THE Tocantins-Araguaia Basin is Brazilian watershed located between the North and Midwest regions of the country. Its area covers the states of Tocantins, Pará, Maranhão, Goiás and Mato Grosso, in addition to the Federal District.
it is about the largest Brazilian basin located entirely in the national territory. Its main rivers are the Tocantins and Araguaia rivers, whose waters are used to generate energy. electricity, navigation, supplying the population and also for the development of economic activities, such as farming.
Read too: Platinum Basin – one of the most important hydrographic basins in South America
Characteristics of the Tocantins-Araguaia Basin
The Tocantins-Araguaia hydrographic basin is the largest basin located exclusively in the Brazilian territory, covering an area of 967.059 km². This value is equivalent to 10.8% of the entire length of the country. It comprises a total of six federation units, being them:
Tocantins;
For;
Maranhão;
Goiás;
Federal District;
Mato Grosso.
The largest area corresponds to the state of Tocantins, which is fully inserted within the limits of this basin. The extension of Goiás is the second largest, while the DF corresponds to only 0.1% of its surface. Longitudinally, the Tocantins-Araguaia Basin extends for 2,600 km from the north of Pará, on Marajó Island, to southwest Goiás, on the border with Mato Grosso and Mato Grosso do Sul.
the basin covers an area covered by two biomes, which helps us to understand its hydrological regime. The first one is the Amazon, which is distributed throughout the north and a portion of the western lands. In these areas, humid climates such as the equatorial predominate. Average temperatures range between 26°C and 27°C, and rainfall is higher than in the southern areas. Annually, the total rainfall can reach up to 3,000 mm. The northern portion of the basin is in the thick Brazil, in which the tropical climate predominates, marked by high temperatures and average rainfall of 1,500 mm.
The terrains found in the Tocantins-Araguaia Basin are mostly plateau, with areas of depressions and plains that predominate to the west and south, in addition to the coastal plain in the far north.
About 409 municipalities are part of the basin, among which stand out Belém, Marabá and Ananindeua, in Pará; Empress, in western Maranhão, and Palmas and Araguaína, in Tocantins. Although it has an average of 8.6 million inhabitants, it is a sparsely populated area, that is, it has a low demographic density (9.3 inhab./km²). Most of its population is urban, concentrated mainly in the metropolitan region of the capital of Pará.
The two main rivers are the same that give the basin its name, being the Tocantins and the Araguaia. Considering the whole set, there is an average flow of 13,799 m³/s, corresponding to 8% of the national total. Water availability, in turn, is 5,447 m³/s. The geology of the region it also allows the formation of large underground water reserves, which are called aquifers. Among them is part of the Barrier systems, Alter of the Floor, Itapecuru and Urucuia-Areado.
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Main rivers and basins that form the Tocantins-Araguaia Basin
the rivers Tocantins and Araguaia are the two main watercourses that drain the area of the hydrographic basin in question, which, for this reason, receives this name. In addition to them, the following rivers stand out:
Baggage;
Ferries;
Kayapo;
cashew trees;
Cane wild;
Of course;
Crixá-Açu;
Of Souls;
Of Deaths;
Of Ducks;
Flour;
Handsome;
Herons;
Manuel Alves Grande;
Moju;
Mopi;
Palm trees;
Paranã;
Saint Teresa;
Sleep;
Tocantinzinho;
Uru
The Tocantins River is the longest of them, covering a total of 2,400 km. It is born at the confluence of the Maranhão and Almas rivers, near the municipalities of Ouro Verde de Goiás and Petrolina de Goiás, in a plateau region located a thousand meters above sea level. Before receiving water from the Araguaia River, which runs to the west, its drainage area corresponds to 306.310 km², covering municipalities in the homonymous state, Goiás and also Maranhão.
In your course, the main hydroelectric plants that supply the region, which are the units of Tucuruí, which is located to the north, Lajeado, Peixe Angical, São Salvador, Cana Brava and Serra da Mesa, which is located further to the south.
Although it crosses important productive areas of the Midwest and North of the country, for which the waterway transport acquires strategic value, the stretches of the Rio Tocantins that precede the confluence with the Araguaia are not navigable. The junction of both rivers takes place in Marabá (PA), from where they continue their course until it flows into the Atlantic Ocean, in the region of Ilha de Marajó.
The Araguaia River flows for a total length of 2,000 km parallel to the Tocantins River. Its drainage area is 385,060 km², greater than that of the second course mentioned. THE source of Araguaia is located near the Emas National Park, in the border between Goiás and Mato Grosso, at an altitude of 850 meters.
Your route includes Ilha do Bananal, in southwestern Tocantins, the largest river island in the world and of great tourist value for the region. It does not have hydroelectric plants before the confluence with Tocantins, but has an extensive navigable stretch, Mainly used for transporting cargo.
See too: Amazon Basin – the largest hydrographic basin in the world
Importance of the Tocantins-Araguaia Basin
The waters of the Tocantins-Araguaia Basin are responsible for the supply of areas with a great ecological diversity, as they cross two of the most important Brazilian biomes, such as productive. In the states within the limits of this region, activities such as mineral extraction and plant, as well as agriculture, which play a central role in many of the municipalities in the Center-North of the Brazil.
In the economic sector, the mining in Pará, in Serra dos Carajás, responsible for a large portion of the Brazilian mineral extraction, and the plantations of commodities agricultural, such as soybeans, corn and cotton in the Cerrado extensions. The drainage system is responsible for supplying the water for the irrigation and for industrial use. At the same time, some of these activities are directly associated with the process of pollution water from springs and resulting environmental degradation.
![The Tucuruí Plant is the largest hydroelectric power plant built entirely in Brazil. [1]](/f/3fd2efcf582f0cca4dcd47548dd22dcd.jpg)
Still on the economic relevance of the rivers in this basin, we cannot fail to mention the fishing, especially for subsistence, and also the tourism, especially the modality of ecotourism.
The navigation potential of the Araguaia River is used mainly through the Tocantins-Araguaia Waterway, which extends from the municipality of Aruanã, in Goiás, to the mouth of Tocantins-Araguaia, in the territory of Pará. This transport route is responsible for the displacement of people and, in particular, cargo, such as grain, oil and fuel.
In addition, of course, to the water supply network that reaches the population, the high hydroelectric potential of the Tocantins River it translates into the plants that are in operation along its course. In total, the Tocantins-Araguaia Basin holds a share of 15% of the installed capacity in Brazil, or 13.14 GW.
The main hydroelectric power plant in operation in the region is Tucuruí, which has two units (Tucuruí I and II) and was built in the municipality of the same name, in the state of Pará, in the 1970s. In addition to representing the largest plant located entirely in Brazil, under this same criterion, was the one that generated the most electricity in 2020.
solved exercises
Question 1 - The largest hydrographic basin located exclusively in the Brazilian territory covers three regions (Midwest, North and one small portion of the Northeast) and more than 400 municipalities, including important metropolitan regions, such as Belém, in the For. In addition to promoting residential supply, its waters are important for river navigation and for generating electricity. We are dealing with the Basin of:
A) Amazons.
B) South Atlantic.
C) Tocantins-Araguaia.
D) San Francisco.
E) Parnaíba.
Resolution
Alternative C. The stretch refers to the Tocantins-Araguaia Basin, located in the Center-North of Brazil.
Question 2 - The Tocantins River is a watercourse that rises in the state of Goiás and flows towards Pará. It runs through an area dominated by plateaus, which guarantees it a high hydroelectric potential. Taking advantage of these characteristics, several plants were installed along its path, one of them at its confluence with the Araguaia River. This stands out as one of the largest electricity generators in the national territory, which is the plant of:
A) Sobrado.
B) Tucuruí.
C) Itaipu.
D) Paulo Afonso.
E) Flagstone.
Resolution
Alternative B. The Tucuruí Plant is located on the Tocantins River, in the Pará municipality of Tucuruí. It is located after the confluence with the Araguaia, and its production is comparable to that of Itaipu, on the southern border of Brazil.
Image credit
[1] Socrates Arantes/Eletronorte / commons
By Paloma Guitarrara
Geography teacher
