The most prominent feature of the
Altiplano is the large lake at its northern end,
Lake Titicaca. At above sea level. With a surface area of , it is larger than
Puerto Rico and is South America's second-largest lake by surface area. Lake Titicaca is also deep, about at its deepest, with an average depth of ; its volume of water is large enough to maintain a constant temperature of . The lake actually moderates the climate for a considerable distance around it, making crops of maize and wheat possible in sheltered areas.
Lake Titicaca drains southward through the slow-moving,
reed-filled
Desaguadero River to
Lake Poopó. In contrast to the
freshwater Lake Titicaca, Lake Poopó is salty and shallow, with depths seldom more than . In western Bolivia, the
Cordillera Occidental is a chain of dormant
volcanoes and
solfataras,
volcanic vents emitting
sulfurous gases. Bolivia's highest peak, the snowcapped
Nevado Sajama , is located here. The entire Cordillera is of volcanic origin and an extension of the volcanic region found in southern Peru. Most of the northern part of this range has an elevation of about ; the southern part is somewhat lower. Rainfall, although scanty everywhere, is greater in the northern half, where the land is covered with
scrub vegetation. The southern area receives almost no
precipitation, and the landscape consists mostly of barren rocks. All of the Cordillera Occidental regions are sparsely populated, and the south is virtually uninhabited. The
Altiplano, the high
plateau between the previous range, and the
Cordillera Oriental, comprises four major basins formed by mountainous spurs that jut eastward from the Cordillera Occidental about halfway to the Cordillera Oriental. Along the Altiplano's eastern side is a continuous flat area, which has served as Bolivia's principal north–south transport corridor since colonial times. The entire Altiplano was originally a deep
rift between the cordilleras that gradually filled with highly porous
sedimentary debris washed down from the peaks. This sedimentary origin explains its gradual slope from north to south; greater rainfall in the north has washed a larger quantity of debris onto the platform floor. Rainfall in the Altiplano decreases towards the south, and the scrub vegetation grows more sparse, eventually giving way to barren rocks and dry red clay. The land contains several
salt flats, the dried remnants of ancient lakes. The largest of these – and the world's largest salt concentration – is the
Uyuni Saltpan, which covers over 9,000 square kilometers. The salt is more than five meters deep in the center of this flat. In the dry season, the lake bed can be traversed by heavy trucks. Near the Argentine border, the floor of the Altiplano rises again, creating hills and volcanoes that span the gap between the eastern and western cordilleras of the Andes. The much older Cordillera Oriental enters Bolivia on the north side of Lake Titicaca, extends southeastward to approximately 17 south latitude, then broadens and stretches south to the Argentine border. The northernmost part of the Cordillera Oriental, the
Cordillera Real, is an impressive snow-capped series of
granite mountains. Some of these peaks exceed and two –
Illimani , which overlooks the city of
La Paz, and
Illampu – have large
glaciers on their upper slopes. South of 17 south latitudes, the range changes character. Called the
Cordillera Central here, the land is a large block of the Earth's crust that has been lifted and tilted eastward. The western edge of this block rises in a series of cliffs from the Altiplano. The backbone of the cordillera is a high, rolling plain, with elevations from , interspersed with irregularly spaced high peaks. Too high to be exploited for large-scale commercial grazing, this area takes its name from the predominant
vegetation type, the
puna. Bolivia has three
drainage basins: • The first is the
Amazon Basin, also called the North Basin (/66% of the territory). The rivers of this basin generally have big
meanders which form lakes such as
Murillo Lake in
Pando Department. The main Bolivian
tributary to the Amazon basin is the
Mamoré River, with a length of running north to the confluence with the
Beni River, in length and the second most important river of the country. The Beni River, along with the
Madeira River, forms the main tributary of the
Amazon River. From east to west, the basin is formed by other important rivers, such as the
Madre de Dios River, the
Orthon River, the
Abuna River, the
Yata River, and the
Guaporé River. The most important lakes are
Rogaguado Lake,
Rogagua Lake, and
Jara Lake. • The second is the
Río de la Plata Basin, also called the South Basin (/21% of the territory). The tributaries in this basin are in general less abundant than the ones forming the Amazon Basin. The Rio de la Plata Basin is mainly formed by the
Paraguay River,
Pilcomayo River, and
Bermejo River. The most important lakes are
Uberaba Lake and
Mandioré Lake, both located in the Bolivian marshland. • The third basin is the
Central Basin, which is an
endorheic basin (/13% of the territory). The
Altiplano has large numbers of lakes and rivers that do not run into any ocean because they are enclosed by the Andean mountains. The most important river is the
Desaguadero River, with a length of , the longest river of the
Altiplano; it begins in
Lake Titicaca and then runs in a southeast direction to
Poopó Lake. The basin is then formed by Lake Titicaca, Lake Poopó, the Desaguadero River, and great salt flats, including the
Salar de Uyuni and
Coipasa Lake. In Bolivia
forest cover is around 47% of the total land area, equivalent to 50,833,760 hectares (ha) of forest in 2020, down from 57,804,720 hectares (ha) in 1990. In 2020, naturally regenerating forest covered 50,771,160 hectares (ha) and planted forest covered 62,600 hectares (ha). Of the naturally regenerating forest 0% was reported to be
primary forest (consisting of native tree species with no clearly visible indications of human activity) and around 24% of the forest area was found within protected areas. For the year 2015, 100% of the forest area was reported to be under
public ownership. ==Valleys==