What Are the Costs and Benefits of Damming a River?
ESU401  Preservation of Natural Areas

Glen Canyon was a beautiful and unique natural area. In The Exploration of the Colorado River and Its Canyons, John Wesley Powell described the naming of the canyon: "We saw a curious ensemble of wonderful features—carved walls, royal arches, glens, alcove gulches, mounds and monuments... We decide to call it Glen Canyon."

This map shows the entire drainage basin of the Colorado River. Different colors on the map represent the sub-basins of tributary rivers that flow into the Colorado.

  !   Click the red dots to see photographs that represent some of the features that were present in Glen Canyon before it was flooded.
Map of Colorado River drainage basin.

7. Describe the former environment of Glen Canyon. What were some of the benefits this natural area offered?

Consider the overall impact of Lake Powell on the preservation of natural areas. On your student answer sheet, use a scale from -2 to +2 to indicate your evaluation of the damís impact on preservation of natural areas.

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