The two rivers are born in the buttresses of the Serra Geral, are fed by the huge Urucuia aquifer and run from East to West to the Rio Tocantins, itself tributary of the Amazon.
Los dos ríos nacen en los contrafuertes de la Serra Geral, abastecidos por el gigantesco acuífero Urucuia, y corren de Este en Oeste hasta el Río Tocantins, afluente del Amazonas.