WATER RESOURCES
Q.1: State the merits and demerits of sprinkle irrigation and drip irrigation.
Merits of sprinkle irrigation:
1. They save water.
2. Even distribution of water.
Demerits of sprinkle irrigation:
1. Initial cost of installation is high.
2. It needs regular supply of electricity.
Merits of drip irrigation:
1. Excellent way of conserving water.
2. Supply water directly to the roots and hence do not cause loss.
3. Prevents soil erosion.
4. Can be used in arid and semiarid areas also.Demerits: It is costly.
Q.2: What is irrigation?
Ans: The process of supplying water by artificial means is called irrigation.
Q.3: State the need for irrigation.
Ans: Irrigation is essential in India because…
1. India is an agricultural country. Hence, round the year supply of water is essential.
2. Rainfall is insufficient and unevenly distributed.
3. India has a yearlong agricultural season, but the rainfall is seasonal.
Thus, irrigation ensures year long cultivation.
4. Crops like rice, wheat, Jute and sugarcane require plenty of water
which can be provided only through irrigation.
5. Due to growing population. There is a great demand for food which is fulfilled by bringing all possible regions under cultivation and providing irrigation to them.
6. Some parts of India are drought prone and are known for uncertain rainfall. Irrigation becomes indispensible in such parts of the nation.
Q.4: Name the modes of irrigation? Which one is the most popular in India?
Ans: Traditional Methods include wells, tanks & inundation canals Modern Methods: Sprinkle and Drip irrigation.Well irrigation is the most popular among them.
Q.5: What are the suitable conditions for digging well? Name the states where this irrigation is prominent.
Ans: Wells are found where:
(a)Sufficient groundwater is available.
(b)Groundwater level is not very deep.
(c) Soil is soft.
Well irrigation is concentrated in the states of Uttar Pradesh,Punjab & Rajasthan.
Q.6: Well irrigation is the main mode of irrigation in India. What are its advantages and disadvantages?
Ans: Advantages of Wells
1. Wells are the simplest & the cheapest means of irrigation.
2. Wells can be dug at any convenient place.
3. It is an independent source of irrigation.
Disadvantages:
Wells dry up during summer and fail to provide water when needed the most.
A well can irrigate only 1 to 2 hectares of land.
Well water is brackish.
Q.7: Why is tank irrigation popular in South India? OR What are the suitable conditions for tank irrigation? Name the states where it is carried out?
Ans: Tank irrigation is important in the Deccan Peninsula because:
The land is undulating and forms natural depression.
The underlying hard, impervious rocks prevent the percolation of water.
Tanks enable people to arrest the river water which otherwise flows away.
It is mainly carried out in Telangana, Andhra Pradesh and Tamil Nadu.
Q.8: State the advantages and disadvantages of tank irrigation.
Advantages:
Ans: Advantages: (i) They are naturally formed so there is no need of construction and hence they are cheap.
(ii)In South India they are found in more number where there are very few perennial rivers.
(iii)It stores the rain water which otherwise will flow away and get wasted.
(iv)This water can be used for irrigation and for domestic purposes.
Disadvantages:
(i)Tanks occupy a large surface area, which could otherwise have been used for cultivation.
(ii)Many tanks dry up during dry season and fail to provide water when it is required most.
(iii)Silting of tanks is a problem and desiliting is often needed.
Q.9: Tube wells are introduced mainly in the Indo Gangetic Plain.Explain.
Ans: Tube wells are introduced in the Indo-Gangetic plains where ground water is ample and available close to the surface.
Q.10: State the advantages of tube well.
Ans: 1. Tube wells irrigate much larger area of about 400 hectares.
2. They are more reliable during summer or drought conditions where ordinary wells dry up.
3. They are also suited for small land holdings.
Q.11: Though initial cost of installation is high, it is still used in N.India. Explain.
Ans:1. Even though the initial cost of installing them is high, they are used in the North Indian Plains where there is abundant ground water and Very fertile soil.
2. They can also irrigate a large area and thus help in increased production. Hence the cost of installing is covered in short time.
Q.12: State the disadvantages of tube well.
Ans: There must be sufficient groundwater.
There must be regular supply of cheap electricity.
The land must be fertile & productive so that the cost of operation can be recovered from increased farm production.
Q.13: Canal irrigation is not practiced on a large scale in Peninsular India. Why?
Ans: The digging of canals in rocky and uneven areas is difficult.
Therefore canals are practically absent in Peninsular India.
Q.14: With respect to inundation canal answer the following questions.
a. What are inundation canals? b. How are they made? C. Which river has them in large number?
These are flood water canals and water in them when river is flooded during the rainy season. These canals are directly taken out by cutting the river banks.
Inundation canal are found in large number on river Satluj.
Q.15: State the advantages and disadvantages of inundation canals.
Disadvantage:
1. They irrigate only a limited land.
2. They have water only when the rivers are flooded.
3. They do not have any regulating systems like weirs or embankments.
Q.15: Mention the merits and demerits of canal irrigation.
Merits:
1. Most of the canals are perennial and provide water whenever needed.
2. Canal water is loaded with sediments which increase the fertility of the soil.
3. Barring initial cost, canal irrigation is quite cheap.
Demerits of Canal Irrigation:
If canals are not lined, canal water seeps underground and causes water logging.Underground salts occupy the upper surface of the soil and make the soil saline. Ex. Punjab, Uttar Pradesh, Haryana.Marshy areas near the canals become the breeding ground for mosquitoes which spread Malaria.
Q.16: State one advantage and disadvantage of sprinkle irrigation.
Ans: Advantage: This method is practiced in arid, semi-arid and hilly areas as it saves water.
Disadvantage: It is expensive.
Q.17: What do you mean by water conservation? Suggest any two methods for sit.
Ans: Conservation of water is essential due to its short supply, increased demand, large-scale pollution & uneven distribution.
Measures:
⦁ Developing water saving technologies.
⦁ Prevent water pollution.
⦁ Encourage watershed development, rain-water harvesting, reuse & recycling of water.
GIVE REASONS
⦁ Well irrigation is the most popular means of irrigation.
Ans: (i) Because it is individual source of irrigation and farmers can use it whenever they want and in whatever quantity they want.
(ii) Wells can be constructed even in hilly and desert areas where canal irrigation, tank irrigation is not possible (iii) They are cheap.
⦁ Canal irrigation is prominent in North India.
Ans: Canal irrigation needs flat topography, fertile soft soil to make digging easy, perennial source of river.(ii) North Indian has plain area and the perennial Himalayan rivers bringing fertile soil and abundant water throughout the year. That is why…
⦁ Irrigation is must in India.
Ans: India is agricultural country so water is must.
(ii) However the rainfall in India is erratic and unevenly distributed
(iii) Due to Irrigation per hectare production increases and
(iv) we can grow crops throughout the year.
⦁ Use of modern irrigation need to be practiced.
Ans: (i) Modern means of irrigation like sprinkle irrigation, drip irrigation supply water evenly..
(ii) They do not cause loss of water.
(iii) They can be used even in arid and semi arid areas. That is why…
⦁ Bhakra Nangal and Hirakud are multipurpose projects.
Ans: Multipurpose projects which fulfill more than one objective such as irrigation, water transport, generation of hydel power, irrigation, a tourism destination etc. As these projects fulfill most of these objectives, they are multipurpose projects.
⦁ Water needs to conserved.
Ans: (i)Water is essential for the cultivation, industries, domestic purposes and for many other things.
(ii)However though the demand for water is increasing due to increased population, its getting scarce. That is why.
⦁ Inundation canals are being converted into perennial canal.
Ans: (i) Inundation canals can supply water only to a limited area.
(ii)They have water only when river is flooded.
(iii) That is why, they are converted into perennial canals which will supply water throughout the year.
⦁ Though costly, tubewells are installed in the north Indian plain on a large scale.
Ans: Tubewells can irrigate a huge area upto 400 hectares. The soil in North India is very fertile and hence productive. Due to irrigation here, the production cost is higher and the cost of istalling it can be recovered easily. That is why….
BOARD QUATIONS
Q.1: What is irrigation? State its importance.
Ans: The process of supplying water by artificial means is called irrigation.
Irrigation is essential in India because…
1. India is an agricultural country. Hence, round the year supply of water is essential.
2. Rainfall is insufficient and unevenly distributed.
3. India has a yearlong agricultural season, but the rainfall is seasonal.
Thus, irrigation ensures year long cultivation.
4. Crops like rice, wheat, Jute and sugarcane require plenty of water which can be provided only through irrigation.
Q.2: Which is the oldest and the most popular mode of irrigation?
Ans: Well irrigation is the oldest and the most popular means.
Q.3: (i) State the conditions necessary for well irrigation. (ii)In which states well irrigation is prominent.
Ans: (i) Wells are found where:
(a)Sufficient groundwater is available.
(b)Groundwater level is not very deep.
(c) Soil is soft.
(ii)Well irrigation is concentrated in the states of Uttar Pradesh,Punjab & Rajasthan.
Q.4: State the advantages and disadvantages of wells.
Ans: Advantages of Wells
1. Wells are the simplest & the cheapest means of irrigation.
2. Wells can be dug at any convenient place.
3. It is an independent source of irrigation.
Disadvantages:
Wells dry up during summer and fail to provide water when needed the most.
A well can irrigate only 1 to 2 hectares of land. Sometimes well water is brackish.
Q.5: Tank irrigation is important in the Deccan Peninsula. Explain.
Ans: Tank irrigation is important in the Deccan Peninsula because:
The land is undulating and forms natural depression.
The underlying hard, impervious rocks prevent the percolation of water.
Tanks enable people to arrest the river water which otherwise flows away.
Q.6: What are the advantages of tank irrigation?
Ans: They are naturally formed so there is no need of construction and hence they are cheap.
In South India they are found in more number where there are very few perennial rivers.
It stores the rain water which otherwise will flow away and get wasted.
This water can be used for irrigation and for domestic purposes.
Q.7: What are the disadvantages of tank irrigation?
Ans: 1. Tanks occupy a large surface area, which could otherwise have been used for cultivation.
2. Many tanks dry up during dry season and fail to provide water when it is required most.
3. Silting of tanks is a problem and desiliting is often needed which incurs cost and time.
Q.8: With reference to tube well irrigation, answer the following.
(i) Where is it introduced?
(ii) State its advantages.
(iii) State its advantages.
Ans: Tube wells are introduced in the Indo-Gangetic plains where ground water is ample and available close to the surface.
Advantages:
Tube wells irrigate much larger area of about 400 hectares.
They are more reliable during summer or drought conditions where ordinary wells dry up.
They are also suited for small land holdings.
Tube wells are feasible in the following situations
There must be sufficient groundwater.
There must be regular supply of cheap electricity.
The land must be fertile & productive so that the cost of operation can be recovered from increased farm production.
Major states States: Tube wells are widely used in Uttar Pradesh, Bihar,Punjab, Haryana, Rajasthan, West Bengal, Andhra Pradesh & Gujarat
BOARD QUESTIONS Continue…
Q.1. (a) Name two states in which well irrigation is widely used. Mention one advantage of well irrigation in India.
A. U.P. and Bihar are the states, where well irrigation is widely used in India.
Advantage: It can be practiced in areas of low rainfall, as it is dependent on underground water. It is simple and cheap.
(b)Mention two disadvantages of tank irrigation.
They occupy large areas of land which could have been actually used for cultivation.
They are usually shallow and have large surface area so there is a great loss of water due to evaporation.
Tanks often have to be desalted (any two)
(c )Give three reasons to justify the need to conserve water.
A. The reasons for the conservation of water are :
⦁ Its increased demand.
⦁ Its short supply and uneven distribution.
⦁ Its large-scale pollution, therefore to improve the quality of groundwater
⦁ Reduce surface run-off.
⦁ Reduce soil erosion, (any three points).
(d)Mention any three water harvesting systems practiced in India. Rooftop harvesting Recharging of groundwater and Watershed management.
1 MARK QUESTIONS:-
Que.No.1. What is the percentage of the earth water exists as oceans and seas?
Ans:- 96.5% of the earth water exists as oceans and seas.
Que.No 2. What is the percentage of fresh water?
Ans:- 2.5%.
Que.No 3. What percentage of the global precipitation received by India?
Ans:- 4% of the global precipitation is received by India.
Que.No 4. What is the rank of India in terms of water avaibility?
Ans:- 133 rank
Que.No 5. Annual precipitation in India as a whole.
Ans:- 114 cm.
Que.No 6. Water stress occurs when ?
Ans:- When water avaibility is between 1000-1600 cubic metre per person per year.
Que.No 7. Why Punjab and Haryana suffer from water scarcity?
Ans:- Because of over utilisation of water for agriculture.
Que.No 8. What percentage of electricity produced by hydroelectric power?
Ans:-22% of electricity produced by hydroelectric power.
Que.No 9. Who proclaimed multipurpose river project consider as the Temple of modern India'?
Ans:-Pandit Jawaharlal Nehru proclaimed multipurpose river project.
Que.No 10. Who built the tank Hauz Khas,Delhi?
Ans:- Iltutmish.
3 MARKS QUESTIONS:-
Que.No 1. Mention disadvantages of Multipurpose River Valley Project?
Ans:- Disadvantages of MPRVP:-
(i)Environmental degradation.
(ii)Regulating and damming of rivers affect rivers' natural flow.
(iii)It also fragment rivers making it difficult for aquatic fauna to migrate.
Que.No 2. Why is the need for water increasing day by day?
Ans:- The need for water is increasing day by day because:-
(i)Rapid urbanisation.
(ii)Large demands of water for rapidly growing population.
(iii)Water resources are being over exploited.
Que.No 3. Why do we conserve water?
Ans:- We conserve water because:-
(i)Protect natural ecosystem.
(ii)Protect ourselves from natural hazards
(iii)Ensure food security.
Que.No 4. Explain any three reasons for water scarcity in India.
Ans:- (i) Intensive industrialisation and urbanisation after independence
(ii) The water is getting polluted by domestic and industrial wastage.
(iii) Population exploitation led to decrease of ground water level .
Que.No 5. Name three multipurpose river valley projects or dams in India.
Ans:- (i)Sardar Sarovar Dam. (ii)Rihand Dam and (iii)Tungabhadra Dam.
Que.No 6. Describe any three hydraulic structures of ancient India.
Ans:- Three examples of hydraulic structure of ancient India:-
(i)Water harvesting system was built in the 1st century BC near Allahabad.
(ii)During the time of Chandra Gupta Maurya dams ,lakes, and irrigation systems were costructed.
Que.No 7. Mention three major sources of irrigation in India.Which source of irrigation is more popular in Southern India? Why?
Ans:- Three major sources of irrigation in India are:- (i)Canals (ii)Tube Wells and (iii)Tanks.
Tank irrigation is most popular in Southern India,because these states mostly come under Deccan Plateau which is not suitable for irrigation by canals.
5 MARKS QUESTIONS:-
Que.No 1. Write the advantages and disadvantages of dams.
Ans:- Dams have the following Advantages:
(i)Flood control.
(ii)Irrigation System
(iii)Generation of hydroelectricity
(iv)Cultures of aquatics.
Disadvantages: -
(i) Create artificial flood.
(ii)Loss of natural habitat of acquatics.
(iii)Sedimentation of the reserviors.
(iv)Problem of rehabilitation of people near by river.
Que.No 2. Explain the traditional rain water harvasting practised in India.
Ans:- (i)Kuls or Guls in Western Himalayans
(ii)Khadins and Johads in Rajasthan.
(iii)Tank or tankas in the arid and semi-arid regions of Bikaner, Phalodi and Barmer.
(iv)Palar Pani -first spell of monsoon is harvested.
(v)Bamboo Drip Irrigation in Meghalaya and Arunachal Pradesh.
Que.No 3. What is water stress? Give examples of inter-state water disputes.
Ans;- Water stress refers to non-availability of water for the people as per demand.
Examples of inter-state dispute:-
(i)Krishna-Godavari water disputes between Karnataka and AndhraPradesh.
(ii)Kaveri water dispute between Karnataka and Tamilnadu.
(iii)Narmada river water dispute among Gujrat,Madhya Pradesh,Rajasthan and Maharashtra.
(iv)Ravi-Beas water disputes between Punjab and Haryana.
Que.No 4. What is a dam?Classify dams.
Ans:- Dam is a barrier across flowing water that obstructs, directs or retards the flow ,often creating a reservior ,lake or impoundment.
Classification of Dams:-
(i)On the basis of structure and material used :- Timber Dam, Embarkment Dam and Masonry Dam.
(ii)On the basis of height:- Major Dam , Medium Dam and Low dam.
(iii)Barrages are built for supply of water to agriculture fields or township near by.
Que.No 5. Explain the modern method of rainwater harvesting?Name the state which has made it compulsory.
Ans:- Rooftop water harvesting is the modern method adopted to harvest rainwater.The followings are the steps:-
(i) Rooftop rainwater is collected using a PVC pipes.
(ii) Filtered using sand and bricks.
(iii) Underground pipe takes water to sump for immediate usage.
(iv) Excess water from the sump is taken to the well.
(v) Water from the well recharges the underground.
(vi) Take water from the well (later).
Tamilnadu has made rooftop water harvesting compulsory in buildings.
