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Dams

Dams. Helpful or Hurtful?. What do you already know?. Brainstorm with your partners what you know about deforestation. Be ready to report out!. What we know:. What is the issue?. Dames are structures built across streams, rivers or estuaries to retain water.

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Dams

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  1. Dams Helpful or Hurtful?

  2. What do you already know? • Brainstorm with your partners what you know about deforestation. • Be ready to report out!

  3. What we know:

  4. What is the issue? • Dames are structures built across streams, rivers or estuaries to retain water.

  5. What do you already know about healthy river ecosystems? • Brainstorm with your partners: what do they look like? What are they comprised of? How would this be changed if a dam is built along the river? Etc. • Be ready to report out!

  6. What we know….

  7. The Environment…before and after dams: What do you notice?

  8. The Environment…before and after dams: What do you notice?

  9. The Environment…before and after dams: What do you notice?

  10. Opinions so far? • Complete the final column of your note sheet for the “What is the Issue?” section.

  11. The process of building dams • Click on the following link to observe environmental changes and varying quality of dam construction. Be ready to think and share! • Dam Construction

  12. Benefits of Using Dams • Dams provide many benefits including: • Recreation • flood control • water supply • hydroelectric power • waste management • river navigation • wildlife habitat

  13. Then what is the problem? • Dams flood a vast area of land • Approximately 400,000 sq km worldwide have been flooded by dams • Forests are flooded and decompose • Dams can break and cause a massive flash flood. • Riverbeds, banks, deltas, estuaries, and coastlines are changed • Disrupts natural seasonal changes in the river • Ends flooding that help to clean out the silt in rivers, causing them to clog • The silt that usually flows down to the Beaches and Estuaries is blocked by the dam. • Sediment load changes • Sediment settles to bottom of river • The settled sediment erodes and leaves poor habitat for fauna • The coast beyond the mouth of the river is eroded

  14. Then what is the problem?cont. • Water Quality- the water stops moving and causes: • Temperature changes • Removal of nutrients • Dissolved gases • Concentration of metals and minerals • pollution • Reduction of biodiversity • Species are isolated upstream and downstream • Migrations are interrupted and often stopped • Other Problems • Dams are expensive to build, and due to drought may become useless, or produce much less power than originally planned.

  15. Opinion Changes? • Adjust your 3rd column as necessary!

  16. Who is causing it? -Predictions?? Of course, man! BUT, why???

  17. Who is Causing it? • Communities across the world use dams • Farmers benefit • Households benefit • Big business benefits

  18. More opinions? • Complete the final column of your note sheet for the “Who is causing it?” section. • Be sure to consider how YOU are a part of the problem!

  19. What is affected? -Predictions?

  20. What is being affected? • Plant and animal species lose habitats • Migrations of fish are interrupted and often stopped • Ecosystems are destroyed (dried/flooded) • Food chains/webs are interrupted • Endangered species are at risk of extinction • Erosion alters the land

  21. More opinions? • Complete the final column of your note sheet for the “What is being affected?” section. • Does this elicit any emotion or concern in YOU?

  22. Reflect on your learning: • Discuss: • How are the biotic and abiotic factors on our planet are affected by the construction of dams? • Are the causes of dams (the reasons we build them) worth the consequences?

  23. What is being done to help? • Suggestions for easing the effects of dam construction • make better use of the dams that already exist • try to make dams that have less environmental impact in the future • release more water from the reservoir that the dam created • inform people about what effects dams and hydroelectric power are having on the environment

  24. Final opinions? • Complete the final column of your note sheet for the “What is being done to help?” section. • What can YOU do?

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