An Environmental Defense report is the latest attempt to sway public opinion in favor of draining Hetch Hetchy Valley in Yosemite National Park and restoring the area to a more natural state.
The report concludes that the Bay Area could receive a majority of its drinking water and hydropower without the Hetch Hetchy reservoir.
The report comes as the Bay Area embarks on a $3.6 billion expansion and retrofit of the aging Hetch Hetchy water system. Seismologists warn that millions could be left without drinking water if a major earthquake strikes.
Located within the Yosemite National Park boundries, the Hetch Hetchy reservoir provides drinking water to nearly 2.5 million residents in San Francisco and its fast-growing suburbs in San Mateo, Santa Clara and Alameda counties.