Question.1

• River Indus rises in Tibet near Mansarovar lake.
• Its total length is 2,900 km and is one of the longest rivers of the world.
• Majority flows through Pakistan and help in agricultural activities.
• The main tributaries of Indus are Nubra, Hunza, Sulley, Beas, Ravi, Chenab, Jhelum. (any two)

Question 2.
Write a short note on the Brahmaputra river system.
Or
Describe the three main features of river Brahmaputra.
Answer:

• The Brahmaputra originates in Tibet where it is known as Tsangpo.
• It flows eastwards parallel to the Himalayas, but it takes a U-tum around the Namcha Barwa and enters India in Arunachal Pradesh.
• It is responsible for creating a havoc of floods in Assam and Bangladesh.
• This river receives less volume of water and has less silt in Tibetan part, but it carries a large volume of water and silt in India.
• It has a braided channel in most of its length in Assam with a few large islands within the channel.

Question 3.
Describe any three features of Ganga-Brahmaputra delta.
Or
Describe the features of the Ganga plain.
Answer:

• The Sundarban Delta derived its name from the Sundari tree which grows well in marshland.
• It is formed by the rivers Ganga and the Brahmaputra.
• It is the world’s largest and fastest growing delta.
• It is also the home of Royal Bengal Tiger.

Question 4.
Why do the Himalayan rivers get flooded every year? What are its advantages?
Answer:

• The Himalayan rivers receive water from the melted snow from the lofty mountains as well as from rain.
• During monsoons, due to heavy rainfall, these rivers get flooded every year.

Advantages:

• The Himalayan rivers flood parts of the northern plains enfiching the soil for the extensive agricultural lands.
• Various food crops and cash crops are grown in these fertile lands.

Question 5.
What progress has been made in the Ganga Action Plan?
Answer:

• Sixty-nine schemes have been completed with positive results.
• Trees have been planted in badly eroded portions.
• Check dams have been repaired in the upper reaches of the river.
• Interception and diversion of several major drains carrying sewage and industrial wastes to the river in some cities like Varanasi, Kanpur, Patna have reduced the pollution level.
• Turtles and the Gangetic dolphins which had disappeared for several years have now reappeared in Varanasi and other places.

Question 6.
Why are most of the Peninsular rivers draining into the Bay of Bengal? Give reasons. Name the two rivers draining into the Arabian Sea.
Answer:
(i)
(a) The main water divide in Peninsular India is formed by the Western Ghats, which runs from north to south close to the western coast..
(b) The Deccan Plateau is higher in the west and slopes gently eastwards.
Thus, most of the peninsular rivers such as Mahanadi, the Godavari, the Krishna and the Kaveri flow eastwards and drain into the Bay of Bengal.
(ii) The river Narmada and river Tapi drain into the Arabian Sea.

Question 7.
Describe the four drainage patterns.
Answer:
The four drainage patterns are as follows:

• Dendritic: The dendritic patterns develop where the river channels follows the slope terrain. The stream with its tributaries resembles the branches of a tree, thus the name dendritic.
• Trellis: A river joined by its tributaries, at approximately right angles, develops a Trellis pattern. A Trellis drainage pattern develops where hard and soft rocks: exist parallel to each other.
• Rectangular: A rectangular drainage pattern develops on a strongly-jointed rocky terrain.
• Radial: The radial pattern develops when streams flows in different directions from a central peak or dome-like structure.

Question 8.
“Rivers constitute the most useful natural resources.” Support the statement with five suitable examples. HOTS
Answer:
Rivers are the most important natural resources because

• Rivers provide water for survival and growth of all organisms.
• Rivers provided ideal conditions for the early man to lead a settled life.
• Rivers have built flood plains, deltas and provide fertile soil for agriculture.
• Water from rivers is used for drinking, irrigation and for generating hydro- electricity.
• Man is able to supplement his food supply with the fish in the rivers. Rivers also serve as natural waterways.
• World’s earliest civilization developed in the river valleys, e.g., Nile Valley civilization, Indus Valley civilization etc. River Valleys are the world’s best agricultural lands, and are densely populated regions.

Question 9.
Explain the main features of the rivers originating from the Himalayas.
Answer:

• Most of the Himalayan rivers are perennial. It means that they have water throughout the year.
• The Himalayan rivers have long courses from their source to the sea.
• These perform intensive erosional activity in their upper courses and carry huge loads of silt and sand.
• They have cut through the mountains making gorges.
• They also have well-developed deltas.

Question.10

• Sewage flowing into the river is to be diverted to other locations for treatment and conversion into energy source.
• Steps have been taken to supply safe drinking water by constructing electric crematoriums and separating bathing Ghats.
• The diversion of several major drains carrying wastes into the river has been completed in cities like Varanasi, Patna and Kanpur and pollution level has been decreased.
• Infrastructure capable of diverting and treatment 835 million litres per day of domestic waste or sewage has been created.
• Ganga Action Plan has been merged with National River Conservation Plan. It now covers 152 towns located along 27 Inter-state rivers in over 16 states.

Important Link

Quick Revision Notes : Drainage

NCERT Solution : Drainage

MCQs: Drainage

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