The Amazon River is 6.868 km long, being considered the longest of the world;

 In the mouth of the Amazon River, the volume of water is from 100 to 300 m ³ /second, depending on the season. Considering a middle flow of 200 meters/ second and considering 100 water liters / day the middle consumption of a person, only 1 second of flow would be enough to provide a city with 2.000.000 persons. The quantity of water of the Amazon River represents 17 % of all the liquid fresh water of the planet;

 The river average depth is from 40 to 50 meters, reaching 100 meters near Óbidos;

 The effect of the tides (bore) can be noticed at1000 km from the sea;

 There are basically three types of rivers in the Amazon region:
- The white water (Solimões, Amazon, Madeira), that presents a visibility between 0, 5 and 1m and pH between 6, 5 and 7m;
- The black water (Negro, Urubu), that present visibility from 1, 5 to 2 meters and pH between 3, 5 and 4, 0;
- The clear water (Tapajós, Trombetas), that present visibility superior to 4, 0 meters and pH between 4, 0 and 7, 0.