More than 9 million people in Lima, Peru’s capital city, rely on three important rivers for their water supply: the Rimac, the Chillon, and the Lurin. The rivers spring from snow and rivers in the high peaks of the Andes Mountain Range and flow into the Pacific Ocean.
These rivers and their valleys were traditionally used – even in Pre-Incan times- to produce food for the people who lived there. Nowadays, urban development has taken over 95 percent of the Rimac River Valley (which provides 75 percent of Lima’s water), 60 percent of the Chillon River Valley, and 20 percent of the Lurin River Valley. And the pressure for urban expansion continues.
The Nature Conservancy is supporting the creation of Aquafondo, the Lima Water Fund, together with Grupo GEA and the Fondo de Las Américas (FONDAM). Similar to the Quito and Bogotá water funds the Conservancy has helped establish in Ecuador and Colombia, the Lima Water Fund will use contributions from major water users in Lima to finance conservation projects that protect and restore the rivers and watersheds that the city depends on.
The Rimac River originates in the western slopes of the Andes Mountain Range, at an altitude of approximately 18,070 feet, in the Paca mountain. Its main tributaries are the Santa Eulalia and Blanco rivers.
This basin covers a total area of 1,209 square miles and it encompasses 191 lagoons that harbor an impressive diversity of both resident and migratory aquatic bird species.
The watershed plays a vital role as a source of water for human, agricultural and energy consumption. It contains five important hydroelectricity plants and sustains a broad range of mining activities that are particularly intense at higher elevations. The main crops produced here are alfalfa, potatoes, cereals, tubers and grains.
The Chillon River is the second source of water for Lima. Its headwaters are located on the western slopes of La Viuda (The Widow) Mountain Range, in the Pucracocha, Aguascocha and Chuchón lagoons, at approximately 15,091 feet. Its most important tributaries are the Yamacoto, Huancho, Ucaña and Quisquichaca rivers.
The basin covers an area of 943 square miles. In the highlands, there is a group of lagoons, most of them fed by glacier melt originating in the La Viuda Mountain Range. The most important lagoons, including those of Chuchon, Azulcocha and Leon Cocha, are used to store water during the summer months. This water is then discharged between May and December, when the river’s flow is at its lowest level.
Of the three valleys that Lima is built on, the Chillon Valley conserves the largest agricultural lands and the main crops grown here are corn, cotton, tomato, potatoes, grasses and fruits.
The Lurin River originates in the snow melts of the Surococha mountain, at an altitude of approximately 16,404 feet, and on its course it incorporates rainfall from the highlands and snow melt from other mountains.
The basin covers an area of 663 square miles and its superficial waters are mainly used to irrigate crops, while the underground waters are used by communities that carry out agriculture and mining activities.
Although the variety of crops diminishes as the altitude decreases, this watershed provides a great diversity of fruits and vegetables, mainly tubers, grains and cereals. Livestock activities take place mainly at higher elevations and include cows, sheep, goats and, to a lesser extent, horses.
The conservation of freshwater resources is one of the main strategies used by the Conservancy to guarantee the survival of nature and people. The three basins contain habitat types – from deserts to mountain grasslands- that are scarcely protected.
In addition, despite the fact that these are mainly arid environments, they contain 57 wetlands that are important for Lima’s inhabitants and for biodiversity. Together with regulating water for the basin, they allow the existence of macroinvertebrates, amphibians and fish, and attract migrating birds and mammals. These wetlands are among the most diverse ecosystems in the desert, with a high number of species found nowhere else in the world, and provide environmental services that are crucial for the quality of life of millions of people.February 11, 2011