Draining an area of 726 square kilometers and covering the municipalities of Belford Roxo, Duque de Caxias, Nilópolis, Nova Iguaçu, Rio de Janeiro and São João de Meriti, the watershed of the Iguaçu River has its headwaters located in Sierra Tinguá; its course develops in the southwest direction, with a total length of 43 km and flowing into the bay. The Capivari, Pati and Tinguá on the left bank and right bank Botasà are the main tributaries of the Iguaçu River.