An intense drought has gripped the American West since before the turn of the millennium. As the area's population booms, its snowpacks are thinning, its rivers are running low and its reservoirs are shrinking. But is the drought a temporary condition or a new and disconcerting normal? Tuesday we're talking about the challenges facing the West as water becomes increasingly scarce. We'll focus on the region's most important water resource, the Colorado River, and how its vital bounty is shared among millions of people.