Last week, there was much interest in the news that satellite data indicated that groundwater pumping in California's Central Valley had extracted the equivalent of one Lake Mead (about 24 MAF at full pool) during the past six years. The data confirmed an earlier report by the U.S. Geological Survey. Yes, Virginia, that's a lot of water, almost double the average annual flow of the Colorado River. But this realization is nothing new, although the amount of pumpage may be. Groundwater has been pumped unsustainably (mined or overdrafted) in the Central Valley for decades.