Water Stress Flashcards
Industry
Water for used for industry grew slowly in the 20th century in Europe, Russia.
It is estimated to grow more rapidly in this century due to large scale industrialisation in countries such as India and China.
Industry is generally more efficient than agriculture.
Agriculture
A major use of water, particularly with growing demand for food. Currently agriculture uses about 69% of the world’s freshwater supply. At present 17% of the global area for growing crops is irrigated.
Water and irrigation do make agriculture more productive but it can be very wasteful.
Poor managements systems can lead to this.
Industry: HEP water use
Continues to use large amounts of water, but this water is available once it has passed through.
How can industry be less efficient?
Through paper manufacturing for example, it is one of the most extravagant uses of water on the planet.
Industry can also cause water pollution issues.
Domestic
The smallest category of consumption, using only 10%.
The amount varies enormously from country to country. Most developed countries need about 100,000 litres per person a year. While in Africa, the figure is about 50,000.
The quality of water also varies.
Water sources: surface water
Rivers, lakes and reservoirs provide large amounts of surface water.
“Mega dams” are found along most major rivers.
The reservoirs of USA, Japan, India and China account for a quarter of freshwater.
Reservoirs
Brings short term economic gains in terms of water supply, HEP and flood control.
But they have longer term environmental and social impacts.
Water sources: Aquifers
The sole source of drinking water for about a quarter of the world’s population. 3/4 of Europe’s drinking water comes from underground.
In many countries such as the USA groundwater is being extracted faster than it can be replaced.
Physical scarcity
More than 75% of a country’s river flows are being used. A quarter of the world’s population live in such areas.
Water stress
Annual supply of water per person falls below 1,700m^3, it becomes water scarcity when that figure falls below 1,000
Economic scarcity
Development of blue water flow sources is limited by human and financial capacities. More than 1 billion people, in areas such as sub-Saharan Africa, use less than 25% of the river resources available.
Pressure of water supplies: India
Has 4% of the world’s freshwater, but 16% of the population. Demand will exceed supply by 2020, as urban water is expected to double and industrial demand triple.
43% of precipitation never reaches aquifers or rivers.
Pressure on water supply: China
8% of the world’s fresh water supply but must meet the needs of 22% of the world’s population.
2/3 of Chinese cities do not have enough water all year round.
Water supplies likely to reach stress levels by 2030.
China uses irrigation to produce 70% of its food.
