Lake Titicaca is at the northern end of the Altiplano basin in the Andes on the border of Bolivia and Peru. The eastern side is located in the Bolivian La Paz Department, while the western side lies within the Puno region of Peru. The overall average depth of Lake Titicaca is 107 m (351 ft).
It is composed of two separate sub-basins that are linked by the Strait of Tiquina, which is 800 m (2,620 ft) across at the narrowest point. The larger sub-basin, Lago Grande or Lago Chucuito, has a maximum depth of 284 m (932 ft) and a mean depth of 135 m (443 ft). Winaymarka, a smaller basin, is also known as Lago Pequeno, meaning “little lake.” It has a maximum depth of 40 m (131 ft) and a mean depth of 9 m (30 ft). Ramis, Coata, Ilave, Huancane, and Suchez are the five major river systems feeding into the lake. Its source is the meltwater from glaciers and rain. In order to maintain its relative flow volumes, at least 20 smaller streams go into Lake Titicaca and it has more than 40 islands, most of which are heavily populated.
Lake Titicaca is monomictic, a closed lake, and has free circulation in a season. Water goes through Lago Huinaimarca and out from the single outlet at the Rio Desaguadero. It also flows south through Bolivia to Lake Poopo. The remaining 90% of the water input is balanced through a process called evapotranspiration, which results from intense sunlight and winds at altitude. The remaining 10% of the lake’s water is from Bolivia to Lake Poopo.
Since 2000, the lake has constantly experienced reduced water levels. The water level sank by 81 cm between April and November 2009 alone and now has reached its lowest level since 1949. This drop in water level is due to the melting of glaciers feeding the tributaries of the lake and the shortened raining seasons.
On August 26, 1998, Lake Titicaca was designated a Ramsar Site. It also holds a large populations of water birds, the huge Titicaca Water Frog, the flightless Titicaca Grebe and the Titicaca Orestias. Most of these species are entirely restricted to Lake Titicaca. There are many threatened species that have gone extinct over time because of predation by several introduced species of trout and silversides as well as competition.
The meaning of the lake’s name is uncertain, but it has been translated as “Rock of the Puma” because it looks like a puma hunting a rabbit, or “Crag of Lead” when translated. The lake is seen between Andean ranges in a large basin and comprises most of the Altiplano of the northern Andes. In the snow-covered Cordillera Real on the northeastern (Bolivian) shore of the lake, some of the highest peaks in the Andes rise to heights of more than 21,000 ft (6,400 m). The locals call the lake several names because the main body is separated from the southeast quarter and the Strait of Tiquina is only where the lake is connected. The Bolivians call the larger part Lago Chucuito Huinaymarca. In Peru, these smaller parts are referred to as Lago Peque and larger parts are referred to as Lago Grande.
The lake waters are slightly brackish and limpid; 5.2 to 5.5 parts per 1,000 is the range of the lake’s salinity. Surface temperatures average 56° F (14° C); from a thermocline at 66 ft (20 m) temperatures drop to 52° F (11° C) at the bottom. Over a cycle of years, Titicaca’s level seasonally fluctuates. The level of the lake rises during the rainy season (summer, from December to March), while during the dry winter months it recedes. Analyses show measurable quantities of calcium sulfate, sodium chloride, magnesium sulfate and sodium sulfate in the water.
Some two million years ago, the lake encompassed areas that today are covered in salt flats and wasteland, and its body of water has been larger. The lake’s origins stem back millions of years. It defined the works that humans have undertaken in the southern Americas and contains the sum of all the ages that have molded it.
The fish life found in the lake include a catfish (Trichomycterus) and a killifish (Orestias) which is small in size, as well as a Telmatobius, which is a big frog found in shallower parts of the lake. In 1939, trout was introduced into the lake.
According to tradition, Incas (a Quechuan people of Peru who established an empire about 1100), the legendary founders of the Inca dynasty, Manco Capac and Mama Ocllo, were sent down to Earth by the Sun. One of the oldest civilizations known in the Americas can be found in the ruins on the shore and on the islands, further attesting to the existence of civilizations antedating the Christian era. The chief site is at Tiahuanaco, Bolivia, at the southern end of the lake.
From the depths of Lake Titicaca, according to Incan mythology, the children of the Sun Manco Capac and Mama Ocllo resurrected to establish their empire. At 3,800 m, the blue-colored lake is one of the Andes’ most enchanting scenes and the symbolic universe of the ancient Peruvians.