Water Resources

In-Text Activities & Margin Questions

Q1. From your everyday experiences, write a short proposal on how you can conserve water.

Answer:

Water Conservation Proposal for Everyday Life:

• Domestic Action Plan: Turn off taps while brushing teeth, use buckets instead of hoses for washing vehicles, and install low-flow aerators on kitchen and bathroom faucets.
• Rainwater Harvesting: Install a simple rooftop collection system connected to a storage drum or percolation pit to recharge local groundwater.
• Greywater Reuse: Reuse water discarded from RO purifiers and washing machines for mopping floors and watering garden plants.
• Community Awareness: Organize periodic checks in residential areas and schools to fix leaking taps and pipe joints immediately.

Q2. Find out more about any one traditional method of building dams and irrigation works.

Answer:

Traditional Irrigation Method: Bamboo Drip Irrigation System of Meghalaya

In Meghalaya, a 200-year-old system of tapping stream and spring water using bamboo pipes is widely practiced:

• Water from perennial hill-top springs is intercepted using long bamboo channels.
• Gravity moves water across hundreds of meters, crossing roads via elevated bamboo bridges.
• The water flow is gradually reduced down to 20–80 drops per minute and delivered directly to the roots of plants (such as black pepper and betel leaf).

Q3. Collect information about floods occurred in different parts of the country due to heavy rainfall in recent times.

Answer:

Heavy rainfall and excessive water release from dams frequently cause severe floods in India:

• Assam Floods: Annual overflow of the Brahmaputra and its tributaries inundates vast rural areas, agricultural fields, and Kaziranga National Park.
• Kerala Floods (2018): Incessant rainfall coupled with the simultaneous opening of sluice gates of over 30 major dams caused widespread landslides and inundation.
• Urban Floods (Chennai & Mumbai): Severe downpours combined with clogged drainage systems and loss of natural wetlands lead to citywide paralysis.

Q4. Make a list of inter-state water disputes.

Answer:

Major inter-state river water disputes in India include:

Q5. Find out other rainwater harvesting systems existing in and around your locality.

Answer:

Common regional rainwater harvesting systems across India include:

• Guls and Kuls: Diversion channels built in the Western Himalayas for agricultural irrigation.
• Khadins and Johads: Rain-fed storage structures built in agricultural fields in Rajasthan to moisten the soil.
• Eris (Tanks): Traditional surface water reservoirs constructed in Tamil Nadu for irrigation and groundwater recharge.
• Bawlis (Stepwells): Ancient decorated masonry wells constructed in North India (e.g., Rajasthan, Delhi) for community water storage.

Q6. Collect information on how industries are polluting our water resources.

Answer:

Industries contribute to severe water pollution in the following ways:

• Untreated Effluents: Direct discharge of toxic chemical waste, heavy metals (lead, mercury, cadmium), and synthetic dyes from textile, leather, and chemical factories into rivers.
• Thermal Pollution: Release of hot water from power plants and factories into water bodies, drastically reducing dissolved oxygen and harming aquatic organisms.
• Agricultural / Industrial Runoff: Industrial fly ash and chemical sludge deposited near industrial estates leach into groundwater during monsoon rains.

Exercises

Q1. Multiple choice questions. (i) Based on the information given below classify each of the situations as ‘suffering from water scarcity’ or ‘not suffering from water scarcity’. (a) Region with high annual rainfall. (b) Region having high annual rainfall and large population. (c) Region having high annual rainfall but water is highly polluted. (d) Region having low rainfall and low population. (ii) Which one of the following statements is not an argument in favour of multi-purpose river projects? (a) Multi-purpose projects bring water to those areas which suffer from water scarcity. (b) Multi-purpose projects by regulating water flow helps to control floods. (c) Multi-purpose projects lead to large scale displacements and loss of livelihood. (d) Multi-purpose projects generate electricity for our industries and our homes. (iii) Here are some false statements. Identify the mistakes and rewrite them correctly. (a) Multiplying urban centres with large and dense populations and urban lifestyles have helped in proper utilisation of water resources. (b) Regulating and damming of rivers does not affect the river’s natural flow and its sediment flow. (c) Today in Rajasthan, the practice of rooftop rainwater harvesting has gained popularity despite high water availability due to the Indira Gandhi Canal.

Answer:

(i) Classification of Water Scarcity:

(ii) Answer:

(c) Multi-purpose projects lead to large scale displacements and loss of livelihood.
(Explanation: This statement highlights a major negative impact/criticism of multipurpose projects, not an argument in their favour.)

(iii) Corrected Statements:

(a) Multiplying urban centres with large and dense populations and urban lifestyles have over-exploited and aggravated the problem of water scarcity rather than helping in proper utilization.

(b) Regulating and damming of rivers severely affects the river's natural flow and causes excessive sedimentation at the bottom of the reservoir.

(c) Today in Rajasthan, the practice of rooftop rainwater harvesting is on the decline due to the plenty of water available from the perennial Indira Gandhi Canal.

Q2. Answer the following questions in about 30 words. (i) Explain how water becomes a renewable resource. (ii) What is water scarcity and what are its main causes? (iii) Compare the advantages and disadvantages of multi-purpose river projects.

Answer:

(i) How Water Becomes Renewable:

Water is a renewable resource because it is continuously renewed and recharged through the hydrological cycle. Evaporation, condensation, and precipitation ensure that water moves constantly between the land, ocean, and atmosphere.

(ii) Water Scarcity and Main Causes:

Water scarcity is the lack of sufficient available freshwater resources to meet regional water demands. Its main causes are over-exploitation, excessive use, unequal access, expanding population, urban lifestyle demands, and water pollution.

(iii) Advantages vs Disadvantages of Multi-Purpose Projects:

Q3. Answer the following questions in about 120 words. (i) Discuss how rainwater harvesting in semi-arid regions of Rajasthan is carried out. (ii) Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water.

Answer:

(i) Rainwater Harvesting in Semi-Arid Regions of Rajasthan:

In the semi-arid and arid regions of Rajasthan (such as Bikaner, Phalodi, and Barmer), traditional rooftop rainwater harvesting is practiced using underground tanks called tankas:

• Structure: The tankas are built inside the main house or courtyard and can be as large as a room (e.g., 6.1m deep, 4.27m long, and 2.44m wide).
• Mechanism: Rain falling on sloping roofs travels down connected PVC pipes into the sealed tankas.
• Process: The first spell of rain is discarded to clean the roof and pipes; subsequent showers are collected.
• Utility: Stored water (called Palar Pani) serves as a vital drinking source during dry summers and keeps adjacent underground rooms cool.

(ii) Modern Adaptations of Traditional Rainwater Harvesting:

Modern India successfully adapts traditional rainwater harvesting concepts to recharge urban and rural aquifers:

• Rooftop PVC Collection: Rain falling on terrace roofs is channelled through PVC pipes, filtered using sand and bricks, and directed into underground sumps or open dug wells.
• Recharge Wells & Hand Pumps: Excess runoff from roofs is routed into abandoned borewells or hand pumps to directly replenish the underground water table.
• Mandatory Legislation: Tamil Nadu made rooftop rainwater harvesting mandatory for all houses by law, setting a regulatory precedent.
• Village Success Stories: In Gendathur (Mysuru, Karnataka), over 200 households installed rooftop harvesting systems, collectively collecting over 1,00,000 litres of rainwater annually to achieve self-sufficiency.