PORCIOSA, ColombiaSeventeen-year-old Virginia Pushaina drops an orange bucket into the murky depths of an open pit to collect muddy water. It's early morning in October, but the temperature's already approaching 90 degrees. Crops of corn and beans have long since shriveled to dust, and emaciated goats scrounging for food in the sand no longer can feed a family or fetch a good price at market.

Six months pregnant, Pushaina often thinks about the baby son she lost to an infection two years ago. She now fears for her young daughter, who often lacks clean water and receives little nourishment apart from a few swallows of chicha, a fermented corn drink.

Since the region’s crippling drought began three years ago, 12 children among Pushaina's