 The river then leaves Tijuca Forest into the Guararapes favela, then into the high-income Cosme Velho neighborhood, and then it is buried completely underground.The river reemerges in Flamengo Park to empty into Guanabara Bay at Flamengo Beach.Research by the Fundação SOS Mata Atlântica in 2015 confirmed that every river in the City of Rio de Janeiro is polluted, including the Carioca River.