Water Resources Class 10 NCERT Solutions 2026 PDF Download

Ans: Water is a renewable resource because it is constantly recycled through the Hydrological Cycle.
1. Water evaporates from oceans and land.
2. It condenses to form clouds and precipitates back as rain/snow.
3. This recharges groundwater and fills rivers, ensuring a continuous supply.

Ans: Water scarcity is the lack of sufficient available water resources to meet the demands of water usage within a region.
Causes:
1. Over-exploitation: Excessive use for irrigation (agriculture) and industries.
2. Growing Population: Higher demand for domestic use and food production.
3. Pollution: Industrial waste and chemicals make water unfit for use (Quality Scarcity).
4. Unequal Access: Water may be available but restricted to certain social groups.

Ans:
Advantages:
1. Irrigation for agriculture.
2. Generation of Hydroelectricity.
3. Flood control and Water supply for industries/homes.
4. Inland navigation and tourism.
Disadvantages:
1. Displaces local communities (tribals) and submerges forests.
2. Affects aquatic life by blocking migration routes.
3. Excessive sedimentation at the bottom of the reservoir.
4. Can induce earthquakes and cause water-borne diseases.

Ans: In semi-arid regions like Bikaner and Barmer:
1. People build underground tanks called Tankas inside their houses for storing drinking water.
2. These tanks are connected to the sloping roofs of the houses through a pipe.
3. Rain falling on the roof travels down the pipe and is stored in the underground tank.
4. The first spell of rain is usually not collected (to clean the roof/pipes). The subsequent rain is collected. This water, called Palar Pani, is used during summer.

Ans: 1. Rooftop Harvesting: Common in cities. Rainwater from rooftops is directed into underground sumps or recharge pits to refill groundwater aquifers.
2. Gendathur Village (Karnataka): Villagers have installed rooftop rainwater harvesting systems in nearly 200 households, making the village water-rich.
3. Tamil Nadu: It is the first state in India to make rooftop rainwater harvesting compulsory for all houses.

Ans: Nehru believed that dams would integrate the development of agriculture and the village economy with rapid industrialization and growth of the urban economy. They were seen as symbols of progress and modernization that would lead India to prosperity.

Ans: (i) Recharge through Hand Pump. (ii) Recharge through Abandoned Dugwell.

Ans: In hilly and mountainous regions (Western Himalayas), people built diversion channels called Guls or Kuls for agriculture.

Ans: The Kosi river. It is known for changing its course frequently and causing devastating floods in Bihar.

Ans: A dam is a barrier across flowing water that obstructs, directs, or retards the flow, creating a reservoir.
Based on structure: Timber dams, Embankment dams, Masonry dams.

Ans: It is a dispute regarding the diversion of more water at Koyna by the Maharashtra government for a multi-purpose project. This would reduce downstream flow in Karnataka and Andhra Pradesh, affecting their agriculture.

Ans:
Quantitative Scarcity: Shortage in the quantity of water available. Caused by low rainfall, drought, or over-population demanding more water than available sources can replenish.
Qualitative Scarcity: Water is available in sufficient quantity, but its quality is poor. It is polluted by domestic waste, industrial effluents, and chemicals, making it hazardous for human use.

Ans: The movement opposed the dam because:
1. Displacement: Large-scale displacement of local communities (tribals) without proper rehabilitation.
2. Environment: Submergence of vast tracts of forests and ecological imbalance.
3. Cost-Benefit: They argued that the benefits (water/electricity) go to the rich landlords and industrialists, while the poor locals bear the cost.

Ans: 1. Himalayas: Diversion channels called Guls or Kuls.
2. Rajasthan: Rooftop harvesting using Tankas for drinking water.
3. Bengal: Inundation channels to divert flood water to irrigate fields.
4. Arid Regions: Agricultural fields converted into rain-fed storage structures called Khadins (Jaisalmer) and Johads.

Ans: 1. Ecological Damage: Regulating rivers affects their natural flow, causing poor sediment flow and excessive sedimentation at the bottom.
2. Aquatic Life: Dams fragment rivers, making it difficult for aquatic fauna to migrate for spawning.
3. Social Conflict: They cause displacement of people and trigger inter-state water disputes (e.g., Cauvery dispute).

Ans: 1. Efficient Irrigation: Use Drip irrigation and Sprinklers to minimize water wastage in agriculture.
2. Rainwater Harvesting: Promoting rooftop harvesting in urban areas and building check dams in rural areas.
3. Recycling: Treating industrial and domestic wastewater for reuse in gardening or cooling industries.

Ans: Meghalaya.

Ans: On the Mahanadi river in Odisha.

Ans: On the Satluj-Beas river basin.

Ans: Precipitation (Rainfall and Snowfall).

Ans: Approximately 22%.