10 Geography Chapter 3 Water Resources

Chapter Notes and SummaryWater – Some Facts and Figures
1. 96.5% of total volume of world’s water is estimated to exist as oceans and only 2.5% as freshwater.
2. Nearly 70% of this freshwater occurs as ice sheets and glaciers in Antarctica, Greenland and mountaineous regions of world while a little less than 30% is stored as ground water in world’s aquifers.
3. India receives nearly 4% of global precipitation and ranks 133 in world in terms of water availability per person per annum.
4. total renewable water resources of India are estimated at 1897 km2 per annum.
5. By 2025, it is predicted that large parts of India will join countries or regions having absolute water scarcity.
Source UN World Water Development Report, 2003.
Factors Responsible for Water Scarcity
1. Quantitative Aspects ‘Shortage of water as compared to its demand is known as water scarcity’.
(a) Growing Population A large population means more water not only for domestic use but also to produce more food.
(b) Commercialisation of Agriculture commercial crops need more water and other inputs. Means of irrigation like tubewells and wells are responsible for falling ground water levels.
(c) Variation in Seasonal and Annual Precipitation
Though average precipitation in India as a whole is estimated at 117 cm in a year yet it is less than
20 cm in part of Thar desert.
(d) Industrialisation and Urbanisation ever increasing number of industries has made matter worse by exerting pressure on freshwater resources.
Urbanisation has also aggrevated problem of water scarcity.
2. Qualitative Aspects
(a) Overutilisation and Misuse of Water Water table in states like Punjab and Haryana has lowered due to over utilisation of water resources.
(b) Pollution Pollution of water resources is another factor for water scarcity. Domestic waste and industrial waste are main factors responsible for water pollution.
Need of Conservation of Water
1. Water is necessary and pre-condition for life on Earth.
2. Cultivation of crops depends on availability of water.
3. Water is used for drinking and domestic consumption.
4. Water is important for industries of India.
5. Conservation of water is important to prevent degradation of our natural ecosystems.
Multipurpose River Projects and Integrated Water Resources Management
1. Multipurpose projects fulfils a variety of purposes for ex-irrigation, food control, fish breeding, soil conservation and generation of electricity.
2. Jawaharlal Nehru proclaimed dams as ‘Temples of Modern India’.
Main Objectives
1. Generation of Power (electricity) According to economic survey 2005–06 these produce more than 30000 MW power.
2. Soil Conservation These conserve soil by slowing down speed of water.
3. Flood Control These projects control floods by storing water in them.
4. Afforestation Trees are systematically planted in and around reservoirs, which helps in preserving wildlife and natural ecosystem.
5. Irrigation These irrigate fields during dry seasons.
6. Water Navigation These provide for inland water navigation through main rivers and canals.
7. Fisheries These provide ideal condition for breeding of fish.
8. Tourist Centres These projects are well cared and are scientifically developed. So, become centres of tourist attraction.
Limitations of these Projects
1. High Cost initial cost of building dams is very high.
2. Adverse Impact on Environment A variety of flora and fauna as well as human settlements get submerged in water of reservoir formed by dam.
3. Adverse Effect on Fertility of Soil Due to construction of dams there are no annual floods in river. This decreases fertility of soil.
4. Non-availability of Water throughout Year Most of rivers in India flow only for few months. So, water is not sufficient to build a dam.
5. Adverse Impact on Aquatic Life Due to construction of dam on river, fish in down stream area do not get sufficient nutrient material.
6. Disputes between Different States This is one of major causes of delay of many projects.
7. Displacement of Local Communities building of large dams results in displacement of local communities.
8. Change in Cropping Pattern Due to formation of these projects most of farmers have changed cropping pattern shifting to water intensive and commercial crops.
9. Multipurpose projects also induced earthquakes, caused water borne disease and pests and pollution resulting from excessive use of water.
Rain Water Harvesting
1. People living in arid regions like Rajasthan, used rooftop rainwater harvesting techniques to store drinking water.
2. People of mountaineous regions had built diversion channels like ‘Guls’ and ‘Kuls’ for agriculture.
3. In semi-arid and arid regions people had tanks or ‘tankas’
for storing water.
4. These tanks were connected to sloping roofs through a pipe.
5. Rooftop rain water is collected using a PVC pipe.
6. Underground pipe takes water to sump for immediate usage.
7. Excessive water from sump is taken to well.
8. Water from well recharges underground.
9. In flood plain areas, inundation channels were used to irrigate fields by people.
Importance of Rain Water Harvesting
1. It is considered as pure form of natural water.
2. It is reliable source of water when all other sources of water dry up.
3. It is also given to sick people.
4. It can be used to beat summer heat if underground rooms adjoining tanks are built.
5. It can be used to meet our growing water needs.

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