Although San Francisco had sought Tuolumne River water as early as the 1890s , this project did not move forward until the disastrous earthquake and fire of 1906 , which underscored the insufficiency of the existing water supply . The Hetch Hetchy Valley – then compared to Yosemite Valley for its scenic beauty – was chosen for its water quality and hydroelectric potential , but the location within the national park generated controversy . An act of Congress was required to circumvent federal protection of the Tuolumne River , with the reasoning that public land should be developed for the public benefit
earthquake and fire of 1906
1906 San Francisco earthquake
O'Shaughnessy Dam (California)