Q1. What is meant by a water divide? Give an example.

Ans 1: Any elevated area separates two drainage basins. Such upland is called a water divide. Example:
Ambala is located on the water divide between The Indus and The Ganga.

Q2. Which is the largest river basin in India?

Ans 2: The Ganga River Basin is the largest river basin in India.

Q3. Where do the rivers Indus and Ganga have their origin?
Ans 3: The Indus River has its origin in Tibet near the Mansarovar Lake whereas the Ganga River originates
from the Gangotri Glacier in Uttaranchal.

Q4. Name the two headstreams of the Ganga. Where do they meet to form the Ganga?
Ans 4: Bhagirathi and Alaknanda are the two headstreams of river Ganga. Both Bhagirathi and Alaknanda
meet at Devaprayag to form the Ganga.

Q5. Why does the Brahmaputra in its Tibetan part have less silt, despite a longer course?
Ans 5: The Brahmaputra river is popularly known as Tsangpo in Tibetan part. Tibet is basically a very cold
and dry area, thus, the river carries very small amount of water leading to very less silt content, despite having
a large course.

Q6. Which two peninsular rivers flow through trough?

Ans 6: Narmada and Tapi are the two peninsular rivers flowing through the trough.

Q7. State some economic benefits of rivers and lakes.

Ans 7: Economic benefits of rivers:
1. Rivers have been a source of food since pre-history, almost all the civilizations developed along the
river banks.
2. Rivers are also used for irrigation, hydropower generation.
3. Rivers are used for navigation. They provide the cheapest inland means of transport.
4. Water from the river is the basic natural resource essential for various day-to-day activities of human
beings.
5. It is also a rich source of fresh water fish.

Benefits of a Lake:
1. A lake helps in preventing flood by regulating the flow of river.
2. During dry seasons, a lake helps to maintain an even flow of the river.
3. Lakes can also be used for generating hydel power.
4. Tourism development.
5. Maintain aquatic ecosystem.

Q8. Below are given names of a few lakes of India. Group them under two categories - natural and
created by human beings.
(a)Wular (b) Dal (c) Nainital (d) Bhimtal (e) Gobind Sagar (f) Loktak (g) Barapani (h) Chilika
(i) Sambhar (j) Rana PratapSagar (k) NizamSagar (I) Pulicat (m) NagarjunaSagar (n) Hirakund

Ans 8: Natural Lakes:

Wular, Dal, Nainital, Bhimtal, Loktak, Barapani, Chilika, Sambhar, Pulicat.
Man-made Lakes:
GobindSagar, RanaPratapSagar, NizamSagar, NagarjunaSagar, Hirakund.
Q9. Why are rivers important for the country's economy?
Ans: Rivers are the major source of water for irrigation and hence are important for a country where farming
is still the occupation of the largest portion of population. Many major rivers serve as important channels for
transporting goods and people and thus play important role in the supply chain. Many multipurpose projects
have been built on most of the major rivers in India.
Following are some of the economic benefits of rivers to a country:
1. Rivers have been a source of food since pre-history, almost all the civilizations developed along the
river banks.
2. Rivers are also used for irrigation, hydropower generation.
3. Rivers are used for navigation. They provide the cheapest inland means of transport.
4. Water from the river is the basic natural resource essential for various day-to-day activities of human
beings.
5. It is also a rich source of fresh water fish.

Q.10. What is a River System?

Ans. A river along with its tributaries is known as a River System or
Drainage system. Ex. Ganga River System, Indus River System etc.

Q.11. Define the term drainage.

Ans. The term drainage describes the river system of an area.

Q.12. What is a drainage basin?

Ans. The area drained by a single river system is called a drainage basin.

Q.13. What are the two types of drainage systems found in India? Ans. Himalayan and Peninsular river
systems.

Q.14. Name the rivers that originate from Mansarovar Lake.

Ans. River Indus, Satluj and Brahmaputra

Q.15. Where the headwaters of Ganga meet at?

Ans. Bhagirathi and Alaknanda meet at Dev Prayag in Uttarakhand.

Q16. Where river Ganga leaves behind the mountains and enter the plains?
Ans. Haridwar

Q.17. Which river flows in Tibet with the name Tsang Po? Ans. Brahamaputra

Q.18 What is the source and mouth of the river?

Ans. The place from where the river originates is called as the Source of the river. The place where the river
meets its end is known as the Mouth of the river.

Q. 19. Apart from Narmada and Tapi, which are the other west flowing rivers?
Ans. Sabarmati, Mahi, Periyar, Bharathpuzha.

Q.20. Name the east flowing rivers of India apart from the major ones.
Ans. Damodar, Brahmani, Subarnrekha, Baitarni.

Q.21. Which peninsular rivers flow through a rift valley?

Ans. Narmada and Tapi

Q.22. Which rivers have the largest river basins in India and in Peninsular India?
Ans. In India: Ganga
In Peninsular India: Godavari

Q.23. What are the characteristics of river Yamuna?

Ans. a. River Yamuna originates from the Yamunotri glacier of the Himalayas.
b. It is the largest tributary of river Ganga.
c. The river moves parallel to Ganga for a long distance and finally meets with Ganga at Allahabad.
d. Many peninsular rivers join the Yamuna like Chambal, Betwa, Sind etc.

Q.24. Explain the Indus Water Treaty.

Ans. a. The Indus Water Treaty was signed between India and Pakistan in 1960.
b. According to the regulations of this treaty India can use only 20% of the total water carried by Indus
system
c. This water is used for irrigation in the Punjab, Haryana and the southern and western parts of
Rajasthan.

Q.25. What are the features of Sundarban Delta?

Ans. a. The delta formed by the rivers Ganga and Brahmaputra which is the largest delta of the world is
known as Sundarban Delta.
b. The delta derived its name from the Sundari trees which grows well in this marshland.
c. It is the world's fast growing delta. d. It is also the home of Royal Bengal Tiger.

Q.26. Differentiate between the following:

Ans. A. Himalayan River system and Peninsular River system.

HIMALAYAN RIVER SYSTEM

1. The Himalayan rivers originates from the Himalayas.
2. Most of the Himalayan rivers are perennial in nature, i.e., both rainfed and snowfed.
3. Himalayan rivers have longer course and carry more sediments in them.
4. These rivers are involved more in doing erosional and depositional activities and therefore, forms
many land features like valleys, gorges, meanders, ox-bow lake, delta etc
5. These rivers have got comparatively larger drainage basin.
6. Ex. Indus river system, Brahmaputra river system, Ganga river system.

PENINSULAR RIVER SYSTEM

1. The Peninsular rivers have their source in the peninsula of the country.
2. Most of the peninsular rivers are seasonal in nature i.e. only rainfed.
3. Peninsular rivers have shorter course and carry less sediments in them .
4. These rivers are involved less in the erosional and depositional activities. Most of the rivers form
only deltas.
5. The drainage basin formed by these rivers is less.
6. Ex. Mahanadi basin, Godavari basin, Tapi basin etc.
B. Distributaries and Tributaries

DISTRIBUTARIES
1. Distributaries are the small channels of rivers that separate themselves from the main river before entering
into the sea
2. Distributaries are formed in the lower course of the river.
3. Distributaries decreases the volume of water and the sediments from the main river.
4. Ex. Hoogli is a distributary of river Ganga.

TRIBUTARIES
1. Tributaries are rivers or streams that join the main river.
2. Tributaries join the main river in the upper and middle course of the river.
3. Tributaries increases the volume of water and sediments deposition of the main river.
4. Ex. Yamuna is a tributary of Ganga.

C. Delta and Estuary

DELTA
1. A delta is formed by the river when is about to enter the sea by forming various distributaries.
2. It is roughly triangular in shape.
3. The delta region is highly fertile because of the sediment deposition.
4. 4. Agriculture can be practiced here
5. Ex. River Ganga, Indus, Godavari, Mahanadi forms delta
ESTUARY
1. When the river directly enter the sea it forms an estuary.
2. It is a funnel shaped land feature.
3. The region near estuary is not very fertile.
4. Estuary regions are good for fishing activities. Ex. Narmada and Tapi forms estuary.

D. East flowing rivers and West flowing rivers.

EAST FLOWING RIVERS
1. These rivers originate from or near to the Western Ghats and flows towards east.
2. These peninsular rivers have longer courses and more sediments deposition.
3. Most of the east flowing rivers forms delta while entering into the Bay of Bengal.
4. Ex. Mahanadi, Godavari, Krishna, Kaveri.

WEST FLOWING RIVERS

1. These rivers originate from east and flows towards western India.
2. These rivers have shorter courses and carry less sediment with them.
3. Most of the rivers forms estuary while entering the Arabian sea.
4. Ex. Narmada and Tapi

Q.27. Why river Godavari is often referred to as 'Dakshin Ganga'? Ans. Since river Ganga and Godavari
are carrying similar characteristics, therefore, river Godavari is often referred to as 'Dakshin Ganga'.
1. As river Ganga is the largest river of India with the largest drainage basin, similarly Godavari is the
largest river of peninsular India with the largest drainage basin.
2. River Godavari and Ganga have the similar religious sentiments of the people attached to it.
Q.28. Why lakes are important for human beings?
Ans. a. Regulate the flow of river.
Lakes help to regulate the flow of a river. During heavy rainfall, it prevents flooding and during the dry
season, it helps to maintain an even flow of water.
b. Generation of Hydel Power
Damming of rivers is done in order to store the water for the generation of Hydro electricity. Ex. Hirakud
dam on Mahanadi river.
c..Promote Tourism
Lakes are always an attraction for tourists for recreation. Lakes enhance the natural beauty of the adjoining
area and hence, promote tourism. Ex. Wularlake, Dal Lake in Jammu & Kashmir.
d. Moderate Climate
Lakes also help in moderating the climate of the adjoining area that supports ecosystem within the lake and
also outside the lake.
e.Source of rivers
Many lakes are also the major source for many rivers. Ex. Indus, Satluj, Brahamaputra have their source in
the Mansarovar lake.

Q.29. What are the main causes of increasing river pollution?

Ans. a. Industrial Effluents:
A heavy load of untreated sewage and industrial effluents are emptied into the rivers. This affects the quality
of water and also the self cleansing capacity of the river.
b. Urbanization:
Modern trends of living consume more water. Moreover, the sewage problems in cities have further added
to the problem of water pollution.
c. Domestic Use:
The use of rivers and lakes done for domestic purposes like washing and bathing is adding to the problem of
water pollution.