What Are the Costs and Benefits of Damming a River?
ESU401  Rate the Glen Canyon Dam
US Department of the Interior/ US Bureau of Reclamation,
Upper Colorado Region
Glen Canyon Dam.

Add up your scores for each of the six aspects you evaluated. Pay careful attention to sum positive and negative values accurately.

A total score from -12 to
-1 indicates you believe that the costs associated with Glen Canyon Dam and Lake Powell outweigh the benefits. A total score from +1 to
+12 indicates you believe the dam and lake have had a beneficial or positive impact. A total score of zero indicates you believe the costs are equal to the benefits.

This type of evaluation scale assumes that all the aspects you rated are equally important. For some people, however, certain aspects are more important than others. For instance, someone might feel that preservation of natural areas is twice as important as hydroelectricity or that opportunities for recreation are more important than the dam's impact on native cultures. Consider whether your total score accurately reflects your opinion of the costs and benefits of Lake Powell.

8. Does your total score accurately represent your overall opinion of the impact of Glen Canyon Dam and Lake Powell? Describe any discrepancies.

9. How could you change the rating system to indicate that some aspects are more important than others?

10. What other aspects of the dam and lake might you rate?

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