Indian Geography

NCERT Notes for

Class IX and XI

Arman Khandelwal
 Table of Contents
Physiographic Divisions................................................................................................................................................2
India – Size and Location..........................................................................................................................................2
Location..................................................................................................................................................................2
Size..........................................................................................................................................................................2
India and the World..............................................................................................................................................2
India and its Neighbours.......................................................................................................................................3
Structure and Physiography – Physical Features of India.....................................................................................3
Major Physiographic Divisions............................................................................................................................4
Drainage System..........................................................................................................................................................15
The River System of an Area..................................................................................................................................15
Drainage System in India....................................................................................................................................15
Climate Division..........................................................................................................................................................21
Climate..................................................................................................................................................................... 21
Unity and Diversity in the Monsoon Climate....................................................................................................21
Factors determining the climate of India...........................................................................................................21
The Indian Monsoon...........................................................................................................................................22
Mechanism of Weather in the Winter Season...................................................................................................22
Mechanism of Weather in the Summer Season.................................................................................................23
The Nature of Indian Monsoon..........................................................................................................................23
El-Nino and the Indian Monsoon.......................................................................................................................24
Characteristics of Monsoon Rainfall..................................................................................................................25
The Rhythm of seasons.......................................................................................................................................25
Natural Vegetation and Wildlife................................................................................................................................28
Natural Vegetation..................................................................................................................................................28
Types of Forests...................................................................................................................................................28
Forest cover in India...........................................................................................................................................30
Wildlife..................................................................................................................................................................... 30

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 Physiographic Divisions

India – Size and Location

Location
India is a vast country lying entirely in the Northern Hemisphere the main land extends between latitudes
8°4 N and 37°6`N and longitudes 68°7’E from Kashmir in the North to Kanyakumari in the south and
Arunachal Pradesh in the East to Gujarat in the West. India’s territorial limit further extends towards the sea
up to 12 Nautical Miles (about 21.9 km) from the coast.
Our Southern boundary extends up to 6°45` N latitude in the Bay of Bengal. The Tropic of Cancer
(68°30`N) divides the country into almost two equal parts.

Size
The land mass of India has an area of 3.28 million square km. Its total area accounts for about 2.4% of the
total geographical area of the world
India has a land boundary of about 15,200 km and the total length of the coastline of the mainland, including
Andaman and Nicobar and Lakshadweep, is 7,516.6 km.
The Size of the India as endowed her with great physical diversity. India is bounded by the young fold
mountains in the north west, north and north east and vast sandy expanse of Marusthali, Purvanchal Hills in
North East. South of about 22° N latitude, it begins to taper, extends towards Indian ocean, diving it into two
seas i.e. Arabian Sea on the West and Bay of Bengal on its East. Its form a great geographic entity known as
the Indian subcontinent.
From Gujarat to Arunachal Pradesh there is a time log of two hours. Hence, time along the Standard
Meridian of India (82°30`E) passing Mirzapur (UP) is taken as the Standard Time for whole country

Peninsular part of India extends towards the Indian Ocean. This has provided the country with a coastline of
6,100 km in the mainland and 7,517 km in the entire geographical coast of the mainland plus the island
groups Andaman and Nicobar located in the Bay of Bengal and the Lakshadweep in the Arabian Sea.

India and the World

The Indian landmass has a central location between the East and the West Asia. India’s contact with the
world have continued through ages but her relationship through the land routes are much older than her
maritime contacts. The various passes across the mountains in the North have provided passages to the
ancient travellers, while the oceans restricted such interaction for a long time.

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No other country has a long coastline on the Indian Ocean as India has and indeed, it is eminent position in
the Indian Ocean which justifies the naming of an Ocean after it. Since the opening of the Suez Canal in
1869, India’s distance from Europe has been reduced by 7,000 km.

India and its Neighbours

India shares its land boundaries with Pakistan and Afghanistan in the North West, China (Tibet), Nepal and
Bhutan in the North and Myanmar and Bangladesh in the East. Sri Lanka and Maldives in the South. Sri
Lanka is separated by India by a narrow channel of Sea formed by the Palk Strait and Gulf of Mannar.
India is located in the south central part of the continent of Asia, bordering the Indian Ocean and its two
arms extending in the form of Bay of Bengal and the Arabian Sea. This Maritime location of Peninsular
India has provided links to its neighbouring regions through the sea and air routes.

Structure and Physiography – Physical Features of

India
India is a large landmass formed during different geological periods which has influenced her relief.
“Theory of Plate Tectonics”, according to this theory, the crust (upper part) of the earth has been formed
out of seven major and some minor plates.
 The movement of plates results in the building up of stresses within the plates and the continental
rocks above, leading the folding, faulting and volcanic activity.
 Broadly, these movements are divergent, convergent and transform.
 The oldest landmass, (The Peninsular Part), was a part of the Gondwana land (India, Australia,
South America, South Africa and Antarctica as one single land mass)
 The conventional currents split the crust into a number of pieces, thus leading to the drifting of the
Indo-Australian plate after being separate from the Gondwana Land, towards North
 This drift resulted in the collision of the plate with much larger Eurasian plate. Due to this collision,
the sedimentary rocks which were accumulated in the geosynclines known as the Tethys were folder
to form the mountain system of Western Asia and Himalaya.
 Based on the variation in its geological structure and formations, India can be divided into three
geological divisions.

1. The Peninsular Block

The northern boundary of the Peninsular Block may be taken as an irregular line running from Kachchh
along the western flank of the Aravalli Range near Delhi and then roughly parallel to the Yamuna and
the Ganga as far as the Rajmahal Hills and the Ganga delta.
 The Karbi Anglong and the Meghalaya Plateau in the northeast and Rajasthan in the west are also
extensions of this block.
 The north-eastern parts are separated by the Malda fault in West Bengal from the Chotanagpur
plateau.
 The Peninsula mostly consists of relict and residual mountains like the Aravali hills, the
Nallamala hills, the Javadi hills, the Veliconda hills, the Palkonda range and the Mahendragiri
hills, etc. The river valleys here are shallow with low gradients.
 Most of the east flowing rivers form deltas before entering into Bay of Bengal.

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2. The Himalayas and other Peninsular Mountains
The Himalayas along with other Peninsular mountains are young, weak and flexible in their geological
structure unlike the rigid and stable Peninsular Block.
 Consequently, they are still subjected to the interplay of exogenic and endogenic forces, resulting
in the development of faults, folds and thrust plains. These mountains are tectonic in origin,
dissected by fast-flowing rivers which are in their youthful stage.

3. Indo-Ganga-Brahmaputra Plain
It comprises the plains formed by the river Indus, the Ganga and the Brahmaputra. Originally, it was a
geo-synclinal depression which attained its maximum development during the third phase of the
Himalayan mountain formation approximately about 64 million years ago.
 Since then, it has been gradually filled by the sediments brought by the Himalayan and
Peninsular rivers. Average depth of alluvial deposits in these plains ranges from 1,000-2,000 m.

Major Physiographic Divisions

‘Physiography’ of an area is the outcome of structure, process and the stage of development. Based on
these macro variations, India can be divided into the following physiographic divisions:
1. The Northern and North-eastern Mountains
2. The Northern Plain
3. The Peninsular Plateau
4. The Indian Desert
5. The Coastal Plains
6. The Islands.

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1. The Northern and North-Eastern Mountains
It consists of the Himalayas and the North eastern hills. The Himalayas, geologically young and
structurally fold mountains stretch over the northern borders of India., it forms an arc which covers a
distance of about 2,400 km. Their width varies from 400 km in Kashmir to 150 km in Arunachal
Pradesh.

The altitudinal variations are greater in the eastern half than those in the western half. The Himalaya
consists of three parallel ranges in its longitudinal extent. A number of valleys lie between these ranges.
The northern-most range is known as the Great or Inner Himalayas or the Himadri. It contains all
prominent Himalayan peaks.

The range lying to the south of the Himadri forms the most rugged mountain system and is known as
Himachal or lesser Himalaya. This region is well known for its hill station. The Pir Panjal range
forms the longest and the most important range, the Dhaula Dhar and the Mahabharat ranges are also
prominent ones.

The outer-most range of the Himalayas is called the Shiwaliks. The longitudinal valley lying between
lesser Himalaya and the Shiwaliks are known as Duns. Dehra Dun, Kotli Dun and Patli Dun are some of
the well-known Duns.

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 The Himalayas have been divided on the basis of regions from west to east like Punjab Himalayas,
Kumaon Himalayas, Assam Himalayas, Purvanchal or the Eastern Hills and Mountains. The
Brahmaputra marks the eastern-most boundary of the Himalayas. Beyond the Dihang gorge, the
Himalayas bend sharply to the south and spread along the eastern boundary of India. They are known as
the Purvachal or the Eastern hills and mountains. The Purvachal comprises the Patkai hills, the Naga
hills, the Manipur hills and the Mizo hills.

On the basis of relief, alignment of ranges and other geomorphological features, the Himalayas
can be divided into the following sub divisions:
(1) Kashmir or North western Himalayas
(2) Himachal and Uttarakhand Himalayas
(3) Darjeeling and Sikkim Himalayas
(4) Arunachal Himalayas
(5) Eastern Hills and Mountains

(1) Kashmir or North Western Himalayas

It comprises a series of ranges such as the Karakoram, Ladakh, Zaskar and Pir Panjal. The north-eastern
part of the Kashmir Himalayas is a cold desert, which lies between the Greater Himalayas and the
Karakoram ranges. Between the Great Himalayas and the Pir Panjal range, lies the world famous valley
of Kashmir and the famous Dal Lake.

The Kashmir Himalayas are also famous for Karewa formations, which are useful for the cultivation of
Zafran a local variety of saffron. Karewas are the thick deposits of glacial clay and other materials
embedded with moraines.

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 Some of the important passes of the region are Zoji La on the Great Himalayas, Banihal on the Pir
Panjal, Photu La on the Zaskar and Khardung La on the Ladakh range and some of the important fresh
lakes such as Dal and Wular and salt water lakes such as Pangong Tso and Tso Moriri are also in this
region. Some famous places of pilgrimage such as Vaishno Devi, Amarnath Cave, Charar -e-Sharif

The southernmost part of this region consists of longitudinal valleys known as ‘duns’. Jammu dun and
Pathankot dun are important examples.

(2) Himachal and Uttarakhand Himalayas

This part lies approximately between the Ravi in the west and the Kali (a tributary of Ghaghara) in the
east. It drained by Indus and the Ganga system.

All the three ranges of Himalayas are prominent in this section also. These are the Great Himalayan
range, the Lesser Himalayas (which is locally known as Dhaoladhar in Himachal Pradesh and
Nagtibha in Uttarakhand) and the Shiwalik range from the North to the South. The two distinguishing
features of this region from the point of view of physiography are the ‘Shiwalik’ and ‘Dun formations’.

Himalayan Mountain Complex: Cross Sectional View from South to North

Some important duns located in this region are the Chandigarh-Kalka dun, Nalagarh dun, Dehra
Dun, Harike dun and the Kota dun. Dehra Dun is the largest of all the duns.

In the Great Himalayan range, the valleys are mostly inhabited by the Bhotia’s. These are nomadic
groups who migrate to ‘Bugyals’ (the summer grasslands in the higher reaches) during summer
months and return to the valleys during winters. The famous ‘Valley of flowers’ is also situated in
this region. The places of pilgrimage such as the Gangotri, Yamunotri, Kedarnath, Badrinath and
Hemkund Sahib are also situated in this part. The region is also known to have five famous Prayags
(river confluences).

(3) Darjeeling and Sikkim Himalayas

They are flanked by Nepal Himalayas in the west and Bhutan Himalayas in the east. It is known for its
fast-flowing rivers such as Tista, it is a region of high mountain peaks like Kanchenjunga
(Kanchengiri), and deep valleys.

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 In place of the Shiwaliks here, the ‘Duar formations’ are important, which have also been used for the
development of tea gardens. Sikkim and Darjeeling Himalayas are also known for their scenic beauty
and rich flora and fauna, particularly various types of orchids.

(4) Arunachal Himalayas

These extend from the east of the Bhutan Himalayas up to the Diphu pass in the east. Some of the
important mountain peaks of the region are Kangtu and Namcha Barwa.

The important rivers are the Kameng, the Subansiri, the Dihang and the Lohit.
An important aspect of the Arunachal Himalayas is the numerous ethnic tribal community inhabiting in
these areas. Some of the prominent ones from west to east are the Monpa, Abor, Mishmi, Nyishi and
the Nagas. Most of these communities practise Jhumming. It is also known as shifting or slash and burn
cultivation. This region is rich in biodiversity which has been preserved by the indigenous communities.

(5) Eastern Hills and Mountains

These are part of the Himalayan mountain system having their general alignment from the north to the
south direction. They are known by different local names. In the north, they are known as Patkai
Bum, Naga hills, the Manipur hills and in the south as Mizo or Lushai hills

The Barak is an important river in Manipur and Mizoram. The physiography of Manipur is unique by
the presence of a large lake known as ‘Loktak’ lake at the centre, surrounded by mountains from all
sides.

Mizoram which is also known as the ‘Molassis basin’ which is made up of soft unconsolidated deposits.

2. The Northern Plain

The northern plain has been formed by the interplay of the three major river systems, namely — the
Indus, the Ganga and the Brahmaputra along with their tributaries. This plain is formed of alluvial
soil.

The rivers coming from northern mountains are involved in depositional work. In the lower course, due
to gentle slope, the velocity of the river decreases, which results in the formation of riverine islands.

The Northern Plain is broadly divided into three sections –

(1) The Western part of the Northern Plain is referred to as the Punjab Plains. Formed by the Indus
and its tributaries, the larger part of this plain lies in Pakistan.
(2) The Ganga plain extends between Ghaggar and Teesta rivers
(3) The Indus and its tributaries — the Jhelum, the Chenab, the Ravi, the Beas and the Satluj
originate in the Himalaya. This section of the plain is dominated by the doabs.

According to the variations in relief features, it can be divided into four regions –

(1) Bhabar - The rivers, after descending from the mountains deposit pebbles in a narrow belt of
about 8 to 16 km in width lying parallel to the slopes of the Shiwaliks. It is known as Bhabar. All
the streams disappear in the Bhabar belt.
(2) Terai - South of this belt, the streams and rivers re-emerge and create a wet, swampy and
marshy region known as terai. This was a thickly forested region full of wildlife.

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 (3) Bhangar - The largest part of the northern plain is formed of older alluvium. It lies above the
floodplains of the rivers and presents a terrace like feature. This part is known as Bhangar. The
soil in this region contains calcareous deposits, locally known as Kankar.
(4) Khadar – The newer, younger deposits of the floodplains are called khadar. They are renewed
almost every year and so are fertile, thus, ideal for intensive agriculture.

3. The Peninsular Plateau

The Peninsular plateau is a tableland composed of the old crystalline, igneous and metamorphic rocks. It
was formed due to the breaking and drifting of the Gondwana land and thus, making it a part of the
oldest
landmass. The plateau has broad and shallow valleys and rounded hills.

It is irregular triangle, Delhi ridge in the northwest, (extension of Aravalis), the Rajmahal hills in the
east, Gir range in the west and the Cardamom hills in the south constitute the outer extent of the
Peninsular plateau.

One of the distinct feature of Peninsular Plateau is the black soil area known as Deccan Trap. This is of
volcanic origin hence the rocks are igneous. The Aravali Hills lie on the western and north-western
margins of the peninsular plateau. These are highly eroded hills and are found as broken hills. They
extend from Gujarat to Delhi in a southwest-northeast direction.

On the basis of the prominent relief features, the Peninsular plateau can be divided into three
broad groups:

(1) The Deccan Plateau

(2) The Central Highlands
(3) The North-Eastern Plateau.

(1) The Deccan Plateau

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This is bordered by the Western Ghats in the west, Eastern Ghats in the east and the Satpura, Maikal
range and Mahadeo hills in the north.

An extension of the Plateau is also visible in the northeast, locally known as the Meghalaya, Karbi
Anglong Plateau and North Cachar Hills. It is separated by a fault from the Chotanagpur Plateau.

The Western Ghats and the Eastern Ghats mark the western and the eastern edges of the Deccan
Plateau respectively. The Eastern and Western Ghats meet each other at the Nilgiris hills.
Western Ghats:

They are comparatively higher in elevation and more continuous than the Eastern Ghats. Their
average elevation is about 1,500 m with the height increasing from north to south. Anaimudi (2,695
m), is the highest peak of located on the Anaimalai hills of the Western Ghats followed by
Dodabetta (2,637 m) on the Nilgiri hills. Most of the Peninsular rivers have their origin in the
Western Ghats. Most of the Peninsular rivers have their origin in the Western Ghats.

Western Ghats are locally known by different names such as Sahyadri in Maharashtra, Nilgiri
hills in Karnataka and Tamil Nadu and Anaimalai hills and Cardamom hills in Kerala.

Eastern Ghats:

The Eastern Ghats stretch from the Mahanadi Valley to the Nigiris in the south. The Eastern Ghats
are discontinuous and irregular and dissected by rivers draining into the Bay of Bengal.

Eastern Ghats comprising the discontinuous and low hills are highly eroded by the rivers such as the
Mahanadi, the Godavari, the Krishna, the Kaveri, etc. Some of the important ranges include the
Javadi hills, the Palconda range, the Nallamala hills, the Mahendragiri hills. Mahendragiri is the
highest peak.

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(2) The Central Highlands
They are bounded to the west by the Aravali range. The Satpura range is formed by a series of
scarped plateaus on the south, generally at an elevation varying between 600-900 m above the mean
sea level. This forms the northernmost boundary of the Deccan plateau

The extension of the Peninsular plateau can be seen as far as Jaisalmer in the West, where it has been
covered by the longitudinal sand ridges and crescent-shaped sand dunes called barchans.

An eastern extension of the Central Highland is formed by the Rajmahal hills, to the south of which
lies a large reserve of mineral resources in the Chotanagpur plateau.

(3) The north-eastern Plateau

The Meghalaya and Karbi Anglong plateau stand detached from the main Peninsular Block.

The Meghalaya plateau is further sub-divided into three:

 The Garo Hills

 The Khasi Hills
 The Jaintia Hills

The named after the tribal groups inhabiting this region. An extension of this is also seen in the Karbi
Anglong hills of Assam.

Similar to the Chotanagpur plateau, the Meghalaya plateau is also rich in mineral resources like coal,
iron ore, sillimanite, limestone and uranium. This area receives maximum rainfall from the south
west monsoon. As a result, the Meghalaya plateau has a highly eroded surface. Cherrapunji displays
a bare rocky surface devoid of any permanent vegetation cover.

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4. The Indian Desert
It lies towards the Western margins of the Aravali Hills. It is an undulating sandy plain covered with
Sand Dunes. Luni is the only large river in this region. Barchans (crescent shaped dunes) cover larger
areas.

This region receives low rainfall below 150 mm per year; hence, it has arid climate with low vegetation
cover. It is because of these characteristic features that this is also known as Marusthali. It is believed
that during the Mesozoic era, this region was under the sea.

5. The Coastal Plains

On the basis of the location and active geomorphological processes, it can be broadly divided into two.

(1) Western Coast plains

(2) Eastern Coastal plains

(1) Western Coast plains

The western coastal plains are an example of submerged coastal plain. The western coast,
sandwiched between the Western Ghats and the Arabian Sea, is a narrow plain.

It consists of three sections.

 The northern part of the coast is called the Konkan (Mumbai – Goa),
 The central stretch is called the Kannad Plain
 The southern stretch is referred to as the Malabar coast.
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 Extending from the Gujarat coast in the north to the Kerala coast in the south, the western coast may
be divided into following divisions –

 The Kachchh and Kathiawar coast in Gujarat

 Konkan coast in Maharashtra,
 Goan coast and Malabar coast in Karnataka and Kerala

(2) Eastern Coastal plains

Eastern Coastal plains are along the Bay of Bengal are wide and level. In the northern part, it is
referred to as the Northern Circar, while the southern part is known as the Coromandel Coast.

Large rivers, such as the Mahanadi, the Godavari, the Krishna and the Kaveri have formed extensive
delta on this coast. Lake Chilika is an important feature along the eastern coast.

6. The Islands
There are two major island groups in India – one in the Bay of Bengal and the other in the Arabian Sea.
In Bay of Bengal we have Andaman and Nicobar Island group and in Arabian Sea we have
Lakshadweep and Minicoy.

Andaman and Nicobar Island Group

 This entire group of Island is divided into two broad categories – the Andaman in the north
and the Nicobar in the South.
 Port Blair, the capital of Andaman Nicobar Islands lies in the South Andaman.
 They are separated by a waterbody which is called the Ten-degree channel.
 The Andaman Islands are further divided into:
(1) Great Andaman consist of North Andaman, Middle Andaman and South Andaman
(2) Little Andaman – It is separated from the Great Andaman by the Duncan Passage.
 Some smaller islands are volcanic in origin. Barren island, the only active volcano in India is
also situated in the Nicobar Islands. Narcondam is supposed to be a dormant volcano but Barren
perhaps is still active.
 Some important mountain peaks in Andaman and Nicobar Islands are, Saddle peak (North
Andaman – 738 m), Mount Diavolo (Middle Andaman – 515 m), Mount Koyob (South Andaman
– 460 m) and Mount Thuiller (Great Nicobar – 642 m).

Lakshadweep Island Group

 This group of island are composed of small coral deposits with three types of islands. i.e.
Amindivi Islands, Laccadive Islands, Minicoy Island. Minicoy is the largest island with an area
of 453 sq. km.
 The entire group of islands is broadly divided by the Ten-degree channel, north of which is the
Amini Island and to the south of the Canannore Island.

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 Drainage System

The River System of an Area

The term drainage describes the river system of an area i.e. the flow of water through well-defined channels
is known as drainage and network of such channels is called drainage system. The area drained by a single
river system is called a drainage basin. A mountain or upland separates two drainage basins such an upland
is known as Water divide.

A river drains the water collected from a specific area, which is called its catchment area. The drainage
pattern of an area is the outcome of the geological time period, nature and structure of rocks, topography,
slope, amount of water flowing and the periodicity of the flow.

Important Drainage pattern

(1) The drainage pattern resembling the branches of a tree is known as dendritic.
(2) When the rivers originate from a hill and flow in all directions, the drainage pattern is known as
radical.
(3) When the primary tributaries of river flow pattern to each other and secondary tributaries join them
at right angles, the pattern is known as trellis
(4) When the rivers discharge their waters from all directions in a lake or depression, the pattern is
known as centripetal.

Drainage System in India

There is difference of opinion about the evolution. However, geologist believe that a mighty river called
Shiwalik or Indo-Brahma traversed the entire longitudinal extent of the Himalayas from Assam to Punjab
and onwards to Sind and finally discharged into the Gulf of Sind near lower Punjab during Miocene period
some 5-24 million year ago.

It is opined that due to course of time Indo-Brahma river was dismembered into three main drainage
systems:

(1) The Indus and its five tributaries

(2) The Ganga and its Himalayas tributaries
(3) The stretch of the Brahmaputra

The dismembered was probably due to Pleistocene upheaval in the western Himalayas, including the uplift
of the Potwar plateau (Delhi Ridge), which acted as the water divide between the Indus and the Ganga
drainage systems.

Likewise, the down thrusting of the Malda gap area between the Rajmahal hills and the Meghalaya plateau
during the mid Pleistocene period, diverted the Ganga and the Brahmaputra system.

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The drainage systems of India are mainly controlled by the broad relief features of the subcontinent.
Accordingly, the Indian rivers are divided into two major groups:

(1) The Himalayan rivers

(2) The Peninsular rivers

1. The Himalayan rivers

The most of the Himalayan rivers are Perennial. The Indus and the Brahmaputra are two major rivers.
They have long courses and form meanders, oxbow lakes etc.

(i) The Indus System

It is one of the largest river basins of the world. It also known as the Sindhu, is the westernmost
of the Himalayan rivers in India. It originates from a glacier near Bokhar Chu in the Tibetan
region in the Kailash Mountain range.

In Tibet it is known as Singi Khamban or Lion’s mouth. It cuts across the Ladakh range,
forming a spectacular gorge near Gilgit in Jammu and Kashmir. It enters into the Pakistan near
Chilas in Dardistan region.

According to the regulations of the Indus Water Treaty (1960), India can use only 20 per cent of
the total water carried by the Indus river system. This water is used for irrigation in Punjab,
Haryana and the southern and the western parts of Rajasthan.

The Indus receives a number of Himalayan tributaries such as the Shyok, the Gilgit, the
Zaskar, the Hunza, the Nubra, the Shigar, the Gasting and the Dras.

Other tributaries – the Khurram, the Tochi, the Gomal, the Viboa, the Sangar. All these originate
in Sulaiman ranges. Finally, it emerges out of the hills near attack where it receives the Kabul
river of its right bank.

The river flows Southward and receivers "Panjnad" a little above Mithankot. The Panjnad is
name given to rivers of Punjab – the Satluj, the Beas, the Ravi, the Chenab and the Jhelum. The
Indus flows in India only through J&K

Tributaries of Indus:

The Jhelum - It rises from a spring at Verinag situated at the foot of Pir Panjal of valley in
Kashmir. It flows through Srinagar and Wular lake before enter Pakistan. Jhelum joins Chenab
near Jhang in Pakistan.

The Chenab – It is the largest tributary, formed by two streams i.e. Chandra and Bhaga hence
known as Chandrabhaga, which joins at Tandi near Keylong in Himachal Pradesh.

The Ravi – It rises west of Rohtang Pass in Kullu hills of Himachal Pradesh and flows through
Chamba valle and join Chenab at Sarai Sindhu.

The Beas – It originates from Beas Kund near Rohtang Pass at elevation of 4000m above the
main sea level. The river flows through Kullu valley and forms gorges at Kati and Largi in
Dhaoladhar range. It enters Punjab plains where it meets the Satluj near Harike.
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 The Satluj – It originates in Rakas lake near Mansarovar at an altitude of 4,555 m in Tibet,
known as Langchen Khambab. It is a very important tributary as it feeds the canal system of the
Bhakra Nangal Project.

(ii) The Ganga System

The Ganga is the most important river of India both from the point of view of its basin and
cultural significance.

The headwater of Ganga called Bhagirathi river is the Gangotri glacier near Gaumukh (3,900 m)
in Uttarkashi district of Uttarakhand here it is known as Bhagirathi. At Devprayag, the
Bhagirathi meets the Alaknanda here it known as Ganga.

Alaknanda's source is in Satopanth glacier above Badrinath. It consists of Dhauli and Vishnu
Ganga which meets at Joshimath or Vishu Prayag. Its tributaries Pindar and Mandakini or Kali
Ganga meets at Rudra Prayag.

Ganga enters the plains at Haridwar and later split into two tributaries i.e. Bhagirathi and the
Hugli.

The son is the major right bank tributary. Left bank tributaries are the Ramganga, the Gomati, the
Ghaghara, the Gandak, the Kosi, the Mahananda. They finally discharge in Bay of Bengal near
Sagar Island.

The Yamuna is the western most and the longest tributary of Ganga. Its source is Yamunotri
glacier on western slopes of Banderpunch range (6,316 km). It joins Ganga at Prayag. The right
bank originates from the Peninsular plateau tributary the Chambal, the Sind, the Betwa and the
Ken while the Hindan, the Rind, the Sengar, the Varuna etc joins it on the left bank.

The Chambal which rises near Mhow in the Malwa plateau of Madhya Pradesh and flows
northwards through a gorge up wards of Kota in Rajasthan (Gandhi Sagar Dam). The Chambal is
famous for its bad land topography called the Chambal ravines.

The Gandak comprises of two streams namely Kaligandhak and Trishulganga. It rises in
Nepal Himalayas between the Dhaulagiri and Mount Everest. It enters Ganga plain in Champaran
and joins Ganga at Sonpur near Patna.

The Ghaghara originates in glaciers of Mapchachungo. Its tributaries are Tila, Seti and Beri.
Its meet Ganga at Chhapra.

Tributaries of Ganga:

The Kosi – It is an antecedent river with source to the north of Mount Everest in Tibet where its
mainstream Arun rises. It forms Sapt Kosi after uniting with the river Arun.

The Ramganga – It is small river rising in Garhwal hills near Gairsain and joins Ganga near
Kannauj.

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 The Damodar – It occupies eastern margins of Chotanagpur Plateau where it flows through a rift
valley and finally joins the Hugli. The Barakar is the main tributary. The Damodar once known
as the "Sorrow of Bengal".
The Sards or Surya – It rises in Milam Glacier in Nepal Himalayas known as Goriganga.
Along Indo-Nepal border, it is called Kali or Chauk, where it joins the Ghaghara.

The Mahananda – It is an important tributary of Ganga rises in Darjeeling hills join Ganga in
West Bengal.

The Son – It is large south bank tributary of Ganga, originating in the Amarkantak plateau. It
reaches Arrah, West of Patna to join the Ganga. In downstream it is known as the Meghna, this
mighty river with waters from ganga and the Brahmaputra flows into Bay of Bengal. The delta
formed by these rivers is known as Sunderban Delta.

(iii) The Brahmaputra System

It originates the Chemayungdung glacier of Kailash range near the Mansarovar lake, it is slightly
longer than Indus.

Traverses eastward longitudinally for distance of nearly 1.200 km. In a dry and flat region of
southern Tibet known as Tsangpo which means "the Purifier". The major tributary is Rango
Tsangpo (Right bank) in Tibet.

The river is emerging from the foothills under the name of Siang or Dihang. It enters India west
of Sadiya town in Arunanchal Pradesh. Its main left bank tributaries i.e. Dibang or Sikang and
Lohit thereafter it is known as the Brahmaputra.

Major left bank tributaries i.e. Burhi Dihing and Dhansari whereas the major right bank
tributaries are Subansiri, Kameng, Manas and Sankosh. The Subansiri origin in Tibet is an
antecedent river.

In Bangladesh, the Tista joins its on its right bank known as Yamuna. Finally merges with river
Padma which falls in the Bay of Bengal. Brahmaputra is well known for floods because most of
its tributaries are large and bring large quality of sediments owning to heavy rainfall in its
catchment area.

On Namcha Barwa (7,757 m) it takes "U" turn. It has a braided channel in Assam hence for
many riverine Islands.

Evolution of Peninsular Drainage System

Three major geological events in distant past have shaped the present system.

(1) Subsidence of western flank of Peninsular leading to its submergence below the sea during the early
tertiary period. Generally, it has distributed the symmetrical plan of the river on either side of the
original water shed.
(2) Upheaval of the Himalayas when the northern flank of the Peninsular block was subjected to
subsidence and the consequent through faulting. The Narmada and the Tapi flow in though trough
faults and fill the original cracks with their detritus materials. Hence there is a lack of alluvial and
deltaic deposits in these rivers.

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 (3) Slight tilting of the Peninsular block from northwest to the southern eastern direction gave
orientation to the entire drainage system towards the Bay of Bengal.

2. Peninsular river System

Peninsular Drainage system make deltas of mouth and it is older than Himalayas. Western Ghats
running close to western coast act as the water divide between major Peninsular rivers. Most of the
major Peninsular rivers except Narmada and Tapi flow from west to East, they are long rivers which
flow west and make estuaries.

The Mahanadi – Rises near Sihawa in Raipur district of Chhattisgarh and runs through Orissa. Its 860
km long. Its drainage basin is shared by Maharashtra, Chhattisgarh, Jharkhand and Odisha.

The Godavari – It is largest Peninsular river system, which is also called Dakshin Ganga. The Godavari
rises Nasik district of Maharashtra. Principles tributaries are the Penganga, the Indravati, the Pranhita,
the Manjra.

The Krishna – It is the second largest east flowing Peninsular river which rises near Mahabaleshwar in
Sahyadri. The major tributaries are the Koyna, the Tungbhadra and the Bhima. Its drainage basin is
shared by Maharashtra, Karnataka, Andhra Pradesh and Telangana. It makes second biggest waterfall i.e.
Sivasamudram.

The Kaveri – It rises in Brahmagiri hills (1,341 m) of Kogadu district in Karnataka. The major
tributaries are the Kabini, the Bhavani and the Amravati. Since upper catchment area receives
rainfall during the southwest monsoon season(summer) and the lower part during the northeast monsoon
season(winter) hence the river carries the water throughout the year.

The Narmada (Dhuadhar falls) – It originates on western flank of Amarkantak Plateau at height at
about 1,057 m. Flowing in rift valley between the Satpura in south and Vindhyan range in north and
meet Arabian sea south of Bharuch, forming a broad 27 km long estuary. The "marble rocks" near
Jabalpur where Narmada flows through deep gorge and the Dhuadhar falls where the river plunges over
steep rocks.

The Tapi – It originates from Multai in Betul district of Madhya Pradesh (Satpura range). There are
some smaller rivers flowing towards the east. The Damoder, the Brahmani, the Baitarni and the
Subarnrekha.

Luni – It is largest river system of Rajasthan, west of Aravali which originates near Pushkar in two
branches i.e. Saraswati and Sabarmati joins at Govindgarh from here river comes out at Aravali and
called Luni. It joins Rann of Kachchh, this entire river system is Ephemeral.

Smaller rivers flowing towards the west

Rivers flowing towards Arabian Sea have short courses i.e. the Shetruniji, the Bhadra, the Dhadhar, the
Sabarmati and the Mahi. The Vaitarna which rises from Trimbak hills in Nasik, the Kalindi rises from
Belgaum district falls in the Karwar bay and the Sharavati originates in Shimoga district.

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Important rivers of Goa are the Mandovi and other is Juari. Kerala has narrow coastline is the longest river
of Kerala is Bharathapuzha rises near Annamalai Hills also known as Ponnani. The Periyar is second
largest river of Kerala

River Regimes
The pattern of flow of water in a river channel over a year is known as its Regime. Rivers of South India do
not originate from glaciers and their flow pattern witnesses fluctuations. There flows increases during
monsoons rain.
The discharge is the volume of water flowing in a river measured over time. The Ganga has minimum flow
during January to June period and minimum flow either in August or September monsoon regimes.

The Narmada and the Godavari two Peninsular rivers display interesting difference in their regimes
compared to Himalayas rivers.

Lakes
India has many lakes. These differ from each other in size and other characteristics. Most lakes are
permanent some contain water only during the rainy season, like the lakes in the basins of inland drainage of
semi-arid regions.

 There are some lakes which are the result of the action of glaciers and ice sheets while others have
been formed by wind, river action and human activities.
 A meandering river across a floodplain forms cut-off that later develops into ox bow lakes. Spits and
bars form lagoons in the coastal areas e.g. Chilika Lake and the Pulicat Lake and the Kolleru Lake.
 Lakes in the region of inland drainage are sometimes seasonal for example Sambhar Lake in
Rajasthan, which is a saltwater lake. Its water is used for producing salt.
 Most of the freshwater lakes are in the Himalayan region. They are of glacial origin. In other words,
they formed when glaciers dug out of the basin, which was later filled with snow melt. The Wular
lake in Jammu and Kashmir in contrast is the result of tectonic activity. It is the largest freshwater
lake in India.
 The Dal lake, the Bhimtal, Nainital, Loktak and Barapani are some other important
freshwater lakes.
 Apart from the natural lakes, the damming of the rivers for the generation of hydel power has also
led to the formation of lakes, such as Guru Gobind Sagar (Bhakra Nangal Project)

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 Climate Division

Climate
Climate refers to the sum total of weather conditions and variations over a large area for a long period of
time. Weather refers to the state of the atmosphere over an area at any point of time.

Elements of weather and climate are same i.e. temperature atmospheric pressure, wind, humidity and
precipitation. There are six major controls of the climate of any place. They are: latitude, altitude, pressure
and wind system, distance from the sea, ocean currents and relief features.

The climate of India is described as the "Monsoon" type. It refers to the seasonal reversal in the wind
direction during a year. The word Monsoon is derived from the Arabic word "mausim" which literally
means season.

Unity and Diversity in the Monsoon Climate

The monsoon regime emphasises the unity of India with the rest of Southeast Asian region. There are
regional variations which differentiate the weather and climatic of different regions of India, yet all have
monsoon type of climate.

Sometimes regional variations or diversities may be described as sub types of Monsoon climate. There is
regional variations in precipitation like snowfall occurs in Himalayas, Cherrapunji and Mawsynram receive
rainfall over 1,080 cm per year, but Jaisalmer in Rajasthan rarely gets more than 9 cm if rainfall during the
same period.

Factors determining the climate of India

1. Factors related to location and relief:

(1) Latitude – Northern part of the India lies in sub-tropical and temperature zone and the part
lying South of the Tropic of Cancer falls in the tropical zone.
(2) The Himalayan mountains – The towering mountain chain provides an invincible shield to
protect the subcontinent from the cold Northern winds, originate from Artic circle.
(3) Distribution of Land and Water – India is flanked by the Indian ocean on three sides,
differential heating of land and sea creates different air pressure zones.

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 (4) Distance from the sea – With a long coastline, large coastal areas have an equable climate.
Areas in the interior of India are far away from the moderating influence of the sea.
(5) Altitude – Temperature decreases with height due to thin air places in the mountains are
cooler than places on the plain.
(6) Relief – The physiography also affects the temperature, air pressure, direction and speed of
wind and the amount and distribution of rainfall.

2. Factors related to air pressure and wind:

To understand the difference in local climates of India, we need to understand the mechanism of the
following three factors:

(1) Distribution of air pressure and winds on the surface of the earth.
(2) Upper air circulation caused by factors controlling global weather and the inflow of different
air masses and jet streams.
(3) Inflow of western cyclones generally known as disturbances during the winter season and
tropical depressions during the south west monsoon period into India, creating weather
conditions favourable to rainfall.
(4) Coriolis force – An apparent force caused by the earth's rotation. It is responsible for
deflecting winds towards right in Northern Hemisphere and left in Southern Hemisphere.
This is also known as Ferrell's Law.

The Indian Monsoon

The Monsoons are experienced in the tropical area roughly between 20° N and 20° S. To understand the
mechanism of the monsoons, the following facts are important.
Monsoon is a familiar though a little-known climatic phenomenon. Despite the observations spread over
centuries, the monsoon continues to puzzle the scientists.
 The differential heating and cooling of land and water creates pressure on the landmass of India
while the seas around experience comparatively high pressure.
 The shift of the position of ICTZ is summer over the Ganga plain.
 The pressure of the high-pressure area, east of Madagascar, approximately at 20° S over the
Indian ocean.
 The Tibetan plateau gets intensely heated during summer, which results in strong vertical air
currents and the formation of low pressure over the plateau.
 The Movement of the westerly jet stream to the North of the Himalayas and the presence of the
tropical easterly jet stream over the Indian Peninsular during summer. Also changes in the
pressure conditions over the southern oceans also affect the monsoons like the phenomenon refer as
ENSO (El Nino Southern Oscillations)
 The onset of the monsoon and withdrawal – The duration of the monsoon is between 100-120
days from early June to mid September. Around the time of its arrival, the normal rainfall increases
suddenly and continues, constantly for several days, known as "the burst" of the monsoon.
 It has Arabian Sea branch and Bay of Bengal branch. Withdrawal or the retreat of the monsoon is a
more gradual process. In north western states it begins in early September. By mid-October, it
withdraws completely from the Northern half of Peninsular. By early December, the monsoon has
withdrawn from the rest of the country.

Mechanism of Weather in the Winter Season

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 1. Surface pressure and winds – In winter months, the weather conditions over India are generally
influenced by the distribution of pressure in central and western Asia. A high-pressure centre in the
region lying to the North of the Himalayas develops during winter.

The surface winds blowing out of the high-pressure centre over central Asia reach India in the form
of a dry continental air mass.

2. Jet stream and upper air circulation – Higher up in the lower troposphere, about 3 km above the
surface of the earth, a different pattern of air circulation is observed.

All of western and central Asia remains under the influence of westerly winds along the altitude of 9-
13 km from west to east. These winds blow across the Asian continent at latitudes North of the
Himalayas roughly parallel to the Tibetan Highlands. These known as Jet Streams.

3. Western Cyclonic Disturbance and Tropical cyclones – The western cyclonic disturbances which
enter the Indian subcontinent from the West and the Northwest during the winter months originate
over the Mediterranean Sea and are brought into India by westerly jet stream.

Tropical cyclones originate over the Bay of Bengal and the Indian ocean. They have very high wind
velocity and heavy rainfall.

Mechanism of Weather in the Summer Season

1. Surface pressure and winds – As the summer sets in and the sun shifts North wards, the winds
circulation over the subcontinent undergoes a complete reversal at both, the lower s well as the upper
levels.

By the middle of July, the low-pressure belt nearer the surface ITCZ shifts northwards, roughly
parallel to the Himalayas between 20° N and 25° N. The ITCZ being a zone of low pressure, attracts
inflow of winds from different directions. The Maritime tropical air mass (MT) from the southern
hemisphere, after crossing the equator, rushes to the low-pressure area in the general South Westerly
direction. It is this moist air current which is popularly known as the South West Monsoon.

2. Jet stream and upper air circulation – An easterly jet stream flows over the southern part of the
Peninsular in June and has a maximum speed of 90 km per hour. In August, it is confined to 15°N
latitude and in September up to 22°N latitudes.

The Easterlies normally do not extend to the North of 30°N latitude in the upper atmosphere.

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 3. Easterly Jet Stream and Tropical cyclones – The Easterly Jet stream steers the tropical depressions
into India. These depressions play a significant role in the distribution of Monsoon rainfall over the
Indian subcontinent.

The Nature of Indian Monsoon

Monsoon is a familiar though a little-known climatic phenomenon. Despite the observations spread over
centuries, the monsoon continues to puzzle the scientists.
Systematic studies of the causes of rainfall in the South Asian region help to understand the causes and
salient features of the Monsoon, such as
(i) The onset of the Monsoon
(ii) Rain bearing system
(iii) Break in the Monsoon
(iv)The onset of the monsoon and withdrawal

(i) The onset of the Monsoon

During April and May when the sun shines vertically over the Tropic of Cancer, the large landmass in
the north of Indian ocean gets intensely heated. This causes the formation of an intense low pressure in
the north western part of the subcontinent.
Since the pressure in the ocean in the south of the landmass is high as water heated slowly, the low-
pressure cell attracts the southeast trades across the Equator. These conditions help in the northward shift
in the position of the ITCZ.

The easterly jet stream sets in along 15°N latitude only after the western jet stream has withdrawn itself
from the region. This easterly jet stream is held responsible for the burst of the monsoon in India.

Entry of Monsoon into India

The southwest monsoon sets in over the Kerala coast by 1 st June and moves swiftly to reach Mumbai and
Kolkata between 10th and 13th June. By mid-July southwest monsoon engulfs the entire subcontinent.

(ii) Rain bearing systems and Rainfall Distribution

There seem to be two rain-bearing systems in India. First originate in the Bay of Bengal and second in
Arabian Sea. The intensity of rainfall over the west coast of India is, however related to two factors.
 The offshore meteorological conditions
 The position of the equatorial Jet stream along the Eastern coast of Africa.
The frequency of the tropical depressions originating from the Bay of Bengal varies from year to year.
Their paths over India are mainly determined by the position of ITCZ which is generally termed as the
Monsoon trough.

(iii) Break in monsoon

During the south west monsoon period after having rains for few days, if rains fail to occur for one or
more weeks it is known as break in monsoon.

These breaks in the different regions are due to different reasons.

 In northern India rains are likely to fail if the rain bearing storms are not very frequent along the
monsoon trough or the ITCZ over this region.
 Over the west coast the dry spells are associated with days when winds blow parallel to the coast.
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El-Nino and the Indian Monsoon
El-Nino is a complex weather system that appears once every three to seven years, bringing drought, floods
and other weather extremes to different parts of the world. It is merely an extension of the Peruvian current
or Humboldt current. This current increases the temperature of water on the Peruvian coast by 10° C. This
results in:
(i) The distortion of equatorial atmospheric circulation.
(ii) Irregularities in the evaporation of sea water
(iii) Reduction in the amount of Planktons which further reduces the number of fish in the sea.
The word El-Nino means "Child Christ" because this current appears around Christmas in December.
December is a summer month in Peru (Southern Hemisphere) it is used in India for forecasting long range
monsoon rainfall.
The monsoon approaches the landmass in two branches:
(i) The Arabian Sea Branch
(ii) The Bay of Bengal Branch

(i) The Arabian Sea Branch

This is further spilt into three branches:
a) It's one branch is obstructed by the Western Ghats. The wind ward side of the Sahyadri and
Western coastal plain receive heavy rainfall and east is rain shadow area.
b) Another branch strikes coast North of Mumbai.
c) Third branch strikes the Saurashtra Peninsular and the Kachchh.

(ii) The Bay of Bengal Branch

Strikes the coast of Myanmar and part of South East Bangladesh. But the Arakan Hills along the coast of
Myanmar deflect a big portion of this branch towards the Indian sub-continents.

However, Tamil Nadu coast remains dry during this season because –
 The Tamil Nadu coast is situated parallel to the Bay of Bengal branch of Southwest Monsoon.
 It has in the rain shadow area of the Arabian Sea branch of the South West Monsoon.

Characteristics of Monsoon Rainfall

1) Rainfall received from the south west Monsoons is seasonal in character.
2) Monsoonal rainfall is largely governed by relief or topography e.g. Like windward side, hills range
etc.
3) The Monsoon rainfall has a declining trend with increasing distance from the sea like Kolkata
receives more rainfall than Patna.
4) The summer rainfall comes in a heavy downpour leading to considerable run off and soil erosion.

The Rhythm of seasons

The meteorologist recognises the following four seasons in India i.e.
1) The Cold Weather Season
2) The Hot Weather Season
3) The South West Monsoon Season
4) Season of Retreating Monsoon

1) The Cold Weather Season

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 Usually, this season sets in by mid-November in Northern India. There are three main reasons for the
excessive cold in North India during this season i.e.
(1) North India are being far away from the moderating influence of sea experience continental
climate.
(2) The snowfall in the nearby Himalayan ranges creates cold wave situation and
(3) Around February, the cold wave along with frost and fog over the North Western pars of India.
Peninsular region of India, however, does not have any well-defined cold weather season. There is
hardly any seasonal change in the distribution pattern of the temperature in coastal areas, because of
moderating influence of the sea and proximity to equator.

Pressure and winds

By the end of December (22nd December), the sun shines vertically over the Tropic of Capricorn in the
Southern Hemisphere. The weather in this season is characterised by feeble High-Pressure conditions
over the Northern Plain.

In South India, the air pressure is slightly lower. As a result, winds start blowing from north-western
high-pressure zone over the Indian ocean in the south. Due to low pressure gradient, the light winds with
a low velocity of about 3-5 km per hour begin to blow outwards. By and large, the topography of the
region influences the wind direction.
Rainfall
Winter monsoon do not cause rainfall as they move from land to the sea. It is because firstly, they have
little humidity and secondly due to anti cyclonic circulation on land, the possibility of rainfall from them
reduces. However, there are some exceptions to it:

(1) In North Western India, some weak temperate cyclones from the Mediterranean Sea cause
rainfall in Punjab, Haryana etc. Although the amount is Meagre, it is highly beneficial for Rabi
crops.
(2) Central part of India and Northern parts of Southern Peninsular also get winter rainfall
occasionally.
(3) Arunanchal Pradesh and Assam also have rains between 25 mm and 50 mm during these winter
months.
(4) During October and November, North East monsoon while crossing over the Bay of Bengal,
picks up moisture and causes torrential rainfall over the Tamil Nadu coast, Southern Andhra
Pradesh, Southeast Karnataka and Southeast Kerala.

2) The Hot Weather Season

Temperature
With the apparent North ward movement of the sun towards the tropic of cancer in March, temperatures
start rising in North India. April, May and June are the months of summer in North India. The hot
weather season in South India is mild and not so intense as found in North India.

Pressure and Winds

The summer months are a period of excessive heat and failing air pressure in the Northern half of the
country. Because of the heating of the subcontinent, the ITCZ moves northwards occupying a position
centred at 25° N in July.

Roughly this is elongated low pressure monsoon trough extends over the Thar Desert in the Northwest
Patna and Chotanagpur plateau in the East-Southeast.

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 Some famous local storms of Hot weather season:
(1) Mongo Shower – Towards the end of summer, there are pre-monsoon showers in Kerala and
Coastal areas of Karnataka. They help in the early ripening of Mangoes.
(2) Blossom Shower – With this shower, coffee flowers blossom in Kerala and nearby areas.
(3) Nor Westers – These are dreaded evening thunderstorms in Bengal and Assam. It is called
"Kalbai Sakhi" in Bengal and "Bardoli Cheerha" in Assam.
(4) Loo – Hot, dry and oppressing winds blowing in the Northern Plains from Punjab to Bihar with
higher intensity between Delhi and Patna.

3) The South West Monsoon Season

As a result of rapid increase of temperature in May over the North western plains, the low-pressure
conditions over there get further intensified. By early June, they are powerful enough to attract the trade
winds of Southern Hemisphere coming from the Indian Ocean.

These southeast trade winds cross the equator and enter the Bay of Bengal and the Arabian Sea only to
be caught up in the air circulation over India.

Passing over the equatorial warm currents, they bring with them moisture in abundance. After crossing
the equator, they follow a South Westerly direction. That is why they are known as South West
Monsoons.

4) Season of Retreating Monsoon

The months of October and November are known as retreating Monsoons. By the end of the
September, the southwest monsoon becomes weak as the low-pressure trough of the Ganga plain starts
moving southward in response to the South ward march of the sun.

The retreating southwest monsoon season is marked by clear skies and rise in temperature. This is
commonly known as the "October Heat". The weather in the retreat monsoon is dry in North India but
it is associated with the rain in the eastern part of the Peninsular. Here October and November are the
rainiest months of the year.

The widespread rain in this season is associated with the passage of cyclonic depressions which originate
over the Andaman Sea and manage to cross the Eastern coast of the Southern Peninsular. These tropical
cyclones are very destructive.

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 Natural Vegetation and Wildlife

Natural Vegetation
Natural Vegetation refer to a plant community which has grown naturally without human aid and has been
left undistributed by humans for a long time. This term is known as Virgin Vegetation.

A huge diversity of flora and fauna kingdom is due to factors like relief such as land. Soil, climate,
temperature, photo period (sunlight), precipitation etc.

Relief
 Land – Land affects the natural vegetation directly and indirectly. The nature of land influences the
type of vegetation. The fertile level is generally devoted to agriculture. The undulating and rough
terrains are areas where grassland and woodland develop and give shelter to a variety of wildlife.
 Soil – The soils are also varying over space. Different type of soils provides basis of different types
of vegetation. The sandy soils of the desert support cactus and thorny bushes while wet, marshy
deltaic soil support mangroves and deltaic vegetation. The hills slopes with some depth of soil have
conical trees.

Climate
 Temperature – The character and extent of vegetation mainly determine by temperature along
humidity in the air, precipitation and soil. On the slopes of the Himalayas and hills of Peninsular
above the height of 915 meters, the fall in the temperature affects the types of the vegetation and its
growth and changes it from tropical to subtropical temperature and alpine vegetation.
 Photoperiod (Sunlight) – The variation in duration of sunlight at different places is due to
differences in latitude, altitude, season and duration of the day. Due to longer duration of sunlight,
trees grow faster in summer.
 Precipitation – In India almost the entire rainfall is brought in by the advancing southwest monsoon
(June to September) and retreating northeast monsoons. Areas of heavy rainfall have more dense
vegetation as compared of areas of less rainfall.

Ecosystem
A system which comprises the physical environment and the organisms living there in. A very large
ecosystem on land having distinct types of vegetation and animal life is called a Biome.

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On the basis of certain common features such as predominant vegetation type and climate regions, Indian
forests can be divided into the following groups.

Types of Forests
(1) Tropical Evergreen and Semi Evergreen Forests
(2) Tropical Deciduous Forests
(3) Tropical Thorn Forests
(4) Montane Forests
(5) Littoral and Swamp Forests

(1) Tropical Evergreen and Semi Evergreen Forests

These forests are found in the western slope of the western Ghats, hills of the northeast region and
Andaman and Nicobar Islands.

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 They are found in warn and humid areas with an annual precipitation of 200 cm. There is no definite
time for trees to shed their leaves as such, these forests appear green all the year around. In these forests,
trees reach great heights up to 60 m or above. Species found in these forests include Rosewood,
Mahogany and Aini ebony etc.

The semi green forests are found in less rainy parts of these regions. Such forests have mixture of
evergreen and moist deciduous trees. Main species are white cedar, hillock and kail.

(2) Tropical Deciduous Forests

These are the most widespread forests in India. They are called the Monsoon forests (Rainfall 200 cm to
70 cm). It can further divide on the basis of the availability of water.

(i) The moist Deciduous Forest (100 cm – 200 cm) – These forests are found in the Northern states
along the foothills of Himalayas, Eastern slopes of the Western Ghats and Odisha. Teak, Sal,
Shisham, Hurra, Mahua, Amla, Semul, Kusum and Sandalwood etc are the main species of these
forests.

(ii) Dry Deciduous Forest (70 cm – 100 cm) – On the wetter margins, it has a transition to the moist
deciduous, while on the drier margins to thorn forests. Tendu, Palas, Amattas, Bel, Khair,
Axlewood etc are common tree.

(3) Tropical Thorn Forests (50 cm)

There consists of the variety of grasses and shrubs. In these forests, plants remain leafless for most part
of the year and give an expression of scrub vegetation. Important species are babool, ber and wild date
palm, khair, neem, khejri and palas etc.

(4) Montane Forests

In mountains areas, decrease in temperature with increasing altitude leads to a corresponding change in
Natural vegetation. It can be classified as:

(i) The Northern Mountain Forest – The Himalayan ranges show a succession of vegetation from
the tropical to the tundra, which changes in with the altitude.

Deciduous forests are found in the foothills of the Himalayas. It is succeeded by the wet
temperature type of forests between and altitude of 1000-2000 m. In the higher hills ranges of
North East India, hilly areas of West Bengal and Uttarakhand evergreen broad leaf tress such as
oak and chestnut are predominant.

(ii) The Southern Mountain Forests – This include the forests found in three distinct areas of
Peninsular India i.e. Western Ghats, the Vindhyan and the Nilgiris.

Vegetation is the temperate in the higher regions and subtropical on the lower regions of the
Western Ghats. The temperate forests are called Sholas in the Nilgiris, Anna Malai and Palani
hills.

Some trees include Magnolia, laurel cinchona and wattle.

(5) Littoral and Swamp Forests
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 India has a rich variety of Wetland habitats about 70% of this comprises areas under paddy cultivation.
The country's wetlands have been grouped into eight categories i.e.

1. The reservoirs of the Deccan Plateau of the South together with the lagoons and other wetlands
of the Southern West coast.
2. The vast saline expenses of the Rajasthan, Gujarat and the Gulf of Kachchh.
3. Freshwater lakes and reservoirs from Gujarat Eastwards through Rajasthan (Keoladeo National
Park) and Madhya Pradesh
4. The delta wetlands and lagoons of India's east coast (Chilika Lake)
5. The freshwater marshes of the Gangetic plain
6. The floodplains of the Brahmaputra
7. The lakes and rivers of the Montane region of Kashmir and Ladakh
8. The Mangroves forest and other wetlands of the Island arcs of the Andaman and Nicobar Islands.
Mangroves grow along the coasts in the Salt Marches, Tidal creeks, mud flats and estuaries.

Forest cover in India

According to state records, the forest areas covers 23.28% of the total land area of the country. The forest
area is area notified and recorded as the forest land irrespective of the existence of trees, it is based on the
records of the state revenue department.
The actual forest cover is the area occupied by forests with canopy. It is based on aerial photographs and
satellite images.
Social Forestry
Means the management and protection of forests and afforestation on barren lands with the purpose of
helping in the environment, social and rural development.
The National Commission on Agriculture (1976) has classified social forestry into three categories. These
are:
1) Urban Forestry – Pertains to the raising and management of trees on public and privately-owned
lands in and around centres such as green belts, parks, roadside avenues etc.
2) Rural Forestry – It lays emphasis on promotion of agro-forestry and community forestry.
3) Farm Forestry – It is a term applied to the process under which farmers grow trees for commercial
and non-commercial purposes on their farmlands.

Wildlife
Like its flora, India is also rich in its fauna. It is approx. 90,000 animal species and about 2000 species of
birds. They constitute 13% of the world's total.
There are 2,546 species of fish, which accounts for nearly 12% of the world's stock it also shares between 5
to 8 percentage of the world's amphibians, reptiles and mammals.
Some of the important reasons of the declining of wildlife are as follows:
1) Industrial and Technological advancement brought about a rapid increase in the exploitation of forest
resources.
2) Grazing by domestic cattle cause an adverse effect on Wildlife and its habitat.
3) Incidence of forest fire, Hunting or poaching.

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Wildlife conservation in India
To protect the flora and fauna of the country, the government has taken many steps i.e.
1) 14 Biosphere have been setup in the country like Sunderban in West Bengal, Nanda Devi in UK etc.
2) Financial and Technical assistance is provided to many Botanical Gardens by the government since
1992.
3) Project Tiger, Project Rhino, Project Great Indian Bustard and many other eco-development projects
have been introduced.
4) 89 National Parks, 490 wildlife sanctuaries and zoological gardens are set up to take care of natural
heritage.

Biosphere Reserves
A unique and representative ecosystem of terrestrial and coastal areas which are internationally recognised
within the framework of UNESCO's man and Biosphere (MAB) program.
Biosphere Reserve aims at achieving the three objectives i.e.
1) Conservation of the biodiversity and ecosystem
2) Development association of environment with development
3) Logistics International network for research and monitoring.

Nilgiri Biosphere
The first of the 14 biosphere reserves of India were established in September 1986. It embraces the
sanctuary complex of Wayanad, Nagarhole, Bandipur and Mudumalai the entire forested hills slopes of
Nilambur, the upper Nilgiri Plateau, silent valley and the Siruvani hills.
It includes the largest known population of two endangered animal species, namely the Nilgiri Tahr and the
lion tailed macaque.
Nanda Devi Biosphere Reserve
Situated in Uttarakhand, the major forest types of the reserve are temperate. A few important species are
silver weed and orchids like latifolie and rhododendron.
Sunderbans Biosphere Reserve
It is located in the swampy delta of the river Ganga in West Bengal. It consists of Mangroves forests, swamp
and forested Islands. In the Sunderbans, the Mangroves forests are characterised by Heritiera forms a species
valued for its timber.
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Gulf of Mannar Biosphere Reserve
It is world's richest regions from a marine biodiversity perspective. The biosphere reserve comprises 21
Islands with estuaries, beaches, sea grasses, coral reefs etc.

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 Soil
Soils
Soil is the mixture of rock debris and organic materials which develop on the earth's surface. The major
factors affecting the formation of soil are relief, parent material, climate, vegetation and other life forms and
time.

Soil consists of three layers which are called horizons i.e.

1) "Horizon A" is the topmost zone, where organic materials have got incorporated with the mineral
matter, nutrients and water, which are necessary for the growth of plants.
2) "Horizon B" is a transition zone between the Horizon A and the Horizon C and contains matter
derived from below as well as from above. It has some organic matter in it, although the mineral
matter is noticeably weathered.
3) "Horizon C" is composed of the loose parent material. This layer is the first stage in the soil
formation process and eventually forms the above two layers.

This arrangement of layers is known as the soil profile. Underneath these three horizons is the rock which is
also known as the parent rock or the bedrock.

Classification of Soil
India has varied relief features, landforms, climatic realms and vegetation types. These have contributed in
the development of various types of soils in India.

In ancient times, soils used to be classified into two main groups i.e. Urvara and Usara which were fertile
and sterile respectively. Based on the texture, main soil types were identified as sandy, clayey, silty and
loam etc. On the basis of colour, they were red, yellow and black etc.

Since independence, scientific surveys of soil have been conducted by various agencies. Soil survey of
India, established in 1956, made comprehensive studies of the soils in selected areas like in Damodar valley.

The National Bureau of Soil survey and the land use planning an Institute under the control of Agricultural
Research (ICAR) did a lot of study on Indian Soils. ICAR has classified the Indian soils on the basis of their
nature and character as per the US Department of Agriculture (USDA) Soil Taxonomy.

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On the basis of genesis colour, composition and location, the soils of India have been classified into
eight i.e.

1) Alluvial Soil
2) Black Soil
3) Red and Yellow Soil
4) Laterite Soil
5) Arid Soil
6) Saline Soil
7) Peaty Soil
8) Forest Soil

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1) Alluvial Soil
These are widespread in the Northern Plains and the river valleys. These soils are covered about 40% of
the total area of the country. They are depositional soil, transported and deposited by rivers and streams.

The alluvial soil varies in nature from sandy loam to clay. They are generally rich in potash but poor in
Phosphorus. In the upper and middle ganga plain two different types of alluvial soils have developed i.e.
Khadar and Bhangar.

The colour of the alluvial soil varies light grey to ash grey, it shades depend on the depth of the
deposition, the texture of the materials and the time taken for attaining maturity.

2) Black Soil

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 This soil covers most of the Deccan Plateau. These soils are also known as the "Regur Soil" or the
"Black Cotton Soil". The black soil is generally clayey, deep and impermeable.

They swell and become sticky when wet and shrink when dried. So, during the dry season, this soil
develops wide cracks. Thus, there occurs a kind of self-ploughing.

Chemically, the black soils are rich in lime, Iron, Magnesia and Alumina. They also contain potash. But
they lack in phosphorus, Nitrogen and Organic matter.

3) Red and Yellow Soil

These soils develop on crystalline igneous rocks in areas of low rainfall in the Eastern and Southern part
of the Deccan Plateau.

The soil developed reddish colour due to wide diffusion of Iron in crystalline and metamorphic rocks. It
looks yellow when it occurs in a hydrated form. They are generally poor in Nitrogen, Phosphorous and
Humus.

4) Laterite Soil
Laterite has been derived from the Latin word "Later" which means brick. The Laterite soil develops in
area with high temperature and high rainfall. These are the result of intense leaching due to tropical
rains. With rain lime and silica are leached away and soil rich in Iron Oxide and Aluminium compound
left behind.

Humus content of the Soil is removed fast by bacteria that thrive well in high temperature. These soils
are poor in organic matter, Nitrogen, Phosphate and Calcium, while Iron Oxide and Potash are in excess.
Hence laterites are not suitable for cultivation.

Laterite soil are widely cut as bricks for use in house construction. These soils have mainly developed in
the higher areas of the Peninsular Plateau.

5) Arid Soil
These soils range from red to brown colour. They are generally sandy in structure and saline nature. Due
to dry climate, high temperature and accelerated evaporation, they lack moisture and humus.

Nitrogen is insufficient and the phosphate content is normal, lower horizons of the soil are occupied by
"Kankar" layers because of the increasing calcium content downwards. Arid soils characterised
developed in western Rajasthan, which exhibit characteristic arid topography.
6) Saline Soils
They are known as Usara soils. These soils contain larger population of Sodium, Potassium and
Magnesium and thus, they are infertile and do not support any vegetative growth.

They occur in arid and semi-arid regions and in waterlogged and swampy areas. Their structure ranges
from sandy to loamy. Saline soils are more widespread in western Gujarat, deltas of eastern coast and in
the Sunderban areas of West Bengal.

Excessive irrigation with dry climatic conditions promotes capillary action, which results in the
deposition of Salt on the top layer of the Soil. Farmers are advised to add gypsum to solve the problem
of Salinity in the Soil.

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7) Peaty Soils
They are found in the areas of heavy rainfall and high humidity where there is a good growth of
vegetation. Thus, large quantity of dead organic matter accumulates in these go even up to 40-50% areas
and this gives a rich humus and organic content of the soil.

These soils are normally heavy and black in colour. At many places they are alkaline also.

8) Forest Soils
They are formed in the forest areas where sufficient rainfall is available. These soils vary in structure and
texture depending on the mountain environment where they are formed. They are loamy and silty on
valley sides and coarse-grained in the upper slopes.

In the snow bound areas of the Himalayas they experience denudation and are acidic with low humus
content. The soils found in the lower valley are fertile.

Soil Degradation
In a broad sense, soil degradation can be identified as the decline in soil fertility, when the nutritional status
declines and depth of the soil goes down due to erosion and misuse. Soil degradation is the main factor
leading to depletion soil resource base in India.

Soil Erosion
The destruction of the soil cover is described as soil erosion. The Soil forming processes and the erosional
processes of running water wind go on simultaneously.
Sometimes such a balance is distributed by natural or human factors, leading to a greater rate of removal of
soil. Wind and water are powerful agents of soil erosion because of their ability to remove soil and transport
it.
Soil erosion is a serious problem for Indian agricultural and its negative effects are seen in other spheres
also. Eroded materials are carried down to rivers and they lower down their carrying capacity, cause
frequent floods and damage to agricultural lands.
Deforestation is one of the major causes of soil erosion, hilly parts of the country are most severely affected.
A fairly large area of arable land in the Irrigated zones of India is becoming saline because of over irrigation.
Chemical fertilisers in the absence of organic manures are also harmful to the soil.

Soil Conservation
It is a methodology to maintain soil fertility, prevent soil erosion and exhaustion and improve the degraded
condition of the soil. Soil erosion is essentially aggravated by faulty practices.
1) The first step in any rational solution is to check open cultivable lands on slopes from farming.
Villagers should be educating about effect or over grazing and shifting cultivation.
2) Contour bunding, contour terracing, regulated forestry, controlled grazing, cover cropping, mixed
farming and crop rotation are other measures.
3) Efforts should be made to prevent gully erosion and control their formation. Finger gullies can be
eliminated by terracing in bigger gullies, the erosive velocity of water may be reduced by
constructing a series of check dams.
4) In arid and semi-arid areas, efforts should be made to protect cultivable lands from encroachment by
sand dunes through developing shelter belts of trees and agro forestry. Experiments have been made
to stabilise sand dunes in western Rajasthan by the central Arid Zone Research Institute (CAZRI).

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 5) The central soil conservation board set up by the Government of India has prepared a number of
plans for soil conservation in different parts of the country.
These plans are based on the climatic conditions, configuration of land and the social behaviour of the
people.

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