Hetch Hetchy is a reservoir located in Yosemite National Park in California. The Hetch Hetchy Valley, once described as "a grand landscape garden", was dammed in the early 20th century to provide water to the San Francisco Bay Area. The damming of the valley has been a controversial topic and has resulted in ongoing conservation efforts. The reservoir is fed by several surface flows, including the Tuolumne River, which originates in the Sierra Nevada mountains. Snowpack from the surrounding mountains also provides water to the reservoir. The water from Hetch Hetchy is used for agricultural purposes, such as irrigation, as well as for domestic and industrial use in the Bay Area. Recreational activities, such as hiking and camping, are also popular in the area.