Introduction:
The hydrological cycle constantly recycles water between the hydrosphere, atmosphere and lithosphere. It allows the interaction and the interdependence of the biosphere on these spheres possible. The important processes of the hydro-cycle is evapo-transpiration, condensation and precipitation, make water available on ground.
Water is found in oceans, rivers, lakes, ponds in the atmosphere and also form of ice sheets and glaciers, altogether forming the hydrosphere. Nearly 70% of the earths surface is covered with water, 96.5% is estimated to exist in oceans and 2.5% as fresh water, nearly 70% of this freshwater occurs as ice sheets and glaciers in Antarctica, Greenland and on the snow caped mountains, a little less than 30% of freshwater is stored in aquifers. Only 0.3% of all water on earth can be used by humans. Oceans are the main source of precipitation on ground. The water that falls to the ground is generally termed as freshwater.
A: WATER SCARCIY IN INDIA:
1. Inefficient use of water: scarcity is usually caused by inefficient use, exploitation, excessive use and unequal access.
2. Variation in Precipitation: 90% of rainfall in India is received in 4 months-Jul to Sept. Water is not available throughout the year in many areas. Many parts of the country face drought during summer months. Sometimes, monsoon fails.
3. Rising Population: per capita of water consumption has come down substantially since 1951 as a result of rapid population growth.
4. Industrialization: besides irrigation water is also used for many industrial uses and since India is growing this water requirement is also increasing.
5. Vegetation: loss of vegetation causes the surface water to become muddy and flow towards the oceans/seas.
6. Community Resources: failure in promoting sustainable use of water resources.
7. Unsustainable use of Ground Water: Individuals, farmers, households utilize the aquifers through wells and tube wells liberally, without assessing potential of resources.
B: WATER-STRESS:
Definition: Water stress occurs when the demand for water exceeds the available amount during a certain period or when poor quality restricts its use. Water stress causes deterioration of fresh water resources in terms of quantity (aquifer over-exploitation, dry rivers, etc.) and quality (eutrophication, organic matter pollution, saline intrusion, etc.) Water stress occurs when the water availability is less than 1000 m3 per person per day.
1. Intensive industrialization and extensive urbanization is taking its toll on the ground water resources. Huge amounts of water are consumed by factories and industries, thermal power plants, cooling plants, ETC.
2. This requirement has put heavy pressure on existing water resources. This huge pressure on water resources has created a condition of water stress.
3. According to physical law, when a stress is applied to a body it produces strain and the body can be distorted or deformed. This happens to the ground on which water flows. Many areas, fields and small river beds are becoming parched and developing cracks for the want of water. Soils in the fields are turning into dust bowls.
4. Inefficient use of water continues, like irrigation through open canals, generating hydel power, etc. creating tension and stress on water resources.
5. Multiplying urban centers, massive population, utilization of ground water resources, are creating conditions of water stress and causing its severe depletion.
C: WATER QUALITY:
Water pollution caused through the discharge of domestic and industrial wastes into water effects quality. Industrial wastes make water hazardous for human, animal and marine life. These have affected the quality and quantity of water in many ways:
1. Vast gap between demand and supply of water. Villages in India are yet to be provided with safe drinking water.
2. Most of the tributaries of the Indian River, streams etc. have become sinks of domestic and industrial wastes.
3. Most rivers are “health hazards” threatening the livelihoods of people.
4. Water contamination and deteriorating water quality has caused degradation of our natural ecosystems.
5. Over-exploitation and mismanagement of water has impoverished our resource base causing ecological balance.
B: MANAGEMENT OF WATER RESOURCES:
Water conservation and management has been practiced since ancient times. Certain hydraulic structures belonging to ancient India have been referred to in “Dying Wisdom”, CSE 1997
I: Hydraulic Structures of Ancient India:
· Water harvesting and management was first seen in the Harappan Civilization.
· The Great Rann of Kutch, a network of reservoirs were installed which were filled with water by seasonal stream. The water from reservoirs in turn replenished wells.
· Reservoirs were built during Asoka’s times at Lallipattam( Nepal). Sudarshana Lake near Junagarh built by Chandragupta Maurya and repaired by the Sakas and Gupta Kings, is an example of equitable water conservation technique. This lake was formed by artificially damming several streams to raise water level.
· One of the largest artificial lakes, the Bhopal Tal Lake was built in the 11th century by a Parmar King., it still has plentiful supply of water.
· The Tank in Hauz Khas, New Delhi was constructed by Illtutmish in the 14th cent., to supply water to Siri Fort area.
· Other important lakes include: Lake Pichhola-Udaipur, Gadsisar-Jaiselmer, Anasagar in Ajmer, Barwasagar-UttarP.
· Cholas were known for building a no. of comm. Wells in the villages. The aqueduct canal built by DevaRaya-I to bring water from Tungabhadra to Hampi is an excellent example of water management. The idea of irrigation dam-“anicut” has emerged from south India.
· Basins of Water, Step-wells called baolis were found in many places.
· In Guj. A step well called “Rani ki Vav” built in 11th cent., is 7 storey deep and its inner walls are decorated with sculptures, built by the Chalukya Kings.
· Kalinga(Orissa), Bennur(Karnataka), Kolhapur(Mah), Nagarajunakonda(An.P), show evidences of very sophisticated irrigation works.
· Sringaverapura near Allahbad had sophisticated water harvesting system channeling the flood water of Ganga in, built nearly in 1 BC.
II: The Need of the Hour:
1. Conserve water resources
2. Safeguard ourselves from health hazards
3. Manage water resources
4. Prevent degradation of our natural ecosystems
5. Ensure food security
6. Continuation of our livelihood and productive activities
III: Modern Dams:
· A Dam is a reservoir, lake or impoundment created by a barrier built across the flowing water, this barrier obstructs retards or directs the flow of water.
· An important part of most dams is the weir or spillway. It is through this or over which the water flows continuously or intermittently.
· A dam has its origin in it usefulness of impounding rivers and harvesting rainwater. This collected water is later used for irrigation.
· Types of Dams:
Ø According to Material Used
§ Timber dams
§ Embarkment or Masonry Dams
Ø According to their intended height
§ High Dams
§ Medium Height Dams
§ Low Dams
· Today dams are meant to tackle problems associated with river valleys in an integrated manner and not just irrigation.
· Dams today check soil erosion, provide water for irrigation and domestic use, generate electricity, provide recreation, promote industrial development, afforestation, fisheries, and support inland navigation.
· Dams are referred to as multi-purpose river valley projects as the uses of the impounded water are in integration with one another.
· Important Multipurpose Projects In India:
NAME | RIVER | BENEFICIARY STATES | USES |
Damodar valley | Damodar | JH, WB | Flood control, irrigation, distribution of electricity. |
Bhakra Nangal | Satluj | PUN, HAR, RAJ | Hydel Power production, irrigation |
Hirakud | Mahanadi | ORISSA | Conservation of water, flood control |
Kosi | Kosi | BIHAR | Soil conservation, vegetation |
Chambal Valley | Chambal | MP, RAJ. | Hydel Power production, irrigation, Soil conservation |
Tungabhadra | Tungabhadra | KAR, AN.P | Flood control, irrigation, |
Nagarjuna Sagar | Krishna | ANP | Irrigation, |
Narmada Valley | Narmada | GUJ, MP, RAJ. | |
Indira Gandhi Canal(Rajasthan Canal) | Beas, Satluj | PUNJAB, HARYANA, RAJASTHAN | Irrigation |
Rihand | Rihand | UP, MP | |
Farraka Barrage | Ganga | WB | |
Tehri Dam | Bhagirathi | UTTARANCHAL. |
IV: Problems Associated With Damming Rivers:
1. Slowing natural flow of the river
2. Excessive sedimentation at the bottom of the reservoir leading to rockier stream beds, poor habitation of aquatic life.
3. Artificial reservoirs submerge some parts of natural vegetation leading to extinction of exotic flora and fauna.
4. Submerging the land and soil of flood plains leading to degradation and decomposition.
5. Fragmenting rivers making it difficult for aquatic fauna to migrate.
V: The Issues Involved in Construction of Dams:
1. Ecological: effects cropping pattern of the concerned region, salination of soil.
2. Social Landscape: Large dams transform the social landscape of that region. Landowners benefit from the water resources whereas landless laborers have to bear the brunt of the doleful situation. The gap between the rich landowners and the landless laborers is widening.
3. Urbanisation: A vast number of villages have been resettled in close proximity of the urban areas leading to forced urbanization.
4. Interstate water dispute: The interstate water disputes linger on without any solution, neglecting the benefits of damming river.
5. Fear of Flooding and Drought, Earthquakes, waterborne diseases.
6. Infringement of dams creates fear amongst the people and people protest against sharing the costs.
VI: Interstate Water Dispute:
· River Yamuna among Delhi, Haryana and UP.
· The Krishna Godavari dispute is based on the Karnataka and Andhra Pradesh.
· Cauvery basin is an interstate basin covering areas in Kerala, Karnataka, Tamil Nadu and Kairakal region of Puducherry.
· Ravi-Beas dispute between Haryana and Punjab
VI: People’s Resistance Movement:
1. Narmada Bachao Andolan, and Tehri Dam Andolan by two different NGO groups have a very wide support among the affected population in these regions. The Koyna Dam has been ascribed the cause of an earthquake to this dam.
2. Villagers have risen in revolt against the displacement imposed on them.
3. Religious organizations are protesting against the submergence of ancient temples and other sacred places.
4. The govt. is bringing out alternative livelihoods and resettlement plans, the affected people have their miseries and hardships to recount.
C: WATER RESOURCE MANAGEMENT THROUGH CONSERVATION:
Our best hope lies with the traditional water management and conservation techniques. These techniques could be supplemented with the latest scientific measures to prevent damage to vegetation.
1. Watershed Management:
· Involves improving the vegetation cover in each watershed area.
· The chief purpose is to prevent rapid run-off and underground water percolation in the water shed area.
· This water can be used as underground water throughout the year.
· For judicious use of water between two or more adjacent basins, integrated development of watershed units is suggested.
· Measures like water harvesting, soil and moisture conservation afforestation and up-gradation of community land resources are taken for the whole area.
2. Prevent Pollution: Wastes when discharged in river, streams and other water bodies pose a great threat to vegetation and wildlife. Polluted water should not be allowed to merge with water bodies.
3. Desalination: this measure involves the use of water of salt lakes, oceans and seas. Desalination requires large amounts of energy and therefore very expensive.
D: RAIN WATER HARVESTING:
Rain water harvesting is done to store rainwater in containers above or below the ground or charged into soil for withdrawal later. It is a method of utilizing rain water for domestic and agricultural use. It has become a widely accepted technique of providing potable water in development projects all over the world. It has wide open application also in urban and semi urban areas where the reliability and quality of water is undependable.
Benefits of Rain Water Harvesting:
1. Increases the availability of water
2. Checks declining water table
3. Is environment friendly
4. Improves the quality of ground water through the dilation of fluoride, nitrate and salinity
5. Prevents soil erosion and flooding especially in urban areas
Top rooftop rainwater harvesting has become a common practice in regions of Meghalaya. Almost all houses in shilling have a rooftop rainwater harvesting system and roughly 15-25% of the total water requirement comes from the rooftop water harvesting.
There are various methods of water harvesting, no uniform technique is adopted. Techniques are prescribed as per regions.
Efficient Management of Water:
1. Preventing pollution of water bodies
2. Repairing leaking pipes and taps
3. Registering all water extraction ponds and checking them periodically.
4. Creating awareness about water conservation and management.
5. Stopping use of treated water for washing and cleaning.
Various Methods Of Rain Water Harvesting:
· In the mountainous regions people construct diversion channels called ‘gul’ for agri. As seen in West. Himalayas.
· In the flood plains of Bengal inundation channels are constructed to irrigate the fields.
· In Rajasthan rooftop rainwater harvesting technique is adopted to collect drinking water.
· In Jaisalmer and other parts of semi arid Rajasthan people use the technique of developing agricultural fields into rain fed storage structures. This allows the water to stand and moisten the soil. Such structures are called ‘khadins’ and ‘johad’.
· In Bikaner Phalodi and Barmer all houses have underground tanks called tankas in which water was stored for drinking. these tankas had water which could last for 3 to 5 years.
· In Rajasthan Palar pani or rainwater is the purest form of natural water.
Long Term Objectives of Rain Water Harvesting:
· Partnership for Sustainable Use of Water: about 300000 people of Delhi draw nearly 18 million gallons of water everyday accounting for 12% of total water supply. This heavy dependence on ground water calls for artificial techniques of recharging tube wells. Delhi needs 850mgd while supply is only 670 mgd. Therefore, recharging of all abandoned wells is necessary.
· Social Forestry: vegetation growth is promoted it creates an accelerating effect to promote more vegetation through soil reclamation, groundwater replenishment as well as evapo-transpiration. The vegetation cover allows the rainwater to soak into the ground in natural course. The scheme has been put into practice in Haryana, west. UP and Raj.
· Public Awareness: participation of community at every level is required to promote water conservation. Lack of public awareness, people should be encouraged to use traditional methods of rainwater harvesting.
· Growing Needs: Management of water resources especially through rainwater harvesting should be a continuous process.
Water is the elixir of life, use it VERY wisely. NO LIVING THING CAN SURVIVE WITHOUT WATER. According to the UN estimates 500 cr. People will be facing severe water shortage by 2015.Water management should be top of the world Sust. Dvpt. Strategy.
Answer the following: Long Answer TypeT
1. Describe how modern adaptation of traditional rainwater harvesting methods is being carried out to conserve & store water?
2. Explain any six factors responsible for the growing scarcity of water.
3. Describe some hydraulic structures of ancient India.
4. How are people resisting constructions of Dams?
5. Describe the issues involved in construction of dams.
6. Explain the term long term objectives of rain water harvesting.
7. The growing scarcity of water has been the result of rapidly growing population. Elaborate and discuss.
8. Explain problem associated with damming of rivers.
9. What is known as national water grid? What does this plan envisage? Give five points of view each for and against this project?
10. Describe the methods of conservation and management of water resources. Also state the objectives of rain water harvesting.
11. Multipurpose projects are referred to as the ‘temples of modern India’. Elucidate.
12. Multipurpose projects and large dams have come under great scrutiny and opposition. Why?
13. ¾ of the world is covered with water and water is a renewable resource. Yet many countries and regions around the globe suffer water scarcity. Explain.
14. What are interstate water disputes? Why are such issues raised? Explain with examples.
15. Write about roof top rainwater harvesting system in Meghalaya. How is the bamboo drip irrigation system employed for water harvesting in Meghalaya.
16. An area or region may have ample water resources but still face scarcity. Explain why such circumstances arise.
17. Identify any three reasons for water scarcity in metropolitan towns. Suggest one measure that in your opinion can lead to a more equitable distribution of available water supply.
18. How intensive industrialization and urbanization have passed a great pressure on existing fresh water resources in India?
19. What is NBA why was it organized? What are issues raised by the movement?
20. What is rainwater harvesting state the objectives of rain water harvesting?
Map Work:
All major river valley projects and their rivers.
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