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Why was Hetch Hetchy Reservoir controversial?

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map of western North America — Sierra Nevada Physical features of western North America.

The Hetch Hetchy Reservoir became a subject of intense controversy in the early 20th century because its construction required the damming of a scenic valley located within the boundaries of Yosemite National Park.12

The project was driven by the city of San Francisco’s need for a reliable water supply and hydroelectric power, which could be delivered from the Sierra Nevada to the city via a long aqueduct without the need for pumping. However, the proposal faced fierce opposition from preservationists, led by the renowned naturalist John Muir and the Sierra Club.12

These opponents argued that the project would destroy a pristine natural landscape and set a dangerous precedent for commercial and municipal development within protected national parks. While the U.S. Congress ultimately approved the dam in 1913, the conflict remains a landmark event in American environmental history, serving as a powerful symbol for those who believe that the preservation of natural heritage must take precedence over industrial utility.2