CHAPTER -3
DRAINAGE
Q.1. What is a River System?
Ans. A river along with its tributaries is known as
a River System or a Drainage system. Ex. Ganga River System, Indus River System etc.
Q.2. Define the term drainage.
Ans. The term drainage describes the river system of an area.
Q.3. What
is
a drainage basin?
Ans. The area drained by a single
river system is called a drainage basin.
Q.4. What do you understand by the term Water Divide?
Ans. Any elevated area such as
a mountain or an upland that separates two drainage basins is called a Water Divide. Ex. Ambala
act
as a water divide between Indus and Ganga River System.
Q.5. Define the following:
Ans. a. Drainage Pattern
The
pattern formed by a river in a drainage basin depending upon the slope of land, rock structure and also climatic condition is referred to as
Drainage Pattern.
b. Perennial Rivers
Perennial rivers are those which have
water throughout the year. These rivers receive water from rain as
well as from melted snow of the mountains. Ex. Ganga, Indus, Brahamaputra.
c. Seasonal Rivers
Seasonal rivers are those which are dependent upon rainfall for their flow. During the dry season, even the large rivers have reduced the flow of water. Ex. Peninsular Rivers like
Mahanadi, Godavari, Narmada etc.
Q.6. What are the two types of drainage
systems found in India?
Ans. Himalayan and Peninsular river systems.
Q.7. Name the rivers that originate from Mansarovar Lake.
Ans. River Indus, Satluj and Brahmaputra
Q.8. Where the headwaters of Ganga meet at?
Ans. Bhagirathi and Alaknanda meet at Dev Prayag in Uttarakhand.
Q.9. Where river Ganga leaves behind the mountains and enter the plains?
Ans. Haridwar
Q.10. Which river flows in Tibet with the name
Tsang Po?
Ans. Brahamaputra
Q.11. 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.12. Apart from Narmada and Tapi, which are the other west flowing rivers?
Ans. Sabarmati, Mahi, Periyar, Bharathpuzha.
Q.13. Name the east flowing rivers of India apart from the major ones.
Ans. Damodar, Brahmani, Subarn rekha, Baitarni.
Q.14. Which peninsular rivers flow through a
rift valley?
Ans. Narmada and Tapi
Q.15. Which rivers have the largest river basins in India and in Peninsular India?
Ans. In India: Ganga
In Peninsular India: Godavari
Q.16. 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.17.
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.18. 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.19. Differentiate between the following:
Ans. A. Himalayan river system and Peninsular river system.
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HIMALAYAN RIVER
SYSTEM
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PENINSULAR
RIVER SYSTEM
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1. The Himalayan rivers originates from the
Himalayas.
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The Peninsular rivers have their source in the
peninsula of the country.
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2. Most of the
Himalayan rivers are perennial in nature, i.e., both rainfed and snowfed.
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Most of the
peninsular rivers are seasonal in nature i.e. only rainfed.
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3. Himalayan rivers have longer course and carry more sediments in them.
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Peninsular rivers have
shorter course and carry less sediments in them.
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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.
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These rivers are involved less in the erosional and depositional activities. Most of the rivers
form only deltas.
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5. These rivers have got comparatively larger drainage basin.
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The drainage basin formed by these rivers is less.
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6. Ex. Indus
river system, Brahmaputra river system, Ganga river system.
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Ex. Mahanadi
basin, Godavari basin, Tapi
basin etc.
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B. Distributaries
and Tributaries
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DISTRIBUTARIES
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TRIBUTARIES
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1. Distributaries are the small channels of rivers that separate themselves from the main river before entering into the
sea.
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Tributaries
are rivers or streams
that join the
main river.
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2. Distributaries are formed in the lower
course of the river.
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Tributaries join the main river in the upper and middle course of the river.
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3. Distributaries decreases the volume
of
water and the sediments from the main river.
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Tributaries increases the
volume of water and sediments deposition of the main river.
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4. Ex. Hoogli is
a distributary of river Ganga.
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Ex. Yamuna is a tributary of Ganga.
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C. Delta and Estuary
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DELTA
|
ESTUARY
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1. A delta is formed by the river when it is
about to enter the
sea by forming various
distributaries.
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When the river directly enter the
sea it forms an estuary.
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2. It is
roughly triangular in shape.
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It
is a funnel shaped land feature.
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3. The delta region is highly fertile because of the
sediment deposition.
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The
region near estuary is not very fertile.
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4. Agriculture can be practiced here.
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Estuary regions
are good for fishing activites.
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5. Ex. River Ganga, Indus, Godavari, Mahanadi forms delta.
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Ex. Narmada and Tapi forms
estuary.
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D.
East flowing rivers and West flowing rivers.
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EAST FLOWING RIVERS
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WEST FLOWING RIVERS
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1. These rivers originate from or
near to
the
Western Ghats
and flows towards east.
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These
rivers originate from east and flows towards western India.
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2. These peninsular rivers have longer
courses and more sediments deposition.
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These rivers have shorter courses and carry less sediment with them.
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3. Most of the
east flowing rivers forms
delta while
entering into the Bay of Bengal.
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Most of the
rivers forms estuary while
entering the Arabian sea.
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4. Ex. Mahanadi, Godavari, Krishna, Kaveri.
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Ex. Narmada and Tapi
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Q.20. Why does the
Brahmaputra in its Tibetan part have less silt, despite a longer course?
Ans. In Tibet, the river carries a smaller volume of water and less silt as it is a cold and a dry area.
When the river enters India, the volume
of water increases by the
tributaries added into it, high
rainfall and melting snow.
Therefore, Brahmaputra in its Tibetan part have less silt, despite a longer course.
Q.21. 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.22.
Explain the four drainage
patterns.
Ans. DENDRITIC PATTERN
The
dendritic
pattern develops where the river channel follows the slope of the terrain. The stream along with its tributaries resembles the branches of a
tree, thus
the
name dendritic. Ex. River Ganga along with its tributaries.
TRELLIS PATTERN
A river joined by its tributaries at approximately right angles, develop a trellis
pattern. It is develop where hard and soft rocks are parallel to each-other. Ex. River Narmada along with its tributaries.
RECTANGULAR PATTERN
A rectangular pattern is
developed on a strongly jointed rocky terrain.
RADIAL PATTERN
The
radial pattern develops when streams flow in different directions from a
central peak or dome like structure. Ex. Rivers like Narmada and Tapi rising from the highlands
of the peninsular plateau.
Q.23.
Study the information regarding the major river systems of India with the help of the
following table:
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RIVER
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SOURCE
|
MOUTH
|
LENGTH
|
TRIBUTARIES
|
COURSE
|
|
Indus river system
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Near Mansarovar lake, in Tibet
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Forms a delta to the
east of
Karachi in
Pakistan
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2900km
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*In Jammu and
Kashmir – Shyok,
Hunza, Zaskar and Nubra.
*Satluj, Beas,
Ravi, Chenab and Jhelum
meets Indus near
Mithankot in Pakistan
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From Tibet, river flows towards west and enters India through Ladakh district (J&K). In Kashmir valley, river flows through
Baltistan and Gilgit and emerges at Attock mountain,
Enters Pakistan and
flows southwards towards Arabian sea.
|
|
Ganga river
system
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Headwaters Bhagirathi from
Gangotri glacier meets with
Alaknanda at
Dev Prayag in
Uttarakhand to form river
Ganga.
|
Meets with Brahmaput
ra in Banglades h and forms the
largest delta of the world
known as Sundarban
Delta (Bay
of Bengal)
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Over 2500km.
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*Left bank tributaries: Ghaghara, Gandak and Kosi
rising from
Nepal Himalayas.
*Right bank
tributaries:
**Yamuna is the
largest tributary.
**Son, a peninsular
river is also a right
bank tributary.
**Sind, Chambal,
Betwa are the
tributaries of Yamuna and
therefore, becomes a part of
Ganga river system.
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From Dev Prayag the river flows in the
rugged mountainous region and enter the
plains at Haridwar.
Crossing the states like
Uttarakhand, Uttar Pradesh, Bihar
and West Bengal
the river enters
Bangladesh. At Farakka in West
Bengal, The river divides itself into
distributaries like Hoogli. From here, the river moves southward to form
the delta towards Bay of
Bengal.
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Brahamaputra River System
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East of Mansarovar lake in Tibet
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Meets with Ganga in
Banglades h and forms the largest delta of the
world known as
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Over 2900km
|
Dibang, Lohit, Kenula, etc.
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It flows eastward
parallel to Himalayas in the Tibet. On reaching
Namcha Barwa, it takes a ‘U’
turn and enters India through a gorge in Arunachal Pradesh. The river
|
|
|
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Sundarban Delta (Bay of
Bengal
|
|
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moves forward
towards Assam and
enters Bangladesh to form the delta with Ganga.
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Narmada basin
|
From Amarkantak
hills in Madhya Pradesh
|
Forms an estuary
while entering into the
Arabian sea.
|
|
All the tributaries of
Narmada are very
short and join the
main stream at
right angle.
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The river flows
towards the west in a rift valley. Near Jabalpur,
the river
flows through a deep gorge. Narmada basin covers parts of Madhya Pradesh and
Gujarat.
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|
Tapi basin
|
Rises in Satpura
range, Betul
district of Meghalaya.
|
Forms an estuary
while entering into the
Arabian sea.
|
Shorter than Narmada
|
|
It also flows in a
rift
valley, parallel to
Narmada. Its basin covers parts Madhya
Pradesh, Maharashtra, and Gujarat.
|
|
Mahanadi Basin
|
Rises in the highlands of
Chattisgarh.
|
Forms a delta while
entering
into Bay of Bengal.
|
About 860km
|
|
The drainage basin of
river Mahanadi is shared by
Maharashtra,
Chattisgarh, Jharkhand and
Orissa.
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Godavari Basin
|
Rises from slopes of the
Western Ghats in Nasik district
of Maharashtra.
|
Forms a delta while
entering
into Bay of Bengal
|
1500km (largest
peninsular river)
|
Purna, Wardha, Penganga, Wainganga etc.
|
Godavari has the
largest drainage basin among the
peninsular rivers. It cover Maharashtra (50%), Madhya
Pradesh, Orissa, and
Andhra Pradesh.
|
|
Krishna Basin
|
Rises from a
spring near
Mahabaleashwar in Maharashtra
|
Forms a delta while
entering
into Bay of Bengal
|
About 1400km
|
Tungabhadra,
Bhima, Musi, Koyana etc.
|
The drainage basin of
river Krishna is shared by
Maharashtra,
Karnataka, and
Andhra Pradesh.
|
|
Kaveri Basin
|
Rises in Brahmagri
range of
Western Ghats.
|
Forms a delta while
entering
into Bay of Bengal to the south of Cuddalore.
|
About 760km
|
Amravati, Bhavani, Hemavati, Kabini.
|
Its basin drains parts of
Karnataka, Kerela, and Tamil
Nadu.
|
Q.24. Explain the
different formations of lakes.
Ans. A. Oxbow lake
An oxbow lake is formed when the meandering river across a flood plain forms cut offs.
B. Lagoons
Spits
and
bars in the
coastal areas formed by the depositional work of oceanic movement
forms a lagoon. Ex. Chilika lake
(largest lake in India), Pulikat lake, Kolleru lake
C. Seasonal Lakes
Lakes in the region of inland drainage are sometimes seasonal which depends upon the rainfall. Ex. Sambhar lake in Rajasthan which is
a salt water lake.
D. Glacial Lake
These
types
of
lakes
are mostly found in Himalayan region. They are formed when glaciers
dug out a basin which was later filled snow melt. Ex. Wular lake in Jammu & Kashmir which is the largest fresh water lake.
E. Artificial Lakes
Damming of rivers for the generation of hydel power has also led to the formation of lakes. Ex. Guru Gobind Sagar on Bhakra Nangal Project.
Q.25. 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. Wular lake, 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.26. What is
the
role
of a river in building up of an economy?
Ans. a. Cradle of Civilization
River banks have attracted settlers from ancient times. All the major civilizations of the world were settled near to the
river banks. Ex. Indus Valley Civilization, Nile Civilization etc. Even today, many important cities of the
world are settled near to the river banks.
b. Basic Natural Resource
Rivers have been of fundamental importance
throughout the human history. Water from the rivers is a basic natural resource, essential for various human activities.
c. Deposition of Sediments
The
deposition of sediments done by the rivers makes the river banks highly good for
cultivation, thus, promoting agriculture over there.
d. Other uses
Using rivers for irrigation, navigation, hydro-power generation is of special significance for a country.
Q.27. 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.
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