From Floodplains to High Andes
The Amazon basin has few large lakes completely surrounded by uplands. However, some slow-flowing river channel water bodies can be considered lakes in function. There are two basic lake types in the Amazon Basin separated by elevation. Andean lakes are found at elevations usually above 3,500 m. The largest lake in the Andes is Titicaca but it does not drain into the Amazon Basin. The largest lake in the Amazon Basin is Lake Junín of Central Peru located in the upper Ucayali Basin at about 4,800 meters. There are hundreds of smaller Andean lakes, usually called in Spanish lagunas rather than lagos, and many are fed, at least in part, by glaciers.
The open water bodies that stud Amazonian floodplains represent the second type of lake and are found only in the lowlands. Meandering rivers such as the Ucayali, Purus and Juruá have hundreds of floodplain oxbow lakes, often in the shape of a horseshoe. Although the Amazon River has minimal meandering its floodplain nevertheless has numerous depressions where lakes because of extensive flooding where water depth is sufficient to prevent colonization by forest. The largest floodplains lakes are found in the lower Amazon River floodplain near Santarém where some reach areas larger than 50 km2 even during the low water season. The largest savanna lakes in the Amazon basin are located in Eastern Bolivia, such as the Lago Rogaguado and Lago Ginebra in the Llanos de Moxos.
Seasonal lakes, such as those recognized by Ramsar Convention on Wetlands, also occur in the Amazon basin. These are found on floodplains, savannas, and in some of the drier regions of the high Andes.