The marijuana business is booming, with private investors pumping money into startups and a market thats expected to grow nearly five-fold to $10 billion over the next four years. A historic drought has made fresh water scarce, and marijuana turns out to be an especially thirsty plant. In January, California declared a statewide drought emergency, and areas like Lake, Humboldt, and Medicino counties — where pot production is estimated to have doubled between 2009 and 2012 — began to crack down on growers who were siphoning water from public streams. We knew people were diverting water for marijuana operations, but we wanted to know exactly how much, Scott Bauer, a biologist with the California Department of Fish and Wildlife, told the Associated Press.