CBSE Class 9 Geography Important Questions Chapter 3 Drainage

1. How does the word "water divide" mean anything? Illustrate.

Ans:

A water divide is a geographical ridge or elevated area that separates different drainage basins, directing the flow of water into distinct river systems. It determines the direction in which rivers and streams flow. For example, the Western Ghats in India act as a major water divide, separating the rivers that flow towards the Arabian Sea (like the Godavari and Tapi) from those flowing towards the Bay of Bengal (like the Krishna and Kaveri).

2. Describe what is meant by "drainage" and "drainage basin."

Ans:

• Drainage refers to the natural or artificial process of removing excess water from an area, typically through rivers, streams, or artificial channels. It involves the flow and distribution of water across a landscape.

• A drainage basin, also known as a watershed or catchment area, is a land area where all the water that falls as precipitation drains into a common outlet, such as a river, lake, or sea. It includes all the tributaries and smaller streams that contribute to the flow of the main river. For example, the Ganges drainage basin encompasses all the areas where rainwater flows into the Ganges River and its tributaries.

3. Compose a brief remark about India's drainage systems.

Ans:

India's drainage systems are diverse and can be broadly classified into two major river systems: the Himalayan Rivers and the Peninsular Rivers.

1. Himalayan Rivers: These rivers originate from the glaciers of the Himalayas and are characterized by their perennial flow due to melting snow. Major rivers in this system include the Ganges, Yamuna, Brahmaputra, and their tributaries. They form a network of rivers that flow across northern and northeastern India, creating vast alluvial plains that are crucial for agriculture.

2. Peninsular Rivers: Unlike the Himalayan rivers, these rivers originate from the plateau regions of Peninsular India and are seasonal, with flow dependent on the monsoon. Key rivers in this system include the Godavari, Krishna, Kaveri, and Mahanadi. These rivers flow towards the east or west and often create deltas and estuaries before emptying into the Bay of Bengal or the Arabian Sea.

4. Describe perennial rivers and those that are not. Why are there perennial rivers in the Himalayan Regions? Explain.

Ans:

• Perennial Rivers are those that flow throughout the year, regardless of seasonal changes. They are typically fed by sources such as glaciers, snowmelt, or underground springs, ensuring a consistent water supply. In contrast, non-perennial rivers only flow during specific seasons, primarily due to rainfall, and may dry up during dry periods.

• The Himalayan regions consist of perennial rivers primarily because of their high-altitude glaciers and snowfields. These rivers, such as the Ganges, Yamuna, and Brahmaputra, receive a continuous supply of water from the melting snow and glaciers throughout the year. This constant supply maintains their flow even during dry months, making them crucial for the region’s water resources and agriculture.

5. Make a note about the system of rivers in India.

Ans:

• The Indus River System is a major river system originating in the Tibetan Plateau near Mount Kailash and flowing through India and Pakistan before emptying into the Arabian Sea. 

• Stretching approximately 3,180 kilometres, it supports agriculture and economy in the region. The system includes key tributaries such as the Jhelum, Chenab, Ravi, Beas, and Sutlej rivers, forming the Indus Basin. 

• This basin is crucial for irrigation and agriculture, especially in Pakistan's Punjab and Sindh provinces, highlighting the river's significant role in the livelihood of millions.

6. Make a note about the River System of the Brahmaputra.

Ans:

• The Brahmaputra River System originates from the Tibetan Plateau, where it is known as the Yarlung Tsangpo. 

• It travels across northeastern India, entering the Assam Valley and flowing through Bangladesh before merging with the Ganges and emptying into the Bay of Bengal. 

• Spanning approximately 2,900 kilometres, the Brahmaputra is one of the major rivers in Asia, renowned for its vast drainage basin and significant contribution to the fertile plains of Assam and Bangladesh. 

• The river supports extensive agriculture, provides water for millions, and is vital for the economy and ecology of the region. Its basin experiences heavy rainfall and flooding, influencing both the environment and human settlements.

7. List any three of the Himalayan Rivers' characteristics.

Ans:

The Himalayan rivers exhibit distinct features due to their origin and geographical setting:

1. Perennial Flow: Himalayan rivers are perennial, meaning they have a continuous flow throughout the year. This is largely due to the melting of snow and glaciers in the Himalayas, which provides a steady supply of water even during dry seasons.

2. Glacial Origins: These rivers originate from glaciers and snowfields in the Himalayan ranges. For example, the Ganges, Yamuna, and Indus rivers have their sources in glacial regions, which contributes to their significant volume and flow.

3. V-shaped Valleys: Himalayan rivers carve out steep, V-shaped valleys as they descend from the mountains. This is a result of their high velocity and erosive power, which shapes the rugged terrain of the region.

8. What are the determinants of drainage patterns?

Ans:

• Topography: The slope and elevation of the land significantly affect drainage patterns. Steeper slopes tend to create more direct and fast-flowing rivers, while flatter areas may result in more meandering streams.

• Geology: The type of rock and soil in an area impacts drainage patterns. Hard, impermeable rocks can lead to the development of parallel or trellis patterns, while softer, more erodible rocks can result in dendritic or radial patterns.

• Climate: Climate influences the amount and distribution of precipitation. Areas with high rainfall may have more complex drainage systems, while arid regions may exhibit more ephemeral or seasonal drainage patterns.

• Tectonic Activity: Geological processes such as uplift, folding, and faulting can alter drainage patterns by creating barriers or changing the slope of the land.

• Human Activity: Human modifications such as dam construction, irrigation, and urban development can significantly alter natural drainage patterns, creating new channels or changing the flow of existing ones.

9. What is the name of the river that is also called the Dakshin Ganga?

Ans:

The river commonly known as the “Dakshin Ganga” (Southern Ganges) is the Godavari River. It is the second-longest river in India and holds significant religious and cultural importance similar to the Ganges in the northern part of the country.

10. Describe a lake. Describe the process by which they form.

Ans:

• A lake is a sizable, naturally occurring body of water surrounded by land. Lakes can be formed through various processes: 

• Tectonic activity creates depressions in the Earth's crust that fill with water, while volcanic activity can form lakes in volcanic craters or calderas. 

• Glacial lakes result from the carving out of depressions by glaciers, which then fill with meltwater. 

• River erosion or sediment deposition can also create lakes by forming natural basins.

• Additionally, human activities like damming rivers can lead to the creation of artificial lakes. Each formation process depends on specific geographical and environmental conditions.

11. Identify India's largest waterfall.

Ans:

The biggest waterfall in India is the Jog Falls, located in Karnataka. It is also known as Gerusoppa Falls or Joga Falls and is renowned for its dramatic and impressive drop.

12. Send a message regarding the National River Protection Plan.

Ans:

The National River Conservation Plan (NRCP) is an initiative by the Government of India aimed at improving the quality of water in the country's major rivers. Launched in 1995, the plan focuses on reducing pollution and restoring the rivers to a cleaner state. It involves:

1. Pollution Control: Implementing measures to treat and manage industrial and domestic waste before it enters the rivers. This includes setting up sewage treatment plants and improving waste disposal systems.

2. Riverfront Development: Enhancing the areas along riverbanks to ensure proper waste management, public sanitation, and conservation efforts.

3. Public Awareness: Educating the public on the importance of river conservation and involving them in maintaining cleanliness.

4. Monitoring and Evaluation: Regular assessment of water quality and the effectiveness of implemented measures to ensure progress and address issues.

13. Rivers have a significant impact on the national economy. In such a case, is it true or false? Provide a rationale for your response.

Ans:

• Yes, rivers play a vital role in a country's economy. They are essential for agriculture, providing water for irrigation which supports crop production and food security. 

• Rivers also serve as important transportation routes, reducing costs and facilitating trade. Additionally, they are a source of hydropower, offering renewable energy that supports electricity generation and reduces reliance on fossil fuels. 

• Rivers contribute to tourism through recreational activities and scenic beauty, boosting local economies. Lastly, they provide crucial drinking water for both urban and rural areas, supporting public health and overall economic development.

14. Give a brief overview of the Ganges River System.

Ans:

• The Ganga River System is one of the most significant and extensive river systems in India. Originating from the Gangotri Glacier in the Himalayas, the Ganga flows southeast across the northern plains of India.

• It traverses several states, including Uttarakhand, Uttar Pradesh, Bihar, and West Bengal, before emptying into the Bay of Bengal.

• The river is fed by several tributaries, including the Yamuna, Ghaghara, Gandak, and Kosi, contributing to its vast drainage basin.

• The Ganga is crucial for agriculture, providing water for irrigation to one of the most fertile regions in India. It also holds immense cultural and religious significance, being revered as a sacred river by Hindus.

• Major cities such as Varanasi, Allahabad, and Kolkata are situated along its banks, highlighting its historical and economic importance. The Ganga supports diverse ecosystems and is a critical resource for millions of people living in its basin.

15. What is India's greatest river basin?

Ans:

The Ganga Basin is the largest river basin in India. It covers an extensive area of about 1,086,000 square kilometres, encompassing several states including Uttarakhand, Uttar Pradesh, Bihar, Jharkhand, and West Bengal. This basin is formed by the Ganga River and its numerous tributaries, such as the Yamuna, Ghaghara, Gandak, and Kosi. It supports a large population and plays a crucial role in the country's agriculture, economy, and cultural practices.

16. Identify the Ganga's two headstreams. The Ganga is formed where do they meet?

Ans:

The two headstreams of the Ganga are the Bhagirathi and the Alaknanda rivers. They meet at the town of Devprayag in Uttarakhand to form the Ganga River. The Bhagirathi originates from the Gangotri Glacier, while the Alaknanda originates from the Satopanth Glacier.

17. Despite having a longer route, why does the Brahmaputra in its Tibetan portion contain less silt?

Ans:

The Brahmaputra River, in its Tibetan part, carries less silt despite its longer course primarily due to the following reasons:

• Glacial Source: The river's source in Tibet is mainly from glaciers, which contribute less sediment compared to rivers originating from areas with more erodible soil.

• Rocky Terrain: In its Tibetan course, the Brahmaputra flows through rocky and less erodible terrains, resulting in a lower sediment load.

• Limited Vegetation: The Tibetan Plateau has sparse vegetation, which means less soil erosion occurs, leading to less silt being carried by the river.

18. List a few of the lakes' and rivers' financial advantages.

Ans:

• Water Supply: They provide a critical source of freshwater for drinking, irrigation, and industrial use, supporting agriculture and various industries.

• Hydropower Generation: Rivers, particularly those with significant flow, are utilised for generating hydroelectric power, contributing to energy supply.

• Transportation: Rivers serve as natural highways for the movement of goods and people, reducing transportation costs and promoting trade.

• Fisheries: Lakes and rivers support fishing industries, which provide livelihoods for many communities and contribute to local and national economies.

• Tourism and Recreation: Scenic lakes and rivers attract tourists for activities like boating, fishing, and sightseeing, generating revenue and supporting local businesses.

19. Talk about how the rivers in the Peninsula and the Himalayas differ significantly from one another.

Ans:

Origin:

• Himalayan Rivers: These rivers originate from the glaciers of the Himalayas, such as the Ganges, Yamuna, and Brahmaputra. Their sources are high-altitude ice fields and snowcaps.

• Peninsular Rivers: These rivers primarily originate from the Western Ghats, such as the Godavari, Krishna, and Kaveri. Their sources are generally in the highlands of the Peninsular Plateau.

Perennial vs. Seasonal Flow:

• Himalayan Rivers: They are perennial, flowing throughout the year due to continuous glacial melt and rainfall. This ensures a steady flow even during dry seasons.

• Peninsular Rivers: Most are non-perennial and seasonal, with flow dependent on the monsoon rains. They often experience significant fluctuations in water levels.

Course and Drainage Patterns:

• Himalayan Rivers: They have long courses and form deep valleys with steep gradients. They are known for their erosive power and can create features such as gorges and rapids.

• Peninsular Rivers: They have shorter courses and more gradual slopes. Their valleys are generally broader, and they often flow through relatively flatter terrain, leading to delta formation at their mouths.

Drainage Basin Size:

• Himalayan Rivers: Their drainage basins are extensive and cover large areas due to the high rainfall and large glaciers feeding them.

• Peninsular Rivers: Their drainage basins are comparatively smaller and are influenced by the limited rainfall and lack of glacial sources.

Economic and Environmental Impact:

• Himalayan Rivers: They are crucial for irrigation, and hydropower generation, and support large populations. They also contribute significantly to the sediment load of the Ganges-Brahmaputra Delta.

• Peninsular Rivers: They support agriculture, particularly in their respective river basins, but are less reliable for irrigation due to their seasonal nature. They also face challenges like water scarcity during dry periods.

20. Examine the differences between the Peninsular Plateau's eastward and westward flowing rivers.

Ans:

Direction of Flow:

• East-Flowing Rivers: These rivers flow towards the eastern coast of India. They include major rivers such as the Godavari, Krishna, and Kaveri.

• West-Flowing Rivers: These rivers flow towards the western coast of India. Prominent examples are the Tapi (Tapti), Narmada, and Mahi rivers.

Source and Course:

• East-Flowing Rivers: They originate from the Western Ghats and generally flow across the Deccan Plateau towards the Bay of Bengal. Their courses tend to be longer and cross a broader range of terrains.

• West-Flowing Rivers: They also originate from the Western Ghats but flow towards the Arabian Sea. Their courses are relatively shorter and tend to run through narrower valleys.

Drainage Pattern:

• East-Flowing Rivers: These rivers form deltas at their mouths due to the extensive sediment carried from their courses. For example, the Godavari and Krishna rivers form large deltas along the eastern coast.

• West-Flowing Rivers: These rivers typically do not form deltas but rather empty into estuaries or have a direct discharge into the Arabian Sea. Their flow is often more direct, and they may create smaller riverine estuaries.

Features and Tributaries:

• East-Flowing Rivers: They are fed by numerous tributaries and have larger drainage basins. The region they traverse is more prone to sediment deposition, contributing to fertile plains.

• West-Flowing Rivers: These rivers usually have fewer tributaries compared to the east-flowing rivers and often have a more rugged terrain. They are more prone to having their flows disrupted by the hilly terrain of the Western Ghats.

Economic and Environmental Impact:

• East-Flowing Rivers: They are crucial for irrigation, agriculture, and water supply in their respective basins. The deltas formed by these rivers are agriculturally significant and support dense populations.

• West-Flowing Rivers: Although they are important for local water supply and agriculture, they face challenges such as water scarcity and limited agricultural use due to their shorter courses and steeper gradients. The rivers are also significant for hydroelectric power generation in some regions.

21. What kind of drainage pattern does the Narmada River create?

Ans:

• The Narmada River exhibits a "Dendritic" drainage pattern.

• In this pattern, the river and its tributaries resemble the branches of a tree, with a central river and several smaller streams flowing out from it like branches. The dendritic pattern typically occurs in regions with a uniform rock type and relatively flat terrain, where the river system follows the natural contours of the landscape.

22. The _______ river has two tributaries: Zaskar and Nubra.

Ans: Indus River

23. Name three rivers in the Himalayan region. List each of its two tributaries.

Ans:

Indus River System

• Jhelum

• Chenab

Ganga River System

• Yamuna

• Ghaghara

Brahmaputra River System

• Dibang

• Subansiri

Important Topics of Class 9 Geography Chapter 3 Important Questions and Answers

Class 9 Geography Chapter 3 Extra Questions and Answers cover topics such as the major river systems of India, their tributaries, drainage patterns, and the significance of rivers for the country's geography and economy.

Benefits of Learning with Drainage Class 9 Important Questions and Answers PDF

Studying Geography Class 9 Chapter 3 Extra Questions Important Questions and Answers offers students several benefits.

• Provides a thorough grasp of India’s river systems, their geographical significance, and their role in the country's economy and environment.

• Helps students understand complex drainage patterns, river basins, and their impact on agriculture, water resources, and regional development.

• Equips students with key concepts and answers, aiding in effective revision and better performance in exams.

• Encourages analysis of geographical patterns and their implications, fostering analytical skills and a deeper appreciation of India’s physical landscape.

Conclusion

Drainage Class 9 Important Questions and Answers PDF provides essential insights into India’s complex river systems and their significance. Understanding the major rivers, their basins, and drainage patterns is important for comprehending the country's geography, natural resources, and regional development. This knowledge not only enhances academic performance but also informs real-world applications related to water management and environmental conservation.

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