Born in the Bolivian highlands, the Pilcomayo River gnaws at crumbling Andean hillsides as it descends southeast. Eventually, it flows onto the plains of Paraguay. That’s where its load of silt becomes a load of trouble. For decades, the Pilcomayo has deposited the bulk of its silt in the Paraguayan department of Boqueron and dried up there. And for decades, this process caused the river mouth to retreat. Though the river had been retreating when Spanish explorers reached present-day Paraguay in the 1500s, the process accelerated dramatically in the past century due largely to land-use changes in Bolivia that increased erosion. From the 1940s until 1991, the river retreated 224 miles (361 kms). A large swath of land has been drying as a... [Log in to read more]