Changes in the supply and demand for water
Increases in supply
There have been rapid increases in the amount of water supply (called 'freshwater withdrawals') over the last 50 years.
This increase in supply has been brought about by:
- increased The process of extracting or withdrawing something. from rivers such as the River Nile
- the development of dams and reservoirs such as in the Colorado drainage basin
- increased use of Where water is stored in rocks beneath the ground. such as in Rajasthan in India
- increased use of ancient groundwater (called 'fossil groundwater') in countries such as Libya
- the development of desalination plants where salt water is purified into freshwater in the United Arab Emirates
Increases in demand
The increase in supply was due to meet the increase in demand from the three main users of water:
- agriculture
- industry
- domestic
Agriculture - has the biggest demand for water and is growing at the fastest rate. This is because the amount of cropland irrigated has increased at a faster rate than the world's population. In addition, meat consumption has also increased which causes issues as 1 kg of beef takes ten times more water to produce than 1 kg of rice. This increase in demand for water for agriculture is a particular problem in China where 70% of its agriculture uses irrigation and as a result many of the major aquifers are running dry.
Industry - the demand for water for industrial use has also grown. As countries such as the BRICS (Brazil, Russia, India, China and South Africa) develop, so does their demand for manufactured products which require water to produce textiles and electronical goods.
Domestic - although this is the smallest demand for water, it too is rising quickly (due partly to the rising world population). People in Countries where people have a high standard of living. use 100,000 litres per person per year whilst people in (Also known as an emerging economy.) A developing country that has some industry and a growing infrastructure. use 50,000 litres per person per year, mainly due to the increased use of luxury goods such as washing machines and dishwashers. Water is needed not only for drinking and washing, but for cooking and cleaning. It is estimated that 1 in 30 people in the US have a swimming pool, which further increases water demand.