Class 12 Geography Chapter 13 Water Resources and Types of Irrigation

Key Concept: Waterlogging Impact

d) Soluble salts diffuse upwards interfering with crop growth
[Solution Description]
When the water-table rises sufficiently close to the surface (within 2 metres), it acts as a continuous source of soluble salts in the soil profile, leading to issues like waterlogging and salinity. These conditions hinder crop growth by preventing proper root fixation and seed germination.

Key Concept: Rainwater Harvesting Techniques

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that roofwater harvesting is effective for recharging groundwater in urban areas, which is true because rooftops provide a large catchment area in cities where open land is scarce. The reason explains how rooftop rainwater is utilized by storing it in tanks or allowing it to percolate, thereby reducing runoff and enhancing groundwater recharge. Both statements are correct, and the reason correctly explains the assertion.

Key Concept: Factors Affecting Percolation

c) Sandy soil
[Solution Description]
Sandy soils have larger particles and more pore spaces compared to clayey soils, allowing water to pass through more easily, hence facilitating faster percolation.

Key Concept: Watershed Management

b) Increasing agricultural production
[Solution Description]
Watershed management aims to conserve water resources, enhance agricultural productivity, prevent ecological degradation, and improve living conditions. Among the options provided, increasing agricultural production is a direct benefit as it ensures sustainable use of soil and water resources.

Key Concept: Watershed Management, Water Conservation

c) Haryali
[Solution Description]
Haryali is a watershed development program sponsored by the Central Government. Its primary aim is to help rural people conserve water for drinking, irrigation, fisheries, and afforestation. It promotes holistic development through various agricultural and allied activities.

Key Concept: Groundwater development, state-wise variations

b) Punjab
[Solution Description]
Punjab has developed 98.34\% of its available groundwater potential, the highest among all Indian states. This is due to its low rainfall and high reliance on groundwater for agriculture, especially for crops like wheat and rice.

Key Concept: Temporal Variability

b) Because most rainfall occurs during monsoons and dry months have little precipitation
[Solution Description]
Most rainfall in India occurs during the monsoon months (June to September), leading to a surplus of water during this period. However, the lack of rainfall during the dry months results in water scarcity.

Key Concept: Tube-Well Efficiency, Sprinkler Irrigation

b) Sprinkler system because it is cheaper over 3 years
[Solution Description]
First, calculate the total cost for the tube-well over 3 years:
Initial cost = \textdollar 10,000
Operational cost per month = \textdollar 500
Total operational cost for 36 months = 500 * 36 = \textdollar 18,000
Total cost for tube-well = 10,000 + 18,000 = \textdollar 28,000
Now, calculate the total cost for the sprinkler system over 3 years:
Initial cost = \textdollar 15,000
Operational cost per month = \textdollar 300
Total operational cost for 36 months = 300 * 36 = \textdollar 10,800
Total cost for sprinkler system = 15,000 + 10,800 = \textdollar 25,800
The sprinkler system is cheaper by \textdollar 2,200 over 3 years.

Key Concept: Water Demand and Utilisation

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that agriculture consumes the largest share of water in India (89\% surface water and 92\% groundwater). This is factually correct as per the given syllabus. The reason explains why agriculture consumes such a large share: because India is an agricultural economy with 54.6\% population dependent on it, requiring extensive irrigation. The reason correctly justifies the assertion by linking agricultural dependency to high water demand for irrigation.

Key Concept: Reclamation of Alkali Soils

b) Gypsum
[Solution Description]
Gypsum is widely used for reclaiming alkali soils as it helps neutralize soil pH and improve soil structure. Other methods include leaching and green manuring.

Key Concept: Dangers of Over-Watering

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that over-watering in canal-irrigated areas leads to soil salinity and waterlogging, which is true according to the syllabus. The reason explains that excessive irrigation raises the water-table, bringing soluble salts to the surface, which is also true and correctly explains why over-watering causes soil salinity and waterlogging. Thus, both are true, and the reason is the correct explanation of the assertion.

Key Concept: Watershed Management

c) To help rural people conserve water for various uses
[Solution Description]
The Haryali programme, sponsored by the Central Government, aims to help rural people conserve water for drinking, irrigation, fisheries, and afforestation.

Key Concept: Surface Water Utilisation in India

c) 32\%
[Solution Description]
According to the syllabus, only about 32\% of the total available surface water (1,869 billion cubic metres) can be utilised in India.

Key Concept: Water Pollution

c) Discharge of industrial wastes like leather effluents
[Solution Description]
Industrial waste discharge, particularly from sectors like leather manufacturing, significantly pollutes rivers. In Kanpur, for instance, 150 leather factories release over 5.8 million litres of untreated wastewater into the Ganga daily, deteriorating water quality.

Key Concept: Sharda Canal, Perennial Features

d) Due to its planned infrastructure ensuring uninterrupted water supply
[Solution Description]
The Sharda Canal was designed as a perennial system from the start, drawing water from the Sharda River via the Banbasa Barrage. Unlike seasonal canals, it provides uninterrupted water supply, ensuring consistent irrigation in Uttar Pradesh. Its success lies in its planned infrastructure that avoids dependency on monsoons, directly contributing to reliable agricultural output.

Key Concept: Water Pollution Sources

b) Untreated city sewage
[Solution Description]
The syllabus highlights that untreated industrial waste, municipal sewage, and agricultural chemicals are major contributors to water pollution in Indian rivers. Among these, untreated city sewage is cited as a significant cause, affecting about 14 river basins.

Key Concept: Agriculture: Largest Consumer of Water

c) Agricultural sector
[Solution Description]
As per the given syllabus, agriculture accounts for approximately 89\% of surface water and 92\% of groundwater utilisation, making it the largest consumer of water in India.

Key Concept: Modern Irrigation Methods, Demerits of Canal Irrigation

b) Both Assertion and Reason are true, but Reason is NOT the correct explanation of Assertion.
[Solution Description]
The Assertion states that perennial canals are more cost-effective than inundation canals as they provide continuous irrigation. This is true because perennial canals are part of multipurpose projects and offer long-term benefits despite high initial costs. The Reason claims that water-logging and soil salinity occur due to sustained high water tables from perennial canals, which is also true. However, the Reason does not explain why perennial canals are cost-effective; it only explains a negative side effect. Therefore, both statements are true, but the Reason does not correctly explain the Assertion.

Key Concept: Concept: Unequal Solar Radiation Distribution

d) Spherical shape of Earth causing varying angles of sunlight
[Solution Description] The Earth's spherical shape causes variations in the angle at which sunlight strikes different regions. Near the equator, sunlight falls directly, making it hotter, while near the poles, sunlight spreads over a larger area due to curvature, resulting in colder temperatures.

Key Concept: Recycling and Reuse, Legislative Support

a) Using treated wastewater for industrial cooling
[Solution Description]
The question focuses on using inferior quality water (e.g., reclaimed wastewater) for non-potable purposes, as encouraged by the Water Act, 1974. The syllabus mentions recycling and reuse, such as using wastewater for industrial cooling, firefighting, or gardening. Options like drip irrigation and rainwater harvesting are unrelated to reusing inferior water. Industrial cooling is explicitly cited in the syllabus as a valid reuse case.

Key Concept: Water pollution, Industrial waste impact

d) Discharge of industrial waste from leather factories
[Solution Description]
The primary reason for the Ganga river's high pollution levels near Kanpur is the discharge of large quantities of untreated industrial waste from approximately 150 leather factories. These factories release more than 5.8 million liters of wastewater daily into the river, containing harmful chemicals and pollutants that degrade water quality.

Key Concept: Groundwater Potential in Peninsular India

c) Tamil Nadu
[Solution Description]
The syllabus states that Maharashtra, Madhya Pradesh, and Tamil Nadu have large groundwater potential due to their large size, even though peninsular India generally has low groundwater potential because of hard, impervious rocks.

Key Concept: Green Revolution, Productivity Enhancement

c) Need for consistent moisture for high-yielding varieties
[Solution Description]
The Green Revolution emphasized high-yielding varieties (HYVs) of crops, which demanded more water than traditional varieties to achieve their full yield potential. These HYVs needed consistent moisture levels, making irrigation indispensable even in regions with adequate rainfall. This shift significantly increased the reliance on irrigation to maintain productivity.

Key Concept: Uneven Spatial and Temporal Rainfall

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The Assertion states that the coefficient of variation (CV) for annual rainfall is higher in Rajasthan compared to Kerala, which is true as per the syllabus (CV for Rajasthan is over 40\%, while Kerala has a CV of around 15\%). The Reason explains that this is because Rajasthan experiences more erratic and unpredictable rainfall due to its geographical location (Thar Desert) and topography, which is also true. Furthermore, the Reason correctly explains why the CV is higher in Rajasthan, linking it to spatial and temporal variability caused by geography. Thus, both Assertion and Reason are true, and the Reason is the correct explanation of the Assertion.

Key Concept: Canal Irrigation

c) Sutlej and Beas
[Solution Description]
According to the syllabus, the Indira Gandhi Canal, located in Rajasthan, draws water from the Sutlej and Beas rivers for irrigation purposes.

Key Concept: Freshwater Availability

b) 3\%
[Solution Description]
The text states that while 71\% of Earth's surface is covered with water, only 3\% is freshwater, which is further divided into various sources like rivers, lakes, and groundwater.

Key Concept: Need for Irrigation

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that irrigation is necessary in India due to the uneven temporal distribution of rainfall. This is true because the syllabus mentions that rainfall is confined to a short duration of 3-4 months in the rainy season, and the rest of the year is dry, requiring irrigation for agriculture. The reason given is that rainfall is confined to a short duration of 3-4 months, which is also true and directly explains why irrigation is necessary. Therefore, both the assertion and reason are true, and the reason correctly explains the assertion.

Key Concept: Productivity, Regional Variations

b) Punjab's cropping pattern and rainfall timing mismatch necessitating irrigation
[Solution Description]
The solution examines regional variation drivers: (1) Punjab's rainfall is seasonal (concentrated in monsoon) while NE has distributed rainfall, (2) Punjab grows water-intensive wheat-rice rotations needing year-round supply, (3) NE grows rain-fed crops suited to local patterns, (4) Punjab's high productivity agriculture demands controlled irrigation. The correct option identifies how crop types and rainfall patterns interact differently in these regions.

Key Concept: Water Utilisation

b) 9\%
[Solution Description]
As mentioned in the syllabus, the domestic sector utilises 9\% of the surface water in India.

Key Concept: Inundation Canals

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that inundation canals are taken off from rivers without regulating devices, which is true as they are constructed directly from rivers during floods without barriers like dams or weirs. The reason explains that these canals depend on seasonal floods and lack controlled water supply, which is also true and correctly explains why no regulating devices are needed for such canals. Thus, both the assertion and reason are true, and the reason is the correct explanation of the assertion.

Key Concept: Tank Irrigation in Tamil Nadu

b) 21\%
[Solution Description]
Tank irrigation accounts for over 21\% of the total irrigated area in Tamil Nadu as per the given syllabus.

Key Concept: Surface water sources in India

b) Rivers
[Solution Description]
Rivers are the most important source of surface water in India, as mentioned in the syllabus.

Key Concept: Rainwater Harvesting Objectives, Groundwater Recharge

c) Generating hydroelectric power
[Solution Description]
The question asks about the non-objective of constructing a small bund for water storage. Key objectives from the syllabus include: increasing groundwater recharge, reducing run-off, preventing floods, and improving water quality. However, "generating hydroelectric power" is not mentioned as an objective for small bunds in rainwater harvesting structures.

Key Concept: Future Trends in Water Consumption

c) Both sectors will increase
[Solution Description]
The text mentions that the share of agriculture in total water consumption is likely to decrease in the future, while the shares of the domestic and industrial sectors are expected to increase as development takes place.

Key Concept: Industrial Waste Pollution

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that discharge of industrial waste deteriorates water quality, which is true as industrial waste contains pollutants like heavy metals and toxic chemicals. The reason correctly explains the assertion by stating that industrial waste contains harmful chemicals and effluents that contaminate water. Both are true, and the reason justifies the assertion.

Key Concept: New Approaches to Water Management

c) They must include a drinking water component where no alternative source exists
[Solution Description]
The National Water Policy (2002) mandates that irrigation and multi-purpose projects must include a drinking water component where no alternative source of drinking water exists. This ensures that drinking water needs are prioritized.

Key Concept: Distribution of Tank Irrigation

d) Andhra Pradesh and Telangana combined
[Solution Description]
Andhra Pradesh (including Telangana) has the largest area under tank irrigation in India, covering approximately 662 thousand hectares, which is about one-third of the total tank-irrigated area in the country.

Key Concept: HYV crops, Irrigation

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that HYV crops need regular irrigation for nutrient uptake and yield stability. This is true because HYV crops have faster growth rates and higher nutrient demands compared to traditional crops, necessitating consistent water supply. The reason explains that the increased metabolic rate of HYV crops makes them more dependent on water for growth and nutrient absorption, which is scientifically accurate. Moreover, the reason directly justifies why HYV crops require regular irrigation, linking the metabolic demand to irrigation necessity. Therefore, both the assertion and reason are true, and the reason correctly explains the assertion.

Key Concept: Prevention of Water Pollution

c) Organic and bacterial contamination
[Solution Description]
According to CPCB investigations, organic and bacterial contamination are the major causes of river water pollution in India. This is clearly stated in the syllabus details provided.

Key Concept: Rainwater Harvesting Techniques, Historical Evidence

c) Roofwater harvesting, recharge through trench and bunds, and abandoned dugwells
[Solution Description]
To tackle both flooding and groundwater depletion, the best approach combines techniques that reduce surface runoff (to prevent floods) and enhance groundwater recharge. Traditional methods like rooftop harvesting reduce runoff by capturing rainwater directly, while modern techniques like percolation pits and trenches allow water to seep into the ground. Abandoned dugwells can also be repurposed for recharge. Thus, the optimal combination includes rooftop harvesting, percolation pits/trenches, and abandoned dugwells.

Key Concept: Major Causes of River Pollution

d) Natural sedimentation
[Solution Description]
The CPCB identifies organic and bacterial contamination as major causes of river pollution. Industrial waste, municipal sewage, and chemical fertilizers are also significant contributors. However, natural sedimentation is not listed as a major cause but rather a natural process.

Key Concept: Basic Definition

c) Variations in rainfall amounts across different regions
[Solution Description]
Uneven spatial rainfall describes variations in rainfall distribution across different geographic locations, such as one region receiving heavy rain while another remains dry.

Key Concept: Rainwater Harvesting

b) To meet increasing water demand
[Solution Description]
Rainwater harvesting primarily aims to meet increasing water demand by capturing and storing rainwater locally. It also helps reduce run-off, augment groundwater storage, and mitigate water scarcity during dry periods.

Key Concept: Urban Gardening

b) Container gardening
[Solution Description]
Container gardening is a popular method in urban gardening, allowing plants to grow in pots or other containers where space is limited.

Key Concept: Polluted Rivers

c) Yamuna river
[Solution Description]
The Yamuna river is explicitly stated as the most polluted river in India between Delhi and Etawah in the provided syllabus.

Key Concept: Assertion-Reason

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The Assertion states that over-irrigation causes soil salinity and alkalinity, which is true as per the syllabus content. This occurs due to the upward diffusion of salts when excessive water is used in irrigation. The Reason explains that the rise in the water-table brings soluble salts to the surface, which is also true and directly supports the Assertion. Therefore, both the Assertion and Reason are correct, and the Reason is the correct explanation for the Assertion.

Key Concept: Groundwater Formation

c) 60\%
[Solution Description]
According to the syllabus, a part of rainwater percolates into the ground through joints and cracks in the rocks and is known as groundwater. About 60\% of the groundwater is confined to the upper layers of the soil.
Therefore, the correct answer is 60\%.

Key Concept: Uneven Spatial Distribution

a) Northern and northeastern regions
[Solution Description]
The northern and northeastern regions of India receive abundant water due to perennial rivers such as the Ganga and Brahmaputra, which flow throughout the year.

Key Concept: Future Trends, Sectoral Water Usage

d) 252 MLD
[Solution Description]
Current demand = 200 MLD.
Annual growth rate = 8\%.
Demand after 1 year = $200 \times 1.08 = 216$ MLD.
Demand after 2 years = $216 \times 1.08 = 233.28$ MLD.
Demand after 3 years = $233.28 \times 1.08 = 251.9424$ MLD ≈ 252 MLD.

Key Concept: Chilika Lake

c) Chilika Lake
[Solution Description]
Chilika Lake, situated in Odisha, is the largest brackish water lagoon in India. It supports rich biodiversity and plays a vital role in the local economy through fishing and agriculture.

Key Concept: Recycle and Reuse of Water

c) For gardening and vehicle washing
[Solution Description]
In urban areas, recycled water from activities like bathing or washing can be reused for gardening, conserving better water for drinking purposes.

Key Concept: Groundwater Potential

b) 42\%
[Solution Description]
The passage states that more than 42\% of the groundwater potential is confined to the states of the Great Plains of North India.

Key Concept: Major Canal Systems in Uttar Pradesh

c) Upper Ganga Canal
[Solution Description]
The Upper Ganga Canal originates from the Ganga at Haridwar and serves irrigation needs in Meerut, Muzaffarnagar, Bulandshahr, and Aligarh districts.

Key Concept: Lagoons and Backwaters, Conservation Challenges

b) Pollution and over-exploitation of resources
[Solution Description]
The sustainability of lagoons and backwaters in India is threatened by pollution from agricultural runoff, industrial discharge, and domestic waste. Over-exploitation of resources, such as excessive shrimp farming and unregulated fishing, also degrades these ecosystems. Climate change-induced sea-level rise and salinity fluctuations further exacerbate these challenges, making conservation efforts crucial.

Key Concept: Prevention of Water Pollution

c) Yamuna
[Solution Description]
The Yamuna river is identified as the most polluted river in India between Delhi and Etawah according to the syllabus.

Key Concept: Assertion-Reason

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that the Yamuna river is the most polluted river in India between Delhi and Etawah, which is true based on the provided syllabus content. The reason given is also true, as the Central Pollution Control Board has identified organic and bacterial contamination as major causes of river water pollution. Moreover, the reason correctly explains why the Yamuna river is highly polluted, as these contaminants are prevalent in the river. Therefore, both the assertion and reason are true, and the reason is the correct explanation of the assertion.

Key Concept: Groundwater, Regional Distribution

b) Punjab
[Solution Description]
According to the text, Punjab has developed 98.34\% of its total groundwater potential, which is the highest among all states mentioned.

Key Concept: Well Irrigation

c) The farmer has control over irrigation timing and usage without external interference.
[Solution Description]
Well irrigation allows farmers to use water independently as per their needs, unlike canal irrigation which is controlled by external agencies. Additionally, it does not lead to issues like reh caused by excessive canal irrigation and can be constructed at any convenient location. It also adds fertility to the soil through natural minerals in groundwater.

Key Concept: Industrial Use, Conservation

c) 2400 liters
[Solution Description]
First, calculate the amount of wastewater recycled: 60\% of 4000 liters = 0.60 $\times$ 4000 = 2400 liters. Since this recycled water is used for firefighting instead of fresh water, the amount of fresh water conserved is equal to the recycled amount, which is 2400 liters.

Key Concept: Process of Percolation

c) Gravity
[Solution Description]
The primary force responsible for rainwater percolating through rocks and soil is gravity, which pulls the water downward through porous materials.

Key Concept: Surface Water

b) Both Assertion and Reason are true, but Reason is NOT the correct explanation of Assertion.
[Solution Description]
The assertion states that rivers are the most important source of surface water in India, which is supported by the syllabus mentioning that rivers obtain water from rainfall or snow melt and are spread across the country with a large annual flow. The reason provides a specific numerical value for the mean annual flow of Indian rivers, which supports the assertion indirectly by quantifying the significance of rivers as a water source. However, the reason does not directly explain why rivers are the most important source—only that they have a substantial flow. Therefore, both statements are true, but the reason does not fully explain the assertion.

Key Concept: Legislative Provisions

c) Water Cess Act, 1977
[Solution Description]
The Water Cess Act, 1977, was enacted to reduce water pollution by imposing a cess on water consumed by industries and local authorities. However, its impact has been minimal due to ineffective implementation.

Key Concept: Lagoons and Backwaters: Economic Impact

c) Through fishing and agriculture
[Solution Description]
The syllabus highlights that lagoons and backwaters enhance livelihood opportunities by providing additional sources of food and income through fishing and agriculture, particularly in states with indented coastlines like Kerala.

Key Concept: Water Availability Formula

b) 50 cm
[Solution Description]
Using the formula for water availability:
$\text{Water Availability} = \text{Rainfall} - \text{Evaporation} - \text{Runoff}$
Substituting the given values:
$\text{Water Availability} = 100\,\text{cm} - 30\,\text{cm} - 20\,\text{cm} = 50\,\text{cm}$

Key Concept: Groundwater Potential

c) 42\%
[Solution Description]
As per the syllabus, more than 42\% of India's total groundwater potential is confined to the states of the Great Plains of North India.

Key Concept: Water Resource Comparison

b) 4.4:1
[Solution Description]
From the syllabus:
India has 17.4\% of world population but only 4\% of world's water resources.
Ratio = Population share : Water share
= 17.4 : 4
= $(17.4 \div 4)$ : $(4 \div 4)$
= 4.35 : 1
Rounding to one decimal place gives 4.4:1

Key Concept: Well Irrigation Depth

b) 3–5 metres
[Solution Description]
According to the syllabus, an ordinary well is about 3–5 metres deep but deeper wells up to 15 metres are also dug.

Key Concept: Tank Irrigation

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that tank irrigation is more prevalent in peninsular India than in northern India. This is true as per the syllabus, which mentions Andhra Pradesh, Telangana, and Tamil Nadu as leading states in tank irrigation. The reason provided explains that the undulating relief and hard rocks in peninsular India make canal and well irrigation difficult, which matches the syllabus's explanation for the prevalence of tank irrigation in this region. Therefore, both the assertion and reason are true, and the reason correctly explains the assertion.

Key Concept: Water Demand, Sectoral Usage

c) 37.5 billion cubic meters
[Solution Description]
Current industrial surface water usage is 5\% of 500 billion cubic meters = 25 billion cubic meters. With 50\% increase, new industrial usage = 25 + (25 * 0.5) = 37.5 billion cubic meters.

Key Concept: Lagoons and Backwaters

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
From the syllabus, it is clear that lagoons and backwaters in states like Kerala are significant for their role in agriculture (paddy, coconut) and fishing due to their brackish water. Both the Assertion (A) and Reason (R) are true, and the Reason correctly explains why lagoons and backwaters are utilized for these purposes.

Key Concept: Water Pollution Multiplier Effect

c) 4.22 million litres/day
[Solution Description]
Current discharge = 5.8 × 10^6 L/day. Annual increase factor = 1.2. After 3 years: New discharge = 5.8 × (1.2)^3 = 10.0224 × 10^6 L/day. Additional pollution = 10.0224 - 5.8 = 4.2224 × 10^6 L/day ≈ 4.22 million L/day.

Key Concept: Water Quality

c) Organic and bacterial contamination
[Solution Description]
The CPCB has identified organic and bacterial contamination as the major causes of river water pollution in India. This information is directly mentioned in the given text.

Key Concept: Hydrogeology, River systems

c) Extensive agricultural irrigation
[Solution Description]
The primary factors contributing to groundwater recharge in northern plains are:
1. Soft porous rocks allowing percolation
2. Abundant river systems from Himalayas
3. Sedimentary deposition over time
While agricultural practices do use groundwater, they don't directly enhance natural recharge rates.

Key Concept: Multi-cropping \& higher productivity

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that irrigation leads to higher agricultural productivity by ensuring regular moisture supply, which is true as per the syllabus (Point 8). The reason explains that high-yielding varieties need consistent water availability, also a valid point (Point 6). Further, the reason correctly explains why irrigation improves productivity for high-yielding crops. Thus, both statements are true, and the reason is the correct explanation of the assertion.

Key Concept: Watershed Management

c) To help rural people conserve water for multiple uses
[Solution Description]
The Haryali programme aims to help rural people conserve water for drinking, irrigation, fisheries, and afforestation, as mentioned in the syllabus.

Key Concept: Drip Irrigation

b) Minimizes evaporation and runoff
[Solution Description]
Drip irrigation delivers water directly to the roots of plants, minimizing water loss due to evaporation and runoff. Unlike flood irrigation, which can waste significant amounts of water through surface runoff and deep percolation, drip irrigation ensures precise water application. This method improves water use efficiency and reduces wastage.

Key Concept: River Basin Analysis

b) Brahmaputra
[Solution Description]
From Table 13.1, the annual run-off (in bcm) for the major rivers are: Indus (73), Ganga (501), Brahmaputra (537), Godavari (119), Krishna (68), Kaveri (21), Pennar (6.8), Mahanadi (67), Brahamani (36), Sabarmati (3.8), Mahi (11.8), Narmada (34.5), Tapi (8.68), Subarnarekha (10.8), Others (15.2). The highest annual run-off is for the Brahmaputra river at 537 bcm.

Key Concept: High Yielding Crops, Irrigation, Regional Variations

d) 83.33
[Solution Description]
First, calculate total water required: 1000 mm × 10 ha × 10 m³/mm-ha = 100,000 m³.
Rainfall provides: 500 mm × 10 ha × 10 m³/mm-ha = 50,000 m³.
Additional water needed after rainfall: 100,000 - 50,000 = 50,000 m³.
Considering irrigation efficiency: 50,000 ÷ 0.6 = 83,333.33 m³.
Convert to million liters: 83,333.33 × 1000 ÷ 1,000,000 = 83.33 million liters.

Key Concept: Groundwater Contaminants

a) Heavy/toxic metals and fluoride
[Solution Description]
According to the syllabus, groundwater pollution is caused mainly by heavy/toxic metals, fluoride, and nitrates. Microplastics are an emerging concern but not mentioned as a primary contaminant here. Agricultural runoff contributes indirectly by leaching chemicals into groundwater.

Key Concept: Conservation of Water Resources

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
Both Assertion (A) and Reason (R) are true. Recycling and reusing water indeed help conserve fresh water by reducing the demand for it, especially when inferior quality water is used for non-drinking purposes like irrigation, cooling, or firefighting. The Reason correctly explains why the Assertion is valid, as it highlights the mechanism through which recycling conserves fresh water.

Key Concept: Irrigation, Groundwater

c) Northern plains
[Solution Description]
Groundwater distribution in India is uneven, with high potential in the northern plains due to soft rocks and low potential in the peninsular plateau due to hard rocks. Punjab, Haryana, and Tamil Nadu have high groundwater development. Among these, the northern plains are specifically mentioned for their high potential due to soft rocks.

Key Concept: River Basins, Usable Surface Water

b) Brahmaputra has lower usable \% than Kaveri
[Solution Description]
To find the percentage of usable flow relative to Kaveri river:
1) For Brahmaputra: Usable \% = (24/537) × 100 = 4.47\%
2) For Kaveri: Usable \% = (19/21) × 100 = 90.48\%
3) Comparative analysis: Brahmaputra's usable \% (4.47\%) is significantly lower than Kaveri's (90.48\%).

Key Concept: Basic Economics

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that when demand increases and supply is limited, prices tend to rise. This is true because scarcity drives prices up in a market economy.
The reason explains that higher demand with restricted supply creates scarcity, which pushes prices upward. This correctly justifies the assertion. Therefore, both assertion and reason are true, and the reason explains the assertion logically.

Key Concept: Fire Fighting

c) Water
[Solution Description]
Water is the most commonly used extinguishing agent for Class A fires as it effectively cools and suppresses flames.

Key Concept: Water Allocation Priorities

a) Drinking water
[Solution Description]
The National Water Policy (2002) clearly states that the first priority for water allocation is drinking water, followed by irrigation, hydro-electric generation, industrial and other miscellaneous uses.

Key Concept: Distribution of Lagoons and Backwaters

d) Rajasthan
[Solution Description]
The syllabus mentions that lagoons and backwaters are prominently found in states like Kerala, Odisha, and West Bengal. Among the given options, Rajasthan does not have a coastline and hence is not known for such water bodies.

Key Concept: Lagoons and Backwaters

c) Chilika Lake
[Solution Description]
The largest brackish water lagoon in India, situated in Odisha, is Chilika Lake. It supports rich biodiversity and is a significant source of livelihood for local communities through fishing and agriculture.

Key Concept: Groundwater Resources

c) Northern Plains
[Solution Description]
The Northern Plains have high groundwater availability because of their soft and permeable rocks, which facilitate easy percolation and storage of water. In contrast, the Peninsular Plateau has hard, impervious rocks that limit groundwater storage.

Key Concept: Recycle/Reuse, Government Initiatives

c) Subsurface storage tanks, desalination training, and greywater integration
[Solution Description]
Coastal adaptation requires subsurface storage (to prevent saltwater mixing), community education on desalination-compatible systems, and integration with existing water recycling programs (like using treated greywater for gardening). This aligns with the syllabus' emphasis on context-specific solutions and participatory management.

Key Concept: Lagoons and Backwaters, Economic Utilization

c) Tourism and houseboat services
[Solution Description]
Kerala's backwaters, locally known as "kayals," are extensively used for tourism, fishing, and transportation. They form an interconnected network of canals and lakes, making them ideal for houseboat tourism, which is a significant contributor to the local economy. Additionally, these water bodies support aquaculture, especially shrimp farming, and irrigation of salt-tolerant crops like paddy and coconut.

Key Concept: Sources of Irrigation

c) Northern Plains
[Solution Description]
The northern plains of India, stretching from Punjab to the Brahmaputra valley, have soft and permeable rocks that allow large quantities of water to percolate into the ground. This makes them rich in groundwater resources, with over 85\% of the net sown area under irrigation in states like Punjab.

Key Concept: Water Pollution, Legislative Measures

d) Lack of strict enforcement and inadequate penalties led to ineffective implementation.
[Solution Description]
The Water Cess Act, 1977 aimed to reduce water pollution by imposing a cess on water consumption by industries. However, the act lacked stringent enforcement mechanisms and penalties. Industries continued to discharge untreated waste due to weak implementation and monitoring by authorities. This resulted in minimal impact on reducing pollution despite the legislative provision.

Key Concept: Groundwater utilization, sector-wise distribution

c) 40.38 BCM
[Solution Description]
Total developed groundwater potential = 161.53 BCM.
Irrigation usage = 75\%, so remaining usage = 25\% for domestic and industrial.
Domestic and industrial usage = $161.53 \times \frac{25}{100} = 161.53 \times 0.25 = 40.38$ BCM.

Key Concept: Reason for irrigation demand

c) Uneven spatial and temporal distribution of rainfall necessitates irrigation.
[Solution Description]
Irrigation is crucial due to the uneven spatial and temporal distribution of rainfall in India. Some regions face deficits, while others experience variability, making artificial water supply necessary for consistent agricultural output.

Key Concept: Tube-Wells

d) Proximity to a perennial river.
[Solution Description]
Tube-wells require sufficient groundwater availability, a water table not deeper than 15-50 metres, and access to electricity or diesel for operation. However, they do not necessarily need proximity to perennial rivers, making option d incorrect.

Key Concept: Basic Concept

c) Diverting floodwater for irrigation
[Solution Description]
Inundation canals are usually constructed to divert floodwater from rivers for irrigation purposes during high-flow periods. They do not have permanent structures like head regulators.

Key Concept: Water Resources Utilization

c) Agricultural sector
[Solution Description]
The question asks about the largest consumer of water in India. According to the data, agriculture accounts for 89\% of surface water and 92\% of groundwater utilization, making it the largest consumer.

Key Concept: Upper Ganga Canal, Conversion to Perennial

c) It enabled multiple cropping seasons and increased productivity
[Solution Description]
The Upper Ganga Canal was made perennial by constructing the Bhimgoda Barrage at Haridwar. This ensured a continuous water supply, enabling multiple cropping seasons and increasing agricultural productivity. Previously, seasonal canals only provided water during monsoons, limiting cultivation to one season. The perennial system stabilized irrigation, supporting diverse crops throughout the year.

Key Concept: Techniques - Rainwater Harvesting

c) Generating electricity
[Solution Description]
Roofwater harvesting, recharging handpumps, recharge through abandoned dugwells, and recharge through trenches and bunds are the techniques mentioned. Generating electricity is not listed as a rainwater harvesting technique.

Key Concept: Recycle and Reuse of Water

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The Assertion states that recycling and reusing water reduces pressure on freshwater resources, which is true because it decreases the demand for fresh water by utilizing reclaimed water. The Reason provides a valid explanation for the Assertion, as using reclaimed wastewater for activities like gardening, cooling, or firefighting preserves higher-quality water for drinking and essential uses. Therefore, both the Assertion and Reason are true, and the Reason correctly explains the Assertion.

Key Concept: Monitoring Bodies

b) Central Pollution Control Board (CPCB)
[Solution Description] The Central Pollution Control Board (CPCB), along with State Pollution Control Boards, monitors water quality at various stations across India.

Key Concept: Future water demand trends

b) Domestic and industrial sectors
[Solution Description]
The passage clearly states that while agriculture currently dominates water usage, its share is likely to reduce while domestic and industrial sectors' shares may increase as development progresses.

Key Concept: Water resources, Population, Agricultural water usage

a) 0.23 times the global average
[Solution Description]
To find the ratio of per capita water availability in India compared to the global average:
1. Let total global water resources be $W$ and total global population be $P$.
2. Global per capita water availability = $\frac{W}{P}$.
3. India's water resources = $0.04W$, India's population = $0.174P$.
4. India's per capita water availability = $\frac{0.04W}{0.174P} = \frac{4}{17.4} \times \frac{W}{P} \approx 0.23 \times \frac{W}{P}$.
5. The ratio is approximately 0.23 or 23\% of the global average.

Key Concept: Rainwater Harvesting

c) Drip irrigation systems
[Solution Description]
Rainwater harvesting techniques include roofwater harvesting, recharging through handpumps, abandoned dugwells, trenches, bunds, stop dams, and percolation pits. Drip irrigation is an efficient method for delivering water directly to plant roots but is not a technique for groundwater recharge.

Key Concept: Regional Variations in Irrigation

c) Punjab, Haryana, and Western Uttar Pradesh
[Solution Description]
Punjab, Haryana, and Western Uttar Pradesh have over 85\% of their net sown area under irrigation, making them the leading regions in irrigation coverage.

Key Concept: Rainwater Harvesting

c) Prevents flooding and increases water availability
[Solution Description]
Rainwater harvesting helps increase groundwater recharge by capturing and storing rainwater locally, which also reduces runoff and flooding.

Key Concept: Major Canal Systems by State

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The Assertion (A) states that both the Upper Ganga Canal and the Lower Ganga Canal originate from the Ganga River but irrigate different regions. This is true as the Upper Ganga Canal takes off at Haridwar and irrigates Saharanpur, Muzaffarnagar, Meerut, Bulandshahr, Aligarh, and Ghaziabad, while the Lower Ganga Canal takes off at Narora and irrigates Bulandshahr, Aligarh, Etah, Farrukhabad, and Mainpuri. The Reason (R) explains that the Upper Ganga Canal serves northern districts and the Lower Ganga Canal serves southern districts, which is also correct and provides a valid explanation for why the two canals serve different regions despite originating from the same river. Hence, both Assertion and Reason are true, and Reason correctly explains the Assertion.

Key Concept: Integrated Water Resources Management

c) Holistic management of water resources, considering surface and groundwater as a single entity
[Solution Description]
The National Water Policy (2003) emphasizes integrated water resources management, treating surface and groundwater as a single entity, and promotes participatory approaches involving stakeholders in water management.

Key Concept: Well Irrigation

c) Controlled usage prevents waterlogging
[Solution Description]
Excessive canal irrigation can lead to waterlogging and salinity (reh problem) due to improper drainage. Well irrigation does not cause this issue as it allows controlled water usage and prevents water stagnation in the soil.

Key Concept: Modern Methods of Irrigation

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The Assertion states that tube-wells are more efficient than ordinary wells for irrigation, which is true because tube-wells can irrigate about ten times the area compared to ordinary wells. The Reason given is also true as tube-wells use electric motors or diesel engines to lift larger quantities of water, which is not possible with ordinary wells. Moreover, the Reason correctly explains why tube-wells are more efficient than ordinary wells, as the ability to lift more water directly contributes to their efficiency.

Key Concept: Groundwater utilization

c) 75\%
[Solution Description]
According to the text, about three-fourths (75\%) of the total groundwater is used for irrigation.
Calculation: $\frac{3}{4} \times 100 = 75\%$
Therefore, 75\% of the total groundwater is utilized for irrigation.

Key Concept: Availability \& Distribution Issues

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that the northern and northeastern regions of India account for nearly 60\% of the total surface water resources. This is true as per the syllabus, which mentions that these regions, with major river systems, have a significant share of surface water. The reason states that these regions have major river systems like the Ganga, Brahmaputra, and Indus, which is also true and correctly explains why these regions have more surface water. Therefore, both the assertion and reason are true, and the reason is the correct explanation of the assertion.

Key Concept: Merits of Tank Irrigation

c) Tanks are natural and involve low construction costs
[Solution Description]
The syllabus highlights that most tanks are natural or involve low construction costs, making them accessible even to individual farmers. This is a significant advantage compared to other forms of irrigation.

Key Concept: Major Canal Systems in Punjab

d) Bhakra Canal
[Solution Description]
The Bhakra Canal is sourced from the Bhakra Dam and supplies water to regions in Punjab, Haryana, and Rajasthan for irrigation.

Key Concept: Groundwater Distribution

b) Northern Plains
[Solution Description]
According to the syllabus, the northern plains, with soft and permeable rocks, have vast groundwater resources, accounting for more than $42\%$ of the potential.

Key Concept: Lagoons and Backwaters

c) Fishing
[Solution Description]
The backwaters in Kerala are primarily used for transportation, irrigation, and fishing, forming a network of interconnected canals, rivers, and lakes. Fishing is one of the major activities providing income to the coastal communities.

Key Concept: Spatial Variation

c) Western Ghats
[Solution Description]
The Western Ghats and northeastern states receive the highest annual rainfall due to orographic lifting and monsoon winds. The western slopes of the Western Ghats, especially regions like Mawsynram and Cherrapunji, receive over 250 cm of rainfall annually.

Key Concept: Green Revolution - HYV Crops Irrigation Requirement

b) Both Assertion and Reason are true, but Reason is NOT the correct explanation of Assertion.
[Solution Description]
High Yielding Variety (HYV) crops are designed to produce higher yields but require consistent moisture levels, which is why irrigation is essential even in areas with sufficient rainfall. The assertion is true as HYV crops indeed need regular moisture. The reason is also true because the long growing period in India allows for multiple cropping, which further increases the need for irrigation to sustain these crops throughout the year. However, the reason does not directly explain why HYV crops require regular moisture; it instead explains the broader need for irrigation in Indian agriculture. Hence, both statements are true, but the reason is not the correct explanation of the assertion.

Key Concept: Assertion-Reason

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description] The assertion states a factual historical context about seasonal canals relying on monsoons. The reason correctly identifies the shift to perennial canals due to reliable water sources, which explains the replacement. Thus, both are true, and the reason justifies the assertion.

Key Concept: Information Unavailable

b) N/A
[Solution Description]
No solution can be provided as no relevant syllabus content was found.

Key Concept: Water Recycling and Reuse

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that using reclaimed wastewater for gardening helps conserve fresh drinking water, which is true as mentioned in the syllabus under "Recycle and Reuse of Water". The reason states that reclaimed wastewater is of inferior quality compared to fresh water, which is also true as per the syllabus. Furthermore, the reason correctly explains why using reclaimed wastewater for gardening conserves fresh drinking water - because it allows higher quality water to be reserved for drinking purposes.
Therefore, both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Key Concept: Hydropower Generation, Multipurpose Projects

c) $1.16 \times 10^8$ kWh
[Solution Description]
Potential energy (PE) is calculated using the formula: PE = Volume $\times$ Density $\times$ g $\times$ Head $\times$ Efficiency.
Substitute the values: PE = $500 \times 10^6 \text{ m}^3 \times 1000 \text{ kg/m}^3 \times 9.81 \text{ m/s}^2 \times 100 \text{ m} \times 0.85$.
Calculate step-by-step:
PE = $500 \times 10^6 \times 1000 \times 9.81 \times 100 \times 0.85$ = $4.16775 \times 10^{14}$ Joules.
Convert to kWh (1 kWh = $3.6 \times 10^6$ J): PE = $4.16775 \times 10^{14} \div 3.6 \times 10^6$ = $1.1577 \times 10^8$ kWh ≈ $1.16 \times 10^8$ kWh.

Key Concept: Assertion-Reason

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that HYV crops require regular moisture for optimal growth, which is true as per the syllabus. The reason explains that HYV crops have intensive growth cycles demanding more water than traditional crops, which is also true. Moreover, the reason correctly explains why HYV crops require regular moisture, as their higher yield potential is directly linked to consistent water supply. Therefore, both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Key Concept: Objectives, Public Awareness

c) To ensure community participation and reduce drainage congestion
[Solution Description]
Public awareness drives community participation, ensuring widespread adoption of rainwater harvesting techniques. It helps reduce urban flooding, augment groundwater, and meet water demands sustainably.
Step 1: Link the need for awareness to urban challenges like flooding and water scarcity.
Step 2: Highlight how awareness translates to action (e.g., installing rooftop systems, reducing runoff).
Step 3: Eliminate options focusing solely on government roles or historical practices, as the question emphasizes current urban needs.

Key Concept: Groundwater development, Geological constraints

b) Maharashtra
[Solution Description]
States like Maharashtra, Madhya Pradesh, and Tamil Nadu have developed a larger share of their limited groundwater resources compared to other peninsular regions due to better management strategies.

Key Concept: Earth's Water Distribution

b) 3\%
[Solution Description]
According to the syllabus, about 71\% of the Earth's surface is covered with oceanic water, but only 3\% of the total water on Earth is freshwater. Therefore, the correct answer is 3\%.

Key Concept: Primitive Methods - Wells

d) Wells may dry up if overused or during droughts.
[Solution Description]
The limitations of well irrigation include drying up during droughts and limited water availability, as wells can only irrigate about 0.2 hectares per day.

Key Concept: Geographical distribution, Groundwater potential

c) 82.08 billion cubic meters
[Solution Description]
To calculate Uttar Pradesh's share:
1. National groundwater potential = 432 billion cubic meters
2. Uttar Pradesh's share = 19\% of 432 billion cubic meters
3. Calculation: $0.19 \times 432 = 82.08$ billion cubic meters

Key Concept: Productivity Comparison, Irrigation Impact

b) 33\%
[Solution Description]
Current production from irrigated: 5 ha × 4 t/ha = 20 tons.
Current production from rain-fed: 5 ha × 2 t/ha = 10 tons.
Total current production: 20 + 10 = 30 tons.
If both were irrigated: 10 ha × 4 t/ha = 40 tons.
Increase in production: 40 - 30 = 10 tons.
Percentage increase: (10 ÷ 30) × 100 = 33.33\%.

Key Concept: Uneven Spatial Distribution of Rainfall

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The Assertion states that North-western India and Deccan plateau are rainfall deficit areas, which is true as per the syllabus. The Reason mentions that these regions receive very low rainfall compared to other parts of India, which is also true. Moreover, the Reason correctly explains why these regions are termed as rainfall deficit areas. Thus, both Assertion and Reason are true, and Reason is the correct explanation of Assertion.

Key Concept: Surface water, River systems

b) 1121.4 BCM
[Solution Description]
Total surface water flow = 1869 BCM. The three rivers carry 60\% of this:
Combined flow = 60\% of 1869 BCM = 0.6 $\times$ 1869 = 1121.4 BCM

Key Concept: Overwatering and Soil Salinity

c) Surface accumulation of salts leading to soil salinity
[Solution Description]
Overwatering leads to rising water tables, which bring soluble salts (like chlorides and sulfides of sodium and calcium) to the surface, causing soil salinity and waterlogging. This reduces soil fertility and crop productivity.

Key Concept: Lagoons and Backwaters, Ecological Importance

c) Acting as a vital ecosystem for diverse species
[Solution Description]
Chilika Lake, the largest brackish water lagoon in India, serves as a vital ecosystem supporting diverse flora and fauna. It acts as a breeding ground for various species of fish and migratory birds. The lagoon also supports local fishing communities by providing livelihood opportunities through aquaculture and fisheries. Its brackish nature creates a unique habitat that balances both marine and freshwater ecosystems.

Key Concept: Water Resources, Conservation, Pollution

b) Both Assertion and Reason are true, but Reason is NOT the correct explanation of Assertion.
[Solution Description]
The assertion states that the Brahmaputra and the Ganga carry a significant portion of India's surface water but are polluted in certain areas. This is true as per the syllabus, which mentions these rivers contribute 60\% of India’s surface water and lists their polluted stretches (e.g., Ganga at Kanpur and Varanasi). The reason identifies organic and bacterial contamination as primary pollutants, which is also correct based on CPCB findings cited in the syllabus. However, while both statements are true, the reason does not directly explain why these large rivers specifically face pollution—it only generalizes the cause of river pollution. Thus, the reason is not the correct explanation of the assertion.

Key Concept: Groundwater Distribution

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The assertion states that the northern plains of India have abundant groundwater resources, which is true as mentioned in the syllabus. The reason given is that the soft and permeable rocks in the northern plains allow large quantities of water to percolate into the ground, which is also true and correctly explains why the northern plains have abundant groundwater. Therefore, both the assertion and reason are true, and the reason is the correct explanation of the assertion.

Key Concept: Tube-Wells, Modern Methods

b) Regular power supply
[Solution Description]
Tube-wells require sufficient groundwater, a water table not deeper than 50 metres, and regular power supply for the pumping set. These conditions are crucial for their operation, unlike other factors such as proximity to rivers or government subsidies.

Key Concept: Upper Ganga Canal

a) Saharanpur, Meerut, Muzaffarnagar, Bulandshahr, Ghaziabad
[Solution Description]
The Upper Ganga Canal is taken from the Ganga at Haridwar and irrigates about 8 lakh hectares in Saharanpur, Meerut, Muzaffarnagar, Bulandshahr, and Ghaziabad districts.

Key Concept: Tube-well Irrigation, Uttar Pradesh, Gujarat

c) Groundwater becomes unavailable when needed most
[Solution Description]
During droughts, the ground water level falls critically below the required level, making tube-wells ineffective when most needed. This is particularly problematic in Uttar Pradesh (having the largest tube-well irrigated area) and Gujarat where groundwater depletion is a major concern.

Key Concept: Water Resources of India

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
According to the syllabus, India occupies 2.45\% of the world's land area but is home to 17.4\% of the global population. At the same time, India has only 4\% of the world's water resources. The reason given is that the high population density in India leads to increased demand for water resources, which explains why the limited water resources are under pressure. Thus, both the assertion and the reason are true, and the reason correctly explains the assertion.

Key Concept: Regions Suitable for Well Irrigation

c) Deccan Trap
[Solution Description]
The Peninsular India has rocky structures, uneven surfaces, and limited groundwater, making it largely unsuitable for well irrigation. Regions like the Great Plains, deltaic areas, and sedimentary zones are more favorable.

Key Concept: Rising Demand \& Limited Supply

c) Agriculture
[Solution Description]
According to the Earth Trends 2001 report, agriculture accounts for 89\% of surface water withdrawals in India, making it the largest consumer. Domestic usage is at 9\%, and industrial usage is at 5\%. Therefore, agriculture is the correct answer.

Key Concept: Irrigation Efficiency

c) 70\%
[Solution Description]
Irrigation efficiency is calculated using the formula:
$\text{Irrigation Efficiency (\%)} = \left( \frac{\text{Water Used by Crops}}{\text{Water Applied}} \right) \times 100$. Here, Water Used by Crops = 350 m$^3$, Water Applied = 500 m$^3$. Plugging in the values: $\left( \frac{350}{500} \right) \times 100 = 70\%$.

Key Concept: Industrial Cooling, Thermodynamics

c) 50 kW
[Solution Description]
The COP of a refrigeration system is given by $COP = \frac{Q_L}{W}$, where $Q_L$ is heat removed and $W$ is work input. Given $Q_L = 200\,kW$ and $COP = 4$, we solve for $W$:
$W = \frac{Q_L}{COP} = \frac{200\,kW}{4} = 50\,kW$
The required compressor power input is $50\,kW$.

Key Concept: Upper Ganga Canal

a) Both Assertion and Reason are true, and Reason is the correct explanation of Assertion.
[Solution Description]
The Assertion correctly states that the Upper Ganga Canal originates from the Ganga River near Haridwar and irrigates regions like Meerut, Muzaffarnagar, Bulandshahr, Aligarh, and Ghaziabad districts. The Reason is also true because the canal derives water from Himalayan rivers, which are perennial due to snowmelt, ensuring a steady water supply. Additionally, the Reason correctly explains why the canal can provide irrigation consistently, making it the correct explanation for the Assertion.

Key Concept: Brahmaputra's Runoff

c) 537 BCM
[Solution Description]
The Brahmaputra Basin has an annual runoff of 537 BCM (billion cubic metres). However, only 24 BCM is utilizable due to geographical challenges.

Key Concept: Water Flow Dynamics, Seasonal Variability

a) Flow capacity increases proportionally with the area.
[Solution Description]

Key Concept: Water resources, Utilizable water availability

b) 60.8\%
[Solution Description]
The utilizable water availability is given as 1137 BCM per annum from a natural runoff of 1869 BCM. To find the percentage of utilizable water:
Percentage = (Utilizable water / Natural runoff) $\times$ 100
Percentage = (1137 / 1869) $\times$ 100 $\approx$ 60.8\%

Key Concept: Sectoral Water Usage

c) 89\%
[Solution Description]
According to FIG. 13.3, the agricultural sector uses 89\% of the surface water in India.

Key Concept: Watershed Management, Pollution Sources

c) Dumping of untreated city sewage.
[Solution Description]
The Central Pollution Control Board (CPCB) identifies organic and bacterial contamination as leading causes of river pollution. Untreated sewage from cities and towns is the primary source, as it introduces harmful microorganisms and organic waste into water bodies. Industrial effluents and agricultural runoff also contribute, but sewage is the dominant factor.

Key Concept: States with Well Irrigation

c) Uttar Pradesh, Rajasthan, Madhya Pradesh
[Solution Description]
The syllabus mentions that Uttar Pradesh, Rajasthan, and Madhya Pradesh account for more than half of well irrigation in India.

Key Concept: River Basin Distribution

a) Ganga
[Solution Description]
From Table 13.1, the Brahmaputra has an annual run-off of 537 BCM, the Ganga has 501 BCM, and the Godavari has 119 BCM. Thus, the Ganga is the second-highest after the Brahmaputra.