Water Resources – Class 10 Geography Notes
Study Chapter 3 from NCERT Contemporary India – II with simple explanations, important facts, topic-wise exam questions, model answers and quick revision resources. Understand why water scarcity occurs even though water is renewable, explore the advantages and disadvantages of multipurpose river projects, and learn traditional and modern methods of rainwater harvesting.
What You Will Learn
Understand why water shortages happen and how population, agriculture, industries and pollution affect availability.
Learn why water must be conserved and managed carefully.
Study dams, their uses, benefits, environmental effects and social concerns.
Learn about guls, kuls, khadins, johads, tankas and inundation channels.
Understand how rainwater can be collected, stored and used to recharge groundwater.
Explore a traditional water-management system practised in Meghalaya.
Quick Navigation
Topic 1: Water Scarcity and the Need for Water Conservation
Textbook reference: Contemporary India – II, Chapter 3, opening sections.
Water as a Renewable Resource
About three-fourths of the Earth's surface is covered with water, but only a small proportion is freshwater that can be used. Freshwater is mainly obtained from surface runoff and groundwater. These sources are continually renewed and recharged through the hydrological cycle, making water a renewable resource.
However, being renewable does not mean that usable water is unlimited or equally available to everyone. Water availability varies from place to place and from season to season, mainly because rainfall is unevenly distributed.
What Is Water Scarcity?
Water scarcity means a shortage of sufficient, usable water to meet the needs of people and activities. It may occur in areas with low rainfall, but rainfall alone does not explain every case. A region can receive plenty of rain and still face shortages because of overuse, unequal access or water pollution.
Main Causes of Water Scarcity
A larger population needs more water for drinking, cooking, sanitation and food production.
Water is extracted to expand irrigated areas and increase food-grain production, often lowering groundwater levels.
Industries use large quantities of water and energy, adding pressure to freshwater resources.
Dense cities, urban lifestyles and groundwater pumping increase demand and can deplete local supplies.
Water may be available in a region but not equally accessible to all communities.
Domestic and industrial waste, chemicals, pesticides and fertilisers can make water unsafe to use.
Why Is Irrigation a Major Concern?
Irrigated agriculture is the largest consumer of water. Farmers may use wells and tube-wells to increase agricultural production, but excessive groundwater extraction can cause falling water tables. This can affect future water availability and food security.
The chapter suggests the need to improve agriculture through drought-resistant crops and dry-farming techniques. Better water management can reduce waste and help conserve groundwater.
Water Conservation Initiatives Mentioned in the Textbook
- Jal Jeevan Mission (JJM): The supplied chapter describes its goal as providing rural households with assured potable piped water, with a service level of 55 litres per capita per day.
- Atal Bhujal Yojana (Atal Jal): The textbook describes it as a programme in water-stressed gram panchayats that encourages community behavioural change from consumption towards conservation and smart water management.
These programme descriptions reflect the supplied textbook edition. Check official government updates separately if you need the latest implementation status.
Why Must Water Be Conserved?
- To protect people from health hazards caused by unsafe water.
- To ensure food security and support livelihoods.
- To sustain domestic, agricultural and industrial activities.
- To prevent the degradation of natural ecosystems.
- To reduce the risk of ecological crises caused by over-exploitation and mismanagement.
Things to Remember
- Water is renewed through the hydrological cycle.
- Only a small proportion of Earth's water is usable freshwater.
- Water scarcity may occur even in places with high rainfall.
- Over-exploitation, excessive use, unequal access and pollution are major causes.
- Irrigated agriculture is the largest consumer of water.
- Conservation supports health, food security, livelihoods and ecosystems.
Exam Practice: Questions from This Topic
Q1. What is the hydrological cycle?
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Q2. What is water scarcity?
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Q3. Give two reasons why a region with high rainfall may still face water scarcity.
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Q4. Explain three major causes of water scarcity in India.
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Q5. Why is water conservation necessary?
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Q6. How can excessive groundwater extraction affect people?
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Topic 2: Multipurpose River Projects and Integrated Water Resources Management
Textbook reference: historical water structures, dams and multipurpose projects.
Water Management in Ancient India
Archaeological and historical records show that people in India constructed sophisticated water-management structures long before modern dams. These included dams made of stone rubble, reservoirs, lakes, embankments and canals for irrigation.
- Sringaverapura: The textbook describes a sophisticated system in the first century B.C. that channelled floodwater of the Ganga.
- Chandragupta Maurya: Dams, lakes and irrigation systems were extensively built during his time.
- Kalinga, Nagarjunakonda, Bennur and Kolhapur: Evidence of irrigation works has been found in these places.
- Bhopal Lake: The textbook mentions its construction in the 11th century.
- Hauz Khas, Delhi: The tank was constructed by Allauddin Khilji in the 13th–14th century to supply water to the Siri Fort area.
What Is a Dam?
A dam is a barrier across flowing water that obstructs, directs or retards the flow, often creating a reservoir, lake or impoundment. Dams can be classified according to their structure, materials, purpose or height.
What Are Multipurpose River Projects?
Traditionally, dams were built to store river water and rainwater for irrigation. Modern dams are used for several purposes, so they are often called multipurpose river projects.
Stores water and supplies it to agricultural fields.
Uses flowing or stored water to generate electricity.
Provides water for household needs.
Supports industrial processes and production.
Can regulate river flow and help reduce flood risks.
May support inland navigation, recreation and fish breeding.
Why Were Multipurpose Projects Considered Important?
After Independence, multipurpose river projects were seen as a way to support national development. They were expected to connect agricultural and village development with industrialisation and urban growth. Jawaharlal Nehru described dams as the “temples of modern India” because of the role they were expected to play in development.
Important Examples from the Chapter
| Project | River / Basin | Purpose or textbook detail |
|---|---|---|
| Bhakra–Nangal Project | Sutluj–Beas river basin | Water is used for both hydroelectric power production and irrigation. |
| Hirakud Project | Mahanadi basin | Integrates water conservation with flood control. |
| Sardar Sarovar Project | Narmada River | The textbook describes its intended irrigation and water-supply benefits across parts of western and central India. |
Things to Remember
- Water-management structures existed in ancient India.
- A dam creates or helps control a reservoir or water flow.
- Multipurpose projects integrate several uses of water.
- Bhakra–Nangal supports hydel power and irrigation.
- Hirakud integrates water conservation and flood control.
- Dams were described by Jawaharlal Nehru as the “temples of modern India”.
Exam Practice: Questions from This Topic
Q1. What is a dam?
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Q2. Why are some river projects called multipurpose projects?
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Q3. Name two multipurpose river projects mentioned in the chapter and state one use of each.
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Q4. Explain three purposes served by multipurpose river projects.
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Q5. Why were dams considered important for development after Independence?
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Q6. Mention any three examples of water-management structures or irrigation works from ancient India in the chapter.
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Topic 3: Advantages and Disadvantages of Multipurpose River Projects
Textbook reference: environmental effects, social impacts and concerns about large dams.
Although multipurpose projects can provide irrigation, electricity and water supplies, large dams and river regulation have also faced criticism. The chapter explains that their effects on river ecosystems, floodplains and local communities need careful consideration.
Advantages
- Provide water for irrigation and help support agricultural production.
- Generate hydroelectric power for homes and industries.
- Supply water for domestic and industrial needs.
- Can help regulate river flow and reduce some flood risks.
- May support inland navigation, recreation and fish breeding.
Disadvantages and Concerns
Damming and regulating rivers can alter natural flow and reduce the movement of sediment downstream.
Reservoirs and fragmented rivers can disrupt habitats and make it difficult for aquatic fauna to migrate, especially for spawning.
Reservoirs may submerge existing vegetation and soil, causing changes to the landscape.
Large projects can displace people and disrupt livelihoods.
Sediment build-up in reservoirs can reduce storage capacity; the chapter notes that dams have not always prevented floods during excessive rainfall.
The chapter mentions soil salinisation, water-borne diseases and pollution among possible consequences.
Changes in Agriculture and Inter-State Water Disputes
Irrigation can change cropping patterns when farmers shift towards water-intensive or commercial crops. This can have ecological consequences, including soil salinisation. River-water sharing may also create disputes when upstream use affects downstream states.
The textbook gives the Krishna–Godavari dispute as an example involving objections by Karnataka and Andhra Pradesh to the diversion of more water at Koyna by Maharashtra for a multipurpose project, which could reduce downstream flow.
Balancing Development and Conservation
Water projects should be assessed not only for their water and electricity benefits but also for their social and environmental consequences. Better planning, efficient irrigation, reduced water wastage, conservation and careful management can help address water needs more sustainably.
Things to Remember
- Multipurpose projects have both benefits and costs.
- Dams may alter natural river flow and sediment movement.
- Reservoirs can fragment habitats and submerge vegetation and soil.
- Large projects may cause displacement and loss of livelihood.
- Irrigation can encourage water-intensive crops and contribute to soil salinisation.
- Inter-state disputes can arise when river water is diverted or shared unequally.
Exam Practice: Questions from This Topic
Q1. Explain any three advantages of multipurpose river projects.
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Q2. Explain any three disadvantages of large dams.
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Q3. How can irrigation affect the environment?
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Q4. Why have multipurpose river projects faced opposition?
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Q5. Compare the advantages and disadvantages of multipurpose river projects.
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Topic 4: Rainwater Harvesting
Textbook reference: traditional systems and local methods of collecting and storing water.
What Is Rainwater Harvesting?
Rainwater harvesting is the collection and storage of rainwater for later use or for recharging groundwater. It is an important conservation method because it can reduce dependence on other water sources and make use of rainfall that would otherwise run off.
The chapter describes rainwater harvesting as a viable alternative in response to the disadvantages and growing opposition to some multipurpose projects. Traditional systems were developed according to local rainfall patterns, soil types, terrain and water needs.
Why Is Rainwater Harvesting Important?
- It collects water that might otherwise flow away as runoff.
- It can provide a source of water during dry periods.
- It can help recharge groundwater where systems are designed for that purpose.
- It uses local knowledge and can be adapted to local conditions.
- It can reduce pressure on existing water supplies.
Traditional Rainwater Harvesting Systems
| System | Region | How It Works |
|---|---|---|
| Guls or Kuls | Western Himalayas | Diversion channels carry water for agricultural use. |
| Inundation Channels | Flood plains of Bengal | Channels use floodwater to irrigate fields. |
| Khadins | Jaisalmer, Rajasthan | Agricultural fields are adapted to store rainwater, allowing it to stand and moisten the soil. |
| Johads | Other parts of Rajasthan | Traditional water-harvesting structures help collect and retain rainwater. |
| Tankas | Arid and semi-arid Rajasthan | Underground tanks store drinking water, often collected from rooftops. |
Rooftop Rainwater Harvesting
In rooftop rainwater harvesting, rain falling on a roof is collected through pipes and directed to a storage tank or a groundwater-recharge structure. In the traditional system described for Rajasthan, the water was collected in underground tankas built inside the house or courtyard.
The textbook explains that the first spell of rain was usually not collected because it cleaned the roof and pipes. Rain from subsequent showers was then collected. Stored rainwater could remain available until the next rainfall and was particularly useful during summer when other sources dried up.
Examples from the Textbook
- Rajasthan: Tankas were traditionally used to store drinking water in arid and semi-arid regions, including Bikaner, Phalodi and Barmer.
- Shillong, Meghalaya: Rooftop rainwater harvesting is common despite the high rainfall received by nearby Cherrapunji and Mawsynram. The chapter states that rooftop harvesting supplied around 15–25 per cent of household water requirements in the city.
- Gendathur, Karnataka: The chapter describes nearly 200 households using rooftop rainwater harvesting to meet their water needs.
- Tamil Nadu: The textbook identifies it as the first state to make rooftop rainwater harvesting compulsory for all houses.
Things to Remember
- Rainwater harvesting collects and stores rainwater or helps recharge groundwater.
- Traditional systems were adapted to local terrain, rainfall and water needs.
- Guls/kuls are diversion channels in the Western Himalayas.
- Khadins are associated with Jaisalmer; johads with other parts of Rajasthan.
- Tankas are underground tanks used for storing water.
- In traditional rooftop harvesting, the first spell of rain was usually discarded to clean the roof and pipes.
- Tamil Nadu is identified in the textbook as the first state to make rooftop harvesting compulsory for all houses.
Exam Practice: Questions from This Topic
Q1. What is rainwater harvesting?
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Q2. Why was the first spell of rain not collected in traditional rooftop harvesting systems?
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Q3. Explain any three benefits of rainwater harvesting.
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Q4. Describe how rooftop rainwater harvesting works.
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Q5. Name three traditional rainwater harvesting systems and state where they are used.
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Q6. Explain how rainwater harvesting is practised in semi-arid regions of Rajasthan.
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Topic 5: Modern Adaptations of Traditional Rainwater Harvesting
Textbook reference: rooftop harvesting in Rajasthan, Shillong and Gendathur.
Traditional rainwater harvesting continues to be adapted in both rural and urban India. These systems use local rainfall and available structures to collect water for household needs or recharge groundwater.
How a Rooftop Harvesting System Works
Some modern arrangements direct filtered roof water to an underground sump for immediate use. Excess water may be channelled to a well or another recharge structure, helping replenish underground water supplies.
Examples and Important Details
| Place | Textbook example | What it shows |
|---|---|---|
| Rajasthan | Underground tankas linked to sloping rooftops. | Rainwater can be stored for drinking and household needs. |
| Shillong, Meghalaya | Rooftop rainwater harvesting is common despite high rainfall in nearby Cherrapunji and Mawsynram. | Water shortages may occur even in high-rainfall areas. |
| Gendathur, Karnataka | Nearly 200 households installed rooftop rainwater harvesting systems. | Community adoption can improve local water availability. |
| Tamil Nadu | The textbook identifies it as the first state to make rooftop rainwater harvesting compulsory for all houses. | Public policy can encourage water conservation. |
Things to Remember
- Rooftop systems can collect rainwater for storage or groundwater recharge.
- Filters can be used to remove debris before water is stored or directed to a recharge structure.
- Rainwater harvesting can be adapted to houses, communities and local water needs.
- Local systems should be maintained and designed to suit local conditions.
Exam Practice: Questions from This Topic
Q1. How can rooftop rainwater harvesting help recharge groundwater?
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Q2. What does the example of Shillong teach us about water scarcity?
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Q3. Suggest three ways a household can conserve water.
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Topic 6: Bamboo Drip Irrigation System
Textbook reference: the traditional irrigation system practised in Meghalaya.
The chapter describes a 200-year-old bamboo drip irrigation system in Meghalaya. It uses bamboo pipes to tap stream and spring water and carry it to plants. The system makes use of gravity and carefully arranged bamboo channels to deliver small amounts of water near plant roots.
How Does Bamboo Drip Irrigation Work?
- Perennial springs on hilltops are tapped to collect water.
- Bamboo pipes divert the water downhill using gravity.
- The water travels through a series of bamboo channels over long distances.
- Smaller channel sections divide and regulate the flow.
- At the final stage, water is delivered near the roots of individual plants in controlled drops.
The textbook states that about 18–20 litres of water enter the bamboo pipe system and that the flow at the plant site can be reduced to approximately 20–80 drops per minute.
Why Is It Useful?
- It uses locally available bamboo.
- It transports water downhill through gravity.
- It regulates the flow to deliver small quantities of water.
- It demonstrates traditional knowledge adapted to local terrain and water needs.
Things to Remember
- The system is practised in Meghalaya.
- It is described as a 200-year-old system.
- Bamboo pipes tap stream and spring water.
- Gravity carries the water from higher ground towards plants.
- Flow is gradually reduced until water reaches plants in controlled drops.
Exam Practice: Questions from This Topic
Q1. In which state is the bamboo drip irrigation system practised?
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Q2. How does the bamboo drip irrigation system deliver water to plants?
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Q3. Describe the main stages of the bamboo drip irrigation system.
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Complete Chapter Revision Sheet
The hydrological cycle continually renews and recharges water sources.
Caused by overuse, unequal access, population pressure and pollution, not just low rainfall.
Irrigated agriculture is identified as the largest consumer of water in the chapter.
Combine uses such as irrigation, electricity generation, water supply and flood control.
Water is used for hydel power and irrigation.
Integrates water conservation with flood control.
Collects rainwater from roofs for storage or groundwater recharge.
Underground tanks traditionally used to store drinking water in Rajasthan.
Traditional gravity-fed irrigation system in Meghalaya.
Mind Map: Water Resources
Important Terms
| Term | Meaning |
|---|---|
| Hydrological cycle | The continuous movement of water through the environment. |
| Water scarcity | A shortage of sufficient usable water to meet needs. |
| Dam | A barrier across flowing water that obstructs, directs or retards its flow. |
| Multipurpose river project | A project that integrates several uses of stored or regulated river water. |
| Rainwater harvesting | Collecting and storing rainwater for later use or groundwater recharge. |
| Tanka | An underground tank traditionally used to store water, particularly in Rajasthan. |
| Khadin | A traditional rain-fed storage system associated with Jaisalmer. |
| Johad | A traditional water-harvesting structure used in parts of Rajasthan. |
| Gul / Kul | A diversion channel used to carry water in the Western Himalayas. |
| Bamboo drip irrigation | A gravity-fed system using bamboo pipes to deliver controlled drops of water to plants. |
Revision Checklist
NCERT Exercise Solutions – Water Resources
These model answers address the exercise questions at the end of the supplied NCERT Chapter 3 PDF. The multiple-choice and written answers are presented for revision; use your teacher's instructions for the expected answer length.
1. Multiple-Choice Questions
Q1(i). Classify each situation as suffering from water scarcity or not suffering from water scarcity.
- (a) Region with high annual rainfall.
- (b) Region having high annual rainfall and a large population.
- (c) Region having high annual rainfall but highly polluted water.
- (d) Region having low rainfall and a low population.
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- (a) Not necessarily suffering: High rainfall may provide enough water if it is collected and managed well.
- (b) May suffer from water scarcity: A large population can create high demand even in a high-rainfall region.
- (c) Suffering from water scarcity: Highly polluted water may be unsafe for use even when rainfall is high.
- (d) Not necessarily suffering: Low rainfall does not automatically mean scarcity if the population and demand are low, although local conditions matter.
Q1(ii). Which statement is not an argument in favour of multipurpose river projects?
(a) They bring water to areas suffering from water scarcity.
(b) They help control floods by regulating water flow.
(c) They lead to large-scale displacement and loss of livelihood.
(d) They generate electricity for industries and homes.
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2. Identify and Correct the False Statements
Q1(iii)(a). “Multiplying urban centres with large and dense populations and urban lifestyles have helped in proper utilisation of water resources.” Rewrite the statement correctly.
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Q1(iii)(b). “Regulating and damming of rivers does not affect the river’s natural flow and its sediment flow.” Rewrite the statement correctly.
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Q1(iii)(c). “Today in Rajasthan, the practice of rooftop rainwater harvesting has gained popularity despite high water availability due to the Indira Gandhi Canal.” Rewrite the statement correctly.
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3. Answer in About 30 Words
Q2(i). Explain how water becomes a renewable resource.
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Q2(ii). What is water scarcity and what are its main causes?
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Q2(iii). Compare the advantages and disadvantages of multipurpose river projects.
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4. Answer in About 120 Words
Q3(i). Discuss how rainwater harvesting in semi-arid regions of Rajasthan is carried out.
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Q3(ii). Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water.
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Final Practice Test – Water Resources
Suggested time: 25–30 minutes. Try the questions before opening the answer key.
Define water scarcity.
Name one traditional rainwater harvesting system used in Rajasthan.
Give two reasons why water scarcity may occur even in areas with high rainfall.
Explain three uses of multipurpose river projects.
Explain three environmental or social concerns associated with large dams.
Describe the rooftop rainwater harvesting system used in traditional Rajasthan homes.
Explain the need for water conservation and describe suitable methods of conserving water.
Show practice-test answer key
- Water scarcity is a shortage of sufficient usable water to meet people's needs.
- Tankas, khadins or johads are acceptable examples.
- Over-exploitation, excessive use, unequal access, population pressure and pollution can cause scarcity despite high rainfall. Any two explained points.
- Irrigation, hydroelectricity, domestic and industrial water supply, and flood control are examples. Explain any three.
- Examples include altered river flow and sediment movement, damage to aquatic habitats, submergence of land, displacement and loss of livelihood, and soil salinisation. Explain any three.
- Rain falling on sloping roofs is carried by pipes into underground tankas. The first spell is generally discarded to clean the roof and pipes, while later rainfall is collected for household use.
- Conservation is needed to protect health, food security, livelihoods and ecosystems. Methods include rooftop rainwater harvesting, traditional systems such as tankas and johads, groundwater recharge, efficient irrigation, fixing leaks and reducing water wastage.
Frequently Asked Questions
1. Which book contains Class 10 Geography Chapter 3, Water Resources?
It is Chapter 3 of the NCERT Class 10 Geography textbook Contemporary India – II.
2. Why is water a renewable resource?
Water is continually renewed and recharged through the hydrological cycle.
3. What are the main causes of water scarcity?
Major causes include over-exploitation, excessive use, unequal access, population growth, intensive irrigation, industrialisation, urbanisation and pollution.
4. What are multipurpose river projects?
They are projects designed to serve multiple purposes, such as irrigation, electricity generation, domestic and industrial water supply, and flood control.
5. What are tankas?
Tankas are underground tanks traditionally used to store rainwater, especially in arid and semi-arid parts of Rajasthan.
6. Which state is associated with bamboo drip irrigation?
Meghalaya.
7. Why is rainwater harvesting important?
It collects water for later use, can help recharge groundwater and reduces pressure on existing water sources.