*The second is the Río de la Plata Basin, also called the South Basin (/21% of the territory). The tributaries in this basin are in general less abundant than the ones forming the Amazon Basin. The Rio de la Plata Basin is mainly formed by the Paraguay River, Pilcomayo River, and Bermejo River. The most important lakes are Uberaba Lake and Mandioré Lake, both located in the Bolivian marshland.