Chapter: 03
WATER RESOURCES
Water resources-Water resources are natural resources of water that are potentially useful. Water is present on the Earth in all its forms.
1.solid 2.liquid 3. gaseous
Significance of water
*Water is used in everyday life, for drinking, farming, construction, agriculture, industries etc.
- Water boosts metabolism, helps in blood circulation. * It Provides oxygen to cells of the body.
*It gives shelter to different aquatic creatures.
- It is used as a means of transportation.
Distribution of freshwater:
Freshwater is unevenly distributed in the world. This is mainly due to
*The differences in the climatic condition. In regions where the precipitation is more than evaporation, there is excess water.
*The regions where precipitation is excess are located between the equator and 20 degree north and South latitude.
*In regions between 20 degree and 40 degree north and South latitude evaporation is more than precipitation.
Water scarcity:
Water scarcity can be defined as a lack of sufficient water, or not having access to safe water supplies.
Factor that have created water scarcity
*Rapid increase in population.
*Modernisation of agricultural techniques. *change in consumption pattern.
The region suffering most are Northern Africa, Central and West Asia, the Middle East, part of South Asia, part of South America and Central and Western Australia.
Contaminants of sources of fresh water: *Untreated or partly treated sewage
*Cleaning fluids that are flushed down drains
*Pesticides.
*Chemical fertilizer
*Leakage from petrol and diesel
.*Industrial effluents
Multipurpose projects: Projects which serve more than one purpose are called
Multipurpose projects. Generally the majority of multipurpose projects are a combination of irrigation and Hydro-power.
Benefits of multipurpose projects
* Irrigation
* Flood control
* Generation of hydroelectricity
* Inland navigation
* Fish breeding
* Afforestation*Recreation
Conservation of water:
Water conservation is the practice of using water efficiently to reduce unnecessary water usage. Important methods of conserving water:
*Afforestation
-planting of trees on a large scale is called afforestation. It can slow down the surface run-off and improve the seepage of water in the soil.
*Efficient irrigation methods
1.Sprinkler
II.Drip irrigation
These irrigation methods must be used so that there is no wastage of water. Over irrigation is neither good for the crop nor for the soil.
*Industrial water may be recycled and used for cleaning and cooling of machines.
*In domestic use, wastage of water should be avoided.
*Rainwater harvesting:Rain water harvesting is a technique of collection and storage of rainwater in surface (storage tanks) or subsurface aquifers before it is lost as surface runoff.
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