Abstract
The so called upper Paraná River system includes the whole Paraná River drainage basin upriver from the former Sete Quedas falls (now drowned by the Itaipu Reservoir) and encompass large sized tributaries like the Rivers Grande, Paranaíba, Tietê and Paranapanema. Geographically , the drainage basin approximately 900.000 km2 includes the north of Paraná State, the south of Mato Grosso do S…