WATER RESOURCE

Water Resource

Water Facts

1.         75% i.e three-fourth of the earth’s surface is covered with water.

2.         96.5 per cent of the total volume of world’s water exists as oceans and sea.

3.         Only 2.5 per cent is fresh water, 1% is water vapour.

4.         Nearly 69 per cent of this freshwater occurs as ice sheets and glaciers in Antarctica, Greenland and the mountainous regions of the world,  

5.         30 per cent is stored as groundwater and less than 1 per cent is in lakes and rivers.

6.         Freshwater is mainly obtained from surface run off and ground water.

7.         Water is continually being renewed and recharged through the hydrological

            cycle thus water is a renewable resource.

8.         India receives nearly 4 per cent of the global precipitation and ranks 133 in the

            world in terms of water availability per person per annum.

9.          In India water consumption is highest in agriculture, second - Industries, thired- domestic

Water Scarcity

· Refers as the situation where there is insufficient water to satisfy normal requirements.

· 1.2 billion people live in water scarce area

.   By 2025- 2 billion live in water scarce area( UNDP report 2003)
.   Israel- 25 cm annual rainfall - no scarcity
.   India - 114 cm annual rainfall - scarcity
.    Acc. to Falken Mark, a Swedish expert, water stress occur when water availability is between
     1,000-1600 cubic meter per person per annum.

Reasons

1.         Variations in seasonal and annual precipitation.

2.         But water scarcity in most cases is caused by over- exploitation,

3.         Unequal access to water among different social groups.

4.         Increased agricultural production due to food insecurity in the country. To achieve higher food-grain production, more irrigation is required.

5.         Water pollution. Bad quality of water

6.         Industrialization: Industries require large amount Eg. soft drinks, water needed to cool steel in steel industry

7.         Urbanization: ground water pumping

8.         Hydro electric power generation: flow of water

Multi-Purpose River Projects

           

            · Dam is a barrier across flowing water that obstructs, directs or retards the flow,

            creating a reservoir or lake.

            · Dams were built under integrated water resources management approach which means that they has many uses of impounded water which are integrated with one another.-

i.          Dams were traditionally built to impound rivers and rainwater that could be used to irrigate agricultural fields.

ii.          Dams are also built for electricity generation, 22% of electricity generation

iii.         For water supply for domestic and industrial uses,

iv.        For controlling floods, For eg. in river Damodar ( sorrow of Bengal ), Kosi river
           ( sorrow of Bihar)

v.          For  the purpose of recreation,

vi.         For inland navigation and

vii.         For fish breeding.

Important dams

1.Mettur- Kaveri                                 2.Naagarjun Sagar - Krishana

3. Sardar Sarover- Narmada                     4. Parvara - Godavari
5. Hirakud - Mahanadi                              6. Rihand - Son
7. Tehri- Ganga                                         8. Bhakra Nangal - Satluj
9. Salal - Chenab                                       10. Maithon - Damodar
11. Gandhi sagar - Chambal

Dams “Temples of modern India”

1.         Jawaharlal Nehru proudly announced the dams as the ‘temples of modern India’.

2.         He called dams as temples because he thought they will integrate the agriculture and village economy with industrialization and urban economy.

Criticism of Multi-Purpose River Projects

Reasons

a.         Affect natural flow of running water:

            i. Hence, it causes excessive sedimentation at the bottom of the reservoir.

            ii. It results in rockier stream beds.

            iii. They also fragment rivers making it difficult for aquatic fauna to migrate, especially for breeding.

b.         Affect natural vegetation and soil:

            i. The reservoirs that are created on the floodplains also submerge the existing vegetation and soil leading to its decomposition over a period of time.

            ii. The flood plains are deprived of silt, a natural fertilizer, further adding on to the problem of land degradation.

c.         Cause of many social movements:

            i. They have been a cause of many new social movements like the ‘Narmada Bachao Andolan’ and the ‘Tehri Dam Andolan’ etc.

d.         Displacement of people:

            i. They results in the large-scale displacement of local communities.

            ii. Local people often had to give up their land, livelihood for the nation.

            iii. The local people are not benefiting from such projects.

e.         Change in cropping pattern:

            i. Availability of irrigation has also changed the cropping pattern.

            ii. Farmers have shifted to water intensive and commercial crops.

            iii. This has great ecological consequences like salinisation of the soil.

            iv. It has increased the social gap between the richer landowners and the landless poor.

f.          Create conflicts:

            i. The dams create conflicts between people wanting different uses and benefits from the same water resources.

            ii. Inter-state water disputes are also becoming common with regard to sharing the costs and benefits of the multi-purpose project.

             Eg.1 Kaveri dispute between Karnataka and Tamil nadu.

             Eg.2 Krishna-Godavari dispute is due to the objections raised by Karnataka and       Andhra Pradesh governments. It is regarding the diversion of more water at
           Koyna  ( Krishna) by the Maharashtra government for a multipurpose project.

              Eg.3  In  Gujarat, the Sabarmati - basin farmers were agitated and almost caused riots over the higher priority given water to urban areas.

g.         Failure to control flood:

            i. The dams that were constructed to control floods have triggered floods due to sedimentation in the reservoir and at the time of excessive rainfall.

            ii. It was also observed that the multi-purpose projects induced earthquakes,

Ancient and Medieval Hydraulic Structures in India

1.         In the first century B.C., Sringaverapura near Allahabad had sophisticated water harvesting system channelling the flood water of the river Ganga.

2.         The Junagarh rock inscription of Rudradaman says that a dam on Sudarshan lake

             (Gujarat) for irrigation was constructed by Pushyagupta, a provincial governor of Chandragupta Maurya

3.         Evidences of sophisticated irrigation works have also been found in Kalinga, (Orissa), Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka), Kolhapur (Maharashtra), etc.

4.         In the 11th Century, Bhopal Lake ( Bhojtal- constructed by Raja Bhoj) one of the largest artificial lakes of its time was built ( earthen dam across river Kolan ). Its surface area was 31 sq. km.)

5.         In the 14th Century, the tank in Hauz Khas, Delhi was constructed by Iltutmish for supplying water to Siri Fort area.

Rainwater Harvesting

1.         Today, in western Rajasthan, the practice of rooftop rainwater harvesting is on the decline as plenty of water is available due to the perennial Rajasthan Canal.

2.         In Shillong nearly every household in the city has a roof top rain water harvesting structure and 15-25 per cent of the total water requirement of the household comes from roof top water harvesting.

3.         In Gendathur, a remote backward village in Mysore, Karnataka, villagers have installed in their household’s rooftop rainwater harvesting system to meet their water needs.

4.         Tamil Nadu is the first and the only state in India which has made roof top rainwater harvesting structure compulsory to all the houses across the state. There are legal provisions to punish the defaulters.

5.         In Meghalaya, a 200-year-old system of tapping stream and spring water by

            using bamboo pipes is common. ( Bamboo Drip irrigation)

Traditional water harvesting systems developed in India.

a.         In hill and mountainous regions, people built diversion channels like the ‘guls’ or ‘kuls’ ( water from melting of  glaciers leads to Kuls )  of the Western Himalayas for agriculture. A kul leads to a circular village tank from which water is released as and when required.

b.         ‘Rooftop rain water harvesting’ was commonly practised to store drinking water,    particularly in Rajasthan.

c.         In the flood plains of Bengal, people developed inundation channels to irrigate their fields.

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

“Tankas” of semi-arid region of Rajasthan (Bikaner, Barmer, Phalodi)

1.         Almost all the houses traditionally had underground tanks or tankas for storing drinking water.

2.         The tanks could be as large as a big room;

3.         One household in Phalodi had a tank that was 6.1 metres deep, 4.27 metres long and 2.44 metres wide.

4.         Rain falling on the rooftops would travel down the pipe and was stored in these underground ‘tankas’.

5.         The first spell of rain was usually not collected as this would clean the roofs and the pipes. The rainwater from the subsequent showers was then collected.

6.         The rainwater can be stored in the tankas till the next rainfall making it an extremely reliable source of drinking water when all other sources are dried up, particularly in the summers.

7.         Many houses constructed underground rooms adjoining the ‘tanka’ to beat the summer heat as it would keep the room cool.

Note:

1          The Bhakra – Nangal project on Sutluj-Beas River is used both for hydel power

            production and irrigation.

2.         Similarly, the Hirakud project in the Mahanadi basin integrates conservation of water with flood control.

3.         The troubles faced by people owing to the flooding of Damodar River have given this river a name as the river of sorrow.

4.         Rain water in Rajasthan is known as “palar pani”