A new report says the valley beneath Hetch Hetchy Reservoir in Yosemite would be worth $100 billion if we were to drain the reservoir and let the valley return to its natural state. Chronicle reporter Kurtis Alexander and I chop up the pros, cons and feasibility of the idea, which has been percolating for more than a century.

Learn more about your ad choices. Visit megaphone.fm/adchoices