General Water Facts & Definitions Flashcards
If deforestation in the Amazon continues at the current rate, how much could precipitation be reduced by?
Over 20% in the next 40 years.
What is blue water flow?
The visible part of the hydrological system; surface flows.
What is green water flow?
The water intercepted, stored and released by vegetation through evaporation and transpiration.
What is grey water?
Polluted water
What percentage of the world’s population lacks clean, safe water?
20%
How many people live in highly water-stressed areas?
2.4bn
By 2020 how much more water than is available will we need to feed the world?
17%
What is 70% of our water used for?
Agriculture
By 2030 what proportion of the global population will be living in areas of acute water shortage?
Nearly half
What percentage of industrial wastewater is released into the environment untreated?
70%
Define water shortage.
Low levels of water supply per person relative to basic needs.
How is water shortage measured?
Annual renewable flows (m3) per head of population or the no. of people dependent on each unit of water.
Define water stress.
Often taken as less than 1700m3 per head of population annually.
What does water stress cause?
Conflict between users, competition for water, harvest failures and food insecurity.
Define water scarcity.
Less than 1000m3 per person per year. Imbalance of supply and demand.
Define physical water scarcity.
When at least 60% of river flows are diverted for agricultural, industrial or municipal purposes.
What are signs of physical water scarcity?
Environmental degradation, declining groundwater supply and unequal distribution.
Define economic water scarcity.
When less than 25% of river flows are used, and there is an abundant supply potential but the poorer people cannot afford to access the water.
Define intermediate technology.
Technology suitable for use in developing countries, typically making use of locally available resources.
Define aquifer.
A rock, such as chalk, which will hold water and let it through.
Define arid and semi-arid.
Conditions where rainfall is less than 250mm and 500mm per year respectively.
What is desalination?
The conversion of saltwater into freshwater.
Define drought.
An an extended period of abnormally dry weather that causes water shortages and crop damage. Starts when total rainfall is well below average for several months.
What is El Niño?
A southerly warm ocean current, which develops off the coast of Ecuador. It is associated with major variations in tropical climates.