Water Resources Class 10 Notes – Easy, Clear & Exam-Focused (CBSE 2025)

 Water Resources Class 10 Notes



Table of Contents

  • Water is a renewable resource
  • Water Scarcity and the Need for Water Conservation and Management:
  • Atal Bhujal Yojana (Atal Jal)
  • Multi-purpose River Projects and Integrated Water Resources Management:
  • Narmada Bachao Andolan or Save Narmada Movement
  • Pradhan Mantri Krishi Sinchayee Yojana (PMKSY)
  • Rainwater Harvesting

Water is a renewable resource

Freshwater is mainly obtained from surface runoff and groundwater that is continually being renewed and rechanged through the hydrological cycle. All water moves within the hydrological cycle ensuring that water is a renewable resource.

The availability of water resources varies over space and time, mainly due to the variations in seasonal and annual precipitation.

Water Scarcity and the Need for Water Conservation and Management:

Water Scarcity is the lack of freshwater resources to meet the demands of water usage within a region.

Main causes of water scarcity:

  • Water scarcity in most cases is caused by over-exploitation, excessive use, and unequal access to water among different social groups.
  • Water scarcity may be an outcome of a large and growing population and consequent greater demands for water and unequal access to it.
  • To facilitate higher food-grain production, water resources are being over-exploited to expand irrigated areas for dry-season agriculture.
  • Intensive industrialization and urbanization exerted pressure on existing freshwater resources.
  • Even if water is sufficiently available to meet the needs of the people, much of it is maybe polluted by domestic and industrial wastes, chemicals, pesticides, and fertilizers used in agriculture, thus causing water scarcity.

Jal Jeevan Mission (JJM)

The Goal of JJM is to enable every rural household to get an assured supply of potable piped water at a service level of 55 liters per capita per day regularly on a long-term basis by ensuring the functionality of the tap water connections.

Need for Water Conservation

  1. Sustainable Resource Management: Conserving water ensures its availability for future generations and sustains ecosystems.
  2. Mitigating Water Scarcity: Many regions face water scarcity, and conservation helps balance supply and demand.
  3. Preserving Aquatic Ecosystems: Conserved water supports healthy habitats for aquatic plants and animals.
  4. Reducing Energy Consumption: Water treatment and distribution consume energy, and conserving water lowers energy demands.
  5. Agricultural Efficiency: Efficient irrigation practices save water and optimize agricultural productivity.
  6. Economic Benefits: Water conservation lowers costs for individuals, businesses, and governments.
  7. Addressing Climate Change: Reduced water wastage contributes to climate change mitigation.
  8. Minimizing Water Pollution: Conservation reduces the need for pollutant removal from water sources.

Atal Bhujal Yojana (Atal Jal)

Implementation:

  • Covers 8,220 water-stressed Gram Panchayats.
  • Implemented in seven states: Gujarat, Haryana, Karnataka, Madhya Pradesh, Maharashtra, Rajasthan, and Uttar Pradesh.

Coverage:

  • The selected states represent 37% of India's total water-stressed blocks (over-exploited, critical, and semi-critical).

Key Focus:

  • Aims to shift community behavior from water consumption to conservation.
  • Promotes smart water management practices.

Multi-purpose River Projects and Integrated Water Resources Management:

A dam is a barrier across flowing water that obstructs, directs, or retards the flow, often creating a reservoir, lake, or impoundment. “Dam” refers to the reservoir rather than the structure.

Jawaharlal Nehru proclaimed the dams as the ‘Temples of modern India’ because

  • They integrate the development of agriculture and the village economy with rapid industrialization and growth of the urban economy.
  • They provide water for irrigation.
  • They provide water for electricity generation
  • Provide water supply for domestic and industrial uses.
  • Helps in flood control.
  • Provide recreation
  • Helps in inland navigation.
  • Useful for fish breeding.

Hence, dams are now referred to as multi-purpose projects where the many uses of the impounded water are integrated with one another.

In recent years, multi-purpose projects and large dams have come under great scrutiny and opposition for a variety of reasons

  • Regulating and damming of rivers affect their natural flow causing poor sediment flow and excessive sedimentation at the bottom of the reservoir, resulting in rockier stream beds and poorer habitats for the rivers’ aquatic life.
  • Dams also fragment rivers making it difficult for aquatic fauna to migrate, especially for spawning.
  • The dams have triggered floods due to sedimentation in the reservoir and the release of excess water during heavy rains.
  • Multipurpose projects induced earthquakes, caused water-borne diseases, and pests, and lead to pollution resulting from excessive use of water.
  • Irrigation has changed the cropping pattern of many regions with farmers shifting to water-intensive and commercial crops. This has great ecological consequences like salinization of the soil.
  • The dams increase the social gap between the richer landowners and the landless poor.
  • The dams create inter-state water disputes with regard to sharing the costs and benefits of the multi-purpose project.

 

Most of the objections to the projects arose due to their failure to achieve the purposes for which they were built.

  • Ironically, the dams that were constructed to control floods have triggered floods due to sedimentation in the reservoir.
  • Moreover, the big dams have mostly been unsuccessful in controlling floods at the time of excessive rainfall. The floods have not only devastated life and property but also caused extensive soil erosion.
  • Sedimentation also meant that the flood plains were deprived of silt, a natural fertilizer, further adding to the problem of land degradation.
  • It was also observed that the multi-purpose projects induced earthquakes, causing water-borne diseases and pests, and pollution resulting from excessive use of water.

Narmada Bachao Andolan or Save Narmada Movement

  • It is a Non-Governmental Organisation (NGO) that mobilized tribal people, farmers, environmentalists, and human rights activists against the Sardar Sarovar Dam being built across the Narmada River in Gujarat.
  • It originally focused on the environmental issues related to trees that would be submerged under the dam water.
  • Recently it has re-focused the aim to enable poor citizens, especially the oustees (displaced people) to get full rehabilitation facilities from the government.

Pradhan Mantri Krishi Sinchaee Yojana (PMKSY)

Objectives of Pradhan Mantri Krishi Sinchaee Yojana (PMKSY):

  • Increase Irrigated Area: Make sure every field gets water. ("Har Khet Ko Pani")
  • Boost Efficiency: Improve water use to avoid wastage.
  • Promote Technologies: Use methods like drip irrigation ("Per Drop More Crop").
  • Conservation Practices: Adopt sustainable water-saving practices.

Rainwater Harvesting

The need for rainwater harvesting are:

  • Rainwater harvesting is needed to provide it for agriculture, collect drinking water, irrigate the fields, and to moisten the soil.
  • Rainwater harvesting is a viable alternative, both socio-economically and environmentally to multipurpose projects.

Traditional methods of rainwater harvesting:

  • In hill and mountainous regions, people built diversion channels like the ‘guls’ or ‘kuls’ of the Western Himalayas for agriculture.
  • ‘Rooftop rainwater harvesting’ was commonly practiced to store drinking water, particularly in Rajasthan.
  • In the flood plains of Bengal, people developed inundation channels to irrigate their fields.
  • In semi-arid and arid regions, agricultural fields were converted into rain-fed storage structures that allowed the water to stand and moisten the soil like the ‘khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan.

Rooftop Rainwater Harvesting

Rainwater is commonly referred to as Palar Pani in the arid and semi-arid regions of Rajasthan.

  • In the semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi, and Barmer, almost all the houses traditionally had underground tanks for storing drinking water.
  • The tanks could be as large as a big room.
  • The tanks were part of the well-developed rooftop rainwater harvesting system.
  • They were connected to the sloping roofs of the houses through a pipe.
  • Rain falling on the rooftops would travel down the pipe and be stored in these underground tanks.
  • The first spell of rain was usually not collected as this would clean the roofs and the pipes.
  • The rainwater from the subsequent showers was then collected.

Tamil Nadu is the first state in India that has made rooftop rainwater harvesting structures compulsory for all houses across the state.

Importance of rooftop rainwater harvesting in Rajasthan:

  • It was commonly practiced to store drinking water.
  • The rainwater can be stored in the tanks till the next rainfall, making it an extremely reliable source of drinking water when all other sources are dried up, particularly in the summers.
  • Rainwater (Palar Pani) is considered the purest form of natural water.
  • Many houses construct underground rooms adjoining the ‘tanks’ to beat the summer heat as it would keep the room cool.
  • Some houses still maintain the tanks since they do not like the taste of tap water.

Bamboo Drip Irrigation system

It is a 200-year-old system of tapping stream and spring water by using bamboo pipes and transporting water from higher to lower regions with the help of gravity.

Features:

  • 18-20 liters of water enter the bamboo pipe system, gets transported over hundreds of meters, and finally reduces to 20-80 drops per minute at the site of the plant.
  • The flow of water into the pipes is controlled by manipulating the pipe positions.
  • If the pipes pass a road, they are taken high above the land.

Water Resources – NCERT Solutions


🔹 Q1: Multiple Choice Questions (MCQs)

(i) Which one of the following is not the source of fresh water?
(a) Glaciers
(b) Groundwater
(c) Oceans
(d) Rivers

👉 Answer: (c) Oceans


(ii) Which one of the following is the main cause of water scarcity in India?
(a) Heavy rainfall
(b) River pollution
(c) Over-exploitation and unequal access
(d) Excessive use of water in agriculture

👉 Answer: (c) Over-exploitation and unequal access


(iii) The highest rainfall in the world occurs in:
(a) Mawsynram
(b) Cherrapunji
(c) Kolkata
(d) Mahabaleshwar

👉 Answer: (a) Mawsynram


(iv) Which of the following is a traditional method of water harvesting in Rajasthan?
(a) Karez
(b) Tankas
(c) Johads
(d) None of the above

👉 Answer: (b) Tankas


🔹 Q2: Answer the following questions briefly


(i) Explain how water becomes a renewable resource.
Answer:
Water is continuously circulated through the hydrological cycle – evaporation, condensation, and precipitation. This natural process makes water a renewable resource.


(ii) What is water scarcity and what are its main causes?
Answer:
Water scarcity refers to the shortage of water in comparison to its demand.
Main causes:

  • Overuse in agriculture

  • Unequal access

  • Deforestation

  • Urbanization and industrial use

  • Pollution of water sources


(iii) Compare the advantages and disadvantages of multi-purpose river projects.

AdvantagesDisadvantages
- Irrigation facilities- Displacement of people
- Hydro power generation- Ecological disruption
- Water supply and flood control- Loss of biodiversity
- Inland navigation and fisheries- Submergence of forests and fertile land

(iv) What is rainwater harvesting? Mention any two traditional methods.
Answer:
Rainwater harvesting is the method of collecting and storing rainwater for future use.
Traditional methods:

  • Tankas in Rajasthan (for storing drinking water)

  • Khadins and Johads (for groundwater recharge)


(v) What are the environmental effects of over-utilisation of water resources?
Answer:

  • Water table depletion

  • Drought and desertification

  • Soil salinization

  • Pollution and drying of rivers/lakes

  • Loss of aquatic life

CBSE PREVIOUS YEAR EXAMINATION QUESTIONS

1-Mark Questions

  1. Which one of the following is not a source of fresh water?
    Year: 2011
    Answer: Oceans, because they contain saline water.

  2. Tungabhadra dam is built on which river?
    Year: 2020
    Answer: Tungabhadra River in Karnataka.

  3. In which Indian state is the Tehri dam located?
    Year: 2018
    Answer: Uttarakhand.

  4. What is bamboo drip irrigation and where is it used?
    Year: 2023
    Answer: A traditional water conservation technique in Meghalaya that uses bamboo pipes to minimize wastage of water.

  5. Which state has made rooftop rainwater harvesting compulsory?
    Year: 2019
    Answer: Tamil Nadu.


2-Mark Questions

  1. Define water scarcity. What are its causes?
    Year: 2014
    Answer: Water scarcity means a lack of sufficient water to meet the needs. Causes include overuse, pollution, increasing demand, and unequal access.

  2. Mention any two traditional methods of water harvesting in India.
    Year: 2017
    Answer: Tankas in Rajasthan and Johads in Haryana/Rajasthan.

  3. Why is there an urgent need to conserve water resources in India?
    Year: 2018
    Answer: Due to growing population, overexploitation, uneven distribution of rainfall, and water pollution.

  4. What is rainwater harvesting? Mention any one benefit.
    Year: 2015
    Answer: Rainwater harvesting is the collection and storage of rainwater for future use. It recharges groundwater and reduces dependency on other sources.

  5. State any two features of multipurpose river valley projects.
    Year: 2022
    Answer: They provide irrigation, generate electricity, control floods, and support inland navigation and fisheries.


3-Mark Questions

  1. Why is the need for water increasing day by day?
    Year: 2007
    Answer: Due to rapid industrialization, expansion of agriculture, urbanization, and increasing population.

  2. What are the advantages of rainwater harvesting?
    Year: 2011
    Answer: It recharges groundwater, reduces runoff and erosion, and is cost-effective for sustainable water management.

  3. Describe the bamboo drip irrigation system.
    Year: 2023
    Answer: Used in Meghalaya; involves a system of bamboo pipes that transport water from higher areas to the fields, conserving water effectively.

  4. How do multipurpose projects and large dams affect the ecology?
    Year: 2016
    Answer: They cause displacement of people, deforestation, loss of biodiversity, and environmental degradation.

  5. Mention three traditional water conservation systems in India.
    Year: 2018
    Answer: Khadins (Rajasthan), Tankas (desert areas), and Johads (village ponds).


5-Mark Questions

  1. Explain rooftop rainwater harvesting in semi-arid regions of Rajasthan.
    Year: 2012
    Answer: In Bikaner and Barmer, homes have underground tankas to collect rainwater from rooftops. This water is used for drinking throughout the year.

  2. Evaluate the pros and cons of multipurpose river valley projects.
    Year: 2019
    Answer:
    Pros: Irrigation, hydroelectricity, flood control, water supply.
    Cons: Displacement, ecological damage, submergence of forests.

  3. Why does water scarcity occur in India despite receiving high rainfall?
    Year: 2016
    Answer: Due to overuse, pollution, uneven distribution of rainfall, lack of planning, and wastage.

  4. How has industrialization and urbanization increased the pressure on water resources?
    Year: 2017
    Answer: Industries consume huge amounts of water and pollute water bodies. Urban growth increases domestic demand and causes sewage disposal into rivers.

  5. Describe any five traditional water harvesting systems practiced in India.
    Year: 2015
    Answer:

  • Karez in Deccan

  • Johads in Rajasthan

  • Tankas in desert regions

  • Khadins in arid zones

  • Baolis in Delhi and Gujarat

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