Water Resources Class 10 Social Science Notes and Questions

Sardar Sarovar Dam

River Narmada

Taanka is a traditional rainwater harvesting technique  indigenous to the Thar desert region of Rajasthan. A Taanka is a cylindrical paved underground pit into which rainwater from rooftops, courtyards or artificially prepared catchments accumulate for later use.

A large population leads to greater demand for water.

(i)   A large population  means  more  water not only for domestic use but also to produce more food in various agricultural practices.

(ii) Most of the Indian cities are facing the problem of water due to growing population.  This happens because large amount of ground water is pumped out in densely populated colonies. This has drastically lowered the water table.

(iii) Large industries also makes huge demand on water. Further industrial pollution often pollutes the water bodies which further aggravates the situation.

(a) It is true that urbanization has aggravated water crisis in India. The urban centers support large populations which increases the water demand for personal uses.

(b) In the city housing societies or colonies have their  own  groundwater  pumping  arrangements to meet the water requirements. Thus, the water resources are over-exploited.

(c) The  urban  centers  also  have  many largenumbers of industries. These industries use a huge quantity  of water and exert pressure on the existing freshwater resources. Quite often the industries also pollute the water resources.

Water is an essential item for human existence but it is also one of the mostmisused commodities. Through the passage of time, early societies understood the importance and need for water and planned  their lives around  it. Civilizations have been born and lost on account of water. Today, we have the advantage of this knowledge.

Rain is the primary source of water, but we get rain only during the monsoon season in India during the months of July, August and September. Even in these three months it has been found that most areas get about 80% of the annual rain in about just 24 days.

A large amount of this precious water just drains away. The only way to save this water from wastage is by rain water harvesting. In its simplest form it involves storing the rain water in tanks, or by making embankments etc. The different methods of rain water harvesting used in India have been as follows:

(a)   Guls or Kuls in the Western Himalayas

(b)  Rooftop rain water harvesting in Rajasthan associated  with  tankas  .Khadins  in  Jaisalmer and Johads in other parts of Rajasthan were also popular.

(c)   Inundation channels in West Bengal

(d)  In Meghalaya which gets copious rain, rain water harvesting is commonly practiced.

(e)  In modern civil construction  and housing societies provision for rain water harvesting

After independence, industries are increasing at a rapid pace and have put pressure on existing fresh water resources, fresh water is limited, though renewable. In India, over-exploitation and mismanagement of this resource by industries is aggravating the water stress day-by-day.

(i)   Industries  especially heavy  industries  use huge amount of fresh water, they also pollute and waste a large amount of water.

(ii) These   industries    often    depend    on hydroelectric projects and this electricity is generated through damming the rivers upstream. So, the river almost dries in the lower stream areas.

(iii) Industries  dump  the chemical waste in the river, lake, etc. which then consequently pollute the water dangerously. These also contaminate the groundwater through seepage of industrial wastes. So, the increasing number of industries exert pressure on existing fresh water resources.

The reasons for water scarcity in India are :

(i)   Seasonal and annual variation in precipitation.

(ii)  Unequal access to water resources.

(iii) Overexploitation of water resources or fresh water bodies

(iv) Large and  growing population  resulting in greater demand for water resources particularly in cities.

A large population  means, not only more water is required for domestic use but also for higher food grain productivity. This has led to over- exploitation of water resources to expand irrigated areas especially for dry season agriculture. It has also contributed to falling ground water levels, adversely affecting the water availability and food security of the people.

(v) Multiplying  urban   areas  with  dense population  and  modern  life styles have created an ever-increasing demand for water and energy resources.

(vi) Pollution of water bodies due to discharge of industrial effluents, use of pesticides, insecticides and fertilizers in agriculture, make the river water hazardous for human consumption.

(i)  In semi-arid and arid regions of Rajasthan almost all the houses traditionally had underground tanks for storing drinking water. They are extremely reliable source  of drinking water when other sources dry up. Rain water is considered the purest form of natural water.

(ii)  The tanks can be as large as big rooms.

(iii) The tanks were part of the well-developed roof-top rainwater harvesting systems.

(iv) The tanks were built inside the main house or the courtyard giving cooling effect to the rooms in the summer.

(v)  Those tanks were connected to the sloping roofs of the houses by a pipe.

(vi) Rain falling on these rooftops would travel down the pipe and get stored in these underground tanks.

(vii) Usually first rain water is not collected as it cleans the rooftop and get the pipe.

The various reasons  why multipurpose projects and large dams have come under  scrutiny and opposition is because of the following reasons.

They 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.

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 fertiliser, further adding on to the problem of land degradation.

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.

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.

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 project.

(iii) This leads to widening of the social gap

(iv) The local people are not benefiting from such projects.

Failure to control flood :

(i)   The dams that  were constructed  to control floods have often 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, caused waterborne diseases.

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.

(i)  Rooftop  rainwater  is  collected using  a PVC pipe.

(ii) Collected water is filtered using sand and bricks.

(iii) Underground pipe is used to take the water to the tank  for immediate usage.

(iv) Excess water from the tank is taken to the well.

(v) Water  from  the  well  recharges  the underground water.

A project where many uses of the impounded water are integrated with one another  is known as multipurpose project. It is built for irrigation, power generation, water supply, flood control, recreation, etc.

(a)   Bhakra Nangal project

(b)  Sardar Sarovar project

(i)  Bamboo Drip irrigation system is a 200 years old system of tapping stream and spring water by using bamboo pipe and transporting water from higher to lower regions through gravity.

(ii)  Features :

(a)   18-20 liters of water entres the bamboo pipe system, get transported  over hundreds of meters and finally reduces to 20-80 drops per minute at the site of the plants.

(b)  The flow of water into the pipes is controlled by manipulating the pipe positions.

Post independence India witnessed intensive industrialisation and urbanisation.

(i)   Arrival of MNC’s :  Apart from fresh water they required electricity which comes from hydroelectric power.

(ii)  Multiplying  urban  centers  with  large  and dense population and urban life styles have only added to water and energy requirements, which has further aggravated the problem.

(iii) Large-scale migration  from  rural  to  urban areas is causing over exploitation of water resources.

Jawaharlal Nehru proclaimed the dams as the “temples of modern India” because :

(i)   They eliminate or reduce flooding

(ii)  Provide water for agriculture.

(iii) Provide  water  for  human  and  industrial consumption.

(iv) Provide  hydroelectricity  for  houses  and industries.

Advantages :

(i)  These are an important  source of power generation.

(ii)  They provide us pollution free and economical energy which is the backbone of industry and agriculture

(iii) These projects control  the floods because water can be stored in them. These projects have converted many, rivers of sorrows into rivers of boon.

(iv) These  projects   are   the   main   source   of irrigation and also help in conserving soil.

Disadvantages.:

(i)   Due to the construction of dams there are no adequate floods in the river. Because of this, the soil of the downstream regions do not get nutrient rich silt.

(ii)  Dams also fragment rivers making it difficult for aquatic fauna to migrate for spawning.

(iii) It result in displacement of local communities. The Local people often have to given up their land and livelihood and their meagre access and control over resources.

The given statement means that most often over exploitation of water resources leads to water scarcity. An important example is growing of crops in dry season with the help of ground water. This had led to severe depletion of ground water levels in different parts of the country.

Distribution of water in terms of precipitation and availability through other sources is quite uneven. For example annual precipitation in Mawsynram, Meghalaya, is,  11,873 mm  while  annual  rain in Jodhpur Rajasthan is less than  100 mm. The uneven rainfall creates its own problems. Where as in areas of scarcity people try to save every bit of precipitation, a lot of water in areas of heavy rain goes waste.

(i)  In hilly and mountainous regions, people build diversion channels like ‘gul’ or ‘kul’ in eastern Himalaya for agriculture.

(ii)  Roof-top rainwater harvesting was commonly practised to store drinking water particularly in Rajasthan.

(iii) In  semi-arid  regions agricultural  fields are converted  into  rainfed  storage  structures  that allow the water to stand and moist the soil.

Many of our  cities face this problem; they have adequate supply of water but much of it is unfit for consumption. Many of our cities are on rive banks, but the river water is no longer suitable for consumption because of the toxic wastes it receives.

This is also seen in many hilly areas where rain water is not adequately conserved.

Sophisticated    hydraulic    structures     like dams build of stone rubble, reservoirs of lakes, embankments and canals for irrigation were built in various regions of the country.

(i) A sophisticated water harvesting system channelling the flood water of river Ganga was build at Sringaverapura near Allahabad in the first century B.C.

(ii)  Nagarjunakonda in Andhra Pradesh, Bennur in Karnataka, Kolhpur in Maharashtra and Kalinga in Odisha have evidences of irrigation structures.

(iii) In the 11th century, Bhopal Lake, one of the largest artificial lakes of its time was built.

(iv) The tank in Hauz Khas, Delhi was constructed by Iltutmish in the 14th century to supply water to the Siri Fort Area.

Groundwater  is a highly overused resource because of the following reasons:

(i)   Due to large and growing population and consequent greater demands for water and unequal access to it.

(ii)  To facilitate higher food grain production for large population, water resources are being over exploited to expand irrigated areas and dry season agriculture.

(iii) In  the housing societies or colonies in the cities, there is an arrangement  of ground  water pumping devices to meet water needs. Often this is over exploited.

(i)  Rooftop  rainwater  is  collected using  a PVC pipe.

(ii) Collected water is filtered using sand and bricks.

(iii) Underground pipe is used to take the water to the tank  for immediate usage.

(iv) Excess water from the tank is taken to the well.

(v) Water  from  the  well  recharges  the underground water.

Roof top  water harvesting is important in Rajasthan because :

(i)   It provides a good source of drinking water.

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

(iii) Rainwater,  or  palar  pani,  as  commonly referred to in these parts, is considered the purest form of natural water.

(iv) Many houses construct underground  rooms adjoining the tanks’ to beat the summer heat as it keeps the room cool.

(v)  Some houses still maintain  the tanks since they do not like the taste of tap water.

(i)  The availability of water resources varies over space and time, mainly due to the variations in seasonal and annual precipitation.

(ii)  Over-exploitation, excessive use and unequal access to water among different social groups land and livelihood and their meagre access and control over resources for the greater need of the nation. Also,

Over exploitation of water resources leads to water scarcity. An important example is growing of crops in dry season with the help of ground water. This had led to severe depletion of ground water levels in different parts of the country.

Distribution of water in terms of precipitation and availability through other sources is quite uneven. For example annual precipitation in Mawsynram, Meghalaya, is,  11,873 mm  while  annual  rain in Jodhpur Rajasthan is less than  100 mm. The uneven rainfall creates its own problems. Where as in areas of scarcity people try to save every bit of precipitation, a lot of water in areas of heavy rain goes waste.

Keeping  into  view the  disadvantages  and rising resistance against the multi-purpose projects, water harvesting system is considered a viable alternative both socio-economically and environmentally.

(i) In ancient India also along with the sophisticated hydraulic structures, there existed and extra-ordinary tradition of various water harvesting systems.

(ii) People adopted  different techniques  in different areas. In hilly regions people build diversion channels like the ‘guls’ or ‘Kuls’ for agriculture.

(iii) Roof-top rain water harvesting was commonly practised to store drinking water, particularly in Rajasthan.

(iv) In  the  flood  plains  of  Bengal, people developed inundation channels to irrigate their fields. Khadins, Johads and Tanks are the forms of rain water harvesting practised in Rajasthan.

Methods  of rain  water  harvesting  used  in India are :

(i) Guls and Kuls : People built guls and kuls in hilly and mountainous  regions to divert water. These are simple channels. They are mainly used in the Western Himalayas.

(ii)  Roof top rain water harvesting : Commonly practised to store drinking water in Rajasthan.

(iii) Inundation Channels : These  channels developed in the flood plains of Bengal to irrigate fields.

(iv) Khadins and Johads : In arid and semi-arid regions, some agricultural fields were converted into rain fed storage structures. These structures are found in Rajasthan.

(v)  Tankas :  The tankas  were build  inside the house or the courtyard. They were connected to the sloping roofs of the houses through  a pipe. Rain falling on the rooftops would travel down the pipe and was stored in these underground tanks’ The rainwater was stored in the tankas.