YOSEMITE NATIONAL PARK, Calif. (KFSN) -- The Hetch Hetchy Valley is located in the northwest corner of Yosemite National Park. It's filled with water held back by O'Shaughnessy Dam. Under the reservoir, is a deep gorge, comparable in grandeur to the Yosemite Valley 40 miles away.
The water held at Hetch Hetchy goes to San Francisco.
Sprek Rosecrans, who heads the group "Restore Hetch Hetchy" believes the dam is no longer needed, "San Francisco can get every drop of their water supply without using Hetch Hetchy Reservoir."
Rosecrans claims newer dams built downstream can hold the city's water and says the continued diversion in this scenic valley violates state law.
Restore Hetch Hetchy lost that argument in a lower court, but attorney Michael Louzeau has taken the case to the state's 5th District Court of Appeals in Fresno.
"In putting in that dam and continuing to operate it over the years they have to comply with California water law," says Louzeau.
Restore Hetch Hetchy argues that back in 1913 when Congress approved the dam, it was stipulated the diversion of the water must comply with California law. Louzeau Hetch Hetchy claims it no longer does.
"Because in this day and age, if we asked anyone can we dam up Yosemite Valley they would say you are crazy. If Hetch Hetchy Valley was currently the way it was one hundred years ago, and you asked someone should we put a dam in Yosemite National Park, they'd say no that's crazy. So whats reasonable today, might not look like anything that was reasonable 80, 90 years ago."
But San Francisco's Deputy City Attorney, Aileen McGrath argued the statute of limitations on the dam project expired in 1928, and it's not reasonable to challenge it now after the city has spent billions over the decades to build and maintain it.
"That water infrastructure serves nearly 3 million people in the Bay Area. It cannot be the case that water infrastructure is subject to constant and repeated challenges at any time."
She also questioned the state's authority over the project, "Remember the dam and reservoir is on federal property, so Congress has the authority to decide how that property is used. Congress has the ability to make that decision and state law can't call that into question."
San Francisco's argument will be tested in court. The judges in Fresno will decide if a lower court or the State Water Board should be able to revisit the case and determine the future of the Hetch Hetchy Valley.