Drainage System
1. Choose the right answer from the four alternatives given below.
(i) Which one of the following rivers was known as the ‘Sorrow of Bengal’?
(a) The Gandak (c) The Kosi
(b) The Son (d) The Damodar
Ans: (d) The Damodar.
(ii) Which one of the following rivers has the largest river basin in India?
(a) The Indus (c) The Ganga
(b) The Brahmaputra (d) The Krishna
Ans: (c) The Ganga.
(iii) Which one of the following rivers is not included in ‘Panchnad’?
(a) The Ravi (c) The Indus
(b) The Chenab (d) The Jhelum
Ans: (c) The Indus.
(iv) Which one of the following rivers flows in a rift valley?
(a) The Son (c) The Yamuna
(b) The Narmada (d) The Luni
Ans: (b) The Narmada.
(v) Which one of the following is the place of confluence of the Alaknanda and the Bhagirathi?
(a) Vishnu Prayag (c) Karan Prayag
(b) Rudra Prayag (d) Deva Prayag
Ans: (d) Deva Prayag
2. State the differences between the following.
(i) River Basin and Watershed
Ans: River Basin vs. Watershed: Exploring the Differences
Both river basins and watersheds are crucial units for understanding water resources and land management. While they are related, they differ in size, scope, and function. Here's a breakdown:
1. Size and Scale:
*River basin: A vast area drained by a river and all its tributaries. Think of it as a giant funnel, where all the water eventually flows into the main river.
*Watershed: A smaller unit within a river basin, drained by a smaller stream or creek. Imagine it as a sub-section of the larger funnel, collecting water for a specific stream or tributary.
2. Focus:
*River basin: Focuses on the entire drainage system, including the main river, tributaries, and the land they drain. It's concerned with the overall water resources and management within the entire basin.
*Watershed: Focuses on the specific area drained by a particular stream or creek. It deals with local water management issues within that specific area, like erosion control or pollution prevention.
3. Example:
*River basin: The Amazon River basin covers a massive area of South America, encompassing several countries and countless tributaries.
*Watershed: The Chesapeake Bay watershed is a smaller unit within the larger Mississippi River basin, focusing on the land and water resources that contribute to the Chesapeake Bay.
4. Importance:
*River basin: Crucial for understanding large-scale water management issues like flood control, irrigation, and hydropower generation.
*Watershed: Vital for localized water resource management, including soil conservation, pollution prevention, and habitat protection.
In a nutshell:
*Think of a river basin as a big umbrella, and watersheds as the smaller sections under it. Both are essential for understanding the flow of water in a landscape, but they operate at different scales and serve different purposes.
(ii) Dendritic and Trellis drainage pattern
Ans: Both dendritic and trellis are common drainage patterns found in nature, but they differ in their appearance and formation:
1. Appearance:
*Dendritic: Resembles the branched pattern of a tree, with tributaries joining the main stream at various angles. Think of veins on a leaf, or lightning striking the ground.
*Trellis: Looks like a grid or rectangular network, with tributaries joining the main stream at nearly right angles. Imagine city streets forming a blocky pattern.
2. Formation:
*Dendritic: Develops in areas with uniform rock types and gentle slopes. Water flows freely in different directions, carving its own channels until a network of streams forms.
*Trellis: Occurs in regions with alternating bands of hard and soft rocks. Erosion is faster in softer layers, creating parallel valleys, while water flows perpendicularly across harder ridges, forming tributaries at right angles.
3. Examples:
*Dendritic: The Amazon River, the Ganges River, and most river systems worldwide.
*Trellis: The Columbia River in the northwestern United States, the Rhine River in Europe.
In a nutshell:
*Dendritic is like a branching tree, found in uniform landscapes.
*Trellis is like a grid, formed by erosion of different rock types.
(iii) Radial and Centripetal drainage pattern
Ans: Both radial and centripetal drainage patterns involve water flowing towards a central point, but they differ in their direction and overall appearance:
1. Direction:
*Radial: Streams flow outwards from a central high point, like a starburst or the spokes of a wheel. Imagine water pouring down a mountain in different directions.
*Centripetal: Streams flow inwards towards a central depression or lake, like water draining into a sinkhole. Think of rainwater converging towards a pond in a valley.
2. Formation:
*Radial: Occurs in areas with a central dome-shaped uplift, like volcanoes or hills. Water flowing down the slopes naturally diverges outwards.
*Centripetal: Found in low-lying areas surrounded by higher terrain, like basins or deserts. Water has nowhere else to go but towards the central point.
3. Examples:
*Radial: The Amarkantak Plateau in India, the volcanic island of Reunion, the Grand Canyon in Arizona (partially).
*Centripetal: The Qattara Depression in Egypt, the Thar Desert in India, the Dead Sea basin.
In a nutshell:
*Radial: Streams flow outwards from a central high point, like spokes of a wheel.
*Centripetal: Streams flow inwards towards a central depression or lake, like water draining into a sink.
Understanding these drainage patterns can tell us about the underlying geology, potential flood risks, and even agricultural possibilities in a region.
(iv) Delta and Estuary
Ans: While deltas and estuaries both involve the interaction of land and water, they are distinct features with key differences:
1. Definition:
*Delta: A landform at the mouth of a river, where sediment carried by the river is deposited, creating a fan-shaped area of low-lying land. Think of the Nile Delta or the Mississippi Delta.
*Estuary: A partially enclosed coastal body of water where freshwater from a river mixes with saltwater from the ocean. Think of the Chesapeake Bay or the Bay of Fundy.
2. Waterbody:
*Delta: Dominated by freshwater from the river, especially near its mouth. However, seawater can penetrate further upstream over time.
*Estuary: Mixture of freshwater and saltwater, creating brackish water with varying salinity levels depending on the tides and river flow.
3. Sediment:
*Delta: Landform built entirely of sediment deposited by the river, gradually extending into the waterbody.
*Estuary: May have some sediment deposition from the river, but also influenced by erosion from waves and tides.
4. Shape:
*Delta: Typically fan-shaped or triangular, with distributaries (smaller channels) fanning out from the main river channel.
*Estuary: Can have various shapes, from elongated bay-like forms to complex networks of channels depending on the coastline and river flow.
5. Ecology:
*Delta: Supports unique ecosystems adapted to freshwater wetlands and brackish water near the coast. May be rich in vegetation and fish species.
*Estuary: Highly diverse ecosystems thriving on the mixture of freshwater and saltwater. Often nursery grounds for many marine species and important bird habitats.
In a nutshell:
*Delta: Landform built by river sediment, freshwater dominant, fan-shaped.
*Estuary: Waterbody with mixed freshwater and saltwater, brackish water, various shapes.
Both deltas and estuaries are crucial natural resources, providing fertile land, fish nurseries, and valuable habitats for diverse wildlife. Understanding their differences helps us appreciate their unique roles in the coastal environment and manage them sustainably.
3. Answer the following questions in about 30 words.
(i) What are the socio-economic advantages of inter-linking of rivers in India?
Ans: Inter-linking rivers in India can bring:
*Reduced floods & droughts: Water diverted from surplus rivers to deficit areas.
*Enhanced irrigation: More consistent water access for agriculture, boosting yields.
*Hydropower generation: Potential to create new hydro stations along connecting canals.
*Improved inland navigation: Connecting rivers creates efficient waterways for transport.
Remember, inter-linking also has environmental concerns to be carefully addressed.
(ii) Write three characterstics of the Peninsular river.
Ans: 1. Seasonal Flow: Dependent on monsoon rains, they roar in the wet season and dwindle or even dry up in the dry season. Imagine a mighty river transforming into a trickle.
2. Shallow & Broad: Carving valleys with gentle slopes, these rivers are typically wider and shallower than their Himalayan counterparts. Picture a tranquil, expansive waterway instead of a deep, rushing gorge.
3. Hard Rock Beds: Flowing over resistant peninsular rocks, they exhibit less erosion and meandering compared to Himalayan rivers. Think straighter courses with fewer dramatic bends.
These characteristics shape the landscapes, resources, and challenges faced by regions along these fascinating rivers.
4. Answer the following questions in not more than 125 words.
(i) What are the important characteristic features of north Indian rivers? How are these different from Peninsular rivers?
Ans: North Indian Rivers vs. Peninsular Rivers: A Tale of Two Terrains
North Indian and Peninsular rivers, born from different geological and climatic parents, wear distinct characteristics:
North Indian Rivers:
*Perennial powerhouses: Fed by glaciers and snow, they flow year-round, unlike their monsoon-dependent southern cousins. Imagine a constant gush, not seasonal bursts.
*Mountain carvers: Flowing through the Himalayas, they etch deep, V-shaped valleys, contrasting with the gentler slopes of Peninsular valleys. Think rushing torrents through gorges.
*Artistic meanderers: Softer Himalayan rocks allow them to curve and loop gracefully, creating intricate patterns compared to the straighter courses of Peninsular rivers. Picture a scenic snake in the landscape, not a rigid line.
Peninsular Rivers:
*Seasonal serenades: Their song depends on the monsoon, roaring in the wet season and turning into gentle whispers or even disappearing acts in the dry months. Imagine a dramatic shift, not a steady hum.
*Gentle giants: Flowing over ancient, hard rocks, they tend to be broader and shallower, carving wider valleys with less dramatic gorges. Picture a tranquil expanse, not a wild plunge.
*Straighter paths: The peninsular terrain dictates a less meandering course, with fewer intricate bends compared to their northern counterparts. Think a determined flow, not a playful dance.
These contrasting features not only shape the landscapes they traverse but also influence the challenges and opportunities they present to the regions they nourish. Understanding their unique stories allows us to appreciate the diverse tapestry of India's waterways.
(ii) Suppose you are travelling from Haridwar to Siliguri along the foothills of the Himalayas. Name the important rivers you will come across. Describe the characteristics of any one of them.
Ans: Embarking on a picturesque journey from Haridwar to Siliguri along the Himalayan foothills, you'll witness a symphony of rivers carving their paths through majestic landscapes. Here are some key encounters:
1. The Ganga: Your journey begins alongside the revered Ganga, its sacred waters meandering through fertile plains and holy towns. This "lifeline of India" boasts immense size and cultural significance.
2. The Kosi: This unpredictable giant, known for its dramatic floods and shifting course, carves a path through the Terai region, leaving behind fertile alluvial plains.
3. The Gandak: Joining the Ganga near Patna, the Gandak offers a serene contrast, flowing placidly amidst lush vegetation and diverse wildlife.
4. The Brahmaputra: As you approach Siliguri, the mighty Brahmaputra steals the show. Originating in Tibet, it carries glacial meltwater, creating a spectacle of power and grandeur.
Let's dive deeper into the Brahmaputra:
1. Perennial Powerhouse: Unlike its monsoon-dependent counterparts, the Brahmaputra flows year-round, fueled by glacial waters. Imagine a relentless torrent, not a seasonal whisper.
2. Mountain Carver: Its journey through the Himalayas results in a deep, V-shaped valley, with dramatic drops and mesmerizing rapids. Think a wild gush, not a gentle meander.
3. Living Legend: Its fertile floodplains and diverse ecosystems support vibrant communities and unique wildlife, making it a treasure trove of both cultural and ecological significance.
So, prepare to be awestruck by the ever-changing tapestry of rivers alongside your Himalayan odyssey. Each with its own story to tell, they paint a mesmerizing portrait of India's northern landscape.
Project/Activity
Study the Appendix III and answer the following questions.
(i) Which river has the largest proportion of catchment area in the country?
(ii) Make a comparative bar diagram on a graph paper to show the length of the
courses of the rivers.
Answer By: Himashree Bora.
