Pebas is a river up to 15 m deep, the Amazon Formation has a very strong undercutting of the riverbed, up to 40 m and has a large amount of iron oxides, the materials are clayey, clay-sandy. As summer arrives (June to November), the water levels drop, revealing forests and beaches on the edges of the rivers and streams. This dynamic or flood pulse conditions the life manifestations of the flora and fauna.