Distribution Of Water Flashcards
What is the distribution of water?
97% saline water in oceans and seas
2% in the form of ice caps and glaciers
1% easily available for human use
What is one of the most valuable resources on earth?
Freshwater
Why is freshwater unevenly distributed?
Mainly due to differences in climatic conditions.
Explain the differences in precipitation and evaporation according to latitude.
Regions located between 20 degrees north and south face more precipitation than evaporation and thus have more excess water.
Regions located between 20-40 degrees north and south face more precipitation than evaporation and have deserts
How is fresh water derived?
The main source of fresh water is rain. When it rains, fresh water gets accumulated in rivers and lakes and is derived using canals and pipes. Some of it seeps down into the surface and is stored as groundwater. This is extracted using wells and tube wells . The upper ground water just below the Earth’s surface is known as water table.
Which regions are suffering the most from water scarcity?
Africa, central and west Asia, Central and Western Australia, parts of South America, Middle East and parts of South Asia.
How many countries are likely to face shortage of water in 2025?
65 including India, Korea, Nigeria, Peru and Poland
List some reasons for contamination of water.
- Untreated sewage
- Cleaning fluids flushed down drains
- Pesticides and chemical fertilisers
- Leakage from petrol and diesel tanks
- Industrial effluents
What health problems are caused by contaminated water?
Typhoid, hepatitis, cholera, diarrhoea, dysentery.
Lead present in water harms the nervous system
List some disinfection and purification methods of water.
Chlorination, UV water purification, distillation, boiling(most common to kill germs)
What are multipurpose river valley projects?
Projects aiming at overall utilisation of rivers and serving many purposes simultaneously
