Why was Glen Canyon Dam controversial?

The Glen Canyon Dam became a focal point of controversy because its construction resulted in the destruction of a vast, pristine landscape, which was submerged under the reservoir known as Lake Powell.12

The project’s history is deeply tied to the evolution of the environmental movement. During the mid-20th century, conservation groups like the Sierra Club initially focused their efforts on preventing a dam at Echo Park within Dinosaur National Monument. In a strategic compromise to save Echo Park, opposition to the Glen Canyon project was dropped.2

Following the dam's completion in 1966, environmentalists came to view the loss of the beautiful, expansive canyon as a significant tragedy. This regret energized a successful campaign to block subsequent dam proposals near Grand Canyon National Park. Ultimately, the controversy surrounding the dam helped shift national policy away from the construction of large-scale dams and toward a greater emphasis on environmental protection, policy analysis, and sustainable water management.12