What are the benefits of building Dams? What are environmental impacts?

Question

How have the relative benefits and negative impacts manifested themselves in the history of the Colorado river?

Answer 1

Benefits are generating electricity, storing water for use in dry periods and flood control.

They also flood land behind the dam, change the water temperature of the river and alter erosion patterns. The Colorado river now runs cold, clear and constantly instead of muddy, warm and with frequent flash floods.