Human Pressure on Water Resources (DP IB Geography): Revision Note

Impact of Population & Economic Growth on Water Quality

• The growth of the world population increases the demand for water

• Population growth is unevenly distributed and so the need for increased water supply is also uneven 

• Urban areas experiencing a rapid increase in population usually experience the most water stress

• The quantity of water currently being used for all purposes is over 3700 cubic kilometres per year

• The growth of population leads to a greater demand for water for all uses:

  • Agriculture

  • Domestic

  • Industrial

• Agriculture is the largest user of water:

  • Consumes over two-thirds of water drawn from rivers and lakes

  • Water for crop irrigation has increased by 70% since 1960

• Industry uses 22% of available water

• The domestic sector uses 8%

• These all impact on water quality and availability

• Many rivers have become polluted, which makes them unusable for human needs

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Sources of water pollution

• Rivers which are contaminated by industrial waste can cause algae blooms

  • This makes the water unsafe to be used by humans

  • The toxins produced by the algae can kill wild animals and livestock

• Many fish deaths are occurring because of the increase in temperatures in rivers

• Overuse of aquifers can result in reduced water supply

• There are many examples of water quality issues around the world

  • China’s rapid economic growth has meant that over 70% of the country’s rivers cannot be used for human consumption

  • Lead poisoning in Flint, USA, because of industrial pollutants in the river waters 

Aral Sea

• The Aral Sea is an endorheic lake which is located in Asia

• The lake is transboundary because half lies in Uzbekistan and half in Kazakhstan 

• Rivers enter the lake from Amu Darya and Syr Darga

• In 1997, the Intergovernmental Panel on Climate Change highlighted the Aral Sea as a case study for what happens when lakes are misused 

• In 1960, the lake was the world’s 4th largest inland water body

Use of water 

• Large-scale irrigation systems were introduced in the 1930s

• Between 1960 and 1980, the area was known for the cotton industry 

  • This required increased irrigation from the Amu Darya and Syr Darga rivers

• The population increased from 14.1 million in 1960 to 47 million in 2008

• According to UNESCO, there are now 51 million people living in the Aral Sea basin

• By September 2011, the lake had separated into four parts and had shrunk in area by 85% and volume by 92%

Impacts on the economy

• The fishing industry, which used to employ 40,000, collapsed

• Camel farming decreased because the grass that camels ate was too salty due to the wind blowing salt from the drying up lake

• Factories in the area which used the lake to transport their goods could no longer use the lake as a trade route, causing rising unemployment 

Impacts on humans

• According to scientists, the Aral Sea could dry up in the next 20 years, which would affect drinking water supplies

• Due to highly toxic winds, there has been an increase in respiratory illnesses caused by dust from fertilizers being spread by wind

The Great Artesian Basin 

• The Great Artesian Basin (GAB) is situated in central Australia

• One of the world’s largest groundwater systems, which supports a variety of ecosystems and springs

• The basin is nearly 1.7 million square kilometres

• There has been little sustainable management of the basin 

  • Leading to much wastage of water through evaporation and seepage

• Water wastage damages the environment through land and water salinization

• Agriculture has dominated groundwater extraction

• Water extraction for mining and oil projects has been increasing

• The Olympic Dam mining project has been extracting groundwater since 1983

Impacts on humans

• More than 180,000 people rely on the groundwater from the basin

• Over 120 towns are supported through the basin including both homes and businesses

• Aboriginal and Torres Strait Islander people have been using the basin for over 60,000 years

• In August 2018, the Australian government announced The Improving Great Artesian Basin Drought Resilience program worth up to $26.7 million