Water — Sources, Cycle and Conservation | CTET EVS P1

Sources of Water — Surface and Ground

Children encounter water from many sources every day — the tap at home, the village well, the pond near the school, the canal that irrigates the field. EVS organises these into two broad categories: surface water and groundwater.

Surface water is water that collects in lakes, ponds, rivers, streams, reservoirs and oceans. It is visible, accessible and supports most agricultural and urban use. India's great rivers — Ganga, Yamuna, Godavari, Krishna, Brahmaputra — are surface-water lifelines for hundreds of millions. Surface water is replenished by rainfall and snowmelt, and is connected through tributaries and basins.

Groundwater is water that has seeped through the soil and rock and is stored in spaces between particles, in layers called aquifers. It is invisible from above but reaches us through:

• Wells (kuan) — open shafts dug to reach the water table.
• Tube wells and borewells — narrow pipes drilled deep using motors and pumps.
• Handpumps — the familiar lever-operated pumps in villages and schools.
• Springs — places where the water table naturally meets the surface, common in hilly regions.

The NCERT Class 3 chapter Drop by Drop and Class 4 chapter The Valley of Flowers introduce children to these ideas through stories rather than definitions. A child in Rajasthan recognises the chapaakal (handpump); a child in Kerala knows the open well in the courtyard.

An important distinction for the teacher: not all water sources give equally clean water. River water is rich in minerals but often polluted; groundwater is generally cleaner but in some regions contains harmful levels of fluoride, arsenic or iron. The CTET often tests this through a scenario — a teacher noticing that a village has fluorosis among children must connect it to groundwater quality.

The Water Cycle

The water cycle (jal chakra) explains how the same water keeps moving between the Earth's surface, atmosphere and underground stores. Although NCERT Class 5 introduces the cycle formally, much earlier chapters prepare the ground — a wet handkerchief drying in the sun, drops forming on a cold glass, clouds appearing before rain.

The cycle has four main processes that should be taught in this order:

• Evaporation — the sun heats water in oceans, rivers, ponds and even from leaves, turning it into invisible water vapour. The rate is faster when temperature is high and surface area is large; slower when temperature is low and surface area is small.
• Condensation — as the vapour rises and cools high in the sky, it changes back into tiny water droplets, forming clouds.
• Precipitation — when the droplets become heavy enough, they fall as rain, snow, sleet or hail.
• Collection — the fallen water collects in oceans, lakes, rivers and soaks into the ground to recharge aquifers. From here the cycle begins again.

Two pedagogical points are tested in CTET:

(a) The cycle is a continuous loop, not a one-way process — water is neither created nor destroyed, only converted between states.

(b) The teacher should demonstrate evaporation and condensation with simple kitchen activities — a kettle boiling, a plate held above it, droplets forming — rather than only memorising the diagram. The NCF 2005 calls this 'doing science' rather than 'studying about science'.

Transpiration from plants is often added as a fifth process, especially when teaching the role of forests in maintaining the cycle. The destruction of forests reduces transpiration, weakens the cycle and contributes to local drying.

Properties and States of Water

Water exists in three states — solid (ice), liquid (water) and gas (water vapour) — and changes from one to another with the addition or removal of heat. These changes are familiar to children before any textbook teaches them: ice cubes melt in a glass, wet clothes dry on a line, steam rises from a cooking pot.

Key changes of state:

• Melting — solid to liquid (ice → water) on adding heat.
• Freezing — liquid to solid (water → ice) on removing heat (below 0°C).
• Evaporation — liquid to gas, occurring at all temperatures from the surface.
• Boiling — rapid liquid-to-gas change at 100°C throughout the liquid.
• Condensation — gas to liquid when vapour cools.

Properties relevant for primary EVS:

• Water has no colour, no taste and no smell when pure.
• It is called the universal solvent — it dissolves salt, sugar, many minerals; this is why drinking water rarely is 'pure' H₂O.
• It expands when it freezes — ice floats on water. This single property keeps aquatic life alive under frozen lakes.
• Water flows from higher to lower ground — the basis for canals, rivers and gravity-fed taps.

The CTET often tests the conditions controlling evaporation — temperature, surface area, humidity and wind. A teacher should help children investigate this through experiments such as drying the same amount of water in a wide plate and a narrow glass, or in shade and in sun. These investigations are not only science learning but also model the process skills of observation, prediction and inference that NCF 2005 places at the heart of EVS.

Water Scarcity and Its Causes

Although water covers about three-fourths of the Earth's surface, less than 1% is freshwater accessible for human use. In India, water scarcity is one of the most visible and politically charged environmental issues — and the NCERT EVS books deliberately bring it into the classroom through stories such as A Day with Nandu, The Valley of Flowers, and the Class 5 chapter Sunita in Space.

Major causes of water scarcity in India:

• Over-extraction of groundwater — borewells dug deeper and deeper for irrigation, leading to falling water tables, especially in Punjab, Haryana, Rajasthan, Tamil Nadu and Karnataka.
• Population pressure and urbanisation — cities expand without proportional investment in water systems; slums often have no piped supply.
• Pollution — sewage, industrial effluents and agricultural chemicals make many surface sources unfit for drinking, effectively reducing the usable stock.
• Loss of traditional water bodies — ponds, tanks and stepwells filled in for construction.
• Deforestation — fewer trees mean less infiltration, more runoff and weaker monsoons locally.
• Climate change — erratic monsoons, melting Himalayan glaciers, and longer droughts.

Social dimensions are inseparable from the physical scarcity. Often it is women and girls who walk for hours to fetch water; lower-caste households may be denied access to common wells; cities consume disproportionately more than villages. NCF 2005 expects EVS teachers to bring these social aspects into the classroom alongside the science — for instance, comparing how much water a family in a slum uses against a family in a flat with a shower.

For the CTET candidate, the takeaway: water scarcity in EVS is taught as both a physical-environmental and a social-justice issue — never one without the other.

Traditional Water Harvesting Structures of India

Long before tanker trucks and government dams, communities across India had developed remarkably sophisticated systems for collecting and storing every drop of monsoon water. The NCERT Class 5 chapter Across the Wall and Class 4 The Valley of Flowers reference several of these. The CTET has repeatedly tested recognition of these regional structures.

• Bawari / Baoli (stepwell) — Rajasthan, Gujarat, Delhi: deep walled wells with stepped sides descending to the water level; both a water source and a community gathering place. Examples include Chand Baori (Abhaneri) and Rani-ki-Vav (Patan, a UNESCO site).
• Johad — Rajasthan, Haryana: small earthen check dams across seasonal streams that capture runoff and recharge groundwater. Famously revived in Alwar by Rajendra Singh's Tarun Bharat Sangh, restoring entire rivers.
• Khadin — Jaisalmer, Rajasthan: a rocky catchment leads runoff into a low field surrounded by an earthen embankment; the water soaks in and crops are sown on the moist soil.
• Tanka — western Rajasthan: underground cisterns inside courtyards for storing rainwater channelled from rooftops and paved compounds.
• Eri — Tamil Nadu: vast networks of tanks (around 39,000 historically) interconnected so that overflow from one feeds the next, irrigating paddy fields.
• Ahar–Pyne — south Bihar: pyne are diversion channels from rivers; ahar are catchment basins; together they irrigate vast tracts.
• Zabo — Nagaland: a combined system of forest, terraced fields, ponds and cattle yards on hill slopes that captures rainwater for paddy and fish farming.
• Bamboo drip irrigation — Meghalaya: 200-year-old system that carries water from springs across long distances using split bamboo pipes.

What these systems share is a deep ecological understanding: each is suited to its terrain, uses local materials, is built and maintained collectively, and combines water for drinking, irrigation and livestock. EVS pedagogy uses these as concrete examples of local wisdom — a key NCF 2005 idea.

Rainwater Harvesting and Modern Methods

Modern rainwater harvesting (RWH) builds on traditional ideas but adapts them to urban roofs, paved areas and concrete buildings. Several states — Tamil Nadu being the first, in 2001 — have made RWH compulsory for new construction.

Two basic approaches:

• Storage for direct use — rooftop rain is channelled through pipes, filtered, and stored in tanks for daily use.
• Recharge of groundwater — rain is directed to soak pits, recharge wells or percolation tanks so the underground water table is replenished.

A typical rooftop RWH system has:

• A clean roof as the catchment.
• Gutters and downpipes to collect and convey the water.
• A first-flush device that diverts the dirty initial runoff (which contains dust and bird droppings).
• A filter chamber (gravel and sand) to clean the water.
• A storage tank, or a recharge structure leading to the aquifer.

Benefits relevant for the classroom:

• Reduces dependence on tankers and groundwater pumping.
• Lowers urban flooding by reducing runoff.
• Replenishes the water table — by far the most cost-effective long-term solution.
• Improves water quality (recharged groundwater is naturally filtered).

EVS teachers are encouraged to take children to see a working RWH system — many government schools have demonstration units, and many cities run school-children's water audits during the monsoon. CTET Q on RWH typically tests the basic purpose — to conserve water and recharge groundwater — so the candidate must avoid distractors that present RWH as increasing flooding or making water unfit for drinking. A simple slogan students recall: 'Catch the rain where it falls, when it falls.'

Water Pollution and Health

Polluted water is the single largest cause of childhood disease in India. The NCERT EVS textbook addresses pollution through stories of a polluted river, a smelly drain, or a community well that becomes unsafe. The pedagogical aim is not to frighten but to enable children to identify, explain and act.

Major sources of water pollution:

• Domestic sewage — untreated wastewater from households entering rivers and lakes.
• Industrial effluents — chemicals from tanneries, textile dyes, paper mills, electroplating units.
• Agricultural runoff — fertiliser and pesticide residues washed by rain into streams; nitrate-rich runoff causes algal blooms.
• Solid waste — plastics, packaging and household waste choking drains and water bodies.
• Natural contamination — fluoride, arsenic and iron in groundwater of specific regions (West Bengal arsenic, Rajasthan fluoride).
• Religious and festival waste — flowers, idols, ashes added to rivers in large quantities.

Common waterborne diseases: diarrhoea, cholera, typhoid, hepatitis A and E, jaundice, dysentery, worm infestations. These are linked closely to lack of sanitation; the Swachh Bharat Abhiyan addresses pollution and disease together.

Simple purification methods to teach:

• Boiling — the most reliable household method.
• Filtration through cloth — removes visible particles only.
• Sand-and-gravel filters — work for moderately dirty water.
• Chlorination — using chlorine tablets in emergencies.
• Solar disinfection (SODIS) — bottles of clear water left in sun for 6 hours.

The CTET often combines water pollution with social themes — a teacher noticing that only one community uses a polluted source, or that hand-washing reduces infections. EVS pedagogy expects the teacher to move from knowing the disease to discussing what the school and the family can change.

Teaching Water Conservation in EVS

EVS does not aim to deliver a lecture on saving water — it aims to create a child who notices a leaking tap and turns it off. NCF 2005 and the Position Paper on EVS emphasise that conservation is best taught through experience, observation and action, not slogans.

Effective classroom strategies (regularly tested in CTET):

• Water audit — children measure how much water their family uses for bathing, cooking, washing; compare across families and across seasons. This integrates EVS with mathematics and data handling.
• Leak hunt — children walk through the school and home noting every dripping tap, broken pipe, or unattended hose; estimate water lost per day.
• Adopt-a-water-source — class adopts a nearby pond, tank or well, observes it through the year, photographs changes and reports to the panchayat or municipality.
• Story and drama — children enact a folk tale, a journey of a water drop, or a community deciding how to share a well.
• Interview an elder — children record how their grandmother used water as a child, what wells existed in the village, what has changed.
• Field visit — to a water treatment plant, an RWH installation, a local stepwell, or a river bank.

Pedagogical principles to remember:

• Move from known to unknown — start from the tap at home, go outward to the river, the dam, the aquifer.
• Integrate language, mathematics, art, social studies — not 'a chapter on water' but a theme.
• Use the 5E model (Engage–Explore–Explain–Elaborate–Evaluate) and the experiential approach explicitly tested in CTET items.
• Assess through projects, posters, surveys and oral presentations — not only paper-pencil tests.

The ultimate test is behavioural: does the child close the tap while brushing? Does she question the relative pouring rice-water down the drain? This is what NCF 2005 means by 'values translated into action'.