Vox: The American West has been wrestling with drought for the past 15 years. California is now facing its worst dry spell in at least a century. So, not surprisingly, the question of how best to manage America's scarce freshwater supplies is coming up more frequently. To that end, the Hamilton Project recently published a helpful primer, "Nine Economic Facts about Water in the United States." The whole thing's worth reading, but four maps and charts in particular stuck out. For starters, some of the...