: mostly economical, not concerning environment </li></ul><ul><ul><li>To produce electricity </li></ul></ul><ul><ul><li>Flood Control (15) </li></ul></ul>
  14. 14. Impact <ul><li>Advantages of dam created </li></ul><ul><ul><li>Reduces chances of flood (controls water levels) </li></ul></ul><ul><ul><li>Provides electricity </li></ul></ul><ul><ul><li>Navigation </li></ul></ul><ul><li>Disadvantages </li></ul><ul><ul><li>Causes ecological changes </li></ul></ul><ul><ul><li>During the process of building- a lot of floods </li></ul></ul><ul><ul><li>Very expensive </li></ul></ul><ul><ul><li>In order to be built, many people moved away (14) </li></ul></ul>
  15. 15. Works Cited <ul><li>&quot;The Effects of Dams.&quot; Stream Biology and Ecology . Web. 9 June 2010. <>. </li></ul><ul><li>McCully, Patrick. &quot;Dams and Water Quality.&quot; International Rivers . Web. 8 June 2010. <>. </li></ul><ul><li>Mirand, Ane. &quot;Dams Cutting Off 400 Million People From Food and Income «.&quot; Peak Water . 05 June 2010. Web. 9 June 2010. <>. </li></ul><ul><li>&quot;Sedimentation Problems with Dams.&quot; International Rivers . Web. 9 June 2010. <>. </li></ul><ul><li>&quot;Tillegra Dam to Pump out CO2.&quot; Carbon Offsets Daily . Web. 9 June 2010. < dam-to-pump-out-co2-21892.htm>. </li></ul><ul><li>&quot;Water Quality.&quot; Kenyon . Web. 8 June 2010. <>. </li></ul><ul><li>&quot;Why Are Dams Potentially Harmful to Fish?&quot; WiseGEEK: Clear Answers for Common Questions . Web. 8 June 2010. < are-dams-potentially-harmful-to-fish.htm>. </li></ul><ul><li>&quot;Aral Sea Disaster – Cause and Effect « All That Is Manfred.&quot; All That Is Manfred . Web. 15 June 2010. <>. </li></ul><ul><li>Antelava, Natalya. &quot;Dam project aims to save Aral Sea&quot;. BBC MMX. 8/06/010 <>. </li></ul><ul><li>&quot;The History of the Aral Sea&quot;. OrexCA. 8/06/2010 <>. </li></ul><ul><li>Lambroschini, Antoine. &quot;Aral Sea Revived by Dam&quot;. Discovery Communications, LLC. 8/06/2010 <>. </li></ul><ul><li>&quot;WWF - Dam Solutions - Flood Management.&quot;  WWF - WWF . Web. 15 June 2010. <>. </li></ul><ul><li>&quot;Dams Capability.&quot;  Hydro Tasmania Consulting . Web. 15 June 2010. < f>. </li></ul><ul><li>&quot;Benefits from Three Gorges Dam&quot;. Travel China Guide. 8/06/2010 <>. </li></ul><ul><li>O’Hara, Laura. “The Three Gorges Dam Project”. 8/06/2010 <>. </li></ul>