National Public Radio: As Californians hope for rain and snow to end the state's extreme drought, a decades-old rule prohibits reservoirs from filling up in the winter, so some water ends up being released. The rule may sound odd given how chronically dry California is, but it's actually to prevent a bigger disaster: flooding. In the winter, reservoirs are not allowed to fill up. That's so they can capture excessive amounts of water that flow out of the mountains during storms. It was a solution engineered to prevent...