Amazon River
CE397 – Transboundary Water Resources Spring 2008
Eusebio Ingol
Current Situation
Amazon River basin has a surface around 6.2 million km2 which is shared by Peru, Colombia,
Brazil, Venezuela, Surinam, and Guyana. From this total area, the 58 % is located in the
Brazilian part. Amazon River is one of the most important rivers in the world, with an average
discharge of 210,000 m3 per second; being the largest in the world’s rivers in terms of the
volume, six times that the Congo River. It has more 1,100 tributaries; 17 of them present lengths
over 1,000 km such Maranon, Purus, Madeira, Negro, Tapajos, Madre de Dios, Huallaga,
between others. The origin of the Amazon River is in the Peruvian Andes. Since its source until
mouth in the Atlantic Ocean from Brazil, it has a length of 6500 km.
Figure 1 Location of the Amazon river Basin
The wide of the main river oscillate from 1.5 km to 10 km in normal periods. However, in rainy
season, the width can reach up 40 km with an average depth of 40 m.
Water Resources
The water resources provided for the Amazon River represent the 20% of the available
freshwater in the world. The flow in the Amazon River increases apart from November to June,
from this month starts to fall until October; being the lowest flow period in August and
September while the highest occurs from January to May. The behavior is different in the Negro
River (one of the most important tributaries of Amazon River) where the rain period starts in
March. Similarly, in the Madeira river, the increase in flow can be noted a part from January;
which starts to fall two months earlier that the main river. In figure 2 is shown the variation of
the monthly precipitation in South America, in which include the Amazon Basin. The annual
average precipitation for Amazon region is over 2000 mm.
Figure 2 variation of the precipitation in South America for the 2001. (Source NASA)
Amazon region is characterized for having low densities of population, with problems of contamination
which causes are related to wastewater treatment in located cities such as Belen and Manaus in Brazil,
and Iquitos in Peru, mineral extraction (gold miners). In the Amazon basin, the water resources are related
to the fishing, navigation, and hydroelectric power. The potential use of the hydropower in Amazon
region represents the 40 percent of total energy in Brazil. Moreover, for generating energy in the
region, dams were built. The Tucurí dam on the Tocantins River in Pará state, the Balbina dam
on the Uatumã River in Amazonas state, and Samuel Dam on the Jamari River in Rondônia state
− which were built to supply electricity both for the cities of the Amazon region Manaus, Belen
and Porto Velho, respectively.
Environmental problems
The main environmental problems in the transboudary water resources in the Amazon River
basin are related fundamentally to the following issues:
Deforestation in the basin causes erosion and soil loss, sedimentation in the rivers, unbalance in
the vital ecosystems.
Expansion of the urbanization; destruction of the fragile ecosystems. Two largest cities in river
basin can be mentioned: Manaus and Belen in Brazil (over 1.5 million). Iquitos in Peru, Leticia
in Colombia, and Lago Agrio in Ecuador.
Water pollution and quality degradation. Use of agriculture pesticides, inadequate wastewater
treatment from populated areas, contamination of the rivers by mercury (This product is used by
gold miners located mostly in the middle and upper basin)
Change in the hydrologic cycle which is related with climate change.
In Brazil, over 60 percent of deforestation in the Amazon basin results from the Cattle ranches;
while the 33 percent corresponds to the agriculture in small scale. This problem causes erosion;
in that sense, more than 1,000 tons/km2 /year of sediment flowing toward the Atlantic Ocean. In
general, 600 to 800 million tons of sediment per year are transported by the Amazon River.
Treaties and projects
The main treaty signed in the Amazon River basin was the following
Treaty cooperation organization (OTCA) among the countries of the Amazon basin Brazil, Peru,
Bolivia, Colombia, Ecuador, Guyana, Surinam, and Venezuela. 07/03/1978.
In this treaty, the Contracting countries agree to carry out joint actions and efforts to promote the
harmonious development of their respective Amazonian territories in such a way that these joint
actions produce equitable and mutually beneficial results; as such as the environment
preservation and the conservation and rational utilization of the natural resources. The principal
objective of this agreement is to achieve an adequate use of the natural and energetic resources.
This treaty was instable during two decades; which determined that it was re launched in 1998.
Likewise, the following treaties of commerce and navigation were signed:
Treaty of commerce and river navigation between Brazil and Colombia August 21, 1908.
Treaty of commerce and river navigation between Brazil and Bolivia August 12, 1910
Treaty of delimitation, commerce and navigation between Brazil y Peru. Treaty 1918 ratified in
1927.
In the Amazon River basin, several projects related to Environmental and water resources have
been carried out. For instance, the project GEF Amazon. OTCA/GEF/PNUMA/OEA. Integrated
and sustainable management of transboundary water resources in the Amazon River basin. United
Nations Environment. Oct 2005. The main objective of this project is strengthen the institutional
framework for planning and carry out activities for the protection and integrated management of the land
and water resources in a coordinated and coherent manner in the Amazon River basin, considering the
climatic change experienced in the basin. In addition, there are some projects leaded by the World Bank
such as integrated management of aquatic resources in the Amazon region project (AQUABIO), Amazon
region protected areas project (ARPA) (2002), Pilot program to conserve the Brazilian rainforest (PPG7)
(1992), Pilot Program floodplain resources management project (PROVERZEA) 1999-2007
Required reading:
Paul E. Little. Abundance is Abundance is not enough. Water‐related conflict in the Amazon River Basin. University of Brasilia. Brazil, 2003. Pages. 4‐12 http://www.unb.br/ics/dan/Serie337empdf.pdf Supplementary reading: Takuji Kulbota. "Global precipitation map using satellite borne Microwave radiometers."CREST, Jepan Science and Technology agency. 2005. World Bank. Integrated management of aquatic resources in the Amazon region. Project AQUABIO . May 15, 2006. http://web.worldbank.org/WBSITE/EXTERNAL/COUNTRIES/LACEXT/BRAZILEXTN/ Amazon. Encyclopedia Britannica. http://www.britannica.com/eb/art‐3439/The‐Central‐and‐Northern‐
Andes‐and‐the‐Amazon‐River‐basin Amazon. UNESCO. Feb12, 1008. http://www.unesco.org.uy/mab/documentospdf/amazon.pdf Water National Agency. Brazil. Feb12, 2008. http://www.ana.gov.br Amazon. Organization of America States. http://www.oas.org/dsd/Events/english/Documents/OSDE_8Amazon.pdf National Aeronautics and Space Administration. NASA. Monthly precipitation in South America for 2001. http://earthobservatory.nasa.gov/Sttudy/LBA/