After a half-decade of drought, California has been buffeted this winter by a series of powerful rain and snowstorms that dumped countless gallons of water on the state’s watersheds. Some of the deluge was captured in the form of mountain snows that will feed rivers and streams during the annual spring melt. But at lower elevations, it was rain, some retained in man-made reservoirs that had been seriously depleted, but most flowing swiftly to the Pacific Ocean.