The Seridó River is a tributary of the Piranhas River in northeastern Brazil. A tributary is a Stream or River which flows into a mainstem (or parent river The Piranhas River, also known as the Açu River, is a river of northeastern Brazil. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld The Seridó originates in the Borborema Plateau in Paraíba state, and flows northwest through Paraíba and Rio Grande do Norte states to join the Piranhas. The Borborema Plateau ( Portuguese Planalto da Borborema, also known as the Serra da Borborema) is a plateau in northeastern Brazil which extends Paraíba (paɾaˈiba is one of the states of Brazil, located in the northeastern part of the country on the Atlantic coast where lies the easternmost Rio Grande do Norte (lit "Large River of the North" xiu ˈgɾɐ̃di du ˈnɔxti is one of the states of Brazil, located in the northeastern part