1. What are the pros and cons of hydropower?

2. What are the pros and cons of hydropower?
Aim: What are the pros and cons to generating electricity from hydropower?

3. Aim: What are the pros and cons of hydropower?
1. Dams are relatively inexpensive to operate.
Yet, they are very expensive to build.
2. Dams generate clean power
Hydropower is renewable and doesn’t emit greenhouse gases or other air pollutants*
*What kinds of energy do you think were used to build this dam?

4. Aim: What are the pros and cons of hydropower?
Pros, continued
Aim: What are the pros and cons of hydropower?
3. Dams improve quality of life
prevent flooding*, create jobs, and provide cheap electricity, irrigation, and drinking water

5. Aim: What are the pros and cons of hydropower?
1. Dams alter river habitats in many ways
upstream: flooding
downstream: not enough water

6. Aim: What are the pros and cons of hydropower?
Cons, Continued
Aim: What are the pros and cons of hydropower?
2. Natural cycles are disrupted
- floodplains don’t receive nutrients from sediments because they get trapped behind dams

7. Aim: What are the pros and cons of hydropower?
Cons, Continued
Aim: What are the pros and cons of hydropower?
3. Temperature of the water is changed
 aquatic populations go extinct

8. Aim: What are the pros and cons of hydropower?
Imagine you are a fish trying to get upstream of the Hoover dam…

9. Aim: What are the pros and cons of hydropower?
Cons, Continued
Aim: What are the pros and cons of hydropower?
4. Dams prevent anadromous fish from laying eggs.
 No fish ladder!
 Fish ladder 

10. Aim: What are the pros and cons of hydropower?
What do you think: do the pros outweigh the cons?

11. Aim: What are the pros and cons of hydropower?
Modern Trends
Aim: What are the pros and cons of hydropower?
In the US, the era of large dam construction is probably over.
Not so in developing countries (Brazil, China, India).
Micro-hydropower :electricity produced in a small stream without having to build a big dam 11

12. Aim: What are the pros and cons of hydropower?
Micro-hydropower
Aim: What are the pros and cons of hydropower?
Much cheaper to build.
Can be used in remote areas 12

13. Aim: What are the pros and cons of hydropower?
Should we use it?

14. Water Diversion
What are the effects of Water Diversion?

15. Water management
Water diversion projects bring water to areas that need it
Central Arizona Project Aqueduct – brings water from the Colorado River to dry areas of Arizona, multiple uses (drinking water, recreation, power, etc.)

16. We divert – and deplete – surface water
People have long diverted water to farm fields, homes, and cities
The once mighty Colorado River has been extensively dammed and diverted

17. The Colorado River is heavily diverted
What water is left after all the diversions comprises just a trickle into the Gulf of California
On some days, water does not reach the gulf
Diversion has drastically altered the river’s ecology

18. The Aral Sea Once the fourth-largest lake on Earth
It has lost more than 80% of its volume in just 45 years
The two rivers leading into the Aral Sea were diverted to irrigate cotton fields
Consequences of a shrinking sea
60,000 fishing jobs are gone
Pesticide-laden dust from the lake bed is blown into the air
The cotton cannot bring back the region’s economy

19. Can the Aral Sea be saved?
People may have begun saving the northern part of the Aral Sea

20. Will we see a future of water wars?
Freshwater depletion leads to shortages, which can lead to conflict
261 major rivers cross national borders
Water is a key element in hostilities among Israel, Palestinians, and neighboring countries
Many nations have cooperated with neighbors to resolve disputes