Lago Titicaca

Lake Titicaca

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Lake Titicaca

View of the lake from the lake's Isla del Sol.

Coordinates 15°45′S 69°25′WCoordinates: 15°45′S 69°25′W

Type Mountain lake

Primary inflows 27 rivers

Primary outflows Desaguadero River

Evaporation

Catchment area 58,000 km2 (22,400 sq mi)[1]

Basin countries Bolivia

Peru

Max. length 190 km (118 mi)

Max. width 80 km (50 mi)

Surface area 8,372 km2 (3,232 sq mi)[1]

Average depth 107 m (351 ft)[1]

Max. depth 281 m (922 ft)[1]

Water volume 893 km3 (214 cu mi)[1]

Residence time 1343 years[1]

Shore length1 1,125 km (699 mi)[1]

Surface elevation 3,812 m (12,507 ft)[1]

Frozen never[1]

Islands 42+ (see article)

Sections/sub-basins

Wiñaymarka

Ramsar Wetland

Designated: 26 August 1998

Settlements Copacabana, Bolivia

Puno, Peru

References [1]

1 Shore length is not a well-defined measure.

View from space, May 1985 (north is at right)

Lake Titicaca (Spanish: Lago Titicaca) is a lake in the Andes on the border of Peru and Bolivia. By volume of water, it is the largest lake in South America.[2][3] Lake Maracaibo has a larger surface area, but it is considered to be a large brackish bay due to its direct connection with the sea.

It is often called the highest navigable lake in the world, with a surface elevation of 3,812 m (12,507 ft).[4][5] Although this refers to navigation by large boats, it is generally considered to mean commercial craft. For many years the largest vessel afloat on the lake was the 2,200-ton, 79-metre (259 ft) SS Ollanta. Today the largest vessel is probably the similarly sized, but broader, train barge/float Manco Capac, operated by PeruRail (berthed, as of 17 June 2013, at 15°50′11″S 70°00′53″W, across the pier from the Ollanta). At least two dozen bodies of water around the world are at higher elevations, but all are much smaller and shallower.[6]

Contents [hide]

1 Overview

2 Temperature

3 Name

4 Ecology

5 Geology

6 Climate

7 Islands

7.1 Uros

7.2 Amantaní

7.3 Taquile

7.4 Isla del Sol

7.5 Isla de la Luna

7.6 Suriqui

8 Transport

8.1 History

9 See also

10 References

11 External links

Overview[edit source]

The lake is located at the northern end of the endorheic Altiplano basin high in the Andes on the border of Peru and Bolivia. The western part of the lake lies within the Puno Region of Peru, and the eastern side is located in the Bolivian La Paz Department.

Map of Lake Titicaca

The lake is composed of two nearly separate sub-basins that are connected by the Strait of Tiquina, which is 800 m (2,620 ft) across at the narrowest point. The larger sub-basin, Lago Grande (also called Lago Chucuito), has a mean depth of 135 m (443 ft) and a maximum depth of 284 m (932 ft). The smaller sub-basin, Wiñaymarka (also called Lago Pequeño, "little lake") has a mean depth of 9 m (30 ft) and a maximum depth of 40 m (131 ft).[7] The overall average depth of the lake is 107 m (351 ft).[1]

Five major river systems feed into Lake Titicaca.[8] In order of their relative flow volumes these are Ramis, Coata, Ilave, Huancané, and Suchez.[2] More than twenty other smaller streams empty into Titicaca, and the lake has 41 islands, some of which are densely populated.

Having only a single season of free circulation, the lake is monomictic,[9][10] and water passes through Lago Huiñaimarca and flows out the single outlet at the Río Desaguadero,[11] which then flows south through Bolivia to Lake Poopó. This only accounts for about 10% of the lake's water balance. Evapotranspiration, caused by strong winds and intense sunlight at high altitude, balances the remaining 90% of the water input. It is nearly a closed lake.[2][7][12]

Since 2000 Lake Titicaca has experienced constantly receding water levels. Between April and November 2009 alone the water level has sunk by 81 cm (32 in) and has now reached the lowest level since 1949. This drop is caused by shortened rainy seasons and the melting of glaciers feeding the tributaries of the lake.[13][14] Water pollution is also an increasing concern because cities in the Titicaca watershed grow, sometimes outpacing solid waste and sewage treatment infrastructure.[15]

Temperature[edit source]

The cold sources and winds over the lake give it an average surface temperature of 10 to 14 °C (50 to 57 °F). In the winter (June–September), mixing occurs with the deeper waters, which are always between 10 to 11 °C (50 to 52 °F).[16]

Name[edit source]

A view of Lake Titicaca taken from the town of Puno

The origin of the name Titicaca is unknown. It has been translated as "Rock Puma", as local communities have traditionally interpreted the shape of the lake to be that of a puma hunting a rabbit. "Titicaca" combines words from the local languages Quechua and Aymara. The word is also translated as "Crag of Lead". Locally, the lake goes by several names. Because the southeast quarter of the lake is separate from the main body (connected only by the Strait of Tiquina), the Bolivians call it Lago Huiñaymarca (also Wiñay Marka, which in Aymara means "The eternal city") and the larger part Lago Chucuito. In Peru, these smaller and larger parts are referred to as Lago Pequeño and Lago Grande, respectively.

Ecology[edit source]

Lake Titicaca holds large populations of water birds and was designated as a Ramsar Site on August 26, 1998. Several threatened species such as the huge Titicaca Water Frog and the flightless Titicaca Grebe are largely or entirely restricted to the lake, and the Titicaca orestias has gone extinct due to competition and predation by various introduced species of trouts and silversides. In addition to the Titicaca orestias, native fish species in the lake's basin are other species of Orestias, and catfish from the genera Astroblepus and Trichomycterus (the last genus not in the lake itself, but in associated ecosystems). Approximately 90% of the fish species in the basin are endemic.[17]

Geology[edit source]

The Tinajani Basin, in which Lake Titicaca lies, is an intermontane basin. This basin is pull apart basin[18] created by strike-slip movement along regional faults starting in the late Oligocene and ending latest Miocene. The initial development of the Tinajani Basin is indicated by volcanic rocks, which accumulated between 27 and 20 million years ago within this basin. They lie upon an angular unconformity cuts across pre-basin strata. Lacustrine sediments of the Lower Tinajani Formation, which are exposed within the Tinajani Basin, demonstrate the presence of a pre-Quaternary, ancestral Lake Titicaca within it between 18 and 14 million years ago.[19] Little is known about the prehistory of Lake Titicaca between 14 million years ago and 370,000 BP because the lake sediments dating to this period lie buried beneath the bottom of Lake Titicaca and have not yet been sampled by continuous coring.[20]

The Lake Titicaca drilling project[20] recovered a 136-m-long drill core of sediments from the bottom of Lake Titicaca at a depth of 235 m and at a location just east of Isla del Sol. This core contains a continuous record of lake sedimentation and paleoenvironmental conditions for Lake Titicaca back to about 370,000 BP. For this period of time, Lake Titicaca was typically fresher and had higher lake levels during periods of expanded regional glaciation that corresponded to global glacial periods. During periods of reduced regional glaciation that corresponded to global interglacial periods, Lake Titicaca had typically low lake levels.[20][21]

Lacustrine sediments and associated terraces provide evidence for the past existence of five major prehistoric lakes that occupied the Tinajani Basin during the Pliocene and Pleistocene. Within the northern Altiplano (Tinajani Basin), these prehistoric lakes were Lake Mataro at an elevation of 3,950 m, Lake Cabana at an elevation of 3,900 m, Lake Ballivián at an elevation of 3,860 m, Lake (North) Minchin at an elevation of 3,825 m, and Lake (North) Tauca at an elevation 3,815 m. The age of Lake Mataro is uncertain and may be as old as Late Pliocene. Lake Cabana possibly dates to the Middle Pleistocene. Lake Ballivián existed between 120,000 and 98,000 BP. Two high lake stands, between 72,000 - 68,000 BP and 44,000 - 34,000 BP, have been discerned for Lake Minchin within the Altiplano. The high lake levels of Lake Tauca have been dated as having occurred between 18,100 and 14,100 BP.[22][23][24]

Climate[edit source]

Lake Titicaca has an Alpine climate with cool to cold temperatures for most of the year. The average annual precipitation is 610 mm. Winters are dry with very cold nights and mornings and warm afternoons. Below are the average temperatures of the town Juliaca in the northern part of the lake.

[hide]Climate data for Juliaca, Peru (1961–1990)

Month Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year

Average high °C (°F) 16.7

(62.1) 16.7

(62.1) 16.5

(61.7) 16.8

(62.2) 16.6

(61.9) 16.0

(60.8) 16.0

(60.8) 17.0

(62.6) 17.6

(63.7) 18.6

(65.5) 18.8

(65.8) 17.7

(63.9) 17.08

(62.76)

Average low

...