Our guest on this edition of ST is Sandra Postel, a well-respected expert on freshwater conservation who's also the founder of the Global Water Policy Project. She co-created Change the Course, a national freshwater conservation and restoration campaign, and in 2010, she was appointed a Freshwater Fellow of the National Geographic Society, where she still serves as the Society's leading water expert. Postel will be featured in an upcoming TV documentary entitled "Water Apocalypse," airing on the National Geographic Channel on Sunday the 13th at 8pm local time. "Water Apocalypse" is part of a six-part science series, "Breakthrough," from executive producer Ron Howard, which will highlight recent discoveries in brain science, longevity, water, energy, pandemics, and cyborg technology. In "Water Apocalypse" specifically, Postel will speak about how California is dealing with a severe and ongoing drought that will, all in all, cost the state billions in lost farm revenue and thousands of jobs. Moreover, she'll elaborate on Change the Course's efforts to bring water back to the Colorado River Delta, much of which became dried-up after that river was diverted to feed the southwestern United States.