Land and Resources, Rivers

In the northern and northeastern valleys and plains, the drainage system consists of the Beni River and its main affluent, the Madre de Dios River; the Guapore River, which forms part of the boundary with Brazil; and the Mamore River. These rivers flow north to join the Amazon River. The Pilcomayo River, the chief river of southeastern Bolivia, flows through the Chaco to feed the Paraguay River, eventually draining into the Rio de la Plata, a large estuary that empties into the Atlantic Ocean between Argentina and Uruguay. The Desaguadero River, outlet for Lake Titicaca, feeds Lake Poopo to the southeast.