Chapter 3: Drainage

An elevated area, like mountain or an upland that separates two drainage basins is called water divide. Ambala is situated on an water divide between the Indus and the Ganga river system.

Question 2(ii)

Which is the largest river basin in India?

Answer

The Ganga basin is the largest river basin in India.

Question 2(iii)

Where do the rivers Indus and Ganga have their origin?

Answer

The river Indus originates in Tibet near lake Mansarowar. The Ganga originates from Gangotri glacier in Himalayas.

Question 2(iv)

Name the two headstreams of the Ganga. Where do they meet to form the Ganga?

Answer

The two headstreams of the Ganga are Bhagirathi and Alaknanda. They meet at Devaprayag to form the Ganga.

Question 2(v)

Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?

Answer

The Brahmaputra in its Tibetan part have less silt, despite a longer course because it has smaller volume of water and the area is cold and dry.

Question 2(vi)

Which two Peninsular rivers flow through trough?

Answer

Two Peninsular rivers that flow through trough are Narmada and Tapi.

Question 2(vii)

State some economic benefits of rivers and lakes.

Answer

Some economic benefits of rivers and lakes include:

Water supply for agriculture, industry, and households.
Navigation and transport.
Hydro-power generation.
Fisheries supporting the fishing industry.
Tourism and recreation opportunities.

Answer the following questions

Question 3

Below are given names of a few lakes of India. Group them under two categories natural and created by human beings.

Wular
Dal
Nainital
Bhimtal
Gobind Sagar
Loktak
Barapani
Chilika
Sambhar
Rana Pratap Sagar
Nizam Sagar
Pulicat
Nagarjuna Sagar
Hirakund

Answer

Natural Lakes	Artificial lakes
Wular	Gobind Sagar
Dal	Rana Pratap Sagar
Nainital	Nizam Sagar
Bhimtal	Barapani
Pulicat	Nagarjuna Sagar
Loktak	Hirakund
Chilika
Sambhar

Question 4

Discuss the significant difference between the Himalayan and the Peninsular rivers.

Answer

Himalayan Rivers	Peninsular Rivers
These rivers are perennial.	These rivers are seasonal.
They receive water from melting snow as well as rains.	They receive water from rains.
They are long with larger drainage basins.	They are relatively shorter and shallower with smaller drainage basins.
They perform intensive erosional activity and bring huge load of silt and sand.	They are less erosive.
Major rivers are the Indus, the Ganga and the Brahmaputra.	Major rivers are the Godavari, the Krishna and the Mahanadi.

Question 5

Compare the east flowing and the west flowing rivers of the Peninsular plateau.

Answer

Differences between east flowing and west flowing rivers of the Peninsular plateau:

East flowing rivers	West flowing rivers
They flow eastwards and drain into Bay of Bengal.	They flow westwards and drain into Arabian sea.
They make deltas at their mouth.	They make estuaries.
They are longer.	They are shorter.
Example: Mahanadi, Godavari, Krishna	Example: Narmada, Tapi, Sabarmati

Question 6

Why are rivers important for the country’s economy?

Answer

Rivers are important for the country's economy in following way:

Rivers are a vital source of freshwater for drinking, irrigation, industrial and household use.
Fertile floodplains and delta regions of rivers are often highly productive agricultural areas.
Rivers are used as inland waterways providing cost-effective transport for bulk goods, such as grains, minerals, industrial products etc.
Multipurpose river valley projects are developed on rivers which provide hydroelectricity, flood control, water supply etc.
Rivers provide tourism and recreation opportunities.
Rivers provide water for industrial use.
Rivers are used for fresh water fishery.

Chapter 3

Drainage

Class 9 - NCERT Geography Contemporary India 1 Solutions