This MCQ module is based on: Water Availability, Hydrology & Sectoral Demand
TOPIC 10 OF 27
Water Availability, Hydrology & Sectoral Demand
🎓 Class 12
Social Science
CBSE
Theory
Chapter 4 — Water Resources
⏱ ~25 min
🌐 Language: [gtranslate]
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Water Resources of India: Availability and Utilisation
NCERT India: People and Economy — Unit III, Chapter 4 (Part 1)
Water: A Cyclic Resource Under Stress
Water is the most fundamental of all resources — without it, agriculture, industry, drinking, sanitation and ecosystems all collapse. Looking at the planet from space, it appears overwhelmingly blue: about 71 per cent of the Earth's surface is covered with water. Yet of this enormous quantity, only about 3 per cent is freshwater, and an even smaller fraction of that is effectively available for human use after we exclude polar ice, deep glaciers and inaccessible groundwater.
Definition
Water as a cyclic resource? means that the same molecules of water move through the atmosphere, oceans, land and living things in a never-ending sequence of evaporation, condensation, precipitation and runoff. The total quantity is fixed; only its location and quality change.
The availability of freshwater varies sharply across space and time. Some regions receive abundant monsoon rain in a few weeks, while others remain dry for most of the year. As populations rise and economies grow, the tensions and disputes over the sharing and control of this scarce resource have become contested issues among communities, regions and states. The careful assessment, efficient use and conservation of water are therefore essential to ensure development. This chapter discusses water resources in India — their geographical distribution, sectoral utilisation, and methods of conservation and management.
Fig 4.1 — The Hydrological Cycle & Earth's Water Budget
The hydrological cycle keeps recycling Earth's fixed water stock. Only a tiny fraction is freshwater that humans can directly tap.
4.1 Water Resources of India
India occupies a striking position in the world's water statistics. The country has about 2.45 per cent of the world's surface area, holds 4 per cent of the world's water resources, but supports more than 17 per cent of the world's population. This mismatch — a small share of resources serving a large share of humanity — explains why water management is one of India's central development challenges.
The total water available from precipitation in the country in a year is about 4,000 cubic km. Out of this, the availability from surface water and replenishable groundwater taken together is 1,869 cubic km. However, only about 60 per cent of this can be put to beneficial uses because of topographical, hydrological and other constraints. Thus the total utilisable water resource? in the country is only about 1,122 cubic km.
2.45%
World's surface area
4%
World's water resources
17%+
World's population
4,000
cu km from precipitation
Fig 4.2 — India's Annual Water Budget (cubic km)
Of the 4,000 cu km that falls as precipitation, 1,869 cu km becomes surface and ground water, and only 1,122 cu km is utilisable.
Surface Water Resources
There are four major sources of surface water? in India: rivers, lakes, ponds and tanks. The country has approximately 10,360 rivers and tributaries longer than 1.6 km each. The mean annual flow in all the river basins of India is estimated at 1,869 cubic km. However, due to topographical, hydrological and other constraints, only about 690 cubic km — roughly 32 per cent of the available surface water — can actually be utilised.
The volume of water flowing in any river depends on the size of its catchment area (or river basin) and the rainfall it receives. Indian precipitation is highly uneven in space and is largely concentrated in the monsoon season. The Ganga, the Brahmaputra and the Indus have huge catchment areas. Because precipitation is relatively high in the catchments of the Ganga, the Brahmaputra and the Barak, these rivers — though they drain only about one-third of the total area of the country — carry about 60 per cent of the total surface water resources. Much of the annual flow in south-Indian rivers like the Godavari, the Krishna and the Kaveri has already been harnessed, but a great deal of work is yet to be done in the Brahmaputra and Ganga basins.
Groundwater Resources
The total replenishable groundwater? resources of the country are about 432 cubic km. The level of groundwater utilisation is relatively high in the river basins of the north-western region and parts of south India. Groundwater utilisation is very high in the states of Punjab, Haryana, Rajasthan and Tamil Nadu. By contrast, states such as Chhattisgarh, Odisha and Kerala use only a small share of their groundwater potential, while Gujarat, Uttar Pradesh, Bihar, Tripura and Maharashtra withdraw at a moderate rate.
Warning
If the present trend of withdrawal continues, the demand for water will exceed available supplies in many basins. Such a situation will be detrimental to development and can cause social upheaval and disruptions.
Lagoons and Backwaters
India has a vast coastline that is deeply indented in some states. Because of this irregular coast, a number of lagoons and lakes have formed where the sea meets the land. The states of Kerala, Odisha and West Bengal have vast surface water resources in these lagoons and backwaters. Although the water in these bodies is generally brackish (slightly salty), it is used for fishing and for irrigating certain salt-tolerant varieties of paddy, coconut and other crops.
Fig 4.3 — India: Major River Basins & Water Resource Distribution
Himalayan rivers (Ganga, Brahmaputra, Indus) carry the bulk of India's surface water; peninsular rivers are smaller but better harnessed; the north-west and Tamil Nadu over-draw groundwater.
LET'S EXPLORE — Where Does Your Tap Water Come From?
L3 Apply
Trace your daily drinking water back to its source. Find out from your municipality or panchayat:
- Is it a surface source (river, dam, tank) or a groundwater source (tube-well, borewell)?
- If surface, which river basin does it draw from?
- How far does it travel before reaching your tap, and how is it treated?
Guidance
Cities like Delhi (Yamuna/Ganga), Mumbai (Bhatsa, Vaitarna) and Bengaluru (Kaveri) draw from surface sources. Many small towns and rural homes depend on groundwater from tube-wells. Treatment generally involves screening, sedimentation, filtration and chlorination before distribution. The journey from source to tap can be 50–200 km in big cities — a reminder of how distant your water really is.
4.2 Water Demand and Utilisation
India has traditionally been an agrarian economy: about two-thirds of the population depend on agriculture for their livelihood. So irrigation has always been the dominant claim on the country's water. From independence onwards, the development of irrigation has been a top priority of the Five Year Plans, and a series of multi-purpose river valley projects — the Bhakra-Nangal, Hirakud, Damodar Valley, Nagarjuna Sagar, Indira Gandhi Canal Project — have been built to harness rivers for irrigation, power and flood control.
As a result, India's water demand at present is dominated by irrigational needs. Agriculture accounts for the largest share of both surface and groundwater utilisation: it consumes about 89 per cent of the surface water and about 92 per cent of the groundwater withdrawn in the country. The industrial sector's share is limited to about 2 per cent of surface water and 5 per cent of groundwater. The domestic sector takes a higher share of surface water (about 9 per cent) than of groundwater. Looking ahead, with continued economic development, the shares of the industrial and domestic sectors are likely to rise, while the agricultural share is expected to fall.
Fig 4.4 — Sectoral Use of Surface Water in India
Irrigation dominates water use in India — about 89% of surface water goes to farms, only 6% to households (combined drinking & sanitation) and 5% to industry.
Demand of Water for Irrigation
In agriculture, water is mainly used for irrigation. Irrigation is essential because rainfall in India is highly variable in space and time. Large tracts — the north-western plains and the Deccan plateau — are deficient in rainfall and prone to drought. Winter and summer are largely dry across most of the country, so it is impossible to practise agriculture without assured irrigation in those seasons. Even in well-watered states like West Bengal and Bihar, breaks in the monsoon or its outright failure create dry spells that damage standing crops.
Different crops have different water needs. Rice, sugarcane and jute require very large quantities of water that can only be supplied through irrigation. The provision of irrigation makes multiple cropping possible — that is, growing more than one crop on the same land in a year — and irrigated land has been found to give significantly higher yields than unirrigated land. Importantly, the high-yielding varieties (HYVs) of crops introduced in the Green Revolution? need a regular supply of moisture, which only a developed irrigation system can guarantee. This is why the Green Revolution strategy has been most successful in Punjab, Haryana and western Uttar Pradesh — states with extensive irrigation networks.
In Punjab, Haryana and western Uttar Pradesh, more than 85 per cent of the net sown area is under irrigation. Wheat and rice are grown mainly with irrigation in these states. Of the total net irrigated area, 76.1 per cent in Punjab and 51.3 per cent in Haryana is irrigated through wells and tube-wells, indicating heavy reliance on groundwater. The over-use of groundwater has caused a decline in the water-table in these states. In some places like Rajasthan and Maharashtra, over-withdrawals have raised fluoride concentration in groundwater, and in parts of West Bengal and Bihar the same practice has increased arsenic concentration — with serious health consequences.
PMKSY (2015–16)
The Pradhan Mantri Krishi Sinchayee Yojana was launched by the Central Government in 2015–16 with the vision of ensuring access to some means of protective irrigation for every farm in the country — "Har Khet Ko Pani" (water for every field). Its companion slogan, "Per Drop More Crop", captures the goal of improving on-farm water-use efficiency through technologies such as drip and sprinkler systems. PMKSY also promotes integration of water source, distribution and efficient use, sustainable conservation, and the integrated development of rain-fed areas.
THINK ABOUT IT — Punjab's Paradox
L4 Analyse
Punjab and Haryana are the granaries of India, producing the bulk of its wheat and rice. But their groundwater levels are falling rapidly and their soils are becoming increasingly saline. Discuss the likely impacts on agriculture if the present pattern of intensive irrigation continues for another 25 years.
Guidance
Continued over-extraction will deepen the water-table beyond the reach of cheap tube-wells, raising pumping costs sharply. Soil salinisation from waterlogged fields will reduce yields and turn productive land barren. Contamination — fluoride in some areas, nitrates in others — will pose health risks to farming households. Eventually, farmers will have to shift to less water-hungry crops, adopt drip/sprinkler systems, and in some areas abandon paddy in favour of pulses, oilseeds or fruit. Without a deliberate policy shift, the Green Revolution success story may turn into an ecological crisis.
Emerging Water Problems: Per Capita Availability
The per capita availability of water in India is dwindling rapidly due to population growth. Available resources are also being polluted with industrial, agricultural and domestic effluents, further limiting the supply of usable water. The decline in per capita water availability? is one of the clearest indicators of approaching water stress.
In 1951, when independent India's first census was taken, per capita annual water availability was about 5,177 cubic metres. By 2025 it is estimated to have fallen to about 1,341 m³, and projections suggest it will drop further to about 1,140 m³ by 2050. According to the international benchmarks of the Falkenmark Indicator, an annual availability below 1,700 m³ per person indicates water stress?, and below 1,000 m³ indicates water scarcity?. India has already crossed into the stress zone and is moving towards the scarcity threshold.
Fig 4.5 — Per Capita Annual Water Availability in India (1951–2050)
Per capita availability has dropped from 5,177 m³ in 1951 to an estimated 1,341 m³ in 2025 and is projected to slip to 1,140 m³ by 2050. The 1,700 m³ line is the water-stress threshold; 1,000 m³ is water scarcity.
Why this matters
Once a country crosses below 1,700 m³ per person per year, it experiences chronic water stress — with periodic shortages for irrigation, drinking and industry. Below 1,000 m³, scarcity becomes a permanent constraint on health, food security and economic growth. India is already in the stress zone.
SOURCE — Reading the Per-Capita Curve
L4 Analyse
Look carefully at the curve in Fig 4.5 above and answer:
- By how many cubic metres has per-capita availability fallen between 1951 and the 2025 estimate?
- Which is the larger driver of this fall — total water becoming smaller, or total population becoming larger?
- If the population stabilises by 2050, what other steps could keep per-capita availability above 1,000 m³?
Guidance
(1) The fall is roughly 5,177 − 1,341 = 3,836 cubic metres per person per year. (2) The dominant driver is population growth: India's total water resource has not changed much, but the denominator (people) has more than tripled since 1951. (3) Even with a stable population, conservation, reuse, watershed development, drip irrigation and pollution control are essential to keep per-capita availability above the 1,000 m³ scarcity line.
India's Frozen Reservoirs: Glaciers & Snowfields
Beyond rivers, lakes and groundwater, India has a vast frozen reserve of freshwater locked up in the Himalayan glaciers and snowfields. These act as natural water towers: they melt slowly through summer and feed the perennial rivers — the Ganga, the Brahmaputra and the Indus — long after the monsoon has retreated. The slow release of meltwater is what gives north-Indian rivers their year-round flow, in sharp contrast to the seasonal peninsular rivers like the Godavari and Krishna.
Climate & Glaciers
Climate change is causing many Himalayan glaciers to retreat. While retreat may temporarily increase river flow, in the longer term it threatens the dry-season water supply of the Indus, Ganga and Brahmaputra basins — and therefore the food and water security of nearly 1.5 billion people downstream.
Putting It All Together
| Water Source | Annual Volume | Key Note |
|---|---|---|
| Total precipitation | ~4,000 cubic km | The starting point of India's water budget |
| Surface + replenishable groundwater | 1,869 cubic km | The combined renewable resource |
| Mean annual flow in all river basins | 1,869 cubic km | 10,360 rivers and tributaries |
| Utilisable surface water | ~690 cubic km (32%) | Limited by topography and hydrology |
| Replenishable groundwater | ~432 cubic km | Over-exploited in NW India and TN |
| Total utilisable water | ~1,122 cubic km | About 60% of 1,869 cu km can be put to beneficial use |
MAP ACTIVITY — India's Water Geography
L3 Apply
On an outline map of India, mark and label the following:
- The river basins of the Ganga, Brahmaputra, Indus, Godavari, Krishna, Kaveri, Narmada.
- States with very high groundwater utilisation — Punjab, Haryana, Rajasthan, Tamil Nadu.
- States with vast lagoon/backwater resources — Kerala, Odisha, West Bengal.
- The Himalayan glacier zone that feeds the perennial rivers.
Guidance
Use blue lines for the Himalayan rivers (Indus, Ganga, Brahmaputra), green for peninsular rivers (Godavari, Krishna, Kaveri, Narmada), red shading for the high-groundwater-stress belt (north-west and Tamil Nadu) and dotted blue circles along the Kerala, Odisha and West Bengal coasts for lagoons. The high-altitude Himalayan band (J&K, Ladakh, Himachal, Uttarakhand, Sikkim, Arunachal) holds the glaciers.
📝 Competency-Based Questions (CBQ)
Scenario: India has only about 4 per cent of the world's water resources but supports more than 17 per cent of the world's population. Of the 4,000 cubic km that falls as precipitation, just 1,122 cubic km is finally usable. Agriculture takes 89% of the surface water, while per-capita availability has slipped from 5,177 m³ (1951) to about 1,341 m³ (2025) — below the international stress threshold of 1,700 m³.
Q1. Which one of the following types describes water as a resource?
L1 Remember
Q2. Of India's 1,869 cubic km of average annual surface flow, how much can actually be utilised, and why is the figure so much smaller than the total flow?
L3 Apply
Q3. The agricultural sector consumes 89% of surface water and 92% of groundwater in India. With urbanisation and industrialisation expected to expand, how should this sectoral mix change by 2050, and why?
L4 Analyse
Q4. Per-capita water availability in India dropped from 5,177 m³ (1951) to about 1,341 m³ (2025) and is projected to fall to 1,140 m³ by 2050. Examine whether India can be classified as a "water-stressed" or "water-scarce" country in 2025.
L5 Evaluate
HOT Q. Imagine you are advising the Government of India on a 25-year water plan. The total water budget of 1,869 cubic km is fixed; population is projected to peak around 2050. Design three flagship interventions — one for surface water, one for groundwater, and one for demand management — and justify each.
L6 Create
✍ Assertion-Reason Questions
Assertion (A): India holds only 4 per cent of the world's water resources but supports more than 17 per cent of the world's population.
Reason (R): India occupies about 2.45 per cent of the world's surface area and has a relatively dry climate compared to global averages.
Reason (R): India occupies about 2.45 per cent of the world's surface area and has a relatively dry climate compared to global averages.
Assertion (A): The Ganga, Brahmaputra and Barak rivers carry roughly 60 per cent of India's surface water, although they drain only one-third of the country's area.
Reason (R): The catchment areas of these three rivers receive comparatively higher precipitation than other parts of the country.
Reason (R): The catchment areas of these three rivers receive comparatively higher precipitation than other parts of the country.
Assertion (A): The over-use of groundwater in Punjab, Haryana and Tamil Nadu has led to a sharp decline in the water-table.
Reason (R): These states consume comparatively little groundwater because their farmers prefer canal irrigation.
Reason (R): These states consume comparatively little groundwater because their farmers prefer canal irrigation.
Frequently Asked Questions
What are the sources of water resources in India?
India's water resources come from four sources: surface water (rivers, lakes, ponds, reservoirs), groundwater (aquifers and wells), atmospheric water (rainfall) and oceanic water. Of these, surface water and groundwater are the most utilised for human needs.
What is the per capita water availability in India?
India's per capita water availability has fallen from about 5,177 cubic metres per year in 1951 to roughly 1,500–1,600 cubic metres in recent years, and is projected to fall further. Below 1,700 cubic metres a country is considered water-stressed.
How is water used in different sectors of India?
Agriculture is the largest user of water in India (around 89%), followed by domestic use (about 9%) and industrial use (about 2%). Demand from industries and households is rising rapidly, intensifying competition with agriculture.
What are surface water resources?
Surface water resources include water in rivers, lakes, tanks, ponds and reservoirs. India has 10,360 rivers and tributaries longer than 1.6 km, and the mean annual flow in all river basins is estimated at 1,869 cubic kilometres.
What is groundwater?
Groundwater is fresh water stored in saturated layers of rock, sand or gravel below the earth's surface, called aquifers. India is the world's largest user of groundwater, drawing on it through wells and tube wells for irrigation and drinking water.
Why is water becoming scarce in India?
Water is becoming scarce in India due to rising population and urbanisation, expansion of irrigated agriculture, industrial demand, over-exploitation of groundwater, pollution of surface and ground water, and climate variability that affects rainfall.
Which states use the most groundwater for irrigation?
Punjab (76.1% of net irrigated area), Haryana (51.3%), Rajasthan and Tamil Nadu rely most heavily on wells and tube-wells for irrigation. This intensive use has caused steep falls in their water tables.
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