Chronicle: California's great Central Valley aquifer and the rivers that feed it, already losing water in the changing climate, are now being drained because of the drought, leaving water levels at their lowest in nearly a decade. Water experts say many farmers who depend on the huge water source beneath the valley for irrigation will have to resort to pumping water from ever deeper levels at greater costs, even as they plant crops on fewer and fewer acres as more of their land is gobbled up for development....