Important Questions: Drainage System | Geography Class 11 - Humanities/Arts PDF Download

Very Short Answer Type Questions

Q1: Where is the dendritic drainage pattern found in India?
Ans: In the Great Plains of North India.

Q2: Name the three rivers that flow into the Arabian Sea.
Ans: Narmada, Tapi and Mahi.

Q3: Give two examples of antecedent rivers.
Ans: Brahmaputra and Kosi are the two antecedent rivers.

Q4: Name two rivers of Central India.
Ans: Sind and Chambal.

Q5: Name the main watershed of peninsular rivers.
Ans: The Western Ghats.

Q6: Which river falls into the Gulf of Khambat?
Ans: Mahi river falls into the Gulf of Khambat.

Q7: What is a river basin?
Ans: The watersheds of large rivers are called river basins.

Q8: What is cuspate deltas?
Ans: The rivers like Ebro of Spain which form the tooth-like delta at their mouth are known as the cuspate delta.

Short Answer Type Questions

Q9: What are the various types of drainage patterns?
Ans: The drainage pattern is of various types:

• Dendritic: When the drainage develops similar to branches of a tree.
• Radial: When the rivers radiate from a hill.
• Centripetal: When the rivers flow into a lake or a depression
• Trellis: When primary tributaries flow more or less parallel to one another and the secondary tributaries join from sides more or less a right angle.

Q10: What are the river basin and watershed?
Ans: A river basin is a form of natural or artificial depression. The total area of the land drained by a river and its tributaries is known as a river basin. On the other hand, watershed means water parting. The watershed may or may not be sharply defined, separating two continuous drainage areas from the head-stream flow in different directions into different river systems or river basins.

Q11: Why flood is a frequent feature in the Brahmaputra basin?
Ans: The Brahmaputra is one of the largest rivers in the world. It is a trans-Himalayan river. It rises in Kailash range near Mansarovar lake. It flows eastward longitudinally covering a distance of 1200 km. It forms a gorge in Namcha Barwa mountains. In India, it enters forming a gorge. It receives Dihang and Lohitas its tributaries. The characteristic feature of Brahmaputra is its flood. It is due to the fact that both the Purvanchal Himalayas and the Shillong plateau receive heavy rainfall.

Q12: What do you mean by cusecs and comes?
Ans: The discharge of the volume of water flowing in the river is measured overtimes. It is measured either in cusecs or incomes. When the water is measured in cubic feet per second it is called cusecs. On the other hand, when the flowing water is measured in cubic metre per second it is called comes.

Q13: What do you mean by consequent rivers?
Ans: The Indus, Satluj, Kosi are the trans-Himalayan rivers. These rivers are known as consequent rivers. These rivers maintain their originals shape, deposit. The rise of the land due to folding rivers keep on flowing in the original direction. These rivers are older than the fold mountains. Rivers cut deep gorges due to down-cutting.

Long Answer Type Questions

Q14: Describe the formation of meanders.
Ans: A river in its flood plain develops loops in its course and shows characteristic features. When water flows under gravity, it seldom flows straight for any long-distance and a winding course develops. The irregularities of the ground force the river to swing in loops. These loops are known as meanders. The ‘meander’ is a term derived from the winding river.

Q15: Why do the rivers on the western coast have no deltas, even though they transport a lot of sediment with them? State three main characteristics of Himalayan and peninsular rivers.
Ans: The rivers over the western coast transport lot of sediment with them but do not form a delta, because they are unable to deposit this sediment at the coast. They are very swift due to the deep slope of the ghats and narrow coastal plain. Therefore they do not form deltas.
Characteristics of Himalayan rivers – The characteristics of the Himalayan rivers are:

• The Himalayan river system consists of some longest rivers.
• The catchment areas and river basins of Himalayan rivers are large.
• These rivers originate from the snow-covered areas and receive water from rainfall as well as from snowmelt. They are periodic.
• These rivers are useful for irrigation and navigation.

Q16: Write a short note on Balanced water in the Ganga basin.
Ans: Ganga is the most important river of the northern plain, from both the point of view of its basin and cultural significance. It rises in the Gangotri glacier near Gomukh in the Uttarkashi district of Uttranchal. Here it is known as Bhagirathi. At Dev Prayag, the Bhagirathi meets the Alaknanda and it is named as Ganga. Ganga enters the plains at Haridwar and flows southwards and south-east splitting into two distributaries namely Bhagirathi and the Hugh: The river is 2,525 km in length. The Ganga basin covers about 9,52,000 km2 in India alone.

Q17: The Indian rivers are useful for the country. Comment on the statement.
Ans: A large number of rivers carry the rainwater of India into the sea. The total volume of annual precipitation in our country is approximately 37,00,400 million cubic metres. Out of this 45% flows through 113 rivers. However, for uneven topography and flow characteristics, all of this is not usable. 33% of the water from the annual flow is used for irrigation.
Large rivers have great water potential. 60% of the total river flow is concentrated in the Himalayas, 16% in the central Indian rivers (the Narmada, Tapi and Mahanadi). The country has an exploitable power potential of about 41 million km. The Ganga and Brahmaputra in the north and north-eastern part, Mahanadi in Orissa, Krishna in Andhra, Narmada and Tapi in Gujarat possess some of the important and useful waterways in the country. The most important navigation rivers are the Ganga, the Brahmaputra and the Mahanadi. The Godavari, the Krishna, the Narmada and Tapi are navigable near their mouths only.
Thus, the major usability of Indian rivers is for irrigation, power generation and navigation. Besides, the rivers also supply water to cities, villages and industrial installations.

Q18: Differentiate between the Himalayan rivers and the Peninsular rivers.
Ans: Himalayan rivers and Peninsular rivers refer to two distinct sets of rivers in India, each with unique characteristics based on their origins, courses, and features. Here are the key differences between the two:

Himalayan Rivers:

• Origin: Himalayan rivers originate from the Himalayan mountain range, which includes major rivers like the Ganges, Yamuna, Brahmaputra, and their tributaries. These rivers are fed by snowmelt and glaciers from the Himalayas.
• Perennial Flow: Himalayan rivers have a perennial flow, meaning they flow throughout the year. They have a steady water supply due to the continuous melting of snow and glaciers, ensuring a consistent water flow even during dry seasons.
• Seasonal Variation: While these rivers have a consistent flow, they still experience seasonal variations in water levels, with increased flow during the monsoon season due to heavy rainfall in the Himalayan region.
• Course: Himalayan rivers generally have a turbulent course with fast-flowing water, steep gradients, and numerous rapids and waterfalls.
• Deposition of Sediments: Due to their swift currents, Himalayan rivers carry large amounts of sediments and contribute significantly to the deposition of fertile alluvial soil in the plains they flow through.

Peninsular Rivers:

• Origin: Peninsular rivers originate within the peninsular plateau of India. Major peninsular rivers include the Godavari, Krishna, Kaveri, Mahanadi, and others. These rivers are primarily rain-fed and do not have a direct connection with glaciers or snowmelt.
• Seasonal Flow: Peninsular rivers are more prone to seasonal fluctuations. They have a significant flow during the monsoon season when the plateau receives heavy rainfall, but their water levels decrease significantly during the dry seasons.
• Course: Peninsular rivers generally have a calmer course compared to Himalayan rivers. They often meander through the plateau, creating broader valleys and estuaries as they approach the coast.
• Deposition of Sediments: Peninsular rivers carry fewer sediments compared to Himalayan rivers due to their gentler flow, leading to the formation of deltaic regions at their mouths.
• Deltas: Peninsular rivers form deltas where they meet the sea, such as the Sundarbans Delta (formed by the Ganges-Brahmaputra river system) and the Godavari Delta. These deltas are important ecologically and agriculturally.

Q19: Give some characteristic features of the Kaveri basin.
Ans: The Kaveri (also spelled Cauvery) River basin is one of the major river basins in India, known for its agricultural significance and ecological diversity. Here are some characteristic features of the Kaveri basin:

• Geographical Extent: The Kaveri River basin is located in Southern India, primarily covering the states of Karnataka and Tamil Nadu. It also extends into small parts of Kerala and Puducherry.
• Origin: The Kaveri River originates from Talakaveri in the Western Ghats of Karnataka. It is one of the few rivers in India that flows in an easterly direction and empties into the Bay of Bengal.
• Agricultural Importance: The Kaveri basin is renowned for its agricultural productivity. The river and its tributaries provide water for extensive paddy fields, sugarcane, and various other crops. The basin supports a significant portion of the agricultural economy in both Karnataka and Tamil Nadu.
• Hydroelectric Potential: The Kaveri basin has several dams and reservoirs, such as the Krishna Raja Sagara Dam in Karnataka and the Mettur Dam in Tamil Nadu. These structures not only regulate water flow but also contribute to hydroelectric power generation.
• Wildlife and Biodiversity: The Kaveri basin is ecologically rich, hosting diverse flora and fauna. The Western Ghats, which form a part of the basin, are a biodiversity hotspot with numerous endemic plant and animal species. The region is also home to several wildlife sanctuaries and national parks.
• Water Disputes: The sharing of Kaveri waters has been a longstanding source of dispute between Karnataka and Tamil Nadu. Various agreements and tribunals have been established to manage the distribution of water resources equitably among the riparian states.
• Cultural Significance: The Kaveri River is culturally significant for the people of Karnataka and Tamil Nadu. It is often referred to as the "Ganga of the South" and is associated with numerous myths, legends, and religious ceremonies.
• Tourism: The picturesque landscapes, waterfalls, and historical sites along the Kaveri River attract tourists and nature enthusiasts. Places like Coorg in Karnataka and Hogenakkal Falls in Tamil Nadu are popular tourist destinations within the Kaveri basin.

Q20: Why do the rivers on the western coast have no deltas?
Ans: Rivers on the western coast of India, such as the Konkan Coast, do not typically form deltas like those on the eastern coast (e.g., the Ganges-Brahmaputra Delta) due to several geological and hydrological reasons:

• Steep Slopes: The Western Ghats, a mountain range running parallel to the western coast of India, have steep slopes. Rivers originating from the Western Ghats tend to have a rapid descent toward the Arabian Sea. The steep gradients prevent the rivers from depositing sediment in a fan-shaped delta, as the sediments are quickly carried into the deeper sea by the swift currents.
• Limited Sediment Supply: Western coastal rivers generally have a limited supply of sediments. Unlike the Ganges and Brahmaputra, which carry vast amounts of sediment from the Himalayas, the rivers on the western coast have shorter courses and smaller drainage basins. This limited sediment load contributes to the absence of large deltas.
• Erosion by Sea Currents: The Arabian Sea along the western coast of India experiences strong tidal and oceanic currents. These currents erode the sediment deposited by the rivers, preventing the accumulation of sediments necessary for delta formation.
• Wave Action: High wave energy along the western coast prevents the deposition of sediments close to the river mouths. Waves disperse sediments along the coastline, making it difficult for sediments to accumulate in a specific area to form a delta.
• Submarine Canyons: The presence of submarine canyons along the western continental shelf allows sediments to be quickly transported and dispersed into deeper oceanic regions, limiting the accumulation of sediments near the coast.

While western coastal rivers do not form classical deltas, they often have estuaries where the river meets the sea. Estuaries are semi-enclosed coastal bodies of water with a mix of fresh water and seawater. These estuarine regions are ecologically rich and support diverse ecosystems, even though they lack the large, fan-shaped deltas seen on the eastern coast.