NCERT
Every NCERT book that matters for UPSC — open a book, then a chapter. Learn each chapter's concepts, then how UPSC tests them — with diagrams, flowcharts and the past questions to attempt.
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← India: People and Economy — all chaptersWater Resources
Start here: why this chapter matters
In simple wordsA family has one water tank refilled only in the rainy months. Every year the family grows, the garden wants more, the neighbour's drain leaks into the tank, and someone has been secretly pumping from below. This chapter is about that tank — how big it is, who drinks from it, how it is being spoiled, and how to make it last.
NCERT predicts that the future will bring demographic change, population shifts, new technology, environmental degradation — and water scarcity, possibly the greatest challenge, as demand rises and supplies shrink through over-use and pollution. About 71 per cent of the earth's surface is water, but freshwater is only about 3 per cent, and very little of it is usable. Disputes over sharing water are growing between communities, regions and States.
- Builds on India: Physical Environment Chapter 3 (Drainage System) — the river basins — and Chapter 4 (Climate) — the uneven monsoon that makes irrigation necessary.
- Builds on Physical Geography Chapter 12 (Water — Oceans) for the hydrological cycle and the tiny share of freshwater.
- Builds on Chapter 3 (Agriculture): irrigation, the Green Revolution and salinisation; this chapter adds the groundwater side.
- Leads into Chapter 5 (Minerals and Energy — hydropower) and Chapter 6 (Planning and Sustainable Development).
- UPSC: GS1 (distribution of water resources, water stress), GS2 (inter-State water disputes), GS3 (irrigation, micro-irrigation, water-use efficiency, pollution, conservation). Groundwater and micro-irrigation have been asked repeatedly since 2011.
| Word | What it means here |
|---|---|
| Replenishable groundwater | Underground water recharged every year by rain and seepage |
| Aquifer | A layer of rock or sediment that holds and yields groundwater |
| Utilisable water | The part of available water that can actually be used, given terrain and hydrology |
| Catchment / river basin | The area drained by a river and its tributaries |
| Water quality | Purity of water — freedom from unwanted foreign substances |
| Watershed management | Conserving and using all resources of a drainage area — land, water, plants, animals, people — together |
| Rainwater harvesting | Capturing and storing rain for use or to recharge aquifers |
| Conjunctive use | Planned joint use of surface water and groundwater |
| Micro-irrigation | Drip and sprinkler irrigation delivering water close to the plant (Beyond NCERT) |
| Desalinisation | Removing salt from sea or brackish water — costly |
Reading the chapter-opening photograph (page 40)An aerial view of a river winding through dense forested hills, with pale sandbars on its bends. It shows water at its source: in the upper, forested, thinly peopled stretches rivers are still clean — the contrast the chapter draws later with polluted plains.
At a glance — the six ideas to carry away
- India: 2.45% of world area, 4% of water, 17%+ of people.
- 4,000 km³ precipitation → 1,869 km³ river flow → utilisable 1,122 km³ = 690 surface + 432 groundwater.
- Ganga–Brahmaputra–Barak: ⅓ of area, 60% of surface water; ~10,360 rivers longer than 1.6 km.
- Agriculture uses 89% of surface and 92% of groundwater; groundwater use highest in Punjab, Haryana, Rajasthan, Tamil Nadu.
- Over-pumping → falling water tables, fluoride (Rajasthan, Maharashtra), arsenic (West Bengal, Bihar); Yamuna most polluted (Delhi–Etawah).
- Answers: watershed management, rainwater harvesting (kund/tanka), recycling, PMKSY (2015–16), Atal Jal, NWP 2012, Jal Kranti Abhiyan.
1. How much water does India have?
In simple wordsRain is like a salary. India ‘earns’ about 4,000 units a year, but most of it evaporates or rushes to the sea before it can be caught — like money spent before it reaches the bank. What can actually be ‘saved and spent’ is a little over a quarter of it.
Total precipitation is about 4,000 cubic km a year. Surface water flow is 1,869 cubic km. Only about 60 per cent of the available water can be put to beneficial use, so the total utilisable water resource is 1,122 cubic km — 690 of surface water and 432 of replenishable groundwater.
Two slips in NCERT's numbers
- Page 41 calls 1,869 km³ ‘the availability from surface water and replenishable groundwater’; page 42 gives 1,869 km³ as the mean annual flow of all river basins, i.e. surface water only. The second is right: 1,122 = 690 (surface) + 432 (groundwater) (Beyond NCERT: Central Water Commission estimates).
- 690 km³ is called ‘32 per cent’ of the surface water; 690 ÷ 1,869 = about 37 per cent.
- For exams: 4,000 / 1,869 / 690 / 432 / 1,122.
2. Surface water: rivers, basins, lagoons
In simple wordsA river carries what its catchment collects. A huge catchment under heavy rain — like the Brahmaputra's — is a giant funnel; a small catchment in a dry region is a teacup. That is why a few northern and north-eastern rivers hold most of India's surface water.
There are four main sources of surface water: rivers, lakes, ponds and tanks. India has about 10,360 rivers and tributaries longer than 1.6 km. The flow in a river depends on the size of its catchment and the rainfall in it. The Ganga, Brahmaputra and Barak basins cover about one-third of the country but carry 60 per cent of surface water. Much of the flow of southern rivers — Godavari, Krishna, Kaveri — has been harnessed; the Ganga and Brahmaputra basins are still to be.
Reading NCERT Figure 4.1 — India: River Basins (page 43)
- Two shades: west-flowing and east-flowing basins.
- West-flowing: the Indus basin in the far north-west; ‘Group 1’ — rivers of Kachchh, Saurashtra and the Luni; the Sabarmati, Mahi, Narmada and Tapi basins; ‘Group 2’ — the short rivers south of the Tapi along the western coast.
- East-flowing: the vast Ganga basin covering most of the north; Brahmaputra and Barak in the north-east; Subarnarekha, Brahmani–Baitarani, Mahanadi, Godavari, Krishna, Pennar, Kaveri; and two groups of small coastal rivers — between the Mahanadi and Pennar, and between the Pennar and Kanniyakumari.
- What the map adds: east-flowing basins cover most of India; the Ganga basin alone is far larger than any other. Basins and drainage patterns are explained in India: Physical Environment Chapter 3.
Lagoons and backwaters. India's long, indented coast has many lagoons and lakes, especially in Kerala, Odisha and West Bengal. Their water is generally brackish, but it is used for fishing and for irrigating certain varieties of paddy and coconut.
Beyond NCERT
- Examples: Chilika (Odisha, India's largest brackish-water lagoon), Vembanad and Ashtamudi (Kerala), Pulicat (on the Andhra Pradesh–Tamil Nadu border).
- The Indira Gandhi Canal, which NCERT lists among big projects, carries Sutlej water (from the Harike barrage, where the Beas joins it) into the Thar (UPSC 1991).
3. Groundwater
In simple wordsGroundwater is a savings account filled a little each monsoon. Punjab and Haryana have been withdrawing faster than they deposit, so the balance — the water table — keeps falling. Kerala and Odisha have barely touched theirs.
Total replenishable groundwater is about 432 cubic km. Use is relatively high in the river basins of the north-west and parts of the south.
Exam traps
- Highest groundwater use among southern States = Tamil Nadu (exercise Q1-ii), not Kerala.
- NCERT's sentence ‘the demands for water would need the supplies’ is a misprint for exceed.
- India has the largest area under groundwater irrigation in the world, and the Central Ground Water Authority was set up under the Environment (Protection) Act, 1986 (UPSC 2020, 2022). The Central Ground Water Board is a different body.
- UN World Water Development Report 2022: India extracts more than a quarter of the world's groundwater withdrawals (UPSC 2023).
Beyond NCERT — groundwater assessmentsThe Central Ground Water Board's recent national assessments put India's overall stage of extraction at around 60 per cent of annual extractable resources, but with many blocks classed as over-exploited, critical or semi-critical, concentrated in Punjab, Haryana, Rajasthan, Delhi and parts of Tamil Nadu and Karnataka — the same States NCERT names. Atal Bhujal Yojana (below) targets exactly these water-stressed blocks.
4. Water demand and irrigation
In simple wordsIn an Indian village, the biggest water user is not the kitchen or the factory — it is the field. Nine of every ten litres drawn go to crops. So saving water in India mostly means saving it on the farm.
With about two-thirds of people once dependent on agriculture, the Five Year Plans gave irrigation top priority through multipurpose projects — Bhakra–Nangal, Hirakud, Damodar Valley, Nagarjuna Sagar, Indira Gandhi Canal. India's demand is dominated by irrigation.
Why irrigation is needed: (i) spatio-temporal variability of rainfall — the north-west and the Deccan are deficient and drought-prone, winter and summer are dry almost everywhere, and even wet West Bengal and Bihar suffer from breaks or failure of the monsoon; (ii) water-hungry crops — rice, sugarcane, jute; (iii) irrigation enables multiple cropping and higher productivity; (iv) HYVs need regular moisture — why the Green Revolution succeeded in Punjab, Haryana and western UP.
In Punjab, Haryana and western UP more than 85 per cent of net sown area is irrigated; of net irrigated area, 76.1 per cent in Punjab and 51.3 per cent in Haryana is watered by wells and tubewells. The result is groundwater depletion, and over-withdrawal has raised fluoride in Rajasthan and Maharashtra and arsenic in parts of West Bengal and Bihar.
⤵ From irrigation need to groundwater crisis
Uneven, unreliable raindry seasons, drought-prone NW and Deccan, monsoon breaks
HYVs + water-hungry cropsrice, wheat, sugarcane need assured moisture
Tubewells everywhere76.1% of Punjab's and 51.3% of Haryana's irrigated area
Falling water tabledeeper pumps, more power, dry wells
Poorer waterfluoride (Rajasthan, Maharashtra) · arsenic (WB, Bihar) · soil salinity
Reading NCERT's box ‘Pradhan Mantri Krishi Sinchayee Yojana (PMKSY)’ (page 44)
- Launched 2015–16; vision: some means of protective irrigation for all farms.
- Objectives: expand assured irrigation (‘Har Khet ko Pani’); integrate source, distribution and efficient use; improve on-farm efficiency with water-saving technology (‘Per Drop More Crop’); sustainable conservation practices; integrated development of rainfed areas by the watershed approach — soil and water conservation, groundwater regeneration, livelihoods.
- The box's ‘waters held’ is a misprint for watershed.
Beyond NCERT — micro-irrigation (asked often)
- Drip irrigation delivers water drop by drop at the root zone; sprinklers spray it like rain. Both are promoted under PMKSY's ‘Per Drop More Crop’.
- Advantages: higher water-use efficiency, less weed growth and soil erosion (UPSC 2016), reduced fertiliser loss and slower fall of the water table (UPSC 2011); it is not the only means of irrigation in drylands.
- Fertigation — fertiliser dissolved in drip water — allows control of water alkalinity, raises nutrient availability and cuts leaching (UPSC 2020).
- Older programmes: Command Area Development (1974–75, to raise water-use efficiency in canal commands) and the Accelerated Irrigation Benefits Programme (1996–97, central loans/grants to States to finish projects — not loans to farmers) (UPSC 2015).
Exam traps
- The largest share of water used is for irrigation (exercise Q1-iii).
- Industry's share is larger in groundwater (5%) than surface water (2%); domestic is larger in surface water (9%).
- Agriculture's share is expected to decline as industry and towns grow (exercise Q2-iii).
5. Emerging problems: scarcity and pollution
In simple wordsA city's water supply is a long pipe from the hills. Every town along the way adds sewage, every field adds fertiliser, every factory adds chemicals. By summer, when the river is thin, the pipe delivers more poison than water.
Per capita availability is falling as population grows, and pollution from industrial, agricultural and domestic effluents further cuts usable water. Water quality is purity — water without unwanted foreign substances such as micro-organisms, chemicals and industrial wastes. Pollutants dissolve or stay suspended, harm aquatic life and can seep into groundwater.
Rivers keep better quality in their less populated upper stretches in the hills. In the plains, drains carrying agricultural (fertilisers, insecticides), domestic (solid and liquid waste) and industrial effluents join them; concentrations peak in summer when flow is low. The Central Pollution Control Board, with State boards, monitored water at 507 stations: organic and bacterial contamination is the main source of river pollution.
Reading NCERT Figure 4.2 — The Ganga and its Tributaries and Towns Located on them (page 45)
- Shows the Ganga and Yamuna with their tributaries across the northern plains, with Delhi, Prayagraj and a large dot for Varanasi, plus other big cities as dots along the rivers down to Bengal.
- Labels: ‘Good quality water here’ on the upper Ganga in the hills; ‘Poor quality water here’ on the Yamuna near Delhi and on the Ganga below Varanasi.
- The legend's heading ‘Area of irrigated land’ does not match what is drawn — it actually marks cities.
- What the map adds: the string of cities along the rivers is the reason quality falls downstream. The activity asks for these towns and their industries (answer below).
| Severely polluted stretches (NCERT) | Notes |
|---|---|
| Yamuna between Delhi and Etawah | The most polluted river stretch in the country |
| Sabarmati at Ahmedabad · Gomti at Lucknow · Kali · Adyar and Cooum (entire stretches) | Urban and industrial rivers |
| Vaigai at Madurai · Musi at Hyderabad · Ganga at Kanpur and Varanasi | Kanpur's tanneries are a classic example (Beyond NCERT) |
| Groundwater | Heavy/toxic metals, fluoride, nitrates in different parts of the country |
Laws — the Water (Prevention and Control of Pollution) Act, 1974, the Environment Protection Act, 1986 and the Water Cess Act, 1977 — have been weakly enforced; in 1997, 251 polluting industries stood along rivers and lakes. NCERT calls for public awareness and action to cut agricultural, domestic and industrial discharges.
⤵ How a river gets polluted, and where to intervene
Domesticsewage, solid waste
Agriculturalfertilisers, insecticides
Industrialeffluents, heavy metals
Drains into the riverworst in plains below cities; peaks in low-flow summer
Effectsunfit for use, aquatic life harmed, seepage into groundwater, disease
Remediestreat at source · enforce the 1974 and 1986 Acts · recycle wastewater · public awareness
Reading the news clippings (page 46)
- ‘Rivers of conflict… but also of peace’: water has caused more than 500 conflicts in a century, but there are over 3,800 declarations or conventions on water, including 286 treaties — water can be an agent of cooperation.
- ‘Rich countries poor in supply of water: WWF’: water stress is not only a poor-country problem.
- ‘Climate change? Barmer grapples with floods’: floods and malaria in desert Barmer; the Indira Gandhi Canal greens the desert but also brings waterlogging and salinity in parts.
- The question ‘Discuss the issues highlighted’ is answered below.
Beyond NCERT
- Per capita availability figures are Ministry of Jal Shakti estimates; below 1,700 m³ a person a year counts as water-stressed and below 1,000 m³ as water-scarce (Falkenmark indicator).
- Drinking-water pollutants found in parts of India include arsenic, fluoride and uranium (UPSC 2013).
- The Ganga Action Plan (1985) was later folded into the National River Conservation Plan (UPSC 2001); today's flagship is Namami Gange (2014), run by the National Mission for Clean Ganga (Mains 2015).
6. Conservation: recycling and watershed management
In simple wordsUse the bath water for the garden, the vehicle-wash water for the lawn — and in the village, stop the rain from running off the hill: let it soak in behind small dams so the wells below fill up. That is recycling and watershed management.
Since freshwater is declining and desalinisation is costly, India must adopt water-saving technology, prevent pollution, and encourage watershed development, rainwater harvesting, recycling and reuse, and conjunctive use of surface and groundwater.
Recycle and reuse. Lower-quality water such as reclaimed wastewater suits industrial cooling and fire-fighting; in towns, water from bathing and washing utensils or vehicles can water gardens, saving good water for drinking. Recycling is still limited, but its scope is enormous.
Watershed management is the efficient management and conservation of surface and groundwater — preventing runoff, storing water and recharging groundwater through percolation tanks, recharge wells and similar methods. In a broad sense it conserves, regenerates and judiciously uses all resources of a watershed — land, water, plants, animals and people — to balance nature and society. Its success depends on community participation.
| Programme (NCERT) | Where | What it does |
|---|---|---|
| Haryali | Central scheme | Watershed development by Gram Panchayats with people's participation — water for drinking, irrigation, fisheries, afforestation |
| Neeru-Meeru (Water and You) | Andhra Pradesh | Water-harvesting structures — percolation tanks, dug-out ponds, check dams — with people's participation |
| Arvary Pani Sansad | Alwar, Rajasthan | A ‘water parliament’ of villages on the Arvari river; johads, check dams |
| Rainwater harvesting by law | Tamil Nadu | No building may be constructed without water-harvesting structures |
| Atal Bhujal Yojana (Atal Jal) | 8,220 water-stressed Gram Panchayats, 229 blocks, 80 districts in 7 States — Gujarat, Haryana, Karnataka, MP, Maharashtra, Rajasthan, UP | These States hold about 37% of India's water-stressed blocks; aim: change behaviour from consumption to conservation and smart water management |
Reading NCERT's case study ‘Watershed Development in Ralegan Siddhi, Ahmadnagar, Maharashtra’ (page 48)
- In 1975 the village was trapped in poverty and illicit liquor. A retired army man settled there and began watershed work — family planning, voluntary labour, no open grazing or tree-felling, liquor prohibition.
- Work began with repairing a leaking percolation tank; the seven wells below filled in summer for the first time in memory.
- A youth group, Tarun Mandal, fought dowry, caste discrimination and untouchability; stall-feeding replaced grazing; sugarcane was banned in favour of pulses, oilseeds and low-water cash crops; local elections by consensus; Nyay Panchayats settled disputes; a ₹22 lakh school was built with village resources only.
- Today water is adequate and farming flourishes, though fertiliser and pesticide use is high, and the question is whether the next generation can sustain it.
- The two photographs: before — a bare, eroded, treeless hillside; after — green terraced fields with trees.
- Beyond NCERT: the leader is the social activist Anna Hazare.
⤵ How Ralegan Siddhi turned around (NCERT's case study)
1975: drought, poverty, liquorleaking tank, dry wells
Community rulesvoluntary labour · no open grazing · no tree-felling · prohibition
Water firstpercolation tank repaired → wells fill in summer
Crop and social changesugarcane banned; pulses, oilseeds · Tarun Mandal · Nyay Panchayats
Resultadequate water, flourishing farms, self-reliance — a national model
Beyond NCERT
- Tarun Bharat Sangh (Rajendra Singh) near Alwar revived the Arvari river through johads — UPSC 2004 asked what it is famous for: rainwater harvesting.
- The hallmark of watershed development in semi-arid India is earthworks, soil conservation and tree planting (UPSC 1994); integrated watershed programmes prevent runoff, harvest rain, recharge groundwater and regenerate vegetation — they do not link rivers (UPSC 2014).
- Mains: micro-watersheds in drought-prone areas (2016); the national watershed project (2019).
7. Rainwater harvesting and national policy
In simple wordsEvery roof is a small catchment. Put a gutter, a filter and a tank under it, and send the overflow into a well — and a house that buys tanker water in May can have its own supply, while the water table below the street rises.
Rainwater harvesting captures and stores rain for use, or guides it into borewells, pits and wells to recharge aquifers. It is low-cost and eco-friendly. NCERT lists its benefits: more water available, a rising water table, better groundwater quality by diluting fluoride and nitrates, less soil erosion and flooding, prevention of salt-water intrusion in coastal aquifers, and energy saved on pumping.
Traditional rural harvesting uses lakes, ponds and irrigation tanks; in Rajasthan, kund or tanka — covered underground tanks — store rainwater near houses. Rooftops and open spaces offer wide scope, especially in cities, where demand already outstrips supply. Other remedies NCERT names: desalinisation (coastal) and of brackish water (arid areas), and inter-linking of rivers to move water from surplus to deficit areas. But for households and communities, the key issue is pricing of water.
Reading NCERT Figure 4.3 — Various Methods of Rainwater Harvesting (page 49)
- Four sketches: Harvesting through watershed management — terraced hill slopes with stone walls and a check dam across a stream; Harvesting through lakes (Eris) — a village around a tank fed by streams from the hills; Harvesting through service wells — a flat-roofed house whose roof-top collection passes through a brick filter into a service well; Harvesting through recharge wells — a sloping roof draining through a sand filter into a collection tank and a recharge well.
- What it adds: ‘eris’ are the traditional irrigation tanks of Tamil Nadu (Beyond NCERT); the four sketches go from landscape scale (watershed, lake) to household scale (two kinds of rooftop systems).
Reading NCERT's box ‘Highlights of India's National Water Policy 2012’ (page 50)
- A national water framework law and comprehensive legislation for inter-State rivers.
- After meeting pre-emptive needs — safe drinking water and sanitation, food security, livelihoods of poor farmers, and a high-priority minimum ecosystem allocation — water should be treated as an economic good to promote conservation.
- Climate-change adaptation in designing water structures; benchmarks for use — water footprints and water auditing; removing the disparity between urban and rural supply norms; community participation in projects.
- Beyond NCERT: earlier policies were 1987 and 2002; the National Water Resources Council that adopts them is chaired by the Prime Minister (UPSC 2009).
Reading NCERT's box ‘Jal Kranti Abhiyan (2015–16)’ (page 51)
- Aim: water security through per capita availability, reviving traditional knowledge, involving local bodies, NGOs and citizens.
- Activities: one water-stressed village in each of 672 districts as a ‘Jal Gram’; model command areas of about 1,000 ha in different regions; pollution abatement — conservation and artificial recharge, less groundwater pollution, arsenic-free wells; mass awareness.
- Its slogan idea: livelihood and food security through water security.
⤵ A household-to-national ladder of water solutions
Householdreuse grey water · rooftop harvesting · fix leaks
Villagewatershed works · johads, tanks, kunds · crop choice (Ralegan Siddhi)
Farm sectorPMKSY: Har Khet ko Pani, Per Drop More Crop · drip and sprinkler
State and nationpollution law enforcement · Atal Jal · NWP 2012 · Jal Kranti · pricing water
Beyond NCERT — newer initiatives
- Ministry of Jal Shakti (2019) merged the water ministries; Jal Shakti Abhiyan (2019) ran a campaign in water-stressed districts, later extended as ‘Catch the Rain’ (2021) (Mains 2020).
- Jal Jeevan Mission (2019) aims at a functional tap connection for every rural household.
- Kavaratti (Lakshadweep) has India's first low-temperature thermal desalination plant (UPSC 2008).
- Virtual water = the water used to produce a commodity; exporting rice or sugar exports water (UPSC 2005).
Exam traps
- Water is an abiotic, renewable, cyclic resource — in exercise Q1(i) only ‘abiotic’ is offered as correct.
- NCERT calls desalinisation negligible as a source because it is costly — not impossible.
- Kund/tanka = Rajasthan; johad = Rajasthan/Haryana; eri = Tamil Nadu (Beyond NCERT for the last two).
NCERT's in-text questions and activities — short answers
Intensive irrigation in Punjab, Haryana and western UP is increasing salinity and depleting groundwater. Discuss its likely impacts on agriculture. (page 44)
Falling water tables raise pumping costs and leave small farmers without water; salinity and waterlogging cut yields and can make land barren; rice–wheat output may stagnate or fall; the region that feeds the public distribution system becomes unsustainable. Needed: crop diversification away from paddy, micro-irrigation, recharge, power and price reforms.
Find the major towns/cities on the Ganga and its tributaries and their major industries. (page 45)
Examples: Haridwar (pilgrimage, BHEL), Kanpur (leather, textiles), Prayagraj, Varanasi (silk, handicrafts), Patna, Bhagalpur (silk), Kolkata–Howrah on the Hugli (jute, engineering); on the Yamuna Delhi and Agra (leather, tourism); on the Gomti Lucknow; on the Chambal Kota. Each adds sewage and effluents.
Discuss the issues highlighted in the news items. (page 46)
(i) Water causes conflicts but also cooperation — hundreds of treaties; (ii) even rich countries face water stress; (iii) in Barmer, canal irrigation and climate change bring floods, malaria, waterlogging and salinity to a desert — every water intervention has side-effects.
Observe how water is used at home and list ways to reuse and recycle it. (page 47)
Reuse RO reject and vegetable-washing water for plants and mopping; bath and washing water for flushing or the garden; vehicle-wash water for lawns; collect AC condensate; fix leaks; harvest rooftop rain.
NCERT exercise — answer outlines
Try each question yourself first, then open the outline to compare. The three multiple-choice questions are in the self-check below.
Discuss the factors responsible for depletion of water resources. (30 words)
Rising population and per capita demand; over-pumping of groundwater for irrigation (Punjab, Haryana); urban and industrial growth; pollution from sewage, effluents and agro-chemicals; deforestation and poor recharge; wasteful flood irrigation; erratic monsoon and climate change.
What factors are responsible for the highest groundwater development in Punjab, Haryana and Tamil Nadu? (30 words)
Punjab–Haryana: Green Revolution rice–wheat, HYVs needing assured water, cheap/free power for tubewells, fertile alluvial aquifers. Tamil Nadu: rain-shadow, limited surface water, dependence on wells, intensive cropping and urban demand.
Why is the share of the agricultural sector in total water use expected to decline? (30 words)
Industry and towns will grow faster than agriculture, raising their demand; water-saving methods (drip, sprinkler) will reduce farm use per hectare; pricing and policy will shift water to higher-value uses.
What can be the possible impacts of consuming contaminated water? (30 words)
Water-borne diseases — diarrhoea, cholera, typhoid, hepatitis, jaundice; fluorosis (fluoride), arsenicosis and cancers (arsenic), blue-baby syndrome (nitrates); child malnutrition and stunting; lost workdays and health costs.
Discuss the availability of water resources in the country and factors that determine its spatial distribution. (150 words)
Availability: 4,000 km³ precipitation; 1,869 km³ river flow; utilisable 1,122 km³ (690 surface + 432 groundwater); India 4% of world water for 17%+ of people.
Spatial pattern: Ganga–Brahmaputra–Barak — ⅓ area, 60% surface water; southern rivers largely harnessed; groundwater rich in alluvial plains, poor in hard-rock Peninsula; lagoons in Kerala, Odisha, WB.
Factors: rainfall amount and seasonality (monsoon); catchment size; relief and topography (limit storage); geology (alluvium vs hard rock for aquifers); glaciers feeding Himalayan rivers; human use and pollution.
Diagram: the water-budget cascade.
Spatial pattern: Ganga–Brahmaputra–Barak — ⅓ area, 60% surface water; southern rivers largely harnessed; groundwater rich in alluvial plains, poor in hard-rock Peninsula; lagoons in Kerala, Odisha, WB.
Factors: rainfall amount and seasonality (monsoon); catchment size; relief and topography (limit storage); geology (alluvium vs hard rock for aquifers); glaciers feeding Himalayan rivers; human use and pollution.
Diagram: the water-budget cascade.
The depleting water resources may lead to social conflicts and disputes. Elaborate with examples. (150 words)
Inter-State: Kaveri (Karnataka–Tamil Nadu), Krishna, Mahadayi, Ravi–Beas, Sutlej–Yamuna Link (Punjab–Haryana) (Beyond NCERT examples).
International: Indus Waters Treaty with Pakistan, Teesta and Ganga (Farakka) with Bangladesh, Brahmaputra dams in China — NCERT's clipping: water causes conflict but also hundreds of treaties.
Within States and villages: farmers vs cities and industry, upstream vs downstream, deep tubewell owners vs small farmers whose wells dry up, caste-based access to village sources.
Drivers: falling per capita availability, over-pumping, pollution, droughts.
Solutions: river-basin authorities, tribunals, NWP 2012's framework law, community management, pricing, conservation.
International: Indus Waters Treaty with Pakistan, Teesta and Ganga (Farakka) with Bangladesh, Brahmaputra dams in China — NCERT's clipping: water causes conflict but also hundreds of treaties.
Within States and villages: farmers vs cities and industry, upstream vs downstream, deep tubewell owners vs small farmers whose wells dry up, caste-based access to village sources.
Drivers: falling per capita availability, over-pumping, pollution, droughts.
Solutions: river-basin authorities, tribunals, NWP 2012's framework law, community management, pricing, conservation.
What is watershed management? Do you think it can play an important role in sustainable development? (150 words)
Define: efficient management and conservation of surface and groundwater — preventing runoff, storing water, recharging aquifers (percolation tanks, recharge wells); broadly, managing land, water, plants, animals and people of a watershed together.
Yes, because: raises water tables and drinking-water security; supports irrigation and crops in drylands; checks soil erosion and floods; regenerates vegetation and fodder; creates local jobs; reduces migration; builds community institutions.
Examples: Ralegan Siddhi; Haryali; Neeru-Meeru; Arvary Pani Sansad; Atal Jal.
Limits: few success stories; needs community participation, awareness and continuity.
Conclude: integrated, participatory watershed management is a core tool for sustainable development.
Diagram: the ridge-to-valley sketch.
Yes, because: raises water tables and drinking-water security; supports irrigation and crops in drylands; checks soil erosion and floods; regenerates vegetation and fodder; creates local jobs; reduces migration; builds community institutions.
Examples: Ralegan Siddhi; Haryali; Neeru-Meeru; Arvary Pani Sansad; Atal Jal.
Limits: few success stories; needs community participation, awareness and continuity.
Conclude: integrated, participatory watershed management is a core tool for sustainable development.
Diagram: the ridge-to-valley sketch.
What to remember
Numbers
Earth's surface under water / freshwater share≈ 71% / ≈ 3% of all water
India's share of world area / water / population2.45% / 4% / 17%+
Annual precipitation≈ 4,000 km³
Mean annual river flow1,869 km³
Utilisable surface water690 km³
Replenishable groundwater432 km³
Total utilisable water1,122 km³ (≈ 60% of available)
Rivers longer than 1.6 km≈ 10,360
Ganga + Brahmaputra + Barak⅓ of area, 60% of surface water
Agriculture's share of use89% surface, 92% groundwater
Industry's share2% surface, 5% groundwater
Domestic share of surface water9%
Irrigated share of NSA in Punjab, Haryana, W. UP> 85%
Wells/tubewells' share of net irrigated areaPunjab 76.1%, Haryana 51.3%
CPCB monitoring stations (NCERT)507
Polluting industries along rivers and lakes (1997)251
Water lawsWater Act 1974 · Water Cess Act 1977 · EPA 1986
PMKSY2015–16
Atal Jal coverage8,220 GPs · 229 blocks · 80 districts · 7 States
Jal Kranti Abhiyan2015–16; one Jal Gram in each of 672 districts
Per capita availability (Beyond NCERT)5,177 m³ (1951) → 1,545 (2011)
One-liners
- Utilisable water = 690 surface + 432 groundwater = 1,122 km³.
- A third of India's land carries three-fifths of its surface water.
- Nine of every ten litres used go to irrigation.
- Tubewells made the Green Revolution — and are emptying the aquifers.
- Rivers are clean in the hills, dirty below the cities, worst in summer.
- Organic and bacterial contamination is the main river pollutant.
- Watershed management succeeds only with the community (Ralegan Siddhi).
- Rainwater harvesting both stores water and recharges aquifers.
Traps to avoid
- 1,869 km³ is surface flow only, not surface + groundwater.
- 690 km³ is ≈ 37% of 1,869, not 32%.
- Highest groundwater use in the south: Tamil Nadu.
- Industry's share is higher for groundwater; domestic share higher for surface water.
- Most polluted river stretch: Yamuna, Delhi to Etawah.
- CGWA (under EPA 1986) ≠ CGWB.
- AIBP gave money to States, not loans to farmers.
- Water is abiotic and renewable.
How to strategise
Prelims — what UPSC asks
- Groundwater and its regulators: CGWA under EPA 1986 and India's largest groundwater-irrigated area (2020, 2022); India's share of world groundwater withdrawal (2023); groundwater resources by State (1998); drinking-water pollutants arsenic, fluoride, uranium (2013).
- Micro-irrigation and farm water-saving: micro-irrigation (2011), drip (2016), fertigation (2020), conservation practices — zero tillage and crop residue (2017); CADP and AIBP (2015).
- Watershed and harvesting: hallmark of watershed development (1994), IWDP benefits (2014), Tarun Bharat Sangh (2004); National Water Mission and recycling (2012), virtual water (2005), Kavaratti desalination (2008).
- Policy and projects: National Water Resources Council chaired by the PM (2009); Ganga Action Plan merged into NRCP (2001); Rajasthan canal from the Sutlej (1991); irrigation projects and States (2008); why irrigation is needed (1982).
Mains — where it appears and how to answer
- GS1: India well endowed yet water-scarce (2015); water stress and its regional variation (2019); freshwater crisis (2023); urban rainwater harvesting (2018); micro-watersheds (2016); land and water management (2016); Gangetic groundwater decline and food security (2024); water as asset and conflict in South Asia (2026).
- GS2–GS3: inter-State water disputes (GS2 2013); National Water Policy and Ganga pollution (2013); Namami Gange (2015); water-use efficiency and micro-irrigation (2016, 2021); national watershed project (2019); storage and irrigation (2020); Jal Shakti Abhiyan (2020); irrigation challenges (2024); freshwater technologies (2024); industrial river pollution (2024); groundwater depletion (2025); seawater intrusion (2025).
- Answer frame: numbers (4,000 / 1,869 / 1,122; 89–92% to farms; per capita decline) → spatial pattern (GBM basins, north-west groundwater) → causes (monsoon variability, Green Revolution, cheap power, urbanisation, pollution) → consequences (falling tables, fluoride, arsenic, salinity, conflict) → solutions (micro-irrigation, watershed, RWH, recycling, pricing, PMKSY, Atal Jal, NWP 2012).
- Draw the water budget, the watershed or the rooftop harvesting sketch — each fits many questions.
Self-check
Tap an option. NCERT's own exercise questions come first; the rest test the figures and common confusions.
1. Which one of the following types describes water as a resource?
2. Which one of the following south Indian States has the highest groundwater utilisation (in per cent) of its total groundwater potential?
3. The highest proportion of the total water used in the country is in which sector?
4. India's total utilisable water resource is about:
5. The Ganga, Brahmaputra and Barak basins together have about one-third of India's area and what share of its surface water?
6. Over-withdrawal of groundwater has raised arsenic concentrations mainly in:
7. Which of these is NOT a benefit of rainwater harvesting listed by NCERT?
UPSC questions from this chapter
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