The drought has pushed down reservoir levels in many places across the West, including the Castaic Lake reservoir in Los Angeles County. The American West is locked in its worst drought on record, bringing renewed water restrictions, wildfire danger and angst to one of the nation’s fastest-growing regions, just as the heat of summer approaches. Much of the West has been mired in a drought stretching back to the beginning of the century— the driest in 1,200 years , according to tree-ring records analyzed by researchers from the University of California, Los Angeles.