An ecosystem is the living (biotic) and non-living (abiotic) parts of a place working together. Water connects all of them. This chapter describes land and water ecosystems, the forest types of Maharashtra, and why some water must always be left for the environment.
Land ecosystems: grasslands, forests, deserts. Forests cover about 9.4% of the earth's surface, about 30% of its land.
Aquatic ecosystems: freshwater (stagnant or flowing) and saltwater (marine). Their life depends on depth, cleanliness, temperature, light, oxygen and flow.
Evergreen (360–600 cm rain): Mahabaleshwar, Matheran, Bhimashankar; hirda, jambhul.
The relationship and interaction between the living and non-living parts of an area, e.g. a forest or a lake.
Q2. Name the two kinds of aquatic ecosystem.
Freshwater (stagnant or flowing) and saltwater (marine).
Q3. What is meant by 'water for the environment'?
A share of available water kept aside so rivers, wetlands and the life in them keep functioning.
Q4. Describe any two forest types of Maharashtra.
Evergreen forests grow where rain is 360–600 cm, as at Mahabaleshwar (hirda, jambhul). Khajan or mangrove forests grow in Konkan's muddy creeks (tiwar, kajla).
Q5. Why are streams drying up after the monsoon? What can we do?
Too much water is pumped out. We should use less water, conserve and recharge it, and keep some water flowing for nature.
Exam tip
Learn the rainfall range of each forest type; it is a favourite one-mark question.
India has a long and rich tradition of understanding and managing water. This chapter looks at the idea of the Panchatatva, ancient texts that studied rain and groundwater, old lakes, wells and irrigation systems, and Maharashtra's own water heritage, which we must now revive.
Key points
Panchatatva: earth, water, fire, air and sky. Living by nature's laws and respecting these five elements shaped Indian culture.
The Rigveda describes a culture on the banks of the Saraswati, a river that later disappeared. A river can build a culture and also destroy it.
The Vedas mention dams and canals.
Varahamihira wrote four chapters on water in Brihatsamhita about 1,500 years ago. He linked groundwater with soil, plants, ant hills and animal behaviour, which is useful in basalt areas like Maharashtra.
Parashar Muni (Krishi-Parashar) recorded signs to forecast rain: winds, animal behaviour, planets.
Kautilya's Arthashastra mentions water lifting, dams, desilting and water tax.
Old structures: Sudarshan lake at Girnar (time of Chandragupta Maurya), Hersul lake near Aurangabad (Satavahanas), Jagatung Sarovar near Kandhar (Rashtrakutas), and barav (stepped wells) of the Chalukya and Yadava periods.
The Maurya, Satavahana, Chalukya and Rashtrakuta periods were a golden age of water management in Maharashtra.
Bhuvandev's Aparajit Prachchha names six lake shapes. Temple lakes are called pushkarani.
Local systems: Khandesh's phad irrigation (Jire Mali community, 13th–15th century), about 10,000 tanks built by the Kohli people in Vidarbha, Beed's Khajina Vihir (1572), and the Bhil 'pat' system in Satpuda.
Shivaji Maharaj made water the first need of every fort.
Important terms
Pushkarani – a temple lake or lotus pond.
Barav – a square stepped well.
Phad system – community-run canal irrigation of Khandesh.
To save water we must first measure it. This chapter explains how rainfall, evaporation, flowing water, stored water, seepage into soil and crop water needs are measured, and the units used.
Key points
All our water comes from the water cycle, so vapour, rain, flowing, stored and seeping water must all be measured.
Rain gauge: a funnel (mouth 127 mm, about 5 inches) leads rain into a bottle inside a cylinder. Its top edge is 30.5 cm above the ground. The narrow pipe stops evaporation. Daily readings are taken at 8.30 a.m. IST, reading the lower edge of the water level.
Evaporation pan: a white-painted iron pan, 1.2 m wide and 30 cm deep, on a wooden frame. The water lost each day is measured at 8 a.m. A coefficient converts pan loss to field loss: 0.65 for western Maharashtra and Konkan, 0.8 for Marathwada and Vidarbha.
Flowing water: orifices, meter gates, weirs, flumes and the V-notch (a plank with a 90° V-cut placed across the stream). Flow is given in litres per second.
Stored water: average length × width × depth (stationary method). Water flowing over a dam is measured from its speed and the time it flows (flow method).
Seepage (zirpa): an iron ring 30 cm wide is pushed 15 cm into the ground, filled with water, and the fall in level is noted every 5 minutes until it is steady. This gives water absorbed per hour.
Crop water requirement: the total water a crop needs from sowing to harvest, given as a depth of water over the field.
Important terms
Rain gauge – an instrument to measure rainfall.
Evaporimeter – a pan used to measure evaporation.
V-notch – a triangular notch used to measure stream flow.
Zirpa – seepage of water into soil.
Key facts
System
Units
English
gallon, million cubic feet, acre-inch, acre-foot
Metric (decimal)
litre, million cubic metres, hectare-mm, hectare-cm, hectare-metre
1 hectare-cm = water 1 cm deep over 1 hectare = 100 m³ (100,000 litres).
5 important questions
Q1. What instrument measures rainfall, and when is the daily reading taken?
A rain gauge; the reading is taken at 8.30 a.m. IST.
Q2. Why is the funnel pipe of a rain gauge kept narrow?
So that the collected rainwater does not evaporate.
Q3. Explain the V-notch method.
A plank with a 90° V-shaped notch is placed across a stream so that all the water passes through the notch. From the height of water in the notch, flow in litres per second is found.
Q4. How is seepage of water into soil measured?
A 30 cm iron ring is driven 15 cm into the soil and filled with water; the drop in level is recorded every 5 minutes until steady. The totals give water absorbed per hour.
Q5. Why should every village measure evaporation?
Evaporation causes a big loss of stored water. Knowing it helps the village prepare a correct water plan.
Exam tip
Note the numbers: 127 mm funnel, 30.5 cm height, 8.30 a.m., pan 1.2 m × 30 cm, coefficients 0.65 and 0.8.
A water plan is a village's account of its water: how much rain falls in the catchment, how much soaks in, how much evaporates, how much is drawn out and how much is left for people. With this picture, the village can plan treatment work and avoid scarcity.
Key points
A water plan answers: how much water is held in our catchment each year, how much seeps in, how much evaporates, how much groundwater is pumped and how much is available for use.
A good plan needs real need, disciplined effort, work given by ability, enough training and honest hard work.
Information needed: rainfall records, groundwater levels in observation wells, a village map with streams (nala), soil and rock types, recharge sites, wells and bore wells, crops of the last three years, number of pumps, drinking water sources, population and livestock.
Timing: start right after the monsoon (after October). Finish the meeting, survey and conclusions within a month. Use January to June for treatment work before the next rain.
Public meeting (gram sabha) of children, youth, women, men and elders. It identifies the problem, the current status and solutions, and chooses a water committee that reviews data at least 4 times a year.
Village round (shivar pheri) with an expert to observe landforms, rocks, crops and water sources.
Mapping and recording all data in a register and on the village map. A toposheet of the watershed helps.
Water balance sheet: availability compared with use (domestic, irrigation, industry, animals, evaporation, outflow).
Action plan and its implementation.
Stages:
Important terms
Water plan – estimating a village's water availability and use to plan its water work.
Water balance sheet – a comparison of total water available with total water used.
Toposheet – a map showing height, streams, roads and settlements of an area.
Water committee – villagers chosen to prepare and review the plan.
Key facts
Plan start: after October; survey within one month; treatment from January to June.
Committee reviews data at least four times a year.
Ready village water plans can be seen on the GSDA (Groundwater Surveys and Development Agency) site.
5 important questions
Q1. What is a water plan?
Calculating how much water a village catchment gets, stores, loses and uses, so that water can be planned properly.
Q2. When should water planning start, and why?
Right after the monsoon (after October), so that survey and analysis are done in time for treatment work before the next rains.
Q3. What is the role of the public meeting?
To involve all villagers, discuss water use and problems, warn of future drought and choose a water committee.
Q4. What information is collected during the village round?
Landforms, soil and rock types, crops grown, wells and bore wells, pumps, streams, recharge and storage sites.
Q5. Write the steps of preparing a water plan.
Public meeting → village round → mapping and registration → water balance sheet → action plan and implementation.
Exam tip
Write the stages as a flow chart; it saves time and earns full marks.
A watershed is the whole area whose rainwater drains into one stream or nala. Developing a watershed means treating it from ridge to valley, so that rain is stopped, soil is held and water seeps into the ground. This raises well levels and farm output. The motto is "block water, seep water" (paani adava, paani jirava).
Key points
A watershed may be 50 to 500 hectares or more. Small watersheds are taken up first.
First survey the area: slopes, direction of flow, soil, rocks, how much water can be stopped.
Treatment always starts at the highest point (ridge) and moves down to the valley.
Things to study: rainfall and climate; size, slope and shape; stream network; soil type and depth; rocks, cracks and joints; seepage rate; vegetation; land use.
Continuous contour trenches (CCT) on steep upper slopes, with vetiver grass and trees.
Loose boulder structures in small gullies.
Nala bunding and cement nala bunds.
Gabion check dams (stones packed in wire mesh).
Vanarai check dams (cheap bunds of sand-filled bags).
Loop (compartment) bunding on farms.
Farm ponds.
Tree and grass planting.
Treatments:
Results: groundwater rises from the first year, wells fill, and horticulture and crop yield increase.
Remedies for water problems: conservation (well recharge, deepening and widening streams), groundwater recharge of wells and bore wells in towns and villages, and stopping pollution (no immersion of nirmalya or rituals in water sources).
Important terms
Watershed – the area that drains into a common stream or outlet.
CCT – trenches dug along contour lines to catch runoff.
Gabion – a wire-mesh cage filled with stones, used as a check dam.
Recharge – putting rainwater back into the ground.
Key facts
Famous water work: Ralegan Siddhi (Anna Hazare), Hiware Bazar (Popatrao Pawar), Vanrai (Mohan Dharia), Shirpur pattern (Suresh Khanapurkar), Rajendra Singh's community water work, Jalsamvad (Dr Datta Deshkar).
5 important questions
Q1. What is a watershed area?
The whole area from which rainwater flows down through small streams into one nala or river.
Q2. Why does watershed treatment start from the ridge?
Water and soil move fastest from the top. Stopping them there lets water seep in gradually all the way down.
Q3. Explain continuous contour trenches.
Trenches dug along the contour on steep slopes catch runoff and silt. Water seeps in, and vetiver and trees planted along them hold the soil.
Water scarcity cannot be solved by tankers or by the government alone. When villagers plan, work and decide together, water conservation succeeds. This chapter explains public participation, government schemes, and two famous examples: Hiware Bazar and the Shirpur pattern.
Key points
Nearly 75% of rural Maharashtra faces water scarcity every year. Tankers are only a temporary fix.
Ways to build participation: awareness workshops, gram sabhas, shramdaan (voluntary labour), prabhat pheri, essay and speech contests. Youth groups, farmer groups, women's savings groups, NSS students and the school National Green Army can all help.
Government schemes: Jalyukt Shivar Yojana, Mahatma Phule Jalbhumi Abhiyan, Atal Bhujal Yojana and others. Local self-government bodies play a key role.
Plan: discuss needs, set goals, outline and detail the action plan.
Implement: explain, share work, act, control and guide.
Evaluate: inspect, report, inform others and thank the participants.
Three steps of participation:
Hiware Bazar (Ahmednagar district, Popatrao Pawar): watershed work began in 1995 and was finished in 3 years by the gram sabha's decision. Wells rose from 97 to 229, and the gram sabha banned new bore wells, keeping bore-well water for drinking only. Crop yield nearly doubled.
Shirpur pattern (Dhule district, Suresh Khanapurkar, since 2004): nalas were widened (80–100 ft) and deepened (25–30 ft) above cement bunds. There are 235 cement dams in 80 villages, and farmers gave land free. It protects against both drought and flood and has spread to 20 districts and other states.
Important terms
Public participation – people giving time, labour, skill and money to plan, do and review common work.
Shramdaan – voluntary physical labour for a public cause.
Gram sabha – the meeting of all adult villagers.
Key facts
Hiware Bazar – 1995 – Popatrao Pawar (Padma Shri).
Q1. Why is public participation needed for water conservation?
No problem is solved by one person or the government alone. Villagers' time, labour, skill and money make the work lasting.
Q2. Name two government water conservation schemes.
Jalyukt Shivar Yojana and Atal Bhujal Yojana.
Q3. What decision of Hiware Bazar's gram sabha protected groundwater?
It banned new bore wells and kept bore-well water only for domestic use.
Q4. Explain the features of the Shirpur pattern.
Nalas were widened and deepened near cement bunds so that more water is stored and seeps in. Farmers donated land and local leaders joined. It works against drought and flood.
Q5. Write the steps of a public participation programme.
Water Condition and Water Challenges in Maharashtra
Quick summary
Maharashtra gets a fair amount of rain, but it is very unevenly spread and poorly managed, so much of the state faces scarcity and drought. This chapter describes rainfall and water availability in Maharashtra and the main water challenges the state faces.
Key points
About 85% of the state's rain comes from the south-west monsoon (June to September). October is the transition period; the north-east (retreating) monsoon brings some rain from October to January.
Average annual rainfall is about 1360 mm, but it varies a lot: Konkan 2000–3500 mm; the rain-shadow area east of the Sahyadri gets only 500–750 mm; eastern Vidarbha gets 1000–1400 mm.
The rain-shadow drought region covers about 61,600 sq km with 300–500 mm of rain; about 126 talukas face permanent drought.
Maharashtra has 9.37% of India's area and about 14.59% of its water resources, yet it suffers frequent drought because of poor planning and management.
Rain becomes useful water as direct use, surface storage (rivers, lakes, dams) and groundwater. Surface water and groundwater are linked, so they must be planned together.
Unequal rainfall: more than half falls in Konkan.
Rising demand from population, agriculture and industry, while about 80% of farmland is still dryland and every year about 1500 villages and 4305 hamlets lack drinking water.
Neglect of groundwater: 92% of the state is hard rock, which stores little water.
Water allocation between irrigation, drinking and industry.
Under-use of irrigation capacity: 3910 projects (87 large, 297 medium, 3526 small), but canals are incomplete and dams fill with silt.
Wasteful use: some cities use about 250 litres per person per day while drought villages get water once a week or less.
Main challenges:
Important terms
Rain-shadow region – the dry area on the leeward (eastern) side of the Sahyadri.
Retreating monsoon – the north-east monsoon rain from October to January.
Dryland farming – farming that depends only on rain.
Key facts
Maharashtra: 9.37% of India's area; 14.59% of its water.
Irrigated area rose from 6.48% (1960–61) to 20.60% (2010–11).
5 important questions
Q1. Why is October called the transitional period?
The south-west monsoon has fully withdrawn by October and the north-east monsoon begins.
Q2. What is a drought region?
The rain-shadow area east of the Sahyadri where rainfall drops sharply (300–500 mm).
Q3. Why must surface water and groundwater be planned together?
They are not separate sources; each feeds the other, and demand is now greater than supply.
Q4. Explain the unequal distribution of water in Maharashtra.
The Sahyadri blocks monsoon winds, so Konkan gets 2000–3500 mm while areas just east get 500–750 mm. More than half the rain falls in Konkan, and 126 talukas face permanent drought.
Q5. Why is the irrigation capacity of the state not fully used?
Canals and distribution works are incomplete, projects are delayed and costs rise, and silt reduces dam storage.
Exam tip
Learn three numbers: 1360 mm average rain, 85% from the south-west monsoon, 92% hard rock.
Irrigation means giving crops water beyond what rain provides. This chapter explains why irrigation is needed, old and new methods of drawing water, and modern water-saving methods like drip and sprinkler irrigation.
Key points
Purposes: grow crops outside the rainy season, take more than one crop a year, supply cash crops, raise yield per hectare and make farming safe and reliable.
Sources: dams, lakes, canals, rivers and groundwater. A large share of irrigation water is lost to evaporation.
Main methods in Maharashtra: surface watering (sari or furrows and wafa or beds), sprinkling from a height (sprinkler) and watering at the roots (drip).
Traditional tools: mot (a leather or iron bag pulled by bullocks; 125–200 litres; from wells 15–20 m deep), dhekli (a pole with a counterweight) and rahat (a wheel turned by bullocks). These are disappearing.
Pond irrigation: about 15% in Maharashtra; uses pumps such as submersible and chain pumps.
Lift irrigation: water pumped up to higher land with oil engines, electric or solar pumps. The book says it covers about 88% of irrigated area.
Drip irrigation: a network of polythene tubes drips water at the roots, more slowly than the soil absorbs it. It was developed by Simcha Blass of Israel (1959–60). Benefits: yield up 20–200%, water saved 30–80%, no erosion, works on uneven, saline or dry land, and fertiliser can be given through the pipes, saving about 30–35% cost.
Sprinkler irrigation: nozzles on aluminium or PVC pipes spray water like rain. It is good where water is scarce; used for wheat, gram, groundnut, vegetables and nurseries.
Canal irrigation carries dam water to fields through main and branch canals.
Important terms
Irrigation – supplying water to crops in addition to rain.
Drip irrigation – drop-by-drop watering at plant roots through tubes.
Sprinkler irrigation – spraying water like rain through rotating nozzles.
Lift irrigation – pumping water to fields at a higher level.
Key facts
Method
Water saving
Suitable for
Flood/furrow
low
flat land
Sprinkler
medium
wheat, gram, vegetables
Drip
highest (30–80%)
fruit, sugarcane, uneven land
5 important questions
Q1. Define irrigation.
Supplying water to crops from dams, wells, canals or rivers, in addition to rainwater.
Q2. What is a mot?
A traditional leather or iron bag pulled by bullocks to lift 125–200 litres of water from a well.
Q3. Give four purposes of irrigation.
Farming outside the rainy season, more than one crop a year, water for cash crops, and higher, safer yield.
Q4. Explain drip irrigation and its benefits.
Water reaches the roots drop by drop through a tube network. It saves 30–80% water, raises yield, prevents erosion, suits uneven or saline land and allows fertiliser through the pipes.
Q5. Distinguish between drip and sprinkler irrigation.
Drip gives water only at the roots, drop by drop. Sprinkler sprays water over the whole crop like rain. Drip saves more water; sprinkler suits close-growing crops like wheat.
Exam tip
Draw a small labelled sketch of drip lines and a sprinkler nozzle; diagrams earn easy marks.
Water is limited, but demand keeps growing, so disputes between countries and states are rising. This chapter explains why water laws and policies are needed, gives examples of world and Indian water disputes, India's water agreements with its neighbours, and Maharashtra's main water laws.
Key points
World population rose from about 100 crore (1750) to 600 crore (2000), but usable fresh water stays the same. Only about 1% of the earth's water is usable fresh water.
About 60 countries face serious water problems, and some say a future world war could be fought over water.
World disputes: Israel and the Arab nations (Jordan river), Egypt, Sudan and Ethiopia (Nile; Egypt's Aswan dam), several African countries, and US states (Colorado river).
With Bhutan (1979): flood and weather data; 35 hydro-met stations.
With Bangladesh: a Joint River Commission (1972) and the Ganga agreement (12 December 1996); flood data for the Ganga, Brahmaputra and Barak.
With China (2002): Brahmaputra flood data.
With Nepal: the Mahakali treaty (1996) and the Pancheshwar project.
With Pakistan: the Indus Waters Treaty, signed in 1960.
India's agreements:
Interstate disputes on the Godavari, Krishna, Narmada, Ravi–Beas and Kaveri go to tribunals or arbitrators.
History lesson: the Rohini river quarrel between Kapilvastu and Koliya was settled by talks, as Prince Siddhartha (Gautama) advised.
The National Water Policy treats water as a national resource; groundwater use must never exceed recharge (1987 policy).
Maharashtra laws: Maharashtra Irrigation Act 1976; Groundwater (Regulation for Drinking Water Purposes) Act 1993; Management of Irrigation Systems by Farmers Act 2005; Maharashtra Water Resources Regulatory Authority (MWRRA) Act 2005. MWRRA, set up in August 2005, was India's first such authority. State water policy was revised in 2019.
In drought, drinking water gets top priority in allocating dam water.
Important terms
Water dispute – a conflict over sharing river or ground water.
Water policy – government rules for fair and sustainable use of water.
Regulatory authority – a body that fixes fair water allocation and charges.
Key facts
MWRRA – August 2005 – first in India.
Indus Waters Treaty – 1960; Ganga treaty with Bangladesh – 1996.
5 important questions
Q1. Why are water laws needed?
Population and demand are rising while fresh water is limited. Laws ensure fair sharing, prevent over-use and settle disputes.
Q2. Which was India's first water regulatory authority?
The Maharashtra Water Resources Regulatory Authority, set up in August 2005.
Q3. What is the India–Bangladesh water cooperation?
A Joint River Commission since 1972, the Ganga water agreement of December 1996, and India giving flood forecasts for the Ganga, Brahmaputra and Barak.
Q4. What lesson does the Rohini river dispute teach?
Water is nature's gift; disputes should be solved by talks and harmony, not war.
Q5. Name four Maharashtra laws or policies about water.
Maharashtra Irrigation Act 1976, Groundwater Regulation Act 1993, MWRRA Act 2005 and the State Water Policy (revised 2019).
Exam tip
Note: some copies of the textbook print the Indus Waters Treaty year as 1996; the correct year is 1960.
Class 10 (SSC Board) · Water Security · Chapter 10
Water Purification and Sewage (Wastewater) Management
Quick summary
River or lake water is not safe to drink directly. This chapter explains turbidity and how to measure it, the stages by which a city plant purifies water, and the filters used at home.
Key points
Turbidity: cloudiness caused by suspended soil and other particles. Muddy rainwater is not waste; it clears on standing or with alum.
A Secchi disc (black and white disc on a rope) checks clarity: depth where it disappears (A) and reappears (B); average = (A + B)/2.
Turbidity is measured accurately with a nephelometer in NTU (Nephelometric Turbidity Units).
Pumping from the source (wire mesh stops fish and weeds).
Aeration: water falls in thin layers over steps to absorb oxygen and lose odour; 0.2–0.5 ppm chlorine is added (pre-chlorination).
Coagulation: alum (or ferric chloride, ferrous sulphate, poly-aluminium) is mixed in.
Flocculation: slow blades make fine particles join into heavy flocs (about 30 minutes).
Sedimentation: flocs settle as sludge in a still tank.
Filtration: through a 90 cm sand bed over 10 cm ballast; turbidity falls below 0.4 NTU.
Disinfection: chlorine (forms hypochlorous acid), ozone (0.8–1.6 ppm; removes colour and smell, but costly), bromine or iodine.
Storage in high tanks and distribution.
Stages of purification at a plant:
Home devices: UV purifier (carbon filter + UV lamp; kills germs but does not remove them; needs electricity), ion exchange (softens hard water), ozone units, iodine-resin tap filters, the LifeStraw (for travel) and the candle filter (clean the candles often and boil them).
Sewage (wastewater) must also be treated before release so that rivers are not polluted.
Important terms
Turbidity – cloudiness of water due to suspended particles.
Coagulant – a chemical (like alum) that makes particles clump.
Flocculation – slow mixing so that clumps grow heavy.
Disinfection – killing germs, mostly with chlorine.
Key facts
Item
Value
Pre-chlorination
0.2–0.5 ppm chlorine
Sand filter
90 cm sand + 10 cm ballast
Filtered water
below 0.4 NTU
Ozone dose
0.8–1.6 ppm
5 important questions
Q1. What is turbidity? In which unit is it measured?
Cloudiness of water due to suspended particles; measured in NTU with a nephelometer.
Q2. Why is alum added to water?
It is a coagulant that makes suspended particles clump and settle.
Q3. Write the stages of water purification at a plant.
Q4. Give the advantages and disadvantages of a UV purifier.
Advantages: kills bacteria and viruses, keeps minerals. Disadvantages: dead germs stay in the water, works poorly in very turbid water, needs electricity.
Q5. Why is untreated river water unsafe to drink?
It carries soil, dissolved impurities, bad gases and germs that cause waterborne diseases.
Exam tip
Learn the eight stages in order; a flow chart answer is quick and complete.
Class 10 (SSC Board) · Water Security · Chapter 11
Environmental Life Style
Quick summary
Our daily habits, from brushing teeth to washing clothes, put chemicals into water and waste it. This chapter shows how a changed, eco-friendly lifestyle, proper waste handling and reuse of treated sewage (as in Singapore) can protect water quality.
Key points
Earth Overshoot Day: the day each year when humans have used up all the resources nature makes in that year. It keeps moving earlier; in 2019 it fell on 29 July (the textbook prints 27 July).
Toothpaste (2–5 g of chemicals): use neem or babul sticks or tooth powder instead.
Shaving cream and soap: chemicals; warm water also softens the beard.
Bathing: a bucket (about 20 L) instead of a shower (50–100 L) or tub (300–400 L).
Washing clothes and utensils: detergents add phosphates; ash, clay or coconut fibre can clean utensils.
Toilet cleaners, cosmetics, and rituals that dump material into rivers.
Hidden pollution in daily life:
Waste and water: rain on open garbage spreads germs and pollutes lakes and groundwater. Polluted groundwater is very hard to clean.
Separate wet and dry waste; compost wet waste (the National Centre of Organic Farming's waste decomposer makes manure in about 40 days); reduce, dispose properly and recycle.
Sewage must be treated and reused (for gardens, toilets, industry); factories and farms must treat their own wastewater.
Singapore model: rainwater harvesting (about one-third of the land kept as protected catchment), lower imports from Malaysia, 'NEWater' (sewage purified to drinking quality, about 35% of supply) and desalinated sea water.
Important terms
Earth Overshoot Day – the date when yearly use of natural resources exceeds what nature can renew that year.
Environmental lifestyle – living in a way that uses fewer resources and causes less pollution.
The day in a year when humanity has used all the natural resources the earth can renew in that year.
Q2. How can bathing save water?
By using a bucket of about 20 litres instead of a shower (50–100 L) or tub (300–400 L), and using less soap.
Q3. How does open garbage spoil water?
Rain falls on it, it rots and spreads germs, and the dirty water flows into lakes or seeps down and pollutes groundwater.
Q4. Explain how Singapore became water-secure.
Rainwater harvesting with protected catchments, cutting imports, purifying sewage into drinking 'NEWater' and desalinating sea water, all backed by strict laws.
Q5. Suggest five lifestyle changes to protect water.
Use bucket baths, eco-friendly tooth powder, less detergent, separate and compost waste, and never dump nirmalya or garbage into rivers.
Exam tip
Tie each daily activity to its harmful chemical and its green alternative; this pattern fits most questions.
Class 10 (SSC Board) · Water Security · Chapter 12
Planning of Underground Saline Water
Quick summary
Saline (salty) water is found not only in the sea but also underground. This chapter explains desalination of sea water, the two causes of saline groundwater, Maharashtra's saline belt in the Purna basin of Vidarbha, and how that problem can be solved.
Key points
12 states and union territories of India have a long coastline; desalinating sea water can ease the water crisis.
Desalination is costly but its cost has fallen to about one-third of the 1990 level. Israel gets about 55% of its domestic water this way; its Sorek project is among the world's largest. There are desalination projects in Tamil Nadu, Andhra Pradesh and Puducherry (one supplies 100 million litres a day to Chennai).
Sea water entering coastal aquifers when fresh water is over-pumped (seen in the Konkan belt).
Natural saline deposits underground.
Two causes of underground saline water:
Fresh and saline groundwater do not mix easily because their densities differ; fresh water floats on top, so over-pumping brings salt water up.
Maharashtra has two sedimentary regions: the Tapi basin (Dhule, Jalgaon, Nandurbar) and the Purna basin (Akola, Amravati, Buldhana).
The Purna saline belt covers about 4692 sq km, with 894 villages and about 19.9 lakh people. The water is so salty that salt was made from it long ago, and conductivity is above 2000 micro-units. Villages get drinking water by pipelines from outside the belt.
Solution suggested by experts: deepen streams up to 20 m and widen them up to 30 m over about 1000 m and build a cement dam. The impermeable yellow clay layer keeps the stored fresh water (about 6 lakh m³ per structure) from mixing with the salt water below.
Important terms
Desalination – removing salt from sea or brackish water.
Saline belt – an area whose groundwater is naturally salty.
Sea-water intrusion – sea water seeping into coastal groundwater due to over-pumping.
Impermeable layer – a soil layer that does not let water pass.
Key facts
District
Villages
Area (sq km)
Amravati
355
1738
Akola
373
1939
Buldhana
166
1015
Total
894
4692
5 important questions
Q1. What is desalination?
The process of removing salt from sea water so that it can be used for drinking, farming and industry.
Q2. Why does sea water enter coastal wells?
Over-pumping of fresh water leaves empty space underground, which sea water fills.
Q3. Which districts make up the Purna saline belt?
Amravati, Akola and Buldhana.
Q4. Why do fresh water and saline groundwater not mix?
They have different densities, so fresh water stays as a layer above the heavier saline water.
Q5. How can the saline water problem of the Purna basin be solved?
By deepening (up to 20 m) and widening (up to 30 m) stream beds and building cement dams. The impermeable yellow clay keeps the stored fresh water separate, and it can be used for drinking and farming.
Exam tip
Remember the three districts and the total of 894 villages; table-based questions are common.