the mud at the bottom is also due to the domestic discharges, and the fluvial sedimentation of the 6 rivers that flow into it,  contributing to the dark color of the water. the channel at the entrance of the bay is 30 meter deep and has a sandy bottom that slowly moves inward in the bay.

flamengo beach, in the neighborhood by the same name, is one of the most famous bay-side beaches - in fact, due to the position facing the entrance to the baía de guanabara, it enjoys cleaner waters than most other bay beaches.