SUPPORT STUDY MATERIAL

Water resources

Water scarcity is a  situation wherein adequate quantity of water is not available to meet its requirement in different uses.

It is used for drinking ,domestic use ,in industries ,irrigation ,to meet the demand of urbanization, for disposable of ever-growing municipal sewage and dirt of all sorts

Facts: 96.5 of total water exist as oceans 2.5 percent fresh water ,70% fresh water exist as ice sheets and glaciers ,while little less than 30% is stored as ground water

India receive 4 % of the global precipitation and ranks 133

Factor  affecting the availability of water :

Large population results in greater demand of water ,it also implies that food grains production is to be increased .To increase food grains production it would be essential to expand area under irrigation ,it will put greater burden  on available resources

Overexploitation of ground water leads to falling groundwater levels

Increasing industrialization  and urbanization put pressure on the limited availability of water resources in a country, industry require power to run machinery and it is generated from water industry is a heavy user of water

Unequal access to water among different social groups

Rapid runoff and quick evaporation of rainwater

Bad quality of water may be due to pollution. Water may be polluted by domestic and industrial wastes, chemicals, pesticides and fertilizers used in agriculture

 Dam:

A dam is a barrier across flowing water. It obstructs, directs or retards the flow. It creates a reservoir, lake or impoundment

Positive points:  it helps in flood control, irrigation, and generation of electricity

It helps in conservation of soil and water through extensive afforestation particularly in catchment area

Promotion of fresh water fisheries and development of inland waterways

It helps in modernization of agriculture and preservation of wildlife and wetlands

It helps in navigation and recreation and promotes tourism

It laid the foundation for improving standard of living of the masses

They are temples for improving material conditions of the masses

These are the vehicles of progress which integrate agriculture and village economy with rapid industrialization and growth of the urban economy

That’s why the multipurpose river valley projects called the ‘new temples of modern India’

Against:

Regulating and damming of rivers affect their natural flow ,causing poor sediment flow and excessive sedimentation at the bottom of the reservoir resulting in rockier stream  beds and poor habitats for the rivers aquatic life

Dams also fragment rivers making it difficult for aquatic fauna to migrate

Reservoir that are created on the flood plains also submerge the existing vegetation and soil

Multipurpose projects and large dams have also been the cause of many new social movements like the ‘Narmada Bachao Andolan’ and the ‘Tehri Dam Andolan’

Construction of dam leads to displacement of local communities .local people often had to give up their land, the local people are not getting benefited, the benefit was taken by the big farmer and landlord  and industrialist.

Irrigation change the cropping pattern of many region with farmers shifting to water intensive and commercial crops, increases the gap between rich and poor

Dams that are constructed to control floods have triggered floods due to sedimentation in the reservoir

Multipurpose project induced earthquakes, caused water –borne diseases pests pollution resulting from excessive use of water

Water harvesting:

It is a technique of increasing the recharge of ground water by capturing and storing rain water

In hill and mountain region people built diversion channels like the guls and kuls of the western Himalayas for agriculture

Roof top rain water harvesting was commonly practiced to store drinking water, particularly in rajasthan

In the flood plain of Bengal, people developed inundation channels to irrigate their fields

In arid and semi-arid regions, agricultural fields were converted into rain fed storage structure like the ‘khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan that allowed the water to stand and moisten the soil.

In the semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, almost all the houses traditionally had underground tanks or  tankas for storing drinking  water