The Loa River (

Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many Latin American countries **Spanish cuisine Other places * Spanish, Ontario, Can ...

: Río Loa) is a U-shaped river in

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east a ...

's northern

Antofagasta Region The Antofagasta Region ( es, Región de Antofagasta, ) is one of Chile's sixteen first-order administrative divisions. The second-largest region of Chile in area, it comprises three provinces, Antofagasta, El Loa and Tocopilla. It is bordered t ...

. At long, it is the country's longest river and the main watercourse in the

Atacama Desert The Atacama Desert ( es, Desierto de Atacama) is a desert plateau in South America covering a 1,600 km (990 mi) strip of land on the Pacific coast, west of the Andes Mountains. The Atacama Desert is the driest nonpolar desert in the ...

Course

The Loa's sources are located on

Andean The Andes, Andes Mountains or Andean Mountains (; ) are the List of mountain ranges#Mountain ranges by length, longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range i ...

mountain slopes at the foot of Miño Volcano. The upper Loa basin is flanked on the west by a ridge with elevations that reach above , whereas to the east lies a volcanic chain, which separates it from endorheic basins as that of

Salar de Ascotán Salar de Ascotán, also known as Salar de Cebollar, is a Salt pan (geology), salt flat in northern Chile. Its drainage basin is and is shared with Bolivia. The basin is bordered on the north by the Salar de Carcote basin, on the east by small end ...

. The river flows south on an elevated plateau, for about , to the

oasis In ecology, an oasis (; ) is a fertile area of a desert or semi-desert environment'ksar''with its surrounding feeding source, the palm grove, within a relational and circulatory nomadic system.” The location of oases has been of critical imp ...

Chiu Chiu San Francisco de Chiu Chiu, or simply Chiu Chiu, is a village located about northeast of the city of Calama, in El Loa Province of Chile's northern Antofagasta Region. It lies at an elevation of above sea level, close to the confluence of the L ...

(CHEE-oo CHEE-oo). The upper courses of the river are at a considerable elevation above sea level and receive a large volume of water from the Andes, mainly of two major tributaries:

San Pedro de Inacaliri River San Pedro de Inacaliri River, or called simply San Pedro River, is a river of Chile located in El Loa Province, Antofagasta Region. It begins at the confluence of the rivers Silala and ''Cajón'', at an elevation over 4,000 m asl. A part of it ...

and Salado River. The former joins the Loa near Conchi

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

and the latter about south of Chiu Chiu. The water of its upper course and tributaries is fresh. However the lower course, as in all the rivers of this region becomes brackish. From Chiu Chiu, the Loa flows west and north in a great curve to

Quillagua Quillagua is an oasis in the Tocopilla Province, in the Antofagasta Region of northern Chile. It is a part of the commune of María Elena. The Loa River is crossed by the Pan-American Highway in this area. According to the ''Dirección Meteorol� ...

(kee-YAH-gwah). After flowing for in this portion of its course and having run through the city of Calama, the Loa receives the waters of San Salvador River at the locality of ''Chacance''. Thence the river flows north for about to Quillagua. From Quillagua, its dry channel turns westward again and marks the border between the regions of

Tarapacá San Lorenzo de Tarapacá, also known simply as Tarapacá, is a town in the region of the same name in Chile. History The town has likely been inhabited since the 12th century, when it formed part of the Inca trail. When Spanish explorer Diego ...

and

Antofagasta Antofagasta () is a port city in northern Chile, about north of Santiago. It is the capital of Antofagasta Province and Antofagasta Region. According to the 2015 census, the city has a population of 402,669. After the Spanish American wars ...

. Along its lower course, the Loa flows through a canyon, which crosses the

Chilean Coastal Range The Chilean Coastal Range ( es, Cordillera de la Costa) is a mountain range that runs from north to south along the Pacific coast of South America parallel to the Andean Mountains, extending from Morro de Arica in the north to Taitao Peninsula, ...

. The river reaches the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

in lat. 21° 26' S., a few miles south of the old port of Huanillos (Wan-EE-yōs). The hydrologic regime of the river basin is rain-dominated. The increase of its water volume occurs mainly in January and February, as a consequence of the phenomenon known locally as

Bolivian Winter Bolivian may refer to: * Something of, or related to Bolivia ** Bolivian people ** Demographics of Bolivia ** Culture of Bolivia Bolivia is a country in South America, bordered by Brazil to the north and east, Paraguay and Argentina to the so ...

History

Its banks have been inhabited from early times. Evidence of this is the notable number of

geoglyph A geoglyph is a large design or motif (generally longer than 4 metres) produced on the ground by durable elements of the landscape, such as stones, stone fragments, gravel, or earth. A positive geoglyph is formed by the arrangement and alignmen ...

petroglyph A petroglyph is an image created by removing part of a rock surface by incising, picking, carving, or abrading, as a form of rock art. Outside North America, scholars often use terms such as "carving", "engraving", or other descriptions ...

s and

pictograph A pictogram, also called a pictogramme, pictograph, or simply picto, and in computer usage an icon, is a graphic symbol that conveys its meaning through its pictorial resemblance to a physical object. Pictographs are often used in writing and gr ...

s that are found along its course and in its upper basin. Another indication of its rich past is the

Pukará de Lasana Lasana is a small village located northeast of the city of Calama in the Calama province of Chile's northern Antofagasta Region. It sits along the banks of the Loa River. Pukará de Lasana, (Quechua ''pukara'' fortress), a pre-Columbian fortress ...

Bridges

To the south of Conchi reservoir, the river is spanned by the

Conchi Viaduct The Conchi viaduct, or Loa viaduct, is located on the Loa River in Chile, from Calama. It was built to carry part of the Ferrocarril de Antofagasta a Bolivia (Antofagasta & Bolivia Railway). It stands above the river and is long. When opened ...

, an old railroad bridge. It is no longer used by the

Ferrocarril de Antofagasta a Bolivia The Ferrocarril de Antofagasta a Bolivia (British company name: Antofagasta (Chili) & Bolivia Railway or FCAB for short) is a private railway operating in the northern provinces of Chile. It is notable in that it was one of the earliest rail ...

, however it still holds the notability of being, at , one of the highest bridges in Chile.Conchi Bridge

Needs

This river supplies many towns with water used to raise shrimp. Lately, mining companies have been polluting this river, making the water unusable.

References

* *This article draws partially on the corresponding article in the Spanish-language Wikipedia, accessed July 10, 2007.

External links

EVALUACION DE LOS RECURSOS HIDRICOS SUPERFICIALES EN LA CUENCA DEL RIO LOA
{{Authority control Rivers of Antofagasta Region Rivers of Tarapacá Region Rivers of Chile