By: Matt Damon When one of the world’s great social entrepreneurs, Gary White, first told me his solution for ending the global water crisis, I honestly thought it sounded absurd. Our conversation took place back in 2008, at the Clinton Global Initiative. Gary and I were at CGI because we were both, at the time,

  Left: Robin Broad; right: John Cavanagh   In the early 2000s, many people in El Salvador were at first excited by the prospect of jobs, progress, and prosperity that the Pacific Rim mining company promised. However, farmer Vidalina Morales, brothers Marcelo and Miguel Rivera, and others soon discovered that the river system supplying water