@mattblaze the water from Hetch Hetchy is some of the cleanest and purest on the planet. Snowmelt held by granite. Few places have water that good (Granada, Spain is one). And the dam provides hydropower that serves a significant amount of the City of San Francisco's needs. It comes at a significant environmental cost, of course. As so many things do. On balance, was it the right thing to do? That's hard to answer, even in retrospect.