As a species we expanded on the margins of large rivers; we took from them the water we drink, cook, bathe and manufacture several products. Part of our electricity comes from their water power; but our relationship with rivers became predatory, lethal in most of the times. Will we be able to improve it someday?

Turtle dipped in algae by Dave Fitzpatrick, U.S. Fish and Wildlife Service (CC0)Museu do Amanhã


Mankind has altered the Earth flows in many ways; the emission of greenhouse gases contributes to the increase of the global temperature; plastics are omnipresent in our daily life; biodiversity is deeply altered by loss of biomes and changes in the food chain caused by invasive species in flora and fauna.

Fishing with nets raises sediments in the seabed by Jiri Rezac/ GreenpeaceMuseu do Amanhã

Human action is also felt in the way we affect the waters life and dynamics; the erosion caused by deforestation has changed the sedimentation pattern and the course of many rivers in the world. Fishing with nets also impacts the sea soil sedimentation – the nets contact with the seabed stirs sediments deposited in the seabed.

Yellow River delta in China by Rebecca Lindsey, NASA (CC0)Museu do Amanhã

The increase or decrease in sedimentation can be quite detrimental to these ecosystems; according to the United Nations Environment Programme – UNEP – more sediments in the bottom of rivers and oceans reduce the amount of light required for the production of algae which would cause the increase in the water temperature and decrease in the vegetation growth.

With no oxygen, fish die in polluted rivers by Dzed/ Pixabay (CC0)Museu do Amanhã

Furthermore, fish populations are also affected by the decrease of oxygen available for reproduction, not to mention a higher risk of floods. On the other hand, a decreased sedimentation caused by mining, for example, may damage ecosystems because of lack of minerals, nutrients and organic matter they carry.

Deforestation in Rondônia between 1975 and 2012 by MODIS/ NASA/ Nasa.gov VideoMuseu do Amanhã

A recent study by researchers in the Americas, Europe and Australia shows that deforestation and large use of soil for cattle pastures and crops have increased the flows of sediments in many rivers. Road construction has caused erosion of surfaces and landslides in different regions of the planet.

The video, produced with images taken by NASA's Terra satellite, shows the progression of deforestation in Rondônia state (Brazil) between 1975 and 2012.

Three Gorges Dam, in China by Pedro Vásquez Colmenares (CC BY-NC 2.0)Museu do Amanhã


The construction of dams in rivers is considered a major impact on rivers in the world. There are now 48 thousand large dams in the world – with more than 15 meters of height – in operation according to the non-governmental organization World Wildlife Fund (WWF). These structures are used to generate electricity, irrigate large areas, provide drinking water and prevent floods; most of them were built in the last 60 years at a speed of more than one large dam a day. Each of them should last between 50 and 200 years interrupting the transport of sediment to the oceans.

Three Gorges Dam seen from space by NASA - Expedition 19 crew (CC BY-NC-SA 2.0)Museu do Amanhã

Three Gorges Dam, in the Yangtze river (China) is so big it can be seen from space

Belo Monte dam seen from Xingu river by GreenpeaceMuseu do Amanhã

These dams also cause losses to populations and drastic changes in ecosystems where they are installed; therefore many activists and researchers question governments around the world on how clean would be the energy produced by hydroelectric plants.

In Brazil, the Belo Monte plant is object of wide political and environmental controversy; the plant is being built in the Xingu River around Altamira, north of Pará, where more than 500 families were displaced to vacate the land for the dam construction.

Mining boat in the Tapajós River by Daniel Beltrá/ GreenpeaceMuseu do Amanhã

The project that provides for the construction of five plants in Tapajós River – Tapajós Complex in the State of Pará – has also generated a lot of stress between the Munduruku people and the Brazilian Government. In August 2016, the IBAMA – Brazilian Institute of Environment and Renewable Natural Resources – shelved the granting of environmental licensing of the Complex; besides being environmentally unfeasible, the works would flood an entire Munduruku village – which is prohibited by the Brazilian Constitution that allows the removal of indigenous peoples from their lands only in case of natural disasters or epidemics.

Colorado River in Arizona, USA by Leonid Yaitskiy (CC BY 3.0)Museu do Amanhã

The reduced flow of sediments from springs to the major world rivers combined with extraction of ground waters causes an increase in hydrocarbons and sediments in the bottom of the rivers; this has caused a fast reduction of volume of many rivers. The process starting in the thirties occurs at speeds higher than the increase of the ocean levels today.

Colorado river delta dying in the Sonoran Desert, between Mexico and the USA by Pete McBride, U.S. Geological Survey/ Wikimedia Commons (public domain)Museu do Amanhã

After having so many dams built along its course, the Colorado River can not flow to the Pacific Ocean any longer - and it ends a little more than eight kilometers from the Sea of Cortez, in the Gulf of California.

Tietê River in Salto, São Paulo countryside by Eurico Zimbres (CC BY-NC 2.5)Museu do Amanhã


In Brazil, the high pollution and change of course are also problems faced by large rivers. According to IBGE – Brazilian Institute of Geography and Statistics – the most polluted river in the Country is Tietê in São Paulo. It is followed by Iguaçu River in the state line between Paraná and Santa Catarina, the Ipojuca River crossing Pernambuco, Sinos River that discharges in Canoas (RS) and Gravataí that crosses the cities of Canoas and Porto Alegre, Rio Grande do Sul.

Tietê River in Barra Bonita, SP by Luciano Silva (CC BY-NC 2.0)Museu do Amanhã

Despite the intense pollution, there are clean portions of water that still exist in the Tietê river

Doce River, one of Brazil's most polluted rivers by Rafa Tecchio (CC BY 3.0)Museu do Amanhã

The Doce River, which crosses Espirito Santo and Minas Gerais, and Paraíba do Sul River, which goes through Rio de Janeiro, São Paulo and Minas, are also among the ten most polluted rivers in the country; chemical industrial waste and use of pesticides in agriculture are the main elements responsible for the degradation of these water courses.

Doce River in Colatina and Baixo Guandu after the busting of Fundão dam in Mariana (MG) by Fred Loureiro/ Secom ES/ Fotos Públicas (13/11/2015)Museu do Amanhã

In November 2015, the Doce River also suffered a major impact resulting from the largest environmental disaster ever occurred in Brazil. The breach of the Fundão mining waste dam in the city of Mariana, Minas Gerais, contaminated its waters and poured a huge amount of waste which reached the River mouth in Linhares, Espírito Santo, discharging in the Atlantic Ocean. Many people living in the area such as the dwellers of Bento Rodrigues, district of Mariana, had their homes totally destroyed. The Doce River sedimentation pattern was also altered and sandbanks remain on its margins.

Gualaxo do Norte River with mining waste by Bruno VeigaMuseu do Amanhã

“It looked as if Gulliver had brushed the trees with brownish-red paint”, commented photographer Bruno Veiga when registering the impact of dam breach on Paracatu de Baixo (MG) in April 2016

Around the Gualaxo do Norte river after the bursting of Fundão dam in Mariana (MG) by Bruno VeigaMuseu do Amanhã

The bursting of Fundão dam in Mariana (MG) affected more than half of Gualaxo river by Bruno VeigaMuseu do Amanhã

The bursting of the Fundão dam in Mariana (MG) affected more than half the course of Gualaxo do Norte River, one of the tributaries to Doce River

Paraíba do Sul river in Campo dos Goytacazes by Gledson Agra de Carvalho (CC BY-NC 4.0)Museu do Amanhã


In March 2014 and February 2015, the non-governmental organization SOS Mata Atlântica analyzed the quality of water of 111 Brazilian Rivers in the States of Rio de Janeiro, São Paulo, Santa Catarina, Minas Gerais, Rio Grande do Sul and the Federal District. The 2015 study showed that almost one in four rivers had their water considered bad or very bad – and only 15% had good quality waters.

Iguazu River, which flows towards Paraná River by Deni Williams (CC BY-NC 2.0)Museu do Amanhã

However, efforts to recover water courses have shown that other scenarios are possible; following the example of the cleanup of the Thames (London) and Rhine (Germany), a private-public partnership created the program ‘Cultivating Good Water’ (Cultivando Água Boa) in Paraná. Since 2003 the project has already cleaned up more than a hundred river micro-basins of the Paraná River, more than 1.000 kilometers of forest have been replanted and there were improvements in the sewage network in almost 30 cities.

Fisherman with Rio-Niterói Bridge on the background (2016) by Gustavo Otero | Collection Museum Of TomorrowMuseu do Amanhã

In Rio de Janeiro, the cleanup of Guanabara Bay is a huge challenge yet to be conquered; in two decades, the State Government has already implemented two programs to improve the environmental quality of the Bay, which receives the contribution of more than 100 rivers and channels located in 16 cities where almost 9 million people live. Today, the sewage treatment in its river basin does not exceed 35%; R$ 4 billion have already been spent but most of the beaches in the Bay still remain improper for bathing.

Munduruku children at the Tapajós River by Otávio Almeida/ GreenpeaceMuseu do Amanhã

But will these endeavors have results in the time we need? In March 1979, the United Nations recognized for the first time that the access to drinking water is a basic human right; the resulting action plan from the UN Conference on Water says that “all peoples, whatever their stage of development and social and economic conditions, have the right to have access to drinking water in quantities and of a quality equal to their basic needs”. In 2010, the UN formally recognized the access to water as a basic human right; will we be able to assure it to the next generations?

Credits: Story

President of the IDG Management Council: Fred Arruda
Director President: Ricardo Piquet
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Photos: Gustavo Otero, Bruno Veiga, US Fish and Wildlife Service, US Geological Survey, Greenpeace, Public Photos, National Aeronautics and Space Administration (NASA), Pixabay, Pedro Vásquez Colmenares, Leonid Yaitskiy, Eurico Zimbres, Luciano Silva, Rafa Tecchio, Gledson Agra de Carvalho, Deni Williams, Google StreetView, Wikimedia Commons
Video: Greenpeace (modified) and Nasa.gov Video (via Youtube)

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