Environmental Issues for the Amazon and Murray River

Environmental Change & Management Rivers

• Rachel Cunningham

All life on earth depends on water. Trees and plants need water to grow, and water helps shape the earth and its islands, continents and countries. About 71% of the earth is covered in water by oceans, rivers and lakes. Almost all river water comes from rain or melted snow. Rivers are large streams of water flowing downwards to the sea along channels they have cut. Some rivers flow into lakes and some join other rivers. A river ends when it flows into another river, ocean or lake. When a smaller river flows into a larger one, the smaller one is called a tributary. This is commonly referred to as the mouth. Commonly, rivers start (the start is known as headwaters) as small streams on high grounds, gradually increasing in volume. Rivers have played an important part in the development of civilisation. Rivers are one of the main ways in which rainwater returns to the sea in the water cycle. On their way to the sea, rivers help shape the land through erosion.

A river is the main part of a river system, which also includes smaller streams that supply water to the river. The second largest river in the world is called the Amazon River, located in South America. The Amazon is 6,436 kilometres long, and carries more water than any other river in the world. The chief river of Australia, the Murray, flows 2,589 kilometres from the Snowy Mountains to the Great Australian Bight at the entrance to the Indian Ocean. It rises near Mount Kosciuszko in south-eastern New South Wales and flows north-westward to form the border between Victoria and New South Wales.

Rivers can be influenced by human actions, sometimes with a positive result and sometimes with a negative result. In both the Murray and the Amazon, humans have cleared the land surrounding the river, constructed dams and weirs and created a hazardous environment for many animal species neighbouring this environment. Pollution is also a major cause for some of the environmental issues that these rivers face. Indigenous people in the Murray and Amazon regions have cared for and maintained the rivers over a long period of time. They have achieved this by taking from the river what it can sustain and by not polluting it excessively.

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The greatest river of South America, the Amazon, is the world’s largest river in water volume and the area of its drainage basin, together with its tributaries the river drains an area of 7,050,000 square kilometres—roughly one third of the continent. It empties into the Atlantic Ocean at a rate of about 220,000 cubic meters per second. The Amazon region is covered by dense tropical rainforest. This has one of the highest rates of rainfall in the world. Agriculture only has a potential on 2% of the floodplain, and the whole Amazon basin supports a population of only four million, of whom 75 000 are native Indians.

The Murray River is the longest permanently flowing river in Australia. It is an important source for irrigation and industry. The Murray River system includes the Darling, Lachlan, and Murrumbidgee rivers, and it drains an area larger then that of France and Spain combined. The Murray rises in the Australian Alps near the eastern boundary between Victoria and New South Wales. It then crosses eastern South Australia and flows into Encounter Bay, south of Adelaide. The Murray River is 2,589 kilometres long. Along the Murray, wheat, sheep and cattle are a main source of income for farmers. However, this is becoming a problem because chemical run off from the crops pollute the river.

In the Amazon, subsistence farming, practised since before the Portuguese settlers arrived in Brazil in the 16^th century, remained the major money making activity until the 19^th century. Indigenous groups such as the Yanomamo and Kayapo have been living in the Amazon for thousands of years.

The first human settlements in the Amazon had populations’ approx 35,000 years ago. Since that time, Amazon people have developed lifestyles that are well incorporated with the benefits and restrictions of rainforests and the Amazon River. Normally, daily meals included wildlife found close to rivers, such as fish, turtles, capybara and crocodiles. Until recently, blowguns, arrows tipped with poison and spears were an everyday tool used to hunt down the wildlife for the daily meals. Unfortunately, these prehistoric weapons have been replaced with guns. The guns cause more damage to the river because they are more accurate, and they kill quicker. Hunter-gatherer groups were once generally nomadic, living in small temporary settlements for 4-5 years until all natural resources had diminished. Due to land colonisation by non-indigenous people, many local (indigenous) groups were forced into inactive lifestyles causing them to become peasants. This started to degrade the river because they weren’t using it in a traditional way. Such changes not only destroyed traditional lifestyles but also caused the local peopleto lose control over their territory and for the river to lose many of its traditional protections. Whilst the new settlers treated the river without concern for its well being.

There are many environmental issues along the Murray. Many of these problems are caused by drought. Some of the problems are so serious that despite two years of rain (2000 – 2002), areas of the river are yet to recover. The Murray mouth closed in 2002, only the second time recorded in history. This was because of the lack of water in the basin. In April 2009 in the Lower Lakes region, 20,000 hectares of acid sulphate soils were exposed and fresh water levels fell dramatically, to more than one metre below sea level. Ecosystems were also affected by this, because of the increase in salinity and exposure of acid sulphate. It also threatened the water supplies for people and livestock. Low water levels also caused some sections of the riverbank to dry out, crack, and eventually give way. There were more than 160 incidents of river bank collapse along the Murray. Many turtles were affected by the rising salt table, and became sick, and finally died.[1]

The salinity problem in the Murray serves as a predicament for all Australians. Salinity is an issue when an excessive quantity of salt in the water and soil causes problems with the use of water and land. Due to land logging, land reproduction and land colonisation, the salt table of the Murray is rising. Water stored in the dams and weirs is mainly used for irrigation, causing the salination problem. Some salt flows naturally into the Murray – Darling, but irrigation, land clearing, dams and weirs have all forced increased amounts of salt up from deep underground. Unfortunately, most of this salt eventually ends up in the rivers which increases the river’s salt content. Every year, three million tonnes of salt flow down the Murray River. Another issue that the Murray faces is stagnentation. Parts of the river, especially the lower Murray, are now more like a series of still lakes rather than a flowing river, resulting in some significant changes. The water is cloudier and contains less oxygen, encouraging the growth of algae and making it difficult for some fish species to survive. The Sand and silt are slowly building up on the river beds behind the dams. Because of the build-up of sand and silt, the fish cannot move from one part of the river to another or from oceans to lakes. This disturbs the food chain by creating over population of some species and lack of others.

The major environmental issue for the Amazon River is deforestation, in the greater Amazon basin. The main sources of deforestation in the Amazon rainforest are human settlement and development of the land. In nine years from 1991 – 2000, the total area of Amazon rainforest cleared rose from 415,000 to 587,000 square kilometres. Most of this lost forest has been replaced with pastures for cattle. Because of this, the salt table has risen dramatically. Deforestation of the Amazon rainforest can be recognised by many different factors. The rainforest is mainly seen as a resource for cattle pasture, hardwoods, housing space, farming space, roads and medicines. The deforestation rate in the Amazon region increased from 1990 to 2003 by 70%. As a result of deforestation, the river effectively dies. The tree roots are no longer present to hold the bank in, therefore the rivers walls collapse. As a consequence of this, the silt builds up. This causes the river to flow slower.

Since approximately 2005, inhabitants along the Amazon have become aware of the need to conserve the river. This has led to conversation with governments regarding management of the river.

Before Europeans arrived, the land surrounding the Murray was occupied by Australian aborigines. The Murray River has been home to the Aboriginal people for thousands of years. This river was commonly known to the indigenous as Milewa or Tongala. The land surrounding, and the river have always been imperative to the indigenous. Near the river, there were once many swamps and billabongs. These were flooded each spring when the melting of the winter snow in the spring, flowed into the Murray.

Indigenous people caught much of their food using nets and dams. The nets were for catching fish, animals and birds. They made them from fibres of rushes that grew beside the creeks. The rushes were chewed and then twisted by rubbing them on the thigh. Aborigines also caught fish by making dams across the narrow creeks. First they pushed the stakes into the creek bed. Then they wove branches through the row of stakes. At flood time the fish swam into the shallow creeks and billabongs. As the flood waters went down, thousands (not the 10’s of 1000’s like the fisherman of today) of fish were trapped behind the dams. Women gathered all the plant food. They dug for bulrush roots and rushes and collected pigface berries. The indigenous also ate bulrush roots with every mean, just as white people ate bread. In the river the women caught crayfish and yabbies and spent much of their time diving for mussels. They carried the food back to the camp in net bags and baskets. The river itself can replenish itself after this sort of gathering. However, the river cannot replenish itself after a bulldozer digs out plants by their roots. Fish and shellfish were the main food of the indigenous people. Men did the hunting with spears or nets as well as dams. Flocks of ducks, pelicans, black swans and other water birds trapped in the nets that they strung across the creeks. They made stronger nets and staked them out between trees. These were catching emus and kangaroos. The cords of these nets were as thick as your finger. To hide from animals they hinted, men made screens of branches woven with grass. They would creep up on the emus and kangaroos until they were close enough to speak to them. The men also made rods to snare waterbirds. For camouflage they put braches through the reeds. They snared them around the neck one by one.

The current environmental issues that the Murray and the Amazon face are primarily caused by modern man. Some of the issues that the Murray faces include rising salt table, water pollution and decreased water flow. The Amazon also faces a major concern – deforestation. These environmental factors have only surfaced since the areas have developed. Indigenous people were conservative and only took from the land what it could sustain. We can learn from these traditions and ensure that rivers remain a sustainable environment in the future.

Bibliography:

Encyclopaedia

Deforestation of the Amazon Rainforest, {Online accessed 13 February 2014}

URL:http://www.en.wikipedia.org/wiki/Deforestation_of_the_Amazon_Rainforest

Impacts of Deforestation on the Amazon, {Online accessed 26 February 2014}

URL:http://www.greenpeace.org/usa/en/news-andblogs/news/impacts-of-deforestation-on-the-Amazon

The Achuar of Peru, {Online accessed 13 February 2014}

URL:http://www.amazonwatch.org/work/achuar

Murray River Aboriginals {Online accessed 26 February 2014}

URL:http://www.murrayriver.com.au/about-the-murray/indigenous-culture/

[1] URL:http://en.wikipedia.org/wiki/Environmental_issues_of_the_Murray_River