Since 1987, seven major institutions have researched various aspects of restoring Hetch Hetchy Valley and all concluded that restoration is both feasible and practical. There are no studies contradicting this conclusion. See for yourself:

1. California Department of Water Resources Report (2006)
2. Restore Hetch Hetchy Report (2005)
3. University of Wisconsin Report (2004)
4. Environmental Defense Report (2004)
5. Journal of the American Water Resources Association, UC Davis (2006)
6. National Park Service Report (1988)
7. U.S Bureau of Reclamation Report (1988)
8. The Water Sustainability and Environmental Restoration Planning Act of 2012