Lesson 11 Flashcards
What is water scarcity?
When the annual level of water per person falls below 1700m3
What is water stress?
When the annual level of water per person falls below 1000m3
How do humans cause water scarcity?
Sewage Chemical fertilisers industrial pollution dams over abstraction
How does sewage cause water scarcity?
In developing countries sewage disposal is predicted to cause 135 million deaths by 2020 (cholera)
In the UK 1.4 million litres of sewage is added to our rivers daily
How does chemical fertilisers cause water scarcity?
contaminates ground water and river supplies.
Sewage adds nutrients which cause algae to grow and cause eutrophication.
This has happened in Mexico.
How does industrial pollution cause water scarcity?
400 billion tones of industrial water is generated each year. Chemicals and heavy metals are put into the water. China is an example.
How do dams cause water scarcity?
Trap sediment reduce floodplain fertility. Nutrients are lowered which damages fish stocks. Effect ecosystems and food chains.
The three gorges dams is an example of this
How does over abstraction cause water scarcity?
if too much water is extracted, it will not return in arid areas. This can cause salt water encroachment and salination.
Pakistan and Bangladesh is an example of this.
What are the physical causes of water scarcity?
Climate variability
Saltwater encroachment
How does Climate variability cause water scarcity?
In warmer climates there will be increased rates rates of evaporation and transpiration leading to less effective precipitation. This also encourages the growth of bacteria which can effect heath and water quality negatively.
How does Saltwater encroachment cause water? scarcity?
Extensive pumping from fresh water wells lowers the water table which allows salt water to move into aquifers or soils.
Salt water encroachment case study?
Pacific Islands
How does Salt water encroachment effect the Pacific Islands?
Rely on aquifers which are threatened by salt water intrusion.
Salt water encroachment social effects on the Pacific Islands? (2)
Population growth caused increase demand for water.
Threatening health, food security and lively hoods
Salt water encroachment environmental effects on the Pacific Islands? (4)
lowers water table.
ENSO climate
El Nino, groundwater pumping tripled
Saltwater damaged crops
