Wall Street Journal: Dwindling water supplies are compounding economic woes in California’s Central Valley, causing farmers to leave fields fallow and confront the prospect of going under. Bill Diedrich, a farmer in California’s Central Valley, inspects his almond trees. His nephew, Todd Diedrich, is letting 1,000 acres of his family’s 1,500-acre farm go fallow this year to concentrate use of scarce water. The state’s water supply has dropped precipitously of late. California is locked in the third …