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Water Scarcity


Examine physical and economic water scarcity, and the factors that control these including the causes and impacts of droughts; the distinction between water quantity and water quality

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Water Scarcity


Examine physical and economic water scarcity, and the factors that control these including the causes and impacts of droughts; the distinction between water quantity and water quality

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Environmental impacts of agriculture and irrigation


Explain the environmental consequences of agricultural activities on water quality, to include pollution (eutrophication) and irrigation (salinisation)

Environmental impacts of agriculture and irrigation


Explain the environmental consequences of agricultural activities on water quality, to include pollution (eutrophication) and irrigation (salinisation)

IMPACTS

  • salinisation of soils due to increased evaporation of surface water (worse in areas with a negative water balance like arid or semi-arid areas)

  • reduction of the water table as water is removed

MAIN POINTS

  • Irrigation techniques range from flood > spray > drip

  • Irrigation occurs in low to high income countries

  • 50% of all agricultural land is irrigated

  • 39% of water in the US is used for irrigation

 
 
 

salinisation

 

eutrophication

eutrophication: excessive richness of nutrients in a lake or other body of water, frequently due to run-off from the land, which causes a dense growth of plant life.

Prior to the start of the Olympic sailing competition in Qingdao in 2008, the algae had to be removed from the water surface by hand.

 
 
 

CASE STUDY: Mexico Dead Zones

 

exam practice

Explain two ways in which agriculture and/or irrigation on flood plains can affect water quality. [6 marks]

 

mark scheme

Explanations are likely to refer to two of the following – salinisation, eutrophication, the impacts of agro-chemicals, effluent run-off. In each case, award [1 mark] for the identification and up to [2 marks] for the explanation/developed exemplification.

The most likely focus for candidates will be:

Eutrophication [1 mark] occurs when fertilisers/nitrates are washed into a lake/river [1 mark]. Algae grow, and then die, leading to oxygen depletion [1 mark].

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Water Conflict


Internationally shared water resources as a source of conflict, including a case study of one internationally shared water resource and the role of different stakeholders in attempting to find a resolution.

Water Conflict


Internationally shared water resources as a source of conflict, including a case study of one internationally shared water resource and the role of different stakeholders in attempting to find a resolution.