The San Juan River is, together with the Jáchal, the most important river of the Argentine
province
A province is almost always an administrative division within a country or state. The term derives from the ancient Roman '' provincia'', which was the major territorial and administrative unit of the Roman Empire's territorial possessions ou ...
Colorado
Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...
system that ends at the
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...
.
Course
The river starts near the town of Calingasta, in the southwest of the province, from the confluence of three main rivers: the
Calingasta River
The Calingasta River is a river of Argentina.
See also
*List of rivers of Argentina
This is a list of rivers of Argentina.
Longest Rivers
By drainage basin
This list is arranged by drainage basin, with respective tributaries indented under ...
above mean sea level
Height above mean sea level is a measure of the vertical distance ( height, elevation or altitude) of a location in reference to a historic mean sea level taken as a vertical datum. In geodesy, it is formalized as '' orthometric heights''.
Th ...
in the west and southwest of the province (in contrast, the Jáchal receives its
Andean
The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S l ...
tributaries from the north of the province).
From Calingasta the river flows eastwards feeding the Los Caracoles, Punta Negra and
Quebrada de Ullum Dam
Quebrada may refer to:
Places Argentina
* Quebrada de Las Flechas, a valley in the province of Salta in northern Argentina
* Quebrada de Humahuaca, World Heritage, a valley in the province of Jujuy in northern Argentina
* Quebrada de Luna, villa ...
s (''Embalse Quebrada de Ullum'') located near San Juan city, from which it continues south-eastwards receiving a few more tributaries, including the
Mendoza River
The Mendoza River is a river in the province of Mendoza, Argentina.Desaguadero River near the ''Salina Pampa de las Latas'' (or ''Salina Bermejo''), at the common border of the provinces of San Juan, Mendoza and San Luis.
The river has an average flow of . Its course is long, and its
drainage basin
A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...
covers an area of . The Ullum Dam is AMSL with a reservoir covering an area of and a volume of around .
The upper course of the river is used for water sports such as
rafting
Rafting and whitewater rafting are recreational outdoor activities which use an inflatable raft to navigate a river or other body of water. This is often done on whitewater or different degrees of rough water. Dealing with risk is often a ...
and
fishing
Fishing is the activity of trying to catch fish. Fish are often caught as wildlife from the natural environment, but may also be caught from stocked bodies of water such as ponds, canals, park wetlands and reservoirs. Fishing techniques inclu ...
, and
windsurfing
Windsurfing is a wind propelled water sport that is a combination of sailing and surfing. It is also referred to as "sailboarding" and "boardsailing", and emerged in the late 1960s from the aerospace and surf culture of California. Windsurfing ga ...
and swimming at the Ullum Dam. Along its whole length, the San Juan River is heavily used for
irrigation
Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow crops, landscape plants, and lawns. Irrigation has been a key aspect of agriculture for over 5,000 years and has been devel ...