NCERT Solutions for Class 12 Geography Chapter 4: Water Resources

These Class 12 Geography Chapter 4 solutions cover Water Resources from the textbook India – People and Economy (Unit III), updated for the 2026–27 session. The chapter explains India’s surface and groundwater resources, the growing problem of water scarcity, sectoral demand and utilisation (especially for irrigation), the deterioration of water quality, and the methods of water conservation and management — rainwater harvesting, watershed development, recycling and reuse, and the National Water Policy. Below you get step-by-step answers to every NCERT exercise question, plus extra practice, MCQs, Assertion–Reason questions and FAQs.

Class: 12 Subject: Geography Book: India – People and Economy Chapter: 4 Unit: III Session: 2026–27
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Class 12 Geography Chapter 4 – Overview

Chapter 4, Water Resources, discusses water as a cyclic resource that is abundant on the globe yet scarce in usable form — about 71% of the earth’s surface is covered with water, but freshwater is only about 3% of the total, and only a tiny fraction is effectively available for human use. India has about 2.45% of the world’s surface area, 4% of its water resources and over 17% of its population. The chapter examines India’s surface water (rivers, lakes, ponds, tanks) and replenishable groundwater (about 432 cubic km), the heavy dependence of agriculture on irrigation (89% of surface water and 92% of groundwater utilisation), and the emerging problems of falling per-capita availability and water pollution. It closes with strategies for conservation and management — preventing pollution, recycling and reuse, watershed management (the Ralegan Siddhi case study), rainwater harvesting, and the National Water Policy 2012.

Key Concepts & Terms

Cyclic resource: water is renewed and circulated through the hydrological (water) cycle — evaporation, condensation and precipitation — so it can be reused, though its usable supply at any place and time is limited.

Water resources of India: total water from precipitation in a year is about 4,000 cubic km; surface water and replenishable groundwater together provide about 1,869 cubic km, of which only about 60% (1,122 cubic km) is usable.

Surface water resources: water in rivers, lakes, ponds and tanks. India has about 10,360 rivers and tributaries longer than 1.6 km; mean annual river flow is about 1,869 cubic km but only about 690 cubic km (32%) can be utilised due to topographical and hydrological constraints.

Groundwater resources: total replenishable groundwater is about 432 cubic km. Utilisation is very high in Punjab, Haryana, Rajasthan and Tamil Nadu, but low in Chhattisgarh, Odisha and Kerala.

Lagoons and backwaters: brackish water bodies formed along the indented coast (Kerala, Odisha, West Bengal) used for fishing and irrigating paddy, coconut, etc.

Water demand and utilisation: agriculture accounts for most use — 89% of surface water and 92% of groundwater; industry uses about 2% (surface) and 5% (ground); domestic use is about 9% of surface water.

Deterioration of water quality: presence of unwanted foreign substances (micro-organisms, chemicals, industrial and domestic wastes) that make water unfit for use; the Yamuna between Delhi and Etawah is the most polluted river.

Watershed management: efficient management and conservation of surface and groundwater — preventing runoff, and storage and recharge of groundwater (percolation tanks, recharge wells) along with judicious use of all natural and human resources within a watershed (e.g. Haryali, Neeru-Meeru, Arvary Pani Sansad, Ralegan Siddhi).

Rainwater harvesting: capturing and storing rainwater for use and to recharge groundwater — a low-cost, eco-friendly technique (e.g. Kund/Tanka in Rajasthan, compulsory rooftop harvesting in Tamil Nadu).

National Water Policy 2012: framework for conservation, development and improved management of water; treats water (after pre-emptive needs) as an economic good and stresses community participation and a national water framework law.

NCERT Exercise — Full Solutions

All questions below are reproduced verbatim from the NCERT textbook’s end-of-chapter Exercises. Answers are original, written in CBSE exam-ready style.

1. Choose the right answers of the following from the given options.

(i) Which one of the following types describes water as a resource? (a) Abiotic resource    (b) Non-renewable Resources    (c) Biotic Resource    (d) Non-cyclic Resource

ANSWER (a) Abiotic resource. Water is a non-living (abiotic) natural resource. It is also a cyclic and renewable resource, so the only correct description among the options is ‘abiotic resource’.

(ii) Which one of the following south Indian states has the highest groundwater utilisation (in per cent) of its total ground water potential? (a) Tamil Nadu    (b) Karnataka    (c) Andhra Pradesh    (d) Kerala

ANSWER (a) Tamil Nadu. Among the south Indian states, Tamil Nadu has the highest level of groundwater utilisation as a percentage of its total groundwater potential, along with Punjab, Haryana and Rajasthan in the north-west.

(iii) The highest proportion of the total water used in the country is in which one of the following sectors? (a) Irrigation    (b) Industries    (c) Domestic use    (d) None of the above

ANSWER (a) Irrigation. Agriculture (irrigation) accounts for the highest share of total water used — about 89% of surface water and 92% of groundwater utilisation — far above the industrial and domestic sectors.

2. Answer the following questions in about 30 words.

(i) It is said that the water resources in India have been depleting very fast. Discuss the factors responsible for depletion of water resources?

ANSWER Rapid population growth, over-irrigation in agriculture, over-withdrawal of groundwater, industrial and urban demand, and pollution of rivers and aquifers by agricultural, domestic and industrial effluents are depleting and degrading India’s usable water resources very fast.

(ii) What factors are responsible for the highest groundwater development in the states of Punjab, Haryana, and Tamil Nadu?

ANSWER Intensive agriculture under the Green Revolution — high-yielding, water-intensive crops like wheat and rice grown on a large net sown area — together with cheap power and tubewell technology, has led to very high groundwater development in Punjab, Haryana and Tamil Nadu.

(iii) Why the share of agricultural sector in total water used in the country is expected to decline?

ANSWER With economic development, the demand for water from the industrial and domestic sectors is rising fast. As their shares increase, the relative (proportional) share of the agricultural sector in the country’s total water use is expected to decline.

(iv) What can be possible impacts of consumption of contaminated/unclean water on the people?

ANSWER Consuming contaminated water spreads water-borne diseases such as diarrhoea, cholera, typhoid and jaundice, and causes poisoning from fluoride, arsenic and heavy metals — harming health, reducing productivity and increasing medical costs.

3. Answer the following questions in about 150 words.

(i) Discuss the availability of water resources in the country and factors that determine its spatial distribution?

ANSWER India receives about 4,000 cubic km of water from precipitation each year. The surface water and replenishable groundwater together amount to about 1,869 cubic km, of which only about 60% (1,122 cubic km) can be put to beneficial use. Surface water is held in roughly 10,360 rivers and tributaries longer than 1.6 km, but only about 690 cubic km (32%) of river flow is utilisable; total replenishable groundwater is about 432 cubic km. Factors determining spatial distribution: the chief factor is rainfall, which is highly uneven in space and time and concentrated in the monsoon season. The size of the catchment area or river basin matters — large basins such as the Ganga, Brahmaputra and Barak, with high rainfall, hold about 60% of the surface water though they cover only one-third of the area. Topography and hydrology limit how much water can be stored and used, while groundwater depends on the nature of the rocks (permeability) and recharge. Hence availability varies widely — abundant in the north-east and along big rivers, scarce in the north-west and the Deccan.

(ii) The depleting water resources may lead to social conflicts and disputes. Elaborate it with suitable examples?

ANSWER Freshwater is a scarce and unevenly distributed resource, so as demand outstrips supply, sharing and controlling water increasingly causes tensions and disputes among communities, regions and states. When several states share the water of a single river basin, disagreements arise over how much each may draw. Examples: long-running inter-state river water disputes such as the Kaveri dispute (Karnataka and Tamil Nadu, also involving Kerala and Puducherry), and disputes over the Krishna, the Godavari, the Ravi-Beas (Punjab and Haryana) and the Narmada show how scarce river water becomes a contested issue. Within states too, over-withdrawal of groundwater in Punjab, Haryana and Rajasthan and falling water tables create competition between farmers and between rural and urban users. Pollution of rivers like the Yamuna further reduces usable water and adds to conflict. Such disputes can disrupt social harmony and development, so fair sharing, conservation and efficient use are essential.

(iii) What is watershed management? Do you think it can play an important role in sustainable development?

ANSWER Watershed management refers to the efficient management and conservation of surface and groundwater resources. It involves preventing runoff and the storage and recharge of groundwater through methods such as percolation tanks and recharge wells. In a broader sense, it includes the conservation, regeneration and judicious use of all resources — natural (land, water, plants, animals) and human — within a watershed, aiming at a balance between natural resources and society. Role in sustainable development: yes, it can play a very important role. By recharging groundwater, checking soil erosion and run-off, and ensuring water availability on a sustainable basis, watershed management supports agriculture, drinking water, fisheries and afforestation. Programmes like Haryali, Neeru-Meeru (Andhra Pradesh) and Arvary Pani Sansad (Alwar, Rajasthan), and the success of Ralegan Siddhi in Maharashtra, show that with active community participation, watershed development can rejuvenate the environment and economy and secure water for future generations.

Extra Practice Questions

Short Answer Type Questions

Q1. Why is freshwater considered a scarce resource despite water covering most of the earth?

ANSWERAbout 71% of the earth’s surface is covered with water, but freshwater is only about 3% of the total, and only a very small proportion of this is effectively available for human use. Its availability also varies greatly over space and time, making freshwater scarce.

Q2. What share of the world’s water resources and population does India have?

ANSWERIndia has about 2.45% of the world’s surface area and about 4% of the world’s water resources, but supports more than 17% of the world’s population. This imbalance puts heavy pressure on its limited water resources.

Q3. Name any two methods of rainwater harvesting practised in India.

ANSWERIn Rajasthan, rainwater is stored in covered underground tanks called Kund or Tanka built near houses or villages. Rooftop rainwater harvesting is another method — in Tamil Nadu, water-harvesting structures in houses have been made compulsory for every new building.

Q4. Which is the most polluted river in the country, and between which places?

ANSWERThe Yamuna is the most polluted river in the country, especially in the stretch between Delhi and Etawah. Other severely polluted rivers include the Sabarmati at Ahmedabad, the Gomti at Lucknow and the Ganga at Kanpur and Varanasi.

Q5. How does recycling and reuse help increase freshwater availability?

ANSWERUsing lower-quality or reclaimed wastewater for purposes that do not need fresh water — industrial cooling and fire-fighting, gardening, and washing vehicles — conserves better-quality water for drinking. This recycling and reuse helps bridge the demand-supply gap and replenish freshwater.

Long Answer Type Questions

Q1. Discuss the pattern of water demand and utilisation among different sectors in India.

ANSWERIndia has traditionally been an agrarian economy, and about two-thirds of its population depends on agriculture. Hence the development of irrigation has been given high priority through Five Year Plans and multipurpose projects like Bhakra-Nangal, Hirakud, Damodar Valley, Nagarjuna Sagar and the Indira Gandhi Canal. As a result, India’s water demand is dominated by irrigational needs. Agriculture accounts for most of the surface and groundwater utilisation — about 89% of surface water and 92% of groundwater. The industrial sector uses only about 2% of surface water and 5% of groundwater, while the domestic sector’s share is higher in surface water (about 9%) than in groundwater. Thus the agricultural sector’s share in total water use is far higher than other sectors. However, with future economic development, the shares of the industrial and domestic sectors are likely to increase, and the relative share of agriculture is expected to decline.

Q2. Explain the measures suggested for the conservation and management of water resources in India.

ANSWERBecause freshwater availability is declining while demand rises, water must be conserved and effectively managed for sustainable development. The chapter suggests several measures. (i) Prevention of water pollution — treating agricultural, domestic and industrial effluents before they join rivers, effective implementation of the Water Act 1974, Environment Protection Act 1986 and Water Cess Act 1977, monitoring by the CPCB, and generating public awareness. (ii) Recycle and reuse of water — using reclaimed or lesser-quality water for industry, gardening and washing to save fresh water for drinking. (iii) Watershed management — preventing run-off, and storing and recharging groundwater through percolation tanks and recharge wells with community participation (Haryali, Neeru-Meeru, Arvary Pani Sansad, Ralegan Siddhi). (iv) Rainwater harvesting — capturing and storing rainwater to recharge aquifers and bridge the demand-supply gap. Watershed development, water-saving technologies, desalination, inter-linking of rivers, and rational pricing of water are also recommended.

Q3. Describe the watershed development achieved at Ralegan Siddhi as a case study.

ANSWERRalegan Siddhi is a small village in Ahmadnagar district, Maharashtra, that has become a national example of watershed development. In 1975 the village was trapped in poverty and the illicit liquor trade. The transformation began when a retired army person settled there and took up watershed development, convincing villagers about family planning, voluntary labour, a ban on open grazing and tree-felling, and liquor prohibition. Work started with a percolation tank repaired through voluntary labour; soon the seven wells below it filled with water in summer for the first time in living memory. A youth group, Tarun Mandal, helped ban the dowry system, caste discrimination and untouchability, and water-intensive crops like sugarcane were replaced with low-water crops such as pulses and oilseeds. Decisions were taken by consensus, informal Nyay Panchayats settled disputes, and a school was built using only village resources. Today water is adequate and agriculture flourishes — showing how community participation can rejuvenate the environment and economy. It illustrates the success of a mitigation approach to water conservation.

MCQs & Assertion–Reason

1. Approximately what percentage of the earth’s surface is covered with water?

(a) 51%    (b) 61%    (c) 71%    (d) 81%

2. The total utilisable water resource in the country is about:

(a) 4,000 cubic km    (b) 1,869 cubic km    (c) 1,122 cubic km    (d) 432 cubic km

3. The total replenishable groundwater resources in India are about:

(a) 432 cubic km    (b) 690 cubic km    (c) 1,122 cubic km    (d) 4,000 cubic km

4. Agriculture accounts for about what share of groundwater utilisation?

(a) 60%    (b) 75%    (c) 89%    (d) 92%

5. The Ganga, Brahmaputra and Barak rivers, though covering about one-third of the area, account for about what share of total surface water resources?

(a) 30%    (b) 45%    (c) 60%    (d) 75%

6. The most polluted river in the country, between Delhi and Etawah, is the:

(a) Ganga    (b) Yamuna    (c) Sabarmati    (d) Gomti

7. In Rajasthan, the covered underground tank used to store harvested rainwater is locally known as:

(a) Johad    (b) Kund or Tanka    (c) Bawri    (d) Ahar

8. Ralegan Siddhi, famous for watershed development, is located in which state?

(a) Gujarat    (b) Rajasthan    (c) Maharashtra    (d) Andhra Pradesh

9. The National Water Policy referred to in the chapter was framed in the year:

(a) 1974    (b) 1986    (c) 2002    (d) 2012

10. Which body, with the State Pollution Control Boards, monitors water quality in the country?

(a) NITI Aayog    (b) Central Pollution Control Board (CPCB)    (c) Central Water Commission    (d) Ministry of Agriculture

Answer key: 1-(c), 2-(c), 3-(a), 4-(d), 5-(c), 6-(b), 7-(b), 8-(c), 9-(d), 10-(b).

For each Assertion–Reason question, choose: (A) Both true and the Reason correctly explains the Assertion; (B) Both true but the Reason is not the correct explanation; (C) Assertion true, Reason false; (D) Assertion false, Reason true.

A-R 1. Assertion: Water is described as a cyclic resource.

Reason: Water is renewed and circulated through the hydrological cycle of evaporation, condensation and precipitation.

A-R 2. Assertion: Despite huge total water resources, India faces water scarcity.

Reason: Freshwater is only a small fraction of total water and its availability varies greatly over space and time.

A-R 3. Assertion: Groundwater tables are falling in Punjab and Haryana.

Reason: These states use a large proportion of their groundwater potential through wells and tubewells for intensive irrigation.

A-R 4. Assertion: The industrial sector uses the largest share of India’s water.

Reason: Agriculture accounts for about 89% of surface water and 92% of groundwater utilisation.

A-R 5. Assertion: Watershed management can support sustainable development.

Reason: It recharges groundwater, checks run-off and ensures water availability on a sustainable basis, especially with community participation.

Answer key: 1-(A), 2-(A), 3-(A), 4-(D), 5-(A).

Exam Tips & Common Mistakes

How to score full marks in this chapter

Memorise the key figures — 4,000 cubic km precipitation, 1,869 cubic km surface + replenishable groundwater, 1,122 cubic km utilisable, 432 cubic km groundwater, and the sectoral shares (89%/92% agriculture). For 150-word answers, structure them in clear parts (availability + factors; problem + examples; definition + role). Always support points with the textbook’s examples — Kaveri/Krishna disputes, the Yamuna as the most polluted river, Ralegan Siddhi, Kund/Tanka, Haryali and the National Water Policy 2012 — to show thorough study.

Common mistakes to avoid

  • Confusing total water resource (1,869 cubic km) with utilisable water (1,122 cubic km).
  • Writing that industry or domestic use is the largest sector — it is agriculture/irrigation.
  • Calling water a non-renewable or biotic resource — it is an abiotic, cyclic, renewable resource.
  • Mixing up surface water (32% utilisable) with groundwater (432 cubic km replenishable).
  • Forgetting to name examples in dispute and conservation answers (Kaveri, Yamuna, Ralegan Siddhi).
  • Answering map/figure questions with diagrams alone — explain the point in words too.

Frequently Asked Questions

What is Chapter 4 of Class 12 Geography (India – People and Economy) about?

Chapter 4, Water Resources, discusses India’s surface and groundwater resources, water scarcity, sectoral demand and utilisation (especially irrigation), deterioration of water quality, and methods of water conservation and management such as rainwater harvesting, watershed development and the National Water Policy 2012.

Which sector uses the most water in India?

The agricultural (irrigation) sector uses the most water in India — about 89% of surface water and 92% of groundwater utilisation — far more than the industrial and domestic sectors.

How many NCERT exercise questions are there in Class 12 Geography Chapter 4?

The end-of-chapter Exercises contain three numbered questions: one set of multiple-choice questions (3 items), four short-answer questions (about 30 words each) and three long-answer questions (about 150 words each) — all answered step by step on this page.

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