Worksheet Solutions: Drainage System

Fill in the Blanks 

Q1: The network of channels through which water flows is called ____________.
Ans: drainage system
A drainage system refers to the natural or artificial network of rivers, streams, and other water bodies that carry and distribute water and runoff from a particular region.

Q2: The boundary separating one drainage basin from another is known as ____________.
Ans: watershed
A watershed is the high point or ridge that divides one drainage basin from another. It is the area where the flow of water is directed to different river systems.

Q3: The catchment area of a river is also called its ____________.
Ans: drainage basin
A drainage basin, also known as a river basin, is the entire land area that contributes water to a particular river and its tributaries.

Q4: A drainage pattern resembling the branches of a tree is known as ____________.
Ans: dendritic
A dendritic drainage pattern is a network of rivers and streams that looks like the branches of a tree. It is characterized by a random and branching pattern.

Q5: The rivers originating from the Amarkantak range have a ____________ drainage pattern.
Ans: radial
A radial drainage pattern is one where rivers originate from a central high point and flow outward in different directions, resembling spokes on a wheel.

Q6: The Arabian Sea drainage and Bay of Bengal drainage are separated by the ____________.
Ans: Western Ghats
The Western Ghats is a mountain range that runs along the western coast of India and separates the rivers that flow into the Arabian Sea from those that flow into the Bay of Bengal.

Q7: The largest river in the Peninsular Drainage System is ____________.
Ans: Godavari
The Godavari River is one of the major rivers in the Peninsular Drainage System, and it is the largest in terms of the size of its basin in peninsular India.

Q8: The Narmada and Tapi flow through a rift valley and lack ____________ and ____________  deposits.
Ans: alluvial and deltaic
These rivers flow through fault lines and therefore do not form deltas.

Q9:The boundary line separating one drainage basin from another is called ____________.
Ans: watershed
It divides the flow of water into different drainage basins.

Q10: The Peninsular rivers flow from ____________ to ____________.
Ans: west to east
Most of the rivers in the Peninsular region of India flow from the western part of the plateau towards the eastern coastal regions.

Assertion and Reason Based

Q1: Assertion: The drainage pattern resembling the branches of a tree is known as 'dendritic.'
Reason: This pattern is common in hilly regions.
(a) Both assertion and reason are true, and the reason is the correct explanation of the assertion.
(b) Both assertion and reason are true, but the reason is not the correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Assertion is false, but the reason is true.
Ans: (a)
Explanation:

• The assertion is correct because a dendritic drainage pattern resembles the branching structure of a tree.
• The reason is also correct because this pattern develops in areas where the rock structure is uniform and offers equal resistance to flowing water.
• This allows streams to develop freely in all directions, forming a branching pattern.
• Thus, the reason clearly explains why the dendritic pattern is formed.

Q2: Assertion: The Himalayan rivers are perennial.
Reason: They are fed by both snowmelt and precipitation.
(a) Both assertion and reason are true, and the reason is the correct explanation of the assertion.
(b) Both assertion and reason are true, but the reason is not the correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Assertion is false, but the reason is true.
Ans: (a)

• The assertion is correct because Himalayan rivers flow throughout the year and are therefore perennial in nature.
• The reason is also correct because these rivers receive water from two main sources, melting snow from glaciers and rainfall.
• This continuous supply of water ensures that the rivers do not dry up even during the dry season.
• Thus, the reason clearly explains why Himalayan rivers are perennial.

Q3: Assertion: The Indus River is one of the largest river basins in the world.
Reason: It enters Pakistan near Chillar in the Dardistan region.
(a) Both assertion and reason are true, and the reason is the correct explanation of the assertion.
(b) Both assertion and reason are true, but the reason is not the correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Assertion is false, but the reason is true.
Ans: (b)

• The assertion is correct because the Indus basin covers a vast geographical area, making it one of the largest river basins in the world.
• The reason is also correct as a factual statement about the course of the river, specifically where it enters Pakistan.
• However, the location where the river enters Pakistan does not explain the large size of its basin.
• Therefore, both statements are true, but the reason is not the correct explanation.

Q4: Assertion: The Ganga is the most important river of India.
Reason: It flows through the Western Ghats.
(a) Both assertion and reason are true, and the reason is the correct explanation of the assertion.
(b) Both assertion and reason are true, but the reason is not the correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Assertion is false, but the reason is true.
Ans: (c)

• The assertion is correct because the Ganga is the most important river in India due to its large basin, economic importance, and cultural significance.
• The reason is incorrect because the Ganga does not flow through the Western Ghats.
• Instead, it originates in the Himalayas and flows through the northern plains.
• Hence, the assertion is true but the reason is false.

Q5: Assertion: The Peninsular rivers have a matured drainage system.
Reason: They flow from east to west.
(a) Both assertion and reason are true, and the reason is the correct explanation of the assertion.
(b) Both assertion and reason are true, but the reason is not the correct explanation of the assertion.
(c) Assertion is true, but the reason is false.
(d) Assertion is false, but the reason is true.
Ans: (c)

• The assertion is correct because Peninsular rivers are older and have reached a mature stage of development, which is reflected in their broad valleys and stable courses.
• The reason is incorrect because most Peninsular rivers flow from west to east towards the Bay of Bengal, not east to west.
• Only a few rivers such as Narmada and Tapi flow westwards.
• Therefore, the assertion is true but the reason is false.

Very Short Answer Type Questions

Q1: What is the other name for the Bay of Bengal drainage?
Ans:  It is commonly referred to as the east-flowing drainage system, as most rivers drain into the Bay of Bengal.

Q2: Name the river that originates from the Chemayungdung glacier.
Ans: The river that originates from the Chemayungdung glacier is the Indus River.

Q3: Which river is known as the Dakshin Ganga?
Ans: The river known as the Dakshin Ganga is the Godavari River.

Q4: In which state does the Ganga rise?
Ans: The Ganga rises in the state of Uttarakhand.

Q5: Where does the Ganga enter the plains?
Ans: The Ganga enters the plains at Haridwar.

Q6: Name the important tributary of the Brahmaputra .
Ans: Dibang / Lohit / Subansiri (any one)

Q7: What is the catchment area of the Mahanadi?
Ans: The catchment area of the Mahanadi is approximately 141,600 square kilometers.

Q8: Which river has a delta near Rajamundri?
Ans: The Godavari River has a delta near Rajamundri.

Q9: What is the name of the westernmost Himalayan river in India?
Ans: The name of the westernmost Himalayan river in India is the Indus River.

Q10: What is the term for the pattern of flow of water in a river over a year?
Ans: The regime of a river refers to the seasonal pattern of its flow or discharge over a year.

Short Answer Type Questions

Q1: Explain the concept of a watershed and how it is related to a river's catchment area.
Ans: A watershed is the boundary that separates one drainage basin from another. It is related to a river's catchment area because it defines the area from which the river collects water and drains it into a common outlet.

Q2: Describe the characteristics of the dendritic drainage pattern and provide an example.
Ans: The dendritic drainage pattern is characterized by a river's tributaries resembling the branches of a tree. An example is the rivers of the northern plain in India.

Q3: Discuss the factors that influence the formation of different drainage patterns.
Ans: The formation of different drainage patterns is influenced by geological factors, topography, rock structure, and slope. Dendritic patterns form in flat areas, radial patterns from hills, trellis patterns from folded rock structures, and centripetal patterns in enclosed basins.

Q4: Explain the evolution of the Himalayan drainage system.
Ans: The evolution of the Himalayan drainage system involved the dismemberment of a mighty river into three main drainage systems: Brahmaputra in Assam, Ganga in the central part, and Indus in the western part due to geological events and the uplift of the Potwar Plateau.

Q5: Describe the major rivers and their characteristics in the Peninsular Drainage System.
Ans: The major rivers in the Peninsular Drainage System include Mahanadi, Godavari, Krishna, and Kaveri. These rivers have specific characteristics and play important roles in the region's water resources.

Q6: Why do Peninsular rivers flow from west to east, except for Narmada and Tapi?
Ans: Peninsular rivers flow from west to east due to the tilting of the Peninsular block from northwest to southeast. Narmada and Tapi flow through rift valleys, which is an exception to this pattern.

Q7: Discuss the geological events that have shaped the Peninsular Drainage System.
Ans: The Peninsular Drainage System's evolution was shaped by subsidence of the western flank of the Peninsula, tilting of the Peninsular block, and upheaval of the Himalayas, causing changes in river courses and patterns.

Q8: Explain the regime of rivers and provide examples of Indian rivers with different regimes.
Ans: The regime of rivers refers to the pattern of water flow over a year. Ganga has a monsoon regime with minimum flow in January-June and maximum in August-September. Narmada has low discharge until August when it suddenly rises. Godavari has a minimum in May and a maximum in July-August.

Long Answer Type Questions

Q1: Differentiate between the Himalayan drainage system and the Peninsular drainage system in terms of their characteristics, rivers, and significance.
Ans: The Himalayan drainage system and the Peninsular drainage system in India differ in terms of their characteristics, rivers, and significance.

• Characteristics:
  
  • Himalayan drainage system: The rivers in this system are perennial, meaning they have a continuous flow throughout the year. The rivers in this system are fed by melting glaciers and receive heavy rainfall during the monsoon season. The terrain is steep, resulting in the formation of deep gorges and valleys.
  • Peninsular drainage system: The rivers in this system are seasonal, meaning their flow depends on the monsoon rains. These rivers have a slower flow rate compared to the Himalayan rivers. The terrain is relatively flat, resulting in the formation of broad river valleys.
• Rivers:
  
  • Himalayan drainage system: Some of the major rivers in this system include the Indus, Ganga, Brahmaputra, and their tributaries. These rivers originate from the Himalayas and flow towards the northern plains and the Bay of Bengal.
  • Peninsular drainage system: Some of the major rivers in this system include the Godavari, Krishna, Mahanadi, and Kaveri. These rivers flow towards the east and drain into the Bay of Bengal, while the Narmada and Tapti rivers flow towards the west and drain into the Arabian Sea.
• Significance:
  
  • Himalayan drainage system: The rivers in this system provide water for irrigation, hydropower generation, and domestic use in the northern plains. They also play a crucial role in the transportation of goods and people.
  • Peninsular drainage system: The rivers in this system are important for irrigation and support agriculture in the region. They also serve as a means of transportation and provide water for industrial purposes.
    
    

Q2: Discuss the challenges faced by the Indian drainage systems, both Himalayan and Peninsular, and their impact on the region.
Ans: The Indian drainage systems, both Himalayan and Peninsular, face several challenges that have significant impacts on the region.

• Flooding: The Himalayan rivers, due to their steep terrain and heavy monsoon rainfall, are prone to flash floods. These floods can cause extensive damage to infrastructure, agriculture, and human settlements. The Peninsular rivers, although not as prone to flash floods, can still cause flooding during the monsoon season.
• Sedimentation: The Himalayan rivers carry a large amount of sediment due to the erosion of the mountains. This sedimentation can lead to the formation of sandbars, which can affect navigation and increase the risk of flooding. The Peninsular rivers also carry sediment, but to a lesser extent.
• Water scarcity: The Peninsular rivers, being seasonal, face water scarcity during the dry season. This scarcity affects agriculture, water supply for domestic use, and industrial activities. In the Himalayan region, water scarcity can occur in the higher altitudes due to the freezing of water sources during winter.
• Pollution: Both the Himalayan and Peninsular rivers face pollution from industrial and domestic waste discharge. This pollution affects the quality of water and poses risks to human health and the environment.
• River interlinking: The proposal to interlink rivers in India to transfer water from surplus regions to deficit regions faces challenges in terms of technical feasibility, environmental impact, and displacement of local communities.

These challenges have significant impacts on the region, including loss of lives and property due to floods, reduced agricultural productivity, water scarcity, and degradation of water quality.

Q3: Explain the historical evolution of the Indian drainage systems and how geological events have played a role in shaping them.
Ans: The Indian drainage systems have evolved over millions of years through various geological events, shaping their current form.

• Tectonic activity: The collision of the Indian Plate with the Eurasian Plate led to the formation of the Himalayas. This tectonic activity resulted in the upliftment of the Himalayas and the creation of deep valleys and gorges. The Himalayan rivers originated from the melting glaciers and the rainwater received in this region.
• Erosion: The Himalayan rivers, with their strong flow and erosive power, carved deep valleys and gorges through the mountainous terrain. The erosion of the mountains led to the deposition of sediment in the plains, forming fertile plains where the rivers eventually meandered.
• Monsoon climate: The monsoon climate of India played a crucial role in shaping the drainage systems. The heavy rainfall during the monsoon season contributed to the high flow rate of the Himalayan rivers and the formation of their extensive river networks. The Peninsular rivers, dependent on the monsoon rains, followed the topography of the region and formed their drainage patterns accordingly.
• Geological uplift and subsidence: The movement of tectonic plates and geological uplift and subsidence over time have influenced the course and direction of the rivers. The Peninsular rivers, with their relatively flat terrain, have followed the subsidence patterns and formed broad river valleys.

Overall, the geological events of tectonic activity, erosion, climate, and uplift/subsidence have played a significant role in shaping the Indian drainage systems into their present form.

Q4: Describe the characteristics of the Peninsular rivers and their importance for the region's agriculture, transportation, and ecology.
Ans: The Peninsular rivers in India have certain characteristics that make them important for the region's agriculture, transportation, and ecology.

• Seasonal flow: Unlike the perennial Himalayan rivers, the Peninsular rivers have a seasonal flow. Their flow is dependent on the monsoon rains, which occur from June to September. This seasonal flow pattern affects the availability of water for various activities throughout the year.
• Broad river valleys: The Peninsular rivers flow through relatively flat terrains, resulting in the formation of broad river valleys. These broad valleys provide fertile soil for agriculture and support the cultivation of crops such as rice, sugarcane, and cotton.
• Irrigation potential: The Peninsular rivers, along with their reservoirs and canals, provide water for irrigation purposes. This irrigation potential contributes to increased agricultural productivity in the region.
• Transportation: The Peninsular rivers serve as important transportation routes for the movement of goods and people. They provide a cost-effective means of transportation, especially for areas not well connected by roads or railways.
• Biodiversity and ecology: The Peninsular rivers support diverse ecosystems and habitats. They provide water for various species of plants and animals, contributing to the region's biodiversity. The rivers also play a crucial role in maintaining the ecological balance and supporting the livelihoods of local communities dependent on fishing and other river-based activities.

In summary, the Peninsular rivers play a vital role in supporting agriculture through irrigation, providing transportation routes, and sustaining the region's ecology and biodiversity.