CAUTION: 1 - During the period from January to August, great amount of trees and vegetation go down the river with a tendency normally to concentrate at the deeper parts of the channels, where the current is stronger.
         2 - The Areas south from Jurupari Island and comprehended between Acará-Açu and Mouratuba Islands and  Itanduba and Mouratuba Islands are subjected to constant batimetric variation, with the appearance, disappearance and great changes of banks and islands. Mariners must navigate at this area only with perfect knowledge of it.