Chapter – 3

Drainage

In this post, we have given the Important Questions of Class 9 Social Science Chapter 3 (Drainage) in English. These Important Questions are useful for the students who are going to appear in Class 9 exams.

Board	CBSE Board, UP Board, JAC Board, Bihar Board, HBSE Board, UBSE Board, PSEB Board, RBSE Board
Textbook	NCERT
Class	Class 9
Subject	Social Science
Chapter no.	Chapter 3
Chapter Name	(Drainage)
Category	Class 9 Social Science Important Questions in English
Medium	English

1 Mark Questions

Q1. What is meant by Water Divide?

Ans. Any elevated area like mountain or an upland which separates two drainage basins is called Water Divide.

Q2. Which river is also known as “Dakshin Ganga”?

Ans. Godavari River

Q3. Which river drains in Arabian Sea and form Estuary?

Ans. Narmada River and Tapti river

Q4. Which river form Dhuandhar waterfall?

Ans. Narmada River

Q5. Name the largest sweet water lake of India. Where is it situated?

Ans. Wular lake, in Jammu & Kashmir

Q6. Which salt water lake is situated in Rajasthan?

Ans. Sambhar Lake

Q7. What is Lagoon?

Ans. Salt water Lake which is separated from sea due to the barrier of sandbar.

Q8. Name two peninsular rivers of India which drains in Bay of Bengal?

Ans. Krishna River, Cauvery River

Q9. Which river is called as “Sorrow of Bihar”?

Ans. Kosi River

Q10.Name two rivers of India which originates from Himalaya Mountain?

Ans. Ganga River and Indus River

 

3/5 Mark Questions:

Q1. Differentiate between Himalayan and Peninsular rivers?

Ans.

Himalayan River System

• They are perennial (water throughout the year) as they are fed by the melting snow.
• They have long course.
• They are mostly flown through unstable areas of new fold mountains of Himalaya.
• They perform high erosion and  depositional work in their course.

Peninsular River System

• They are seasonal as they are fed on rain-water.
• They have shorter course.
• They are mostly flown through stable areas of Gondwana land.
• They don’t perform these activities on such scale.

Q2. Explain Indus River System.

Ans. 

• It originates from Mansarovar Lake in Tibet.
• It flows westward to enter India in Ladhak.
• its tributary rivers are Zasker, Shyok, Sautlaj, vyas, Ravi, Jhelum etc.
• The total length of this river is approx 2900 km of which only a third is in India while rest is in Pakistan,
• it drains into Arabian Sea.

Q3. List the characteristics of Ganga River System.

Ans.

• Ganga is one of the most sacred and longest flowing river of india.
• it originates from Gangotri Glacier in Himalaya.
• The headwater of Ganga, called Bhagirathi, is joined by Alaknanda River at Devaprayag in Uttarakhand.
• At Haridwar the Ganga emerges from the mountains on to the plains.
• Yamuna, Ghagara, Kosi, Chambal, Betwa, Son etc are some of the tributaries of it.
• it has a gentle slope of around 1 m for every 6 km.
• Its total length is around 2500 km.
• It drains in Bay of Bengal before which it forms world’s largest delta “Sundarban” with Brahmaputra River.

Q4. Why Brahmaputra River does not contain silt while passing long distance in Tibet?

Ans.

• Brahmaputra River originates in Mansarovar Lake and mostly flows in Tibet parallel to Himalaya
• Tibet is cold and dry region.
• Due to low quantity of water its erosion power is less, hence it has less silt even though it flows a longer distance.

Q5. Why lakes are important for human?

Ans. Lakes are not only a place of scenic beauty but also have socio-economic

Importance like-

• Encourages Tourism
• Generation of hydroelectricity.
• Regulates the flow of river water.
• During excessive rainfall it controls the flood whereas during draught it ensures the supply of water.
• Helps in balancing the aquatic ecosystem.
• They are also a source of salt manufacturing site.

Q6. List the economic importance of rivers?

Ans. 

• one of the most important inland route for trade since ancient times.
• A great source of irrigation which helps in the development of agriculture.
• The alluvial soil along its bank is the most fertile soil to grow various commodities.
• Due to the surplus production that it gave enables the other economic activities like setting up of manufacturing Industries and other related activities.
• Now a days it also acts as a major source of energy (i.e. hydroelectricity) which is the backbone of other economic activities.

Q7. Explain the causes of river pollution?

Ans.

• Demand in domestic as well as industrial use affected its quality.
• Dumping of untreated Sewage Water from home and industries.
• Excessive use of chemical fertilizers also pollutes the river bodies.
• Industrial pollution combined with acid rain also pollutes river.
• Excessive deforestation led to reduction in rainfall which ultimately affects the water level in pollutes the river.

Q8. What are Estuaries?

Ans.

• The part of river where it joins the sea and where fresh water of river and saline water of sea is mixed is called Estuary.
• it is formed when river drains into ocean or sea where steep slope is present.
• due to the steep slope no depositional work by river takes place hence no delta is formed.

Q9. How tributaries are different from Distributaries?

Ans.

Tributaries

• The small river which joins a large river is called the tributary of the large River.
• it increases the water level of the main River.
• Yamuna, Kosi, Gandak etc. are the tributaries of Ganga River.

Distributaries

• In its lower course river water is divided into many channels forming distributaries
• It reduces the water level of main river.
• Bhagirathi- Hooghly is the distributary of Ganga river.

Q10.Explain the drainage pattern of rivers with suitable example.
Ans.

• Dendrite pattern develops where the river channel follows the slope of the terrain. The stream with its tributaries resembles the branches of a tree.
• A river joined by its tributaries at approximately right angle develops a trellis pattern. It develops where hard and soft rocks exist parallel to each other
• A rectangular drainage pattern develops on a strongly rocky terrain.
• The radial pattern develops when stream flow in different directions from a central peak or dome like structure. For picture see the content

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