1. Dams Helpful or Hurtful?

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

3. What we know:

4. What is the issue?  Dams 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 Dam Construction Dam Construction

12. Benefits of Using Dams  Dams provide many benefits including: Recreation Recreation flood control flood control water supply water supply hydroelectric power hydroelectric power waste management waste management river navigation river navigation wildlife habitat 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 Approximately 400,000 sq km worldwide have been flooded by dams Forests are flooded and decompose Forests are flooded and decompose Dams can break and cause a massive flash flood. Dams can break and cause a massive flash flood.  Riverbeds, banks, deltas, estuaries, and coastlines are changed Disrupts natural seasonal changes in the river Disrupts natural seasonal changes in the river Ends flooding that help to clean out the silt in rivers, causing them to clog 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. The silt that usually flows down to the Beaches and Estuaries is blocked by the dam. Sediment load changes Sediment load changes Sediment settles to bottom of river Sediment settles to bottom of river The settled sediment erodes and leaves poor habitat for fauna The settled sediment erodes and leaves poor habitat for fauna The coast beyond the mouth of the river is eroded 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 Temperature changes Removal of nutrients Removal of nutrients Dissolved gases Dissolved gases Concentration of metals and minerals Concentration of metals and minerals pollution pollution  Reduction of biodiversity Species are isolated upstream and downstream Species are isolated upstream and downstream Migrations are interrupted and often stopped 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. 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 3 rd 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? 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? 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 make better use of the dams that already exist try to make dams that have less environmental impact in the future try to make dams that have less environmental impact in the future release more water from the reservoir that the dam created release more water from the reservoir that the dam created inform people about what effects dams and hydroelectric power are having on the environment 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?