Indian Geography Notes
Indian Geography Notes
✓ The southernmost point of the country is the Pygmalion Point or Indira Point is located at 6° 45′ N
latitude.
✓ North-south extent from Indira Col in Kashmir to Kanniyakumari is 3,214 km.
✓ East-west width from the Rann of Kachachh to Arunachal Pradesh is 2,933 km.
✓ With an area of 32,87,263 sq km, India is the seventh largest country of the world.
✓ India accounts for about 2.4 per cent of the total surface area of the world.
✓ The Tropic of Cancer passes through the middle of the country dividing it into two latitudinal
halves.
✓ The area to the north of Tropic of Cancer is nearly twice the area which lies to the south of it.
✓ South of 22° north latitude, the country tapers off over 800 km into the Indian Ocean as a
peninsula.
✓ The earth moves [rotation and revolution] around its axis through 360° in 24 hours. Thus, a
difference of 1° longitude will make a difference of 4 minutes in time.
✓ The temperate part (north of Tropic of Cancer) is twice the area of tropical part.
✓ But India has always been treated as a tropical country for two different reasons – physical and
cultural.
✓ Settlements, diseases, agricultural and primary economic activities are all tropical in nature.
✓ India has 15106.7 Km of land border running through 92 districts in 17 States and a coastline
of 7516.6 Km [6100 km of mainland coastline + coastline of 1197 Indian islands] touching 13
States and Union Territories (UTs).
✓ Barring Madhya Pradesh, Chhattisgarh, Jharkhand, Delhi, Haryana and Telangana, all other
States in the country have one or more international borders or a coastline and can be regarded
as frontline States from the point of view of border management.
✓ India’s longest border is with BANGLADESH while the shortest border is with Afghanistan.
✓ The length of India’s land borders with neighbouring countries is as under:
✓ This is the second longest border of India, next only to its border with Bangladesh.
✓ Separates Jammu and Kashmir state of India from the Sinkiang (Xinjiang) province of China.
✓ The western sector boundary is largely the outcome of the British policy towards the state of
Jammu and Kashmir.
✓ China claims the Aksai Chin district, the Changmo valley, Pangong Tso and the Sponggar Tso area
of north-east Ladakh as well as a strip of about 5,000 sq km down the entire length of eastern
Ladakh.
✓ China also claims a part of Huza-Gilgit area in North Kashmir (ceded to it in 1963 by Pakistan).
✓ Two Indian states of Himachal Pradesh and Uttarakhand touch this border.
✓ The 1,140 km long boundary between India and China runs from the eastern limit of Bhutan to a
point near Diphu pass (Talu Pass) at the trijunction of India, Tibet and Myanmar.
✓ This line is usually referred to as the Mc Mahon Line after Sir Henry Mc Mahon, then foreign
secretary of British India, who negotiated the boundary agreement between Great Britain and
Tibet at Shimla accord in 1913-14.
✓ Five states of India, namely Uttarakhand, Uttar Pradesh, Bihar, West Bengal and Sikkim touch the
Nepalese border with India. The border is a porous one with unrestricted movement of goods and
people between Indian and Nepal.
✓ Major portion of Indo-Nepalese border runs in the east-west direction almost along the foothill of
the Shiwalik Range.
✓ Quite peaceful border and there is no boundary dispute between the two countries.
✓ The Indo-Pakistan boundary is the result of partition of the country in 1947 under the Radcliffe
award of which Sir Cyril Radcliffe was the chairman.
✓ Jammu and Kashmir, Sir Creek are the major disputed regions.
✓ This boundary runs roughly along the watershed between the Brahmaputra and Ayeyarwady
[Irrawaddy].
✓ It passes through thickly forested regions, with Mizo Hills, Manipur and Nagaland on the Indian
side and Chin Hills, Naga Hills and Kachin state on the Myanmar side.
✓ India and Sri Lanka are separated from each other by a narrow and shallow sea called Palk Strait.
✓ Dhanushkodi on the Tamil Nadu coast in India is only 32 km away from Talaimanar in Jaffna
peninsula in Sri Lanka. These two points are joined by a group of islets forming Adam’s Bridge.
• Formation period ranges from 4 billion years ago to – 1 billion years ago.
• Highly metamorphosed sedimentary rock-system. [formed due to metamorphosis of sediments of
Archaean gneisses and schists].
• They are the oldest metamorphosed rocks.
• Found in abundance in the Dharwar district of Karnataka.
• Economically the most important rocks because they possess valuable minerals like high grade
iron-ore, manganese, copper, lead, gold, etc.
• Includes two divisions: the Cuddapah System and the Vindhyan System.
Cuddapah System
• This system derives its name from the great Vindhyan mountains.
• The system comprises of ancient sedimentary rocks (4000 m thick) superimposed on the Archaean
base.
• Mostly Unfossiliferous.
• Large area of this belt is covered by the Deccan trap.
• The Vindhayan system have diamond bearing regions from which Panna and Golconda
diamonds have been mined.
• It is devoid of metalliferous minerals but provides large quantities of durable stones, ornamental
stones, limestone, pure glass making sand etc..
• The Carboniferous rocks (350 million years) comprise mainly of limestone, shale and quartzite.
• Mount Everest is composed of Upper Carboniferous limestones.
• Coal formation started in the Carboniferous age.
• Carboniferous in geology means coal bearing. [most of the coal found in India is not of
Carboniferous period; High quality coal of Great Lakes Region-USA, U.K and Ruhr region is
Carboniferous coal].
Gondwana System
• The Gondwana System [derives its name Gonds, the most primitive people of Telangana and
Andhra Pradesh]
• They are deposits laid down in synclinal troughs on ancient plateau surface.
Gondwana Coal
Jurassic System
• The marine transgression in the latter part of the Jurassic gave rise to thick series of shallow water
deposits in Rajasthan and in Kuchchh.
• Coral limestone, sandstone, conglomerates and shales occur in Kuchchh.
• Another transgression on the east coast of the Peninsula is found between Guntur and
Rajahmundry.
Deccan Trap
• Volcanic outburst over a vast area of the Peninsular India from the end of the Cretaceous till the
beginning of the Eocene gave rise to Deccan Traps.
• Basaltic lava flowed out of fissures covering a vast area of about ten lakh sq km.
• These volcanic deposits have flat top and steep sides and therefore called ‘trap’ meaning a ‘stair’
or ‘step’ in Swedish.
• The process of weathering and erosion (denudation) since millions of years has reduced the
Deccan Trap to almost half of its original size.
• Present Deccan Trap covers about 5 lakh sq km mainly in parts of Kuchchh, Saurashtra,
Maharashtra, the Malwa plateau and northern Karnataka.
• Thickness of the Deccan Traps is 3,000 metres along the west which is reduced to 600-800 metres
towards the south, 800 metres in Kuchchh and only 150 metres at the eastern limit.
• The weathering of these rocks for a long time has given birth to black cotton soil known as ‘regur’.
Layers of volcanic
Group Found in Inter-trappean beds
ash
Maharashtra and
The Upper Trap Present Present
Saurashtra
The Middle Trap Central India and Malwa Very rare to absent Present
Tertiary System
Peninsular Plateau
• Includes the entire south India, central India, Aravalis, Rajmahal hills, Meghalaya plateau, Kuchchh-
Kathiawar region (Gujarat) etc..
• It is the oldest and the most stable landmass of India.
Himalayas
• Includes the Himalayas, Purvanchal and their extensions Arakan Yoma (Myanmar) and Andaman
and Nicobar Islands (but we will consider these as islands only).
• It is the youngest and highly unstable landmass of India. [Continent – Continent Convergence]
• Tectonic movements are very common.
Indo-Gangetic Plain
Coastal Plains
Indian Islands
Plains 43
Himalayan Ranges
• Shiwaliks were formed last of all the ranges (2-20 million years ago).
• The Shiwaliks are consolidated sands, gravels and conglomerate deposits [Alluvial fans] which
were brought by the rivers flowing from the higher ranges.
• These deposits were folded and hardened due to compression offered by the northward
movement of Indian plate.
• Shiwalik Hills were formed by the accumulation of conglomerates (sand, stone, silt, gravel, debris
etc.).
• These conglomerates, in the initial stages of deposition, obstructed the courses of the rivers
draining from the higher reaches of the Himalayas and formed temporary lakes.
• With passage of time, these temporary lakes accumulated more and more conglomerates. The
conglomerates were well settled at the bottom of the lakes.
• When the rivers were able to cut their courses through the lakes filled with conglomerate
deposits, the lakes were drained away leaving behind plains called ‘duns’ or ‘doons’ in the west
and ‘duars’ in the east.
• Dehra Dun in Uttarakhand is the best example [75 km long and 15-20 km wide]
• Kotah, Patli Kothri, Chumbi, Kyarda, Chaukhamba, Udhampur and Kotli are other important duns.
• In between the Shiwaliks in the south and the Greater Himalayas in the north.
• Runs almost parallel to both the ranges.
• It is also called the Himachal or Lower Himalaya.
• Lower Himalayan ranges are 60-80 km wide and about 2400 km in length.
• Elevations vary from 3,500 to 4,500 m above sea level.
• Many peaks are more than 5,050 m above sea level and are snow covered throughout the year.
• Lower Himalayas have steep, bare southern slopes [steep slopes prevents soil formation] and
more gentle, forest covered northern slopes.
• In Uttarakhand, the Middle Himalayas are marked by the Mussoorie and the Nag Tibba ranges.
• The Mahabharat Lekh, in southern Nepal is a continuation of the Mussoorie Range
• East of the Kosi River, the Sapt Kosi, Sikkim, Bhutan, Miri, Abor and Mishmi hills represent the
lower Himalayas.
• The Middle Himalayan ranges are more friendly to human contact.
Majority of the Himalayan hill resorts like Shimla, Mussoorie, Ranikhet, Nainital, Almora and
Darjeeling, etc. are located here.
• The Pir Panjal range in Kashmir is the longest and the most important range.
• It extends from the Jhelum river to the upper Beas river for over 300 km.
• It rises to 5,000 metres and contains mostly volcanic rocks.
• Pir Panjal Pass (3,480 m), the Bidil (4,270 m), Golabghar Pass (3,812 m) and Banihal Pass (2,835 m).
• The Banihal Pass is used by the Jammu-Srinagar highway and Jammu-Baramula railway.
• The Kishanganga, the Jhelum and the Chenab cut through the range.
• Southeast of the Ravi, the Pir Panjal continues as Dhaola Dhar range, passing through Dalhousie,
Dharmshala, and Shimla.
Important Valleys
• Between the Pir Panjal and the Zaskar Range of the main Himalayas, lies the valley of Kashmir.
(average elevation is 1,585 m above mean sea level)
• The synclinal basin of the valley is floored with alluvial, lacustrine [lake deposits], fluvial [river
action] and glacial deposits. {Fluvial Landforms, Glacial Landforms}
• Jehlum River meanders through these deposits and cuts a deep gorge in Pir Panjal through which
it drains. (Kashmir is like a basin with very few outlets)
• In Himachal Pradesh there is Kangra Valley. It is a strike valley and extends from the foot of the
Dhaola Dhar Range to the south of Beas.
• On the other hand, the Kulu Valley in the upper course of the Ravi is transverse valley.
• Mount Everest was first located by George Everest, the then Surveyor General of India in 1841 and
in 1852 it was established as the highest peak of the world by the Great Trigonometrical Survey of
India.
• The passes because they are generally higher than 4,570 m above sea level and are snowbound for
most of the year.
1. Bara Lacha La
1. Thaga La
2. Niti Pass
Uttarakhand
3. Lipu Lekh
• Eastern Hills or The Purvanchal are the southward extension of Himalayas running along the north-
eastern edge of India.
• At the Dihang gorge, the Himalayas take a sudden southward bend and form a series of
comparatively low hills which are collectively called as the Purvanchal.
• Purvanchal hills are convex to the west.
• They run along the India-Myanmar Border extending from Arunachal Pradesh in the north to
Mizoram in the south.
• Patkai Bum hills are made up of strong sandstone; elevation varying from 2,000 m to 3,000 m;
merges into Naga Hills where Saramati (3,826 m) is the highest peak.
• Patkai Bum and Naga Hills form the watershed between India and Myanmar.
• South of Naga Hills are the Manipur hills which are generally less than 2,500 metres in elevation.
• The Barail range separates Naga Hills from Manipur Hills.
• Further south the Barail Range swings to west into Jaintia, Khasi and Garo hills which are an
eastward continuation of the Indian peninsular block. They are separated from the main block by
Ganga and Brahmaputra rivers.
• Himalayas extend in the east-west direction from the Indus gorge in the west to the Brahmaputra
gorge in the east.
• Himalayan ranges take sharp southward bends at these gorges. These bends are called syntaxial
bends of the Himalayas.
• The western syntaxial bend occurs near the Nanga Parbat where the Indus river has cut a deep
gorge.
• The eastern syntaxial bend occurs near the Namche Barwa.
Punjab Himalayas
Assam Himalayas
Western Himalayas
• Between the Indus in the west and the Kali river in the east (880 km).
• Spread across three states of Jammu and Kashmir, Himachal Pradesh and Uttarakhand.
• It encompasses three physiographic provinces namely Kashmir Himalaya, Himachal
Himalaya and Kumaon Himalaya (Uttarakhand Himalayas).
• The Ladakh plateau and the Kashmir valley are two important areas of the Kashmir Himalayan
region.
• In Himachal Himalayas, The Greater Himalaya is represented by the Zaskar range, lesser Himalaya
by Pir Panjal and Dhauladhar ranges and the Outer Himalaya by the Shiwalik range.
• The southern slopes are rugged, steep and forested while the northern slopes are bare, gentle and
show plains with lakes.
• The Kumaon Himalayas lie in Uttarakhand and extend from the Satluj to the Kali river.
• The Lesser Himalayas in Kumaon Himalaya is represented by the Mussoorie and Nag Tiba ranges.
• The Shiwalik in this region runs south of the Mussoori range between the Ganga and the Yamuna
rivers.
• The flat valleys between the Lesser Himalaya and the Shiwalik range are called ‘doons’ or ‘Duns’
of which Dehra Dun is the most famous.
• 800 km between river Kali in the west and river Tista in the east.
• The Great Himalaya range attains maximum height in this portion.
• Some of the world famous peaks Mt. Everest, Kanchenjunga, Makalu, Annapurna, Gosainthan and
Dhaulagiri are located here.
• The Lesser Himalaya is known as Mahabharat Lekh in this region.
• The range is crossed by rivers like Ghaghara, Gandak, Kosi, etc.
• In between the Great and the Lesser Himalayas, there are Kathmandu and
Pokhra lacustrine valleys (previously, they were lakes).
• The Shiwalik range come very close to the lesser Himalaya towards the east and is almost non-
existent beyond Narayani (Gandak).
Eastern Himalayas
• This part of the Himalayas lies between the Tista river in the west and the Brahmaputra river in the
east and stretches for a distance of about 720 km.
• Also known as the Assam Himalayas, the Eastern Himalayas occupy mainly the areas of Arunachal
Pradesh and Bhutan.
• The Assam Himalayas show a marked dominance of fluvial erosion due to heavy rainfall.
• The Himalayas take a sudden southward turn after the Dihang gorge and the hill ranges running in
more or less north-south direction along India’s border with Myanmar are collectively known as
the Purvanchal.
These are known by various local names such as Patkai Bum, Naga hills, Kohima hills, Manipur
hills, Mizo hills (previously known as the Lushai hills), Tripura hills and Barail range.
• The extension of the Purvanchal Himalaya continues southwards upto Andaman and Nicobar
Islands through the Myanmar range (Arakan Yoma) and even upto the Indonesian archipelago.
• In the eastern section the Himalayas rise abruptly from the plains of Bengal and Oudh and
suddenly attain great elevations within a short distance from the foot of the mountains. Thus the
peaks of Kanchenjunga and Everest are only a few kilometres from the plains and are clearly
visible from there.
• In contrast, the western Himalayas rise gradually from the plains through a series of ranges. Their
peaks of perpetual snow are 150 to 200 km away from the plain areas.
Karewas
• Karewas are lacustrine deposits [deposits in lake] in the Valley of Kashmir and in Bhadarwah Valley
of the Jammu Division.
Formation
• During the Pleistocene Period (1 million years ago), the entire Valley of Kashmir was under water.
• Subsequently, due to endogenetic forces, the Baramullah Gorge was created and the lake was
drained through this gorge.
• The deposits left in the process are known as karewas.
• The thickness of karewas is about 1400 m.
• In fact, the karewas have been elevated, dissected and removed by subaerial denudation as well
as by the Jhelum river giving them the present position.
Economic Significance
• The karewas are mainly devoted to the cultivation of saffron, almond, walnut, apple and orchards.
• The karewas, devoted to saffron cultivation are fetching good income to the growers.
• In Eastern Himalayas and Kumaon Himalays the snowline is around 3,500 m above sea level
whereas in western Himalays snowline is about 2,500 m above sea level.
• This difference in snowline is partly due to the increase in latitude from 28° N in Kanchenjunga to
36° N in the Karakoram.
• But the major factor is precipitation. Precipitation in western Himalayas is comparatively low and
occurs mostly as snowfall where as in eastern Himalayas the precipitation is greater and occurs
mostly in the form of rain.
• In the Great Himalayan ranges, the snow line is at lower elevation on the southern slopes than on
the northern slopes because the southern slopes are steeper and receive more precipitation as
compared to the northern slopes.
Glaciers in Himalayas
• The glaciers of the Pir Panjal Range are less numerous and smaller in size as compared to those of
the Karakoram Range.
• The longest Sonapani Glacier in the Chandra Valley of Lahul and Spiti region is only 15 km long.
• In the Kumaon-Garhwal region of the Himalayas, the largest is the 30 km long Gangotri Glacier
which is the source of the holy Ganga.
Garhwal Region
• Lying in the Himalayas, it is bounded on the north by Tibet, on the east by Kumaon region, on
the south by Uttar Pradesh state, and on the northwest by Himachal Pradesh state.
• It includes the districts of Chamoli, Dehradun, Haridwar, Pauri Garhwal, Rudraprayag, Tehri
Garhwal, and Uttarkashi.
• They intercept the summer monsoons coming from the Bay of Bengal and Arabian Sea causing
precipitation in the entire Ganga Plains, North-Eastern Hills.
• They direct the monsoon winds towards north-western India (Punjab, Haryana etc.. But these
regions receive most of the rainfall due to Western Disturbances coming from the Mediterranean
regions).
• They protect northern-plains from the cold continental air masses of central Asia.
• The Himalayas influence the path of Sub-tropical Jet stream flowing in the region. They split the jet
stream and this split jet stream plays an important role in bring monsoons to India.
• Had there been no Himalayas, the whole of India would have been a desert and its winters would
have been very severe. [Mechanism of monsoons will be explained in detail later]
Defense
Source of Rivers
• Rivers that feed nearly half a billion population of India originate in Himalayas. [we will study this
in detail later in drainage system]
• All the rivers are perennial supplying water year round.
• The swift flowing rivers from Himalayas bring enormous amount of silt (alluvium) which constantly
enrich the Ganaga and Bramhaputra plains.
Hydroelectricity
• Due to its natural topography and swift flowing perennial rivers, the Himalayan region offers
several natural sites with great hydroelectric power generation potential.
• Many hydroelectric power plants have already been constructed.
• But all this comes at a great environmental costs.
Forest Wealth
• The Himalayan host rich coniferous and evergreen forests. Lower levels have tropical evergreen
forests and higher levels have Alpine vegetation (Coniferous).
• The Himalayan forests provide fuel wood and a large variety of timber for industries.
• Himalayan forests host wide variety of medicinal plants.
• Several patches are covered with grass offering rich pastures for grazing animals.
Agriculture
• Due to rugged and sloped terrain, the Himalayas are not potential agricultural sites.
• Some slopes are terraced for cultivation. Rice is the main crop on the terraced slopes. The other
crops are wheat, maize, potatoes, etc.
• Tea is a unique crop which can be grown only on the Shiwalik hill slopes in the region.
• Fruit cultivation is a major occupation. A wide variety of fruits such as apples, pears, grapes,
mulberry, walnut, cherries, peaches, apricot, etc. are also grown in the Himalayan region.
Tourism
Cultural Tourism
• Geosynclinical deposits in tertiary rocks are regions of potential coal and oil reserves.
• Coal is found in Kashmir, Copper, lead, zinc, gold, silver, limestone, semi-precious and precious
stones occur at some places in the Himalayas.
• But the exploitation of these resources require advanced technologies which are not yet available.
• The rivers which were previously flowing into Tethys sea (Before Indian Plate collided with
Eurasian Plate – continental drift, plate tectonics) deposited huge amount of sediments in
the Tethys Geosyncline. [Geosyncline – a huge depression]
• Himalayas are formed out of these sediments which were uplifted, folded and compressed due to
northern movement of Indian Plate.
• Northern movement of Indian Plate also created a trough to the south of Himalayas.
Depositional Activity
• During the initial stages of upliftment of sediments, the already existing rivers changed their
course several times and they were rejuvenated each time (perpetual youth stage of rivers {Fluvial
Landforms}).
• The rejuvenation is associated with intense headward and vertical downcutting of the soft strata
overlying the harder rock stratum.
• Headward erosion and vertical erosion of the river valley in the initial stages, lateral erosion in
later stages contributed huge amount of conglomerates (detritus)(rock debris, silt, clay etc.) which
were carried downslope.
• [Head ward erosion == Erosion at the origin of a stream channel, which causes the origin to move
back away from the direction of the stream flow, and so causes the stream channel to lengthen]
• These conglomerates were deposited in the depression (Indo-Gangetic Trough or Indo-Gangetic
syncline) (the base of the geosyncline is a hard crystalline rock) between peninsular India and the
convergent boundary (the region of present day Himalayas).
• The raising of Himalayas and subsequent formation of glaciers gave rise to many new rivers. These
rivers along with glacial erosion {Glacial Landforms}, supplied more alluvium which intensified the
filling of the depression.
• With the accumulation of more and more sediments (conglomerates), the Tethys sea started
receding.
• With passage of the time, the depression was completely filled with alluvium, gravel, rock debris
(conglomerates) and the Tethys completely disappeared leaving behind a monotonous
aggradational plain.
• [monotonous == featureless topography; aggradational plain == plain formed due to depositional
activity. Indo-Gangetic plain is a monotonous aggradational plain formed due to fluvial
depositions].
• Upper peninsular rivers have also contributed to the formation of plains, but to a very small
extent.
• During the recent times (since few million years), depositional work of three major river systems
viz., the Indus, the Ganga and the Brahmaputra have become predominant.
• Hence this arcuate (curved) plain is also known as Indo-Gangetic-Brahmaputra Plain.
The Bhabar
The area is not suitable for agriculture and only big trees with large roots thrive in this belt.
The Terai
• Terai is an ill-drained, damp (marshy) and thickly forested narrow tract to the south of Bhabar
running parallel to it.
• The Terai is about15-30 km wide.
• The underground streams of the Bhabar belt re-emerge in this belt.
• The Terai is more marked in the eastern part than in the west because the eastern parts receive
comparatively higher amount of rainfall.
• Most of the Terai land, especially in Punjab, Uttar Pradesh and Uttarakhand, has been turned into
agricultural land which gives good crops of sugarcane, rice and wheat.
The Bhangar
• The Bhangar is the older alluvium along the river beds forming terraces higher than the flood
plain.
• The terraces are often impregnated with calcareous concretions known as ‘KANKAR’.
• ‘The Barind plains’ in the deltaic region of Bengal and the ‘bhur formations’ in the middle Ganga
and Yamuna doab are regional variations of Bhangar.
[Bhur denotes an elevated piece of land situated along the banks of the Ganga river especially in
the upper Ganga-Yamuna Doab. This has been formed due to accumulation of wind-blown sands
during the hot dry months of the year]
The Khadar
• The Khadar is composed of newer alluvium and forms the flood plains along the river banks.
• A new layer of alluvium is deposited by river flood almost every year.
• This makes them the most fertile soils of Ganges.
Reh or Kollar
1. Sindh Plain
2. Rajasthan Plain.
3. Punjab Plain.
4. Ganga Plain.
5. Brahmaputra Plain.
6. Ganga – Brahmaputra Delta
Saline Lakes
• North of the Luni, there is inland drainage having several saline lakes. They are a source of
common salt and many other salts.
• Sambhar, Didwana, Degana, Kuchaman, etc. are some of the important lakes. The largest is the
Sambhar lake near Jaipur.
Punjab Plain
Ganga Plain
• This is the largest unit of the Great Plain of India stretching from Delhi to Kolkata (about 3.75 lakh
sq km).
• The Ganga along with its large number of tributaries originating in the Himalayans have brought
large quantities of alluvium from the mountains and deposited it here to build this extensive plain.
• The peninsular rivers such as Chambal, Betwa, Ken, Son, etc. joining the Ganga river system have
also contributed to the formation of this plain.
• The general slope of the entire plain is to the east and south east.
• Rohilkhand plains
• Avadh Plains
• Mithila Plain
• Magadh Plain.
Ganga-Brahmaputra Delta
Brahmaputra Plain
• This is also known as the Brahmaputra valley or Assam Valley or Assam Plain as most of the
Brahmaputra valley is situated in Assam.
• Its western boundary is formed by the Indo-Bangladesh border as well as the boundary of the
lower Ganga Plain. Its eastern boundary is formed by Purvanchal hills.
• It is an aggradational plain built up by the depositional work of the Brahmaputra and its
tributaries.
• The innumerable tributaries of the Brahmaputra river coming from the north form a number of
alluvial fans. Consequently, the tributaries branch out in many channels giving birth to river
meandering leading to formation of bill and ox-bow lakes.
• There are large marshy tracts in this area. The alluvial fans formed by the coarse alluvial debris
have led to the formation of terai or semi-terai conditions.
• This one fourth of the land of the country hosts half of the Indian population.
• Fertile alluvial soils, flat surface, slow moving perennial rivers and favorable climate facilitate
intense agricultural activity.
• The extensive use of irrigation has made Punjab, Haryana and western part of Uttar Pradesh the
granary of India (Prairies are called the granaries of the world).
• The entire plain except the Thar Desert, has a close network of roads and railways which has led to
large scale industrialization and urbanization.
• Cultural tourism: There are many religious places along the banks of the sacred rivers like the
Ganga and the Yamuna which are very dear to Hindus. Here flourished the religions of Budha and
Mahavira and the movements of Bhakti and Sufism.
• Roughly triangular in shape with its base coinciding with the southern edge of the great plain of
North India. Apex of the triangular plateau is at Kanniyakumari.
• It covers a total area of about 16 lakh sq km (India as a whole is 32 lakh sq km).
• The average height of the plateau is 600-900 m above sea level (varies from region to region).
• Most of the peninsular rivers flow west to east indicating it’s general slope.
• Narmada-Tapti are the exceptions which flow from east to west in a rift (rift is caused by
divergent boundary (Go back to Interaction of plates).
• The Peninsular Plateau is a one of the oldest landforms of earth.
• It is a highly stable block composed mostly of the Archaean gneisses and schists {Rock System}.
• It has been a stable shield which has gone through little structural changes since its formation.
• Since few hundred million years, Peninsular block has been a land area and has never been
submerged beneath the sea except in a few places.
• Peninsular Plateau is an aggregation of several smaller plateaus, hill ranges interspersed with river
basins and valleys.
• It is the plateau of eastern Rajasthan. [Marwar plain is to the west of Aravalis whereas Marwar
plateau is to the east].
• The average elevation is 250-500 m above sea level and it slopes down eastwards.
• It is made up of sandstone, shales and limestones of the Vindhayan period.
• The Banas river, along with its tributaries [Berach river, Khari rivers] originate in the Aravali Range
and flow towards northwest into Chambal river. The erosional activity of these rives make the
plateau top appear like a rolling plain.
[Rolling Plain: ‘Rolling plains’ are not completely flat: there are slight rises and fall in the land
form. Ex: Prairies of USA]
Central Highland
Bundelkhand Upland
• Yamuna river to the north, Madhya Bharat Pathar to the west, Vindhyan Scarplands to the east
and south-east and Malwa Plateau to the south.
Malwa Plateau
• The Malwa Plateau roughly forms a triangle based on the Vindhyan Hills, bounded by the Aravali
Range in the west and Madhya Bharat Pathar to the north and Bundelkhand to the east.
• This plateau has two systems of drainage; one towards the Arabian sea (The Narmada,
the Tapi and the Mahi), and the other towards the Bay of Bengal (Chambal and Betwa, joining the
Yamuna).
• In the north it is drained by the Chambal and many of its right bank tributaries like the Kali, the
Sindh and the Parbati. It also includes the upper courses of the Sindh, the Ken and the Betwa.
• It is composed of extensive lava flow and is covered with black soils.
• The general slope is towards the north [decreases from 600 m in the south to less than 500 m in
the north]
• This is a rolling plateau dissected by rivers. In the north, the plateau is marked by the Chambal
ravines.
Baghelkhand
Chotanagpur Plateau
Meghalaya Plateau
• The peninsular plateau extends further east beyond the Rajmahal hills to from Meghalaya or
the Shillong plateau.
• Garo-Rajmahal Gap separates this plateau from the main block.
• This gap was formed by down-faulting (normal fault: a block of earth slides downwards). It was
later filled by sediments deposited by the Ganga and Brahmaputa.
• The plateau is formed by Archaean quartzites, shales and schists.
• The plateau slopes down to Brahmaputra valley in the north and the Surma and Meghna valleys in
the south.
• Its western boundary more or less coincides with the Bangladesh border.
• The western, central and the eastern parts of the plateau are known as the Garo Hills (900 m),
the Khasi-Jaintia Hills (1,500 m) and the Mikir Hills (700 m).
• Shillong (1,961 m) is the highest point of the plateau.
Deccan Plateau
Maharashtra Plateau
Telangana plateau
Chhattisgarh Plain
• The Chhattisgarh plain is the only plain worth the name in the Peninsular plateau.
• It is a saucer shaped depression drained by the upper Mahanadi.
• The whole basin lies between the Maikala Range and the Odisha hills.
• The region was once ruled by Haithaivanshi Rajputs from whose thirty six forts (Chhattisgarh) it
derives its name.
• The basin is laid with nearly horizontal beds of limestone and shales.
• The general elevation of the plain ranges from 250 m in the east to 330 m in the west.
Hills of Peninsular India: Aravalis, Vindhyas, Satpuras, Western & Eastern Ghats
The Aravali Mountain Range
• The literal meaning of Aravalli Range is ‘line of peaks’. It is the oldest fold mountain ranges in the
world which stretching about 300 miles from the northeast to the southwest. The length of the
Aravalis is about 1100 km which extends from Delhi to Ahmadabad. Guru Shikhar is the highest
point which is located in Mount Abu. The Aravalli range is very rich in natural resources and gave
rise of numerous peninsula rivers like Banas, Luni, Sakhi, and Sabarmati. This region is also famous
for heavily forested consisting of large areas of sand and stone and of masses of rose-coloured
quartzite.
• Kadaya (giving medicinal gum), Gugal, amla, Moosli, Khair, Salai, Modad, Dhavada, Khakhara,
Timru are rare flora of this region.
✓ Abu pond The Abu Creatures Haven was recognized of year 1960 and protects 291 km⊃2; of
mountain. Mount Abu can be regarded as house to number of the Jain wats. These Dilwara
Temples are complicated of wats, designed of white-coloured stone, that were designed between
Eleventh and Thirteenth hundreds of years AD. This Achalgarh ft, designed of Fourteenth
millennium through Mewar Rana Kumbha, appears close by. Nakki Lake and well-known guest
fascination of Abu. This mountain is house to the several Hindu wats, such as Adhar Devi
Forehead, designed out of the strong rock; Shri Raghunathji Temple; and shrine and temple of
Dattatreya designed on top of Expert Shikhar optimum.
Vindhyan Range
• The Vindhyan Range, overlooking (have a view of from above) the Narmada valley, rises as an
escarpment (a long, steep slope at the edge of a plateau or separating areas of land at different
heights) flanking (neighboring on one side) the northern edge of the Narmada-Son Trough (the rift
through which the Narmada river flows)(trough is opposite of ridge. It is a narrow depression).
• It runs more or less parallel to the Narmada Valley in an east-west direction from Jobat in Gujarat
to Sasaram in Bihar for a distance of over 1,200 km.
• The general elevation of the Vindhyan Range is 300 to 650 m.
• Most parts of the Vindhayan Range are composed of horizontally bedded sedimentary rocks of
ancient age. {Rock System}
• The Vindhyas are continued eastwards as the Bharner and Kaimur hills.
• This range acts as a watershed between the Ganga system and the river systems of south India.
• The rivers Chambal, Betwa and Ken rise within 30 km of the Narmada.
Satpura Range
• Satpura range is a series of seven mountains (‘Sat’ = seven and ‘pura’ = mountains)
• It runs in an east-west direction south of the Vindhyas and in between the Narmada and the Tapi,
roughly parallel to these rivers.
• It stretches for a distance of about 900 km.
• Parts of the Satpuras have been folded and upheaved. They are regarded as structural uplift
or ‘horst’.
• Dhupgarh (1,350 m) near Pachmarhi on Mahadev Hills is the highest peak.
• Amarkantak (1,127 m) is another important peak.
✓ The range is called Sahyadri in northern Maharashtra and Sahya Parvatam in Kerala. The Biligiri
ranges southeast of Mysore in Karnataka, meet the Shevaroys (Servarayan range) and Tirumala
✓ The ‘Gersoppa’ or ‘Jog’ waterfall on Sharavati River is located in Western Ghats which is India’s
highest waterfall. The famous hill station ‘Kodaikanal’ (Tamil Nadu) is on the Palni Hill whereas
‘Ooty’ (Udagamandalam or Ootacamund) is located on the Nilgiri in Tamil Nadu.
• Senkota pass: It is located between the Nagercoil and the Cardmom hills links Thiruvanathpuram
and Madurai
✓ The northernmost part of the Eastern Ghats is called Simulia which is found in the mountains of
Orissa. Meghasini or Meghasani (the seat of the clouds) is the highest peak of this region.
Malayagiri is the highest peak of the region. The Karanthamalai is located in the southern part of
this region and Sirumalai Hills located in the south of Tamil Nadu. The central region of the Eastern
Ghats comprise of 2 parallel ranges, namely the lower Velikonda Range in the east, and the higher
Palikonda-Lankamalla-Nallamalla Ranges in the west. Asia's biggest tiger reserve, Nagarjunasagar-
Srisailam Tiger Sanctuary is located in the Nallamala range of Eastern Ghats.
• There are huge deposits of iron, manganese. copper, bauxite, chromium, mica, gold, etc.
• 98 per cent of the Gondwana coal deposits of India are found in the Peninsular Plateau.
• Besides there are large reserves of slate, shale, sandstones, marbles, etc.
• A large part of north-west plateau is covered with fertile black lava soil which is extremely useful
for growing cotton.
• Some hilly regions in south India are suitable for the cultivation of plantation crops like tea, coffee,
rubber, etc..
• Some low lying areas of the plateau are suitable for growing rice.
• The highlands of the plateau are covered with different types of forests which provide a large
variety of forest products.
• The rivers originating in the Western Ghats offer great opportunity for developing hydroelectricity
and providing irrigation facilities to the agricultural crops.
• The plateau is also known for its hill resorts such as Udagamangalam (Ooty), Panchmarhi,
Kodaikanal, Mahabaleshwar, Khandala, Matheron, Mount Abu, etc.
• India has a coastline of 7516.6 Km [6100 km of mainland coastline + coastline of 1197 Indian
islands] touching 13 States and Union Territories (UTs).
• The straight and regular coastline of India is the result of faulting of the Gondwanaland during the
Cretaceous period. {Continental Drift}
• As such the coast of India does not offer many sites for good natural harbours.
[Indented coastlines of Europe provide good natural harbours whereas African and Indian
coastlines are not indented].
• The Bay of Bengal and the Arabian Sea came into being during the Cretaceous or early Tertiary
period after the disintegration of Gondwanaland.
• The west coast strip extends from the Gulf of Cambay (Gulf of Khambhat) in the north to Cape
Comorin(Kanniyakumari).
• Starting from north to south, it is divided into (i) the Konkan coast, (ii) the Karnataka coast and (iii)
the Kerala cost.
• It is made up of alluvium brought down by the short streams originating from the Western Ghats.
• It is dotted with a large number of coves (a very small bay), creeks (a narrow, sheltered waterway
such as an inlet in a shoreline or channel in a marsh) and a few estuaries. {Marine Landforms}
• The estuaries, of the Narmada and the Tapi are the major ones.
• The Kerala coast (Malabar Coast) has some lakes, lagoons and backwaters, the largest being
the Vembanad Lake.
Coastlines
• Coastline of emergence is formed either by an uplift of the land or by the lowering of the sea level.
Coastline of submergence is an exact opposite case.
• Bars, spits, lagoons, salt marshes, beaches, sea cliffs and arches are the typical features of
emergence. {Marine Landforms}
• The east coast of India, especially its south-eastern part (Tamil Nadu coast), appears to be a coast
of emergence.
• The west coast of India, on the other hand, is both emergent and submergent.
• The northern portion of the coast is submerged as a result of faulting and the southern portion,
that is the Kerala coast, is an example of an emergent coast.
• Kutch and Kathiawar, though an extension of Peninsular plateau (because Kathiawar is made of
the Deccan Lava and there are tertiary rocks in the Kutch area), they are still treated as integral
part of the Western Coastal Plains as they are now levelled down.
• The Kutch Peninsula was an island surrounded by seas and lagoons. These seas and lagoons were
later filled by sediment brought by the Indus River which used to flow through this area. Lack of
rains in recent times has turned it into arid and semi-arid landscape.
• Salt-soaked plain to the north of Kutch is the Great Rann. Its southern continuation, known as
the Little Rann lies on the coast and south-east of Kachchh.
• The Kathiawar Peninsula lies to the south of the Kachchh. The central part is a highland of Mandav
Hills from which small streams radiate in all directions (Radial Drainage). Mt. Girnar (1,117 m) is
the highest point and is of volcanic origin.
• The Gir Range is located in the southern part of the Kathiawar peninsula. It is covered with dense
forests and is famous as home of the Gir lion.
Gujarat Plain
• The Gujarat Plain lies east of Kachchh and Kathiawar and slopes towards the west and south west.
• Formed by the rivers Narmada, Tapi, Mahi and Sabarmati, the plain includes the southern part of
Gujarat and the coastal areas of the Gulf of Khambhat.
• The eastern part of this plain is fertile enough to support agriculture, but the greater part near the
coast is covered by windblown loess (heaps of sand).
Konkan Plain
• The Konkan Plain south of the Gujarat plain extends from Daman to Goa (50 to 80 km wide).
• Goa to Mangalore.
• It is a narrow plain with an average width of 30-50 km, the maximum being 70 km near
Mangalore.
• At some places the streams originating in the Western Ghats descend along steep slopes and
make waterfalls.
• The Sharavati while descending over such a steep slope makes an impressive waterfall known
as Gersoppa (Jog) Falls which is 271 m high. [Angel falls (979 m) in Venezuela is the highest
waterfall on earth. Tugela Falls (948 m) in Drakensberg mountains in South Africa is the second
highest.]
• Marine topography is quite marked on the coast.
Kerala Plain
• Extending from the Subarnarekha river along the West Bengal-Odisha border to Kanniyakumari.
• A major part of the plains is formed as a result of the alluvial fillings of the littoral zone (relating to
or on the shore of the sea or a lake) by the rivers Mahanadi, Godavari, Krishna and Cauvery
comprising some of the largest deltas.
• In contrast to the West Coastal Plains, these are extensive plains with an average width of 120 km.
• This plain is known as the Northern Circars between the Mahanadi and the Krishna rivers
and Carnatic between the Krishna and the Cauvery rivers.
Utkal Plain
• South of the Utkal Plain and extends upto Pulicat Lake. This lake has been barred by a long sand
spit known as Sriharikota Island (ISRO launch facility).
• The most significant feature of this plain is the delta formation by the rivers Godavari and Krishna.
• The two deltas have merged with each other and formed a single physiographic unit.
• The combined delta has advanced by about 35 km towards the sea during the recent years. This is
clear from the present location of the Kolleru Lake which was once a lagoon at the shore but now
lies far inland {Coastline of Emergence}.
• This part of the plain has a straight coast and badly lacks good harbours with the exception
of Vishakhapatnamand Machilipatnam.
• The Tamil Nadu Plain stretches for 675 km from Pulicat lake to Kanniyakumari along the coast of
Tamil Nadu. Its average width is 100 km.
• The most important feature of this plain is the Cauvery delta where the plain is 130 km wide.
• The fertile soil and large scale irrigation facilities have made the Cauvery delta the granary of
South India.
• Large parts of the coastal plains of India are covered by fertile soils on which different crops are
grown. Rice is the main crop of these areas.
• Coconut trees grow all along the coast.
• The entire length of the coast is dotted with big and small ports which help in carrying out trade.
• The sedimentary rocks of these plains are said to contain large deposits of mineral oil (KG Basin).
• The sands of Kerala coast have large quantity of MONAZITE which is used for nuclear power.
• Fishing is an important occupation of the people living in the coastal areas.
• Low lying areas of Gujarat are famous for producing salt.
• Kerala backwaters are important tourist destinations.
• Goa provides good beaches. This is also an important tourist destination.
✓ The Bay of Bengal island groups consist of about 572 islands/islets. These are situated roughly
between 6°N-14°N and 92°E -94°E. The two principal groups of islets include the Ritchie’s
archipelago and the Labyrinth Island. The entire group of island is divided into two broad
categories – the Andaman in the north and the Nicobar in the south. They are separated by a
water body which is called the Ten degree channel. It is believed that these islands are an
elevated portion of submarine mountains. However, some smaller islands are volcanic in origin.
Barren Island, the only active volcano in India is also situated in the Nicobar Islands. The coastal
line has some coral deposits, and beautiful beaches. These islands receive convectional rainfall and
have an equatorial type of vegetation.
✓ The islands of the Arabian Sea include Lakshadweep and Minicoy. These are scattered between
8°N-12°N and 71°E -74°E longitude. These islands are located at a distance of280 km-480 km off
the Kerala coast. The entire island group is built of coral deposits. There are approximately 36
islands of which 11 are inhabited. Minicoy is the largest island with an area of 453 sq. km. The
Drainage pattern
A Drainage pattern can be defined in the shadow of topographical features from which a stream
gets runoff, through flow, and groundwater flow which can be divided by topographic barriers
called a watershed. A watershed can be defined as all of the stream tributaries that flow to some
location along the stream channel.
3. Subsequent Rivers
A tributary stream that is eroded along an underlying belt of non-resistant rock after the main
drainage pattern (Consequent River) has been established is known as a subsequent river. Due to
the northward slope of the Peninsula towards the Great Plains, the rivers originating from the
Vindhyan and the Satpura ranges flow northward into the Ganga system. The Chambal, Sind, Ken,
Betwa, Tons and Son meet the Yamuna and the Ganga at right angles.
4. Superimposed, Epigenetic (Discordant) or Superinduced Drainage
It is formed when a stream with a course originally established on a cover of rock now removed by
erosion, so that the stream or drainage system is independent of the newly exposed rocks and
structures. The Damodar, the Subarnarekha, the Chambal, the Banas and the rivers flowing at the
Rewa Plateau present some good examples of superimposed drainage.
5. Dendritic Drainage
A pattern of drainage which is branching, ramifying or dichotomising, thereby giving the
appearance of a tree. Most of the rivers of the Indo-Gangetic Plains are of dendritic type.
6. Trellis Drainage
Drainage System
India's 90 per cent total surface water drained into the Bay of Bengal and rest are in the Arabian
Sea. The drainage systems flowing into the Arabian Sea and the Bay of Bengal are separated by a
water divide extending approximately along the Western Ghats, Aravallis and Yamuna Sutlej
divide. The Indian drainage system consists of a large number of small and big rivers. It is the
outcome of the evolutionary process of the three major physiographic units and the nature and
characteristics of precipitation.
The Himalayan Drainage System
1. Subsidence of the western flank of the Peninsula leading to its submergence below the sea
during the early tertiary period. Generally, it has disturbed the symmetrical plan of the river on
either side of the original watershed.
2. Upheaval of the Himalayas when the northern flank of the peninsular block was subjected to
subsidence and the consequent trough faulting. The Narmada and The Tapi flow in trough faults
and fill the original cracks with their detritus materials. Hence, there is a lack of alluvial and deltaic
deposits in these rivers.
3. Slight tilting of the peninsular block from northwest to the South-eastern direction gave
orientation to the entire drainage system towards the Bay of Bengal during the same period.
• The river flows for 1,180 km before entering into Pakistan. The Ravi is another important tributary
of the Indus. It rises west of the Rohtang pass in the Kullu hills of Himachal Pradesh and flows
through the Chamba valley of the state. Before entering Pakistan and joining the Chenab near
Sarai Sidhu, it drains the area lying between the south-eastern part of the Pir Panjal and the
Dhauladhar ranges. The Beas is another important tributary of the Indus, originating from the Beas
Kund near the Rohtang Pass at an elevation of 4,000 m above the mean sea level. The river flows
through the Kullu valley and forms gorges at Kati and Largi in the Dhaoladhar range. It enters the
Punjab plains where it meets the Satluj near Harike.
• The Satluj originates in the Rakas Lake near Mansarovar at an altitude of 4,555 m in Tibet where it
is known as Langchen Khambab. It flows almost parallel to the Indus for about 400 km before
entering India, and comes out of a gorge at Rupar. It passes through the Shipki La on the
Himalayan ranges and enters the Punjab plains. It is an antecedent river. It is a very important
tributary as it feeds the canal system of the Bhakra Nangal project.
Place Confluence
Devprayag Bhagirathi + Alaknanda
Rudraprayag Mandakini + Alaknanda
Karnaprayag Pindar + Alaknanda
Vishnuprayag Dhauliganga + Alaknanda
From Haridwar, it flows first to the south, then to the south-east and east before splitting into two
distributaries, namely the Bhagirathi and the Hugli. The river has a length of 2,525 km. It is shared
by Uttarakhand (110 km) and Uttar Pradesh (1,450 km), Bihar (445 km) and West Bengal (520 km).
The Ganga basin covers about 8.6 lakh sq. km area in India alone. The Ganga river system is the
largest in India having a number of perennial and non-perennial rivers originating in the Himalayas
in the north and the Peninsula in the south, respectively.
Tributaries of Ganga
The important tributaries of Ganga are the Ramganga, the Gomati, the Ghaghara, the Gandak, the
Kosi and the Mahanada. The river finally discharges itself into the Bay of Bengal near the Sagar
Island.
• The Yamuna, the western most and the longest tributary of the Ganga, has its source in the
Yamunotri glacier on the western slopes of Banderpunch range (6,316 km). It joins the Ganga at
Prayag (Allahabad). It is joined by the Chambal, the Sind, the Betwa and the Ken on its right bank
which originates from the Peninsular plateau while the Hindan, the Rind, the Sengar, the Varuna,
etc. join it on its left bank. Much of its water feeds the western and eastern Yamuna and the Agra
canals for irrigation purposes.
• The Chambal rises near Mhow in the Malwa plateau of Madhya Pradesh and flows northwards
through a gorge up wards of Kotain Rajasthan, where the Gandhisagar dam has been constructed.
From Kota, it traverses down to Bundi, Sawai Madhopur and Dholpur, and finally joins the
Yamuna. The Chambal is famous for its badlands topography called the Chambal ravines.
• The Gandak comprises two streams, namely Kaligandak and Trishulganga. It rises in the Nepal
Himalayas between the Dhaulagiri and Mount Everest and drains the central part of Nepal. It
enters the Ganga plain in Champaran district of Bihar and joins the Ganga at Sonpur near Patna.
• The Ghaghara originates in the glaciers of Mapchachungo. After collecting the waters of its
tributaries – Tila, Seti and Beri, it comes out of the mountain, cutting a deep gorge at Shishapani.
The river Sarda (Kali or Kali Ganga) joins it in the plain before it finally meets the Ganga at
Chhapra.
• The Kosi is an antecedent river with its source to the north of Mount Everest in Tibet, where its
main stream Arun rises. After crossing the Central Himalayas in Nepal, it is joined by the Son Kosi
from the West and the Tamur Kosi from the east. It forms Sapt Kosi after uniting with the river
Arun.
• The Ramganga is comparatively a small river rising in the Garhwal hills near Gairsain. It changes
its course to the southwest direction after crossing the Shiwalik and enters into the plains of Uttar
Pradesh near Najibabad. Finally, it joins the Ganga near Kannauj.
• The Damodar occupies the eastern margins of the Chotanagpur Plateau where it flows through a
rift valley and finally joins the Hugli.
It traverses eastward longitudinally for a distance of nearly 1,200 km in a dry and flat region of
southern Tibet, where it is known as the Tsangpo, which means ‘the purifier.’ The Rango
Tsangpo is the major right bank tributary of this river in Tibet. It emerges as a turbulent and
dynamic river after carving out a deep gorge in the Central Himalayas near Namcha Barwa (7,755
m).
The river emerges from the foothills under the name of Siang or Dihang. It enters India west of
Sadiya town in Arunachal Pradesh. Flowing southwest, it receives its main left bank tributaries,
viz., Dibang or Sikang and Lohit; thereafter, it is known as the Brahmaputra. Among the
tributaries Subansiri, Manas, Jiabharali, Pagladiya, Puthimari and Sankosh etc. are snow fed.
Major tributaries of Brahmaputra River System
Tributaries from North bank Tributaries from South bank
The Jiadhal The Noa Dehing
The Subansiri The Buridehing
The Siang The Debang
The Kameng (Jiabharali in Assam) The Dikhow
The Dhansiri(North) The Dhansiri(S)
The Puthimari The Kopili
The Pagladiya The Digaru
The Manas The Dudhnai
The Champamati The Krishnai
The Saralbhanga
The Aie
The Sankosh
• Subsidence of the western flank of the Peninsula leading to its submergence below the sea
during the early tertiary period. Generally, it has disturbed the symmetrical plan of the river on
either side of the original watershed.
• Upheaval of the Himalayas when the northern flank of the peninsular block was subjected to
subsidence and the consequent trough faulting. The Narmada and The Tapi flow in trough faults
and fill the original cracks with their detritus materials. Hence, there is a lack of alluvial and deltaic
deposits in these rivers.
• Slight tilting of the peninsular block from northwest to the south-eastern direction gave
orientation to the entire drainage system towards the Bay of Bengal during the same period.
• The Godavari: It is the largest peninsular river system due to this it is also called the Dakshin
Ganga. It rises in the Nasik district of Maharashtra and discharges its water into the Bay of Bengal.
Its tributaries run through the states of Maharashtra, Madhya Pradesh, Chhattisgarh, Orissa and
Andhra Pradesh. The Penganga, the Indravati, the Pranhita, and the Manjra are its principal
tributaries. The Godavari is subjected to heavy floods in its lower reaches to the south of
Polavaram, where it forms a picturesque gorge. It is navigable only in the deltaic stretch. The river
after Rajamundri splits into several branches forming a large delta.
• The Krishna: It is the second largest east flowing Peninsular River which rises near
Mahabaleshwar in Sahyadri. Its total length is 1,401 km. The Koyna, the Tungbhadra and the
Bhima are its major tributaries.
• The Shetruniji is one such river which rises near Dalkahwa in Amreli district.
• The Bhadra originates near Aniali village in Rajkot district. The Dhadhar rises near Ghantar
village in Panchmahal district. Sabarmati and Mahi are the two famous rivers of Gujarat.
• The Vaitarna originates from the Trimbak hills in Nasik district at an elevation of 670 m. The
Kalinadi rises from Belgaum district and falls in the Karwar Bay. The source of Bedti River lies in
Hubli Dharwar and traverses a course of 161 km.
• The Sharavati is another important river in Karnataka flowing towards the west. The Sharavati
originates in Shimoga district of Karnataka and drains a catchment area of 2,209 sq. km.
• The Mandovi and the Juari is two important rivers of Goa.
• Kerala has a narrow coastline. The longest river of Kerala, Bharathapuzha rises near Annamalai
hills. It is also known as Ponnani. It drains an area of 5,397 sq. km. The Periyar is the second largest
river of Kerala. Its catchment area is 5,243 sq. km. You can see that there is a marginal difference
in the catchment area of the Bhartapuzha and the Periyar rivers. Another river of Kerala worth
mentioning is the Pamba River which falls in the Vemobanad lake after traversing a course of 177
km. lake after traversing a course of 177 km.
River Catchment area (sq. Km)
Sabarmati 21,674
Mahi 34,842
Dhandhar 2,770
Kalinadi 5,179
Sharavati 2,029
Bharathapuzha 5,397
Periyar 5,243
• The term monsoon has been derived from the Arabic word mausin or from the Malayan
word monsin meaning ‘season’.
• Monsoons are seasonal winds (Rhythmic wind movements)(Periodic Winds) which reverse their
direction with the change of season.
• Above points +
• Subtropical Jet Stream (STJ).
• Tropical Easterly Jet (African Easterly Jet).
• Inter Tropical Convergence Zone.
• Strengths of Low pressure over Tibet and high pressure over southern Indian Ocean.
• Somali Jet (Findlater Jet).
• Somali Current (Findlater Current).
• Indian Ocean branch of Walker Cell.
• Indian Ocean Dipole.
• Formation and strengthening of high pressure cells over Tibetan plateau and Siberian Plateau in
winter.
• Westward migration and subsequent weakening of high pressure cell in the Southern Indian
Ocean.
• Migration of ITCZ to the south of India.
Classical Theory
• Monsoons are mentioned in scriptures like the Rig Veda. But these scriptures didn’t make any
mention of the monsoon mechanism.
• The first scientific study of the monsoon winds was done by Arab traders.
• Arab traders used the sea route to carry out trade with India and monsoon patterns were of prime
importance for them.
• In the tenth century, Al Masudi, an Arab explorer, gave an account of the reversal of ocean
currents and the monsoon winds over the north Indian Ocean.
• In seventeenth century, Sir Edmund Halley explained the monsoon as resulting from thermal
contrasts between continents and oceans due to their differential heating.
Modern Theories
• Besides differential heating, the development of monsoon is influenced by the shape of the
continents, orography (mountains), and the conditions of air circulation in the upper troposphere
{jet streams}.
• Therefore, Halley’s theory has lost much of its significance and modern theories based on air
masses and jet stream are becoming more relevant.
Summer Monsoon
• In summer the sun’s apparent path is vertically over the Tropic of Cancer resulting in high
temperature and low pressure in Central Asia.
• The pressure is sufficiently high over Arabian Sea and Bay of Bengal. Hence winds flowed from
Oceans flow towards landmass in summer.
• This air flow from sea to land bring heavy rainfall to the Indian subcontinent.
Winter Monsoon
• In winter the sun’s apparent path is vertically over the Tropic of Capricorn.
• The north western part of India grows colder than Arabian Sea and Bay of Bengal and the flow of
the monsoon is reversed.
• The basic idea behind Classical theory is similar to land and sea breeze formation except that in
the case of monsoons the day and night are replaced by summer and winter.
Drawbacks: The monsoons do not develop equally everywhere on earth and the thermal concept
of Halley fails to explain the intricacies of the monsoons such as the sudden burst of
monsoons, delay in on set of monsoons sometimes, etc..
Indian Monsoons – Modern theory: Air Mass Theory
• According to this theory, the monsoon is simply a modification of the planetary winds of the
tropics.
• The theory is based on the migration of ITCZ based on seasons.
• The southeast trade winds in the southern hemisphere and the northeast trade winds in the
northern hemisphere meet each other near the equator.
• The meeting place of these winds is known as the Inter-Tropical Convergence Zone (ITCZ).
• This is the region of ascending air, maximum clouds and heavy rainfall.
• The location of ITCZ shifts north and south of equator with the change of season.
• In the summer season, the sun shines vertically over the Tropic of Cancer and the ITCZ shifts
northwards.
• The southeast trade winds of the southern hemisphere cross the equator and start blowing in
southwest to northeast direction under the influence of Coriolis force.
• These displaced trade winds are called south-west monsoons when they blow over the Indian sub-
continent.
• The front where the south-west monsoons meet the north-east trade winds is known as
the Monsoon Front (ITCZ). Rainfall occurs along this front.
• In the month of July the ITCZ shifts to 20°- 25° N latitude and is located in the Indo-Gangetic Plain
and the south-west monsoons blow from the Arabian Sea and the Bay of Bengal. The ITCZ in this
position is often called the Monsoon Trough [maximum rainfall].
• The seasonal shift of the ITCZ has given the concept of Northern Inter-Tropical Convergence Zone
(NITCZ) in summer (July – rainy season) and Southern Inter-Tropical Convergence Zone (SITCZ) in
winter (Jan – dry season).
• NITCZ is the zone of clouds and heavy rainfall that effect India.
• Jet stream Theory is the latest theory regarding the origin of the monsoons and has earned
worldwide acceptance from the meteorologists.
• To understand how Jet streams affect Indian monsoons, we need to know the basic mechanism of
Jet Stream induced weather conditions.
Indian Monsoons: Role of Tropical Easterly Jet, Tibet, Somali Jet & Indian Ocean Dipole
Indian Monsoons – Role of Tropical Easterly Jet (TEJ)
• The establishment and maintenance of the TEJ is not fully understood but it is believed that the jet
may be caused by the uniquely high temperatures and heights over the Tibetan Plateau during
summer.
• The TEJ plays an important role in kick starting southwest monsoon.
• This jet descends over the Indian Ocean (near Madagascar) and intensifies its high pressure cell so
as to move as south-west monsoon.
• Polar and subtropical jet streams are the permanent jet streams which greatly influence the
weather of temperate regions.
• Temporary jet streams are narrow winds with speeds more than 94 kph in the upper, middle and
sometimes in lower troposphere. They are few. Important ones are Somali Jet and The African
Easterly jet or Tropical Easterly Jet.
• These two jet streams play an important role in the formation and progression of Indian
Monsoons.
• Indian ocean Dipole is a recently discovered phenomena that has a significant influence on Indian
monsoons.
• Indian ocean Dipole is a SST anomaly (Sea Surface Temperature Anomaly – different from normal)
that occurs occasionally in Northern or Equatorial Indian Ocean Region (IOR).
• The Indian Ocean Dipole (IOD) is defined by the difference in sea surface temperature between
two areas (or poles, hence a dipole) – a western pole in the Arabian Sea (western Indian Ocean)
and an eastern pole in the eastern Indian Ocean south of Indonesia.
• IOD develops in the equatorial region of Indian Ocean from April to May peaking in October.
• With a positive IOD winds over the Indian Ocean blow from east to west (from Bay of Bengal
towards Arabian Sea). This results in the Arabian Sea (western Indian Ocean near African Coast)
being much warmer and eastern Indian Ocean around Indonesia becoming colder and dry.
• In the negative dipole year, reverse happens making Indonesia much warmer and rainier.
• Positive IOD is good for Indian Monsoons as more evaporation occurs in warm water.
• Similar to ENSO, the atmospheric component of the IOD is named as Equatorial Indian Ocean
Oscillation (EQUINOO)(Oscillation of pressure cells between Bay of Bengal and Arabian Sea).
• During the positive phase of the ‘Equatorial Indian Ocean Oscillation (EQUINOO),’ there is
enhanced cloud formation and rainfall in western part of the equatorial ocean near the African
coast while such activity is suppressed near Sumatra.
• While EQUINOO and IOD go in step during strong positive IOD events, they do not always do so.
• In the winter season, the sub-tropical jet (STJ) is bifurcated into two branches due to physical
obstruction of the Himalayas and Tibetan Plateau.
• One branch is flows to the south of the Himalayas, while the second branch is positioned to the
north of the Tibetan Plateau.
• The ridge of the jet stream creates anticyclonic (with clockwise air circulation) conditions over
North-West India.
• Consequently, the winds tend to descend over the north-western parts of India, resulting into the
development of atmospheric stability and dry conditions (anticyclonic condition = no rainfall).
• But the sub-tropical jet (STJ) causes periodic changes in general weather conditions.
• The STJ drives the temperate low pressures over Mediterranean Sea towards east across
Afghanistan, Pakistan and reach north-west India.
• The arrival of these temperate storms [remnants of temperate cyclones] [western disturbances]
causes precipitationleading to an abrupt decrease in air temperature over North-West India.
• The weather becomes clear after the western disturbances passes away.
• Western Disturbances also bring heavy snowfall in the Himalayan Region and a cold wave to
north Indian plains.
• The western disturbances affect weather conditions during the winter season up to Patna (Bihar)
and give occasional rainfall which is highly beneficial for the standing rabi crops, (wheat, barley,
mustard, gram, lentil, etc.).
• A cloudburst is an intense torrential rainfall brought by a thunderstorm that lasts for a relatively
short duration (few minutes to few hours).
• Cloudburst leads to flash floods and causes lot of damage to life and property.
• Every intense rainfall is not a Cloudburst. Cloudburst specifically occurs when an air mass with high
humidity is struck at a place due to various reasons.
• In 2010, South-Western strip of Russia (Caucasus Region, Moscow etc.) saw higher than normal
temperatures (highest in in the last 100 years) and there were numerous cloudbursts in Jammu
and Kashmir.
• A strong upper-atmospheric high was located over European Russia towards the beginning of
summer.
• It diverted the jet stream (meandering of Sub-Tropical Jet Stream) and its rain-giving train (trough)
of summer storms farther north than usual, giving much of Southern European Russia drought
conditions.
• In addition, southern desert heat from central Asia, the Arabian Peninsula and North Africa began
to flow northward, which strengthened this ridge of STJ and tightened its hold over the region.
• The stalled system prevented weather systems being drawn across Russia and the obstacle acted
as a barrier trapping hot air to the south and cold air to the north.
• The consequence of this static mass of hot air was the heat wave that devastated Russia.
• With the jet stream stalled the Sub-Tropical Jet was unable to transit across the Himalayas as it
would do ordinarily, the monsoon cell to the south, fed by warmer waters in the Indian Ocean,
had nowhere to go and as a consequence it deposited vast amounts of rain over Pakistan,
Himalchal Pradesh and Jammu and Kashmir and this led to extensive flooding.
• India’s climate closely resembles the climate that of a tropical country although its northern part
(north of tropic of cancer) is situated in the temperate belt.
• Indian subcontinent is separated from the rest of Asia by the lofty Himalayan ranges which block
the cold air masses moving southwards from Central Asia.
• India has high Regional Climatic Diversity because of its topographical diversity (location, altitude,
distance from sea and relief).
Rainfall
• The climate in most of the regions is characterized by distinct wet and dry seasons. Some places
like Thar desert, Ladakh have no wet season.
• Mean annual rainfall varies substantially from region to region. Mawsynram and Cherrapunji in
Meghalaya receives around 1,000 cm of annual rainfall while at Jaisalmer the annual rainfall rarely
exceeds 12 cm.
• The Ganga delta and the coastal plains of Odisha see intense rainfall in July and August while the
Coromandel Coast goes dry during these months.
• Places like Goa, Hyderabad and Patna receive south-west monsoon rains by the first quarter of
June while the rains are awaited till early July at places in Northwest India.
Temperature
• Latitudinal location
• Distance from the Sea
• The Himalayas
• Physiography
• Monsoon Winds
• Upper Air Circulation
• El Nino and La Nina
• Tropical Cyclones and Western Disturbances
• Coastal regions have moderate or equable or maritime climate where as interior locations are
deprived of the moderating influence of the sea and experience extreme or continental climate.
• The monsoon winds first reach the coastal regions and hence bring good amount of rainfall.
Why rainfall decreases form east to west in plains region (Indus-Ganga Plains)?
• In summer, there are many minor low pressure cells that exist all over the plain region.
• As the monsoon winds move from east to west the moisture levels decrease due to successive
rainfall at each low pressure regions.
• By the time winds reach western parts of the plains (Delhi, Haryana etc.) all the moisture in the
monsoon winds in exhausted.
Then how come Haryana and Punjab not deserts like Rajasthan?
• They receive rainfall due to Western Disturbances in winter. (In summer the rainfall is very low.)
• Physiography is the most important factor that determines the mean annual rainfall received by a
region.
• Places on the windward side of an orographic barrier receive great amount of rainfall where as
those on the leeward side remain arid to semi-arid due to rain-shadow effect.
• Example: The south-west monsoon winds from the Arabian sea strike almost perpendicular at the
Western Ghats and cause copious rainfall in the Western Coastal plain and the western slopes of
the Western Ghats.
• On the contrary, vast areas of Maharashtra, Karnataka, Telangana, Andhra Pradesh and Tamil
Nadu lie in rain-shadow or leeward side of the Western Ghats and receive scanty rainfall.
Why no significant rainfall in Gujarat and Rajasthan? Explain the formation of Thar Desert?
• Monsoons winds flowing in Rajasthan and Gujarat are not obstructed by any orographic
barrier and hence these regions receive no rainfall.
• [Monsoon winds blow almost parallel to Aravalis and hence there is no orographic rainfall].
• [No convection cell or vertical wind movements arise in Rajasthan and Gujarat: Monsoon winds
blow towards low pressure cells in Tibet and hence only horizontal wind movements exist in
Gujarat and Rajasthan]
• [Sub-tropical high pressure belt: In winter the region experiences strong divergence because of the
STJ – Sub-Tropical Jet.]
• The most dominating factor of the Indian climate is the ‘monsoon winds’.
• The complete reversal of the monsoon winds brings about a sudden change in the seasons.
• The harsh summer season suddenly giving way to monsoon or rainy season.
• The south-west monsoons from the Arabian sea and the Bay of Bengal bring rainfall to the entire
country.
• The north-eastern winter monsoon do not cause much rainfall except along the Caromandel coast
(TN coast) after getting moisture from the Bay of Bengal.
• The changes in the upper air circulation over Indian landmass is brought about by Jet
streams. (Explained in detail in Indian Monsoons)
• Westerly jet stream blows at a very high speed during winter over the sub-tropical zone.
• Southern branch of the jet stream exercises a significant influence on the winter weather
conditions in India.
• This jet stream is responsible for bringing western disturbances from the Mediterranean region in
to the Indian sub-continent.
• Winter rain and heat storms in north-western plains and occasional heavy snowfall in hilly regions
are caused by these disturbances.
• These are generally followed by cold waves in the whole of northern plains.
• Reversal in upper air circulation takes place in summer due to the apparent shift of the sun’s
vertical rays in the northern hemisphere.
• The westerly jet stream is replaced by the easterly jet stream which owes its origin to the heating
of the Tibet plateau.
• This helps in the sudden onset of the south-west monsoons.
• Tropical cyclones originate in the Bay of Bengal and Arabian Sea and the influence large parts of
the peninsular India.
• Majority of the cyclones originate in the Bay of Bengal and influence the weather conditions
during the south-west monsoon season (low intensity cyclones).
• Some cyclones are born during the retreating monsoon season, i.e., in October and
November (high intensity cyclones) and influence the weather conditions along the eastern coast
of India.
• The western disturbances originate over the Mediterranean sea and travel eastward under the
influence of westerly jet stream.
• They influence the winter weather conditions over most of Northern-plains and Western
Himalayan region.
El Nino
La Nina
• Southern Oscillation is simply the oscillation or alternating positions of low pressure and high
pressure cells over eastern and western Pacific.
• Southern Oscillation coinciding with El Nino is called ENSO or El Nino Southern Oscillation. (SO
usually coincides with EL Nino. This why El Nino is usually referred to as ENSO)
• ENSO = [warm water in eastern Pacific + low pressure over eastern Pacific] + [cool water in
western Pacific + high pressure in western Pacific]
• Climatic conditions same as El Nino.
• High air pressure prevails over large parts of north-west India due to low temperatures coupled
with divergence induced by the ridge of the STJ.
• Pressure is comparatively lower in south India.
• The winds start blowing from high pressure area of north-west to low pressure area of south-east.
The wind velocity is low due to low pressure gradient.
• The path of the winds depend on pressure gradient and physiography.
• The spell of fine weather over north-western and northern India is often broken due to inflow of
western disturbances.
• The retreating winter monsoons pick up some moisture while crossing the Bay of Bengal and
cause winter rainfall in Tamil Nadu, south Andhra Pradesh, south-east Karnataka and south-east
Kerala (Usually in the first weeks of November).
• The highest seasonal rainfall of about 75 cm between October and December.
• Most of it occurs along the south-eastern coast of Tamil Nadu and adjoining parts of Andhra
Pradesh. Thereafter, it gradually decreases.
• The western disturbances also cause a little rainfall in north-west India.
• The amount of rainfall gradually decreases from the north and north-west to east (it is opposite in
rainy season).
• The northeastern part of India also gets rainfall during the winter months.
• March to June.
• High temperature and low humidity are the chief characteristics.
• Sometimes referred to as pre-monsoon period.
• High sun’s insolation due to apparent movement of sun between the equator and the Tropic of
Cancer.
• The southern parts of the country are distinctly warmer in March and April whereas in June, north
India has higher temperatures.
• In March, the highest temperatures occur in the southern parts (40-45°C).
• In April the highest temperature of about 45°C is recorded in the northern parts of Madhya
Pradesh.
• In May the highest temperature shifts to Rajasthan where temperatures as high as 48°C may be
recorded.
• In June the maximum temperature is in Punjab and Haryana.
• The highest temperatures recorded are 50.5°C at Alwar on 10th May, 1956 and 50.6°C at
Ganganagar on 14th June, 1935.
• The highest temperatures are recorded just before the onset of the southwest monsoons (late
May).
• Most of the heat waves develop over Rajasthan, Punjab and Haryana (location far away from the
sea). From here they spread over Uttar Pradesh and Bihar.
• The strong north westerly winds (caused due to strong divergence in north-west India) with a long
land journey over hot regions check the onward march of the sea breeze over eastern coastal belt
and create heat wave conditions over Odisha and Andhra Pradesh.
• The heat waves strike by the end of April and their maximum occurrence is in May. They last till
the onset of southwest monsoon.
• The normal duration of heat waves is 4 to 5 days. However, heat waves are rare over the
peninsula south of 13°N latitude due to maritime conditions prevailing there.
• The atmospheric pressure is low all over the country due to high temperature.
• But strong dynamically induced divergence over north-west India prevents the onset of south-
west monsoons.
• There is a marked change in the direction and speed of the winds from winter.
• The winds are by and large light and variable.
Loo
Andhis
• The strong dust storms resulting from the convective phenomena are locally known as andhis
(blinding storms). They move like a solid wall of dust and sand.
• The wind velocity often reaches 50-60 kmph and the visibility is reduced to a few metres.
• Such dust storms are common in Rajasthan, Haryana, Punjab, Jammu region, Delhi, Uttar Pradesh,
Bihar and Madhya Pradesh.
• They are short lived. The squall and showers which follow these storms bring down the
temperature sharply temporarily.
• The strong convectional movements related to the westerly jet stream lead to thunderstorms in
eastern and north-eastern part of the country.
• They normally originate over Chota Nagpur plateau and are carried eastwards by westerly winds.
• The areas with highest incidence of thunderstorms are Assam, Arunachal Pradesh, Nagaland,
Mizoram, Manipur, Tripura, Meghalaya, West Bengal and the adjoining areas of Odisha and
Jharkhand.
• In West Bengal and the adjoining areas of Jharkhand, Odisha and Assam, the direction of squalls is
mainly from the northwest, and they are called norwesters.
• They are often very violent with squall speeds of 60 to 80 km per hour.
• Hailstones sometimes accompany showers and occasionally attain the size of a golf ball.
• They cause heavy damage to standing crops, trees, buildings, livestock and even lead to loss of
human lives.
• However, they are, sometimes, useful for tea, jute and rice cultivation. In Assam, these storms are
known as ‘Barodoli Chheerha’.
• The period of maximum occurrence of these storms is the month of Vaisakh (mid-March to mid-
April) and hence, they are locally known as Kalabaisakhis, the black storms or a mass of dark
clouds of Vaiasakha.
• In the south the thunderstorms occur in Kerala (Mango Showers) and adjoining parts
of Karnataka (Blossom Showers) and Tamil Nadu, particularly during evenings and nights.
• This season is not totally rainless (only one per cent of the annual rainfall).
• In the northeastern parts of the country, dust storms bring little rainfall.
• The precipitation in Kashmir is mainly in the form of snow caused by western disturbances.
• The norwesters bring some rainfall in Assam, West Bengal and Odisha. The intensity of rainfall is
high.
• The rainfall brought by the norwesters is known as the spring storm showers.
• This small amount of rainfall is very useful for the cultivation of tea, jute and rice and is known
as tea showers in Assam.
• Coastal areas of Kerala and Karnataka receive rainfall from thunderstorms.
• Such showers are called mango showers in Tamil Nadu and Andhra Pradesh because they are very
beneficial to mango crop.
• In Karnataka they are called cherry blossoms due to their effect on the coffee plantations.
• ISOLINE: imaginary lines joining regions with equal rainfall or any other parameter.
• ISOBAR: imaginary lines joining regions with equal pressure.
• ISOTHERM: imaginary lines joining regions with equal temperature.
• ISOHYET: imaginary lines joining regions with equal rainfall.
• Sudden onset of South West Monsoons leads to significant fall in temperature [3° to 6°C].
• The temperature remains less uniform throughout the rainy season.
• The temperature rises in September with the cease of south-west monsoons.
• There is rise in temperature whenever there is break in the monsoons.
• The diurnal range of temperature is small due to clouds and rains.
• The highest temperatures are experienced at places west of the Aravali [38° to 40°C]. This is due to
lack of clouds and hot continental air masses.
• Other parts of Northwest India also have temperatures above 30°C.
• The temperatures are quite low over the Western Ghats due to heavy rainfall.
• The coastal areas of Tamil Nadu and adjoining parts of Andhra Pradesh have temperatures above
30°C as they receive little rainfall during this season.
• Low pressure conditions prevail over northwest India due to high temperature.
• ITCZ (monsoon trough) lies along the Ganga plain. There are frequent changes in its location
depending upon the weather conditions.
• The atmospheric pressure increases steadily southwards.
• Over the peninsular region, due to pressure gradient between north and south, winds blow in a
southwest to northeast direction from Arabian sea and Bay of Bengal.
• Their direction undergoes a change in Indo-Gangetic plain where they move from east to west.
• Three fourths of the total annual rainfall is received during this season.
• The average rainfall over the plains of India in this season is about 87 per cent.
• Normal date of the arrival of the monsoon is 20th May in Andaman and Nicobar Islands.
• The advance of the monsoon is much faster in the Bay of Bengal than in the Arabian Sea.
• The normal date of onset of the southwest monsoon over Kerala i.e. the first place of entry in the
mainland of India is 1st June.
• The monsoons advance quickly accompanied with a lot of thunder, lightning and heavy downpour.
This sudden onset of rain is termed as monsoon burst.
• Sometimes monsoons are delayed or they come much earlier than normal.
• Normally the onset occurs between 29th May and 7th June.
• The earliest onset was on 11th May in 1918 and 1955, while the most delayed onset was on 18th
June in 1972.
South West Monsoons – Arabian Sea branch and Bay of Bengal branch
• Monsoon winds beyond south Kerala progress in the form of two branches viz. the Arabian Sea
branch and the Bay of Bengal branch.
• The Arabian Sea branch gradually advances northwards. It reaches Mumbai by 10th June.
• The Bay of Bengal branch spreads rather rapidly over most of Assam. The normal date of its arrival
at Kolkata is 7th June.
• On reaching the foothills of the Himalayas the Bay branch is deflected westward by the
Himalayan barrier and it advances up the Gangetic plain.
• The two branches merge with each other mostly around Delhi to form a single current.
• Both the branches reach Delhi more or less at the same time.
• The combined current gradually extends to west Uttar Pradesh, Haryana, Punjab, Rajasthan and
finally to Himachal Pradesh and Kashmir.
• By the end of June the monsoon is usually established over most parts of the country.
• By mid-July, the monsoon extends into Kashmir and the remaining parts of the country.
• By this time it reaches Kashmir, it has shed most of its moisture.
• Arabian Sea branch of the monsoon is much powerful than the Bay of Bengal branch for reasons:
The Arabian Sea branch of the southwest monsoons is divided into three distinct streams on
arriving in the mainland of India.
The Bay of Bengal Branch of the southwest monsoon is divided into two distinct streams.
• The first stream crosses the Ganga-Brahmaputra delta and reaches Meghalaya. Here that the
orographic effect results in intense rainfall. Cherrapunji receives an annual rainfall of 1,102 cm,
major portion of which occurs from June to August.
• Mawsynram (present champion) located at 1,329 m above sea level just 16 km to the west
of Cherrapunji (X champion) records higher annual rainfall of 1,221 cm.
• Both the stations are located on the southern slopes of the Khasi hills at the northern end of a
deep valley running from south to north.
• The second stream of the Bay of Bengal branch moves along Himalayan foothills as they are
deflected to the west by the Himalaya and brings widespread rainfall to Ganga plain.
• The rainfall by this stream is characterized by a steady decline as we move from east to west up
the plain. [Previous Prelims Question]
• The Tamil Nadu coast remains relatively dry during the south-west monsoon period because of
• During the Monsoon season, there are periods when the Monsoon trough shifts to the foothills of
Himalayas, which leads to sharp decrease in rainfall over most parts of the country but increase
along the Himalayas and parts of Northeast India and Southern Peninsula.
• During July and August, there are certain periods when the monsoons become weak. Rainfall
practically ceases over the country outside the Himalayan belt and southeast peninsula. This is
known as break in the monsoon.
• Breaks are likely to occur during the second week of August and last for a week.
• The breaks are believed to be brought about by the northward shifting of the monsoon trough
(minimum low pressure cell in ITCZ). The axis of the trough lies at the foothills of the Himalayas
during the break period.
The monsoon trough is a portion of the Intertropical Convergence Zone as depicted by a line on a
weather map showing the locations of minimum sea level pressure, and as such, is a convergence
zone between the wind patterns of the southern and northern hemispheres.
• During the break period, heavy rainfall occurs over the sub-Himalayan regions and the southern
slopes of the Himalayas.
• A major part of the South West Monsoon rainfall is generated by depressions [intense low
pressure] originating in the Arabian Sea and Bay of Bengal. Some depressions develop over land
also.
• About 3-4 depressions are formed per month from June to September.
• Almost all of them are sucked inward through the deltas of great rivers [They need moisture to be
alive], the Ganga, the Mahanadi, the Godavari, the Krishna and the Cauvery and cause heavy rain
in these areas.
• The location of depressions strongly coincide with the latitudinal position of ITCZ.
• Most of the depression originate to the west of 90⁰ E in Bay of Bengal and move in north-west
direction.
• In the Arabian Sea in June-July, the depressions move either in north-west or in northerly direction
and may affect west Gujarat or Maharashtra.
• Storms during August and September are rare and are formed close to Maharashtra-Gujarat coast.
• Most of the rainfall in central and northern parts of the country is caused by these depressions.
• The absence of depressions or a change in their tracks result in deficit or no rain.
• Major part of monsoon rains are received between June and September.
• Monsoonal rainfall is largely governed by relief and is orographic in its mode.
• The amount of rainfall decreases with increasing distance from the sea.
• The rainless interval during south west monsoon season is known as ‘breaks’. The breaks in rainfall
are related to tropical cyclones which originate in the Bay of Bengal.
• There are large scale spatial variations in the distribution of rainfall.
• Monsoons often fail to keep date. Sometimes the monsoons withdraw before the scheduled time
causing considerable damage to the crops.
• Starts with the beginning of the withdrawal of southwest monsoon [middle of September –
November] and lasts till early January.
• The monsoons withdraw from the extreme north-west end of the country in September, from the
peninsula by October and from the extreme south-eastern tip by December.
• In Punjab the south-west monsoons reach in the first week of July and withdraw from there in the
second week of September.
• The south-west monsoons reach Coromandel coast in the first week of June and withdraw from
there only in the middle of December.
• Unlike the sudden burst of the advancing monsoons, the withdrawal is rather gradual and takes
about three months.
• With retreat of the monsoons, the clouds disappear and the sky becomes clear.
• As the monsoons retreat, the monsoon trough weakens and gradually shifts southward.
Consequently the pressure gradient is low.
• Unlike south-west monsoon, the onset of the north monsoon is not clearly defined.
• The direction of winds over large parts of the country is influenced by the local pressure
conditions.
• Most severe and devastating tropical cyclones originate in the Indian seas especially in the Bay of
Bengal.
• The highest frequency of the cyclones is in the month of October and the first half of November.
More cyclones are born in October and then in November and more cyclones originate in the
Bay of Bengal than in the Arabian Sea.
• In October, the Cyclones of the Bay of Bengal originate between 8°N and 14°N.
• Initially they move in a west or northwesterly direction, but many of them later recurve and move
towards the north-east.
• Near 55 per cent of the Bay storms cross or affect the Indian coast.
• The area’s most vulnerable to these storms include the coastal belts of Tamil Nadu, Andhra
Pradesh, Odisha and West Bengal.
• Many of the cyclones which strike the eastern coast of India, south of 15°N latitude cross the
southern Peninsula and enter Arabian Sea.
• During this process, they may weaken, but on re-entry over the Arabian sea they intensify into
cyclonic storms.
• The storms of Arabian sea originate between 12°N and 17°N latitudes in October and between 8°
N and 13° N latitudes in November.
• Generally they move away from the coast in a north-westerly direction. But about 25% of them
later recurve northeast and strike the Maharashtra or Gujarat coast.
• In north-west India the western disturbances produce clouding and light rainfall in the otherwise
fine weather.
• The precipitation is in the form of snow in higher reaches of Jammu and Kashmir, Himachal
Pradesh and in Kumaon Hills.
• The humidity and cloud cover are much reduced with the retreat of the south-west monsoons and
most parts of the country remain without much rainfall.
• October-November is the main rainy season in Tamil Nadu and adjoining areas of Andhra
Pradesh to the south of the Krishna delta as well as a secondary rainy period for Kerala.
• The retreating monsoons absorb moisture while passing over the Bay of Bengal and cause this
rainfall.
Meghalaya (the abode of clouds) is the wettest part of the country with Mawsynram and
Cherrapunji getting 1,221 and 1,102 cm of annual rainfall respectively.
• These are desert and semi-desert areas receiving less than 50 cm of annual rainfall.
• They include large areas of western Rajasthan, Kachchh and most of Ladakh region of Jammu and
Kashmir.
Natural Vegetation of India: Moist Tropical, Dry Tropical, Montane Sub-tropical, Montane
Temperate & Alpine Forests
Forests – Natural Vegetation of India
• Climate, soil and topography are the major factors that influence Natural Vegetation of a place.
• The main climatic factors are rainfall and temperature. The amount of annual rainfall has a great
bearing on the type of vegetation.
• Temperature is the major factor in Himalayas and other hilly regions with an elevation of more
than 900 metres.
• As the temperature falls with altitude in the Himalayan region the vegetal cover changes with
altitude from tropical to sub-tropical, temperate and finally alpine.
• Soil is an equally determining factor in few regions. Mangrove forests, swamp forests are some of
the examples where soil is the major factor.
• Topography is responsible for certain minor types e.g. alpine flora, tidal forests, etc..
• Classification of Natural Vegetation of India is primarily based on spatial and annual variations in
rainfall. Temperature, soil and topography are also considered.
• India’s vegetation can be divided into 5 main types and 16 sub-types as given below.
E. Alpine Forests
• Sub-Alpine
• Moist Alpine scrub
• Dry Alpine scrub
Tropical Semi-Evergreen 4
Rest below 4 %
Climatic Conditions
Characteristics
• Evergreen: Due to high heat and high humidity, the trees of these forests do not shed their leaves
together.
• Mesosphytic: Plants adopted to neither too dry nor too wet type climate.
• Unlike hydrophytic plants, such as water lily or pondweed, that grow in saturated soil
or water, or xerophytic plants, such as cactus, that grow in extremely dry soil,
mesophytes are ordinary plants that exist between the two extremes.
• Mesophytic environments are marked by average to hot temperatures and soil that
is neither too dry nor too wet.
• Less undergrowth: The sun light cannot reach the ground due to thick canopy. The undergrowth is
formed mainly of bamboos, ferns, climbers, orchids, etc.
Distribution
• Western side of the Western Ghats (500 to 1370 metres above sea level).
• Some regions in the Purvanchal hills.
• In the Andaman and Nicobar Islands.
Timber
• They are transitional forests between tropical wet evergreen forests and tropical deciduous
forests.
• They are comparatively drier areas compared to tropical wet evergreen forests.
Climatic Conditions
Distribution
• Western coast
• Assam
• Lower slopes of the Eastern Himalayas
• Odisha and
• Andamans.
Characteristics
• The important species are laurel, rosewood, mesua, thorny bamboo – Western Ghats, white cedar,
Indian chestnut, champa, mango, etc. – Himalayan region.
Timber
• Hardwood: Similar to that in tropical evergreen forests except that these forests are less dense
with more pure stands (timber industry here is better than in evergreen forests).
Climatic Conditions
Characteristics
• The trees drop their leaves during the spring and early summer when sufficient moisture is not
available.
Distribution
• Belt running along the Western Ghats surrounding the belt of evergreen forests.
• A strip along the Shiwalik range including terai and bhabar from 77° E to 88° E.
• Manipur and Mizoram.
• Hills of eastern Madhya Pradesh and Chhattisgarh.
• Chota Nagpur Plateau.
• Most of Odisha.
• Parts of West Bengal and
• Andaman and Nicobar islands.
Timber
• They can survive and grow both in fresh as well as brackish water (The mixture of seawater and
fresh water in estuaries is called brackish water and its salinity can range from 0.5 to 35 ppt).
• Occur in and around the deltas, estuaries and creeks prone to tidal influences (delta or tidal
forests).
• Littoral (relating to or on the shore of the sea or a lake) forests occur at several places along the
coast.
• Swamp forests are confined to the deltas of the Ganga, the Mahanadi, the Godavari, the Krishna
and the Cauvery.
• Dense mangroves occur all along the coastline in sheltered estuaries, tidal creeks, backwaters, salt
marshes and mudflats. It provides useful fuel wood.
• The most pronounced and the densest is the Sunderban in the Ganga delta where the
predominant species is Sundri (Heriteera).
Timber
• It provides hard and durable timber which is used for construction, building purposes and making
boats.
• The important species found in these forests are Sundri, agar, rhizophora, screw pines, canes and
palms, etc.
Distribution
Climatic Conditions
• Annual rainfall of 100 cm [mostly from the north-east monsoon winds in October – December].
• Mean annual temperature is about 28°C.
• The mean humidity is about 75 per cent.
• The growth of evergreen forests in areas of such low rainfall is a bit strange.
Characteristics
Climatic Conditions
Characteristics
• These are similar to moist deciduous forests and shed their leaves in dry season.
• The major difference is that they can grow in areas of comparatively less rainfall.
• They represent a transitional type – moist deciduous on the wetter side and thorn forests on the
drier side.
• They have closed but uneven canopy.
• The forests are composed of a mixture of a few species of deciduous trees rising up to a height of
20 metres.
• Undergrowth: Enough light reaches the ground to permit the growth of grass and climbers.
Distribution
• They occur in an irregular wide strip running from the foot of the Himalayas to Kanniyakumari
except in Rajasthan, Western Ghats and West Bengal.
• The important species are teak, axlewood, rosewood, common bamboo, red sanders, laurel,
satinwood, etc.
• Large tracts of this forest have been cleared for agricultural purposes.
• These forests have suffer from over grazing, fire, etc.
Climatic Conditions
Characteristics
Distribution
Climatic conditions
Distribution
• Eastern Himalayas to the east of 88°E longitude at altitudes varying from 1000 to 2000 m.
Characteristics
Distribution
• Western Himalayas between 73°E and 88°E longitudes at elevations between 1000 to 2000 metres
above sea level.
• Some hilly regions of Arunachal Pradesh, Manipur, Naga Hills and Khasi Hills.
Timber
• Chir or Chil is the most dominant tree which forms pure stands.
• It provides valuable timber for furniture, boxes and buildings.
• It is also used for producing resin and turpentine.
Distribution
• Found in the Bhabar, the Shiwaliks and the western Himalayas up to about 1000 metres above sea
level.
Climatic Conditions
Characteristics
• Low scrub forest with small evergreen stunted trees and shrubs.
• Olive, acacia modesta and pistacia are the most predominant species.
Climatic Conditions
Distribution
• Higher hills of Tamil Nadu and Kerala, in the Eastern Himalayan region.
Characteristics
Climatic Conditions
Distribution
• Occurs in the temperate zone of the Himalayas between 1500 and 3300 metres.
• Cover the entire length of this mountain range in Kashmir, Himachal Pradesh, Uttarakhand,
Darjeeling and Sikkim.
Characteristics
Timber
• It provides fine wood which is of much use for construction, timber and railway sleepers.
Climatic Conditions
Characteristics
• Coniferous forests with xerophytic shrubs in which deodar, oak, ash, olive, etc are the main trees.
Distribution
• Such forests are found in the inner dry ranges of the Himalayas where south-west monsoon is very
feeble.
• Such areas are in Ladakh, Lahul, Chamba, Kinnaur, Garhwal and Sikkim.
Alpine Forests
Soil Types: Sandy, Clayey & Loamy | Soil Profile (Soil Horizon)
Soil
• Soil is the thin top layer on the earth’s crust comprising rock particles mixed with organic matter.
• Pedology is the study of soils in their natural environment. Pedogenesis is the natural process of
soil formation that includes a variety of processes such as weathering, leaching, calcification etc..
• The Soil formation is mainly related to the parent rock material, surface relief, climate and natural
vegetation.
• The soil is formed by the breaking down of rocks by the action of wind, water and climate.
• The soil is classified on the basis of the proportion of particles of various sizes.
• If soil contains greater proportion of big particles it is called sandy soil.
• If the proportion of fine particles is relatively higher, then it is called clayey soil.
• If the amount of large and fine particles is about the same, then the soil is called
1. Water can drain quickly through the spaces between the sand particles. So, sandy soils tend to be
light, well aerated and dry.
2. Clay particles, being much smaller, pack tightly together, leaving little space for air. Unlike sandy
soil, water can be held in the tiny gaps between the particles of clay. So clay soils have little air.
But they are heavy as they hold more water than the sandy soils.
3. The best topsoil for growing plants is Loamy soil is a mixture of sand, clay and another type of soil
particle known as silt. Silt occurs as a deposit in river beds. The size of the silt particles is between
those of sand and clay. The loamy soil also has humus in it. It has the right water holding capacity
for the growth of plants.
• Clayey and loamy soils are both suitable for growing cereals like wheat, and gram. Such soils are
good at retaining water.
• For paddy, soils rich in clay and organic matter and having a good capacity to retain water are
ideal.
• For lentils (masoor) and other pulses, loamy soils, which drain water easily, are required.
• For cotton, sandy loam or loam, which drain water easily and can hold plenty of air, are more
suitable.
• A vertical section through different layers of the soil is called the soil profile.
• Each layer differs in feel (texture), colour, depth and chemical composition. These layers are
referred to as
• A soil horizon is a layer generally parallel to the soil surface, whose physical characteristics differ
from the layers above and beneath.
• Horizons are defined in most cases by obvious physical features, chiefly colour and texture.
• The uppermost horizon is generally dark in colour as it is rich in humus and minerals. The humus
makes the soil fertile and provides nutrients to growing plants.
O Horizon
E horizon
B Horizon or Subsoil
• Weathered parent material accumulates in this layer, i.e. the parent material in sedimentary
deposits.
• It is a layer of large unbroken rocks.
• This layer may accumulate the more soluble compounds (inorganic material).
R Horizon or Bedrock
• This layer denotes the layer of partially weathered bedrock at the base of the soil profile.
• Unlike the above layers, R horizons largely comprise continuous masses of hard rock.
• Soils formed in situ will exhibit strong similarities to this bedrock layer.
• Parent Material
• Relief
• Climate
• Natural Vegetation
Parent Material
• The rocks from which soils are formed are called parent materials.
• In most of the cases, the parent material determines the colouration, mineral composition and
texture of the soil.
• In some cases, the soil formed may or may not have the same physical properties of the parent
rock.
• Climatic factors induce chemical changes which also affect physical properties of the soil.
• The surface rocks are exposed to the process of weathering. In this process, the rocks are
converted into fine grains and provide a base for the soil formation.
• In Indian Conditions, parent material is generally categorized into:
• They are the Oldest rocks [(pre-Cambrian era)(formed due to solidification of molten magma
about 4billion years ago)].
• They form the ‘Basement Complex’ of peninsular India.
• They are basically granites, gniesses and schists.
• These rocks are rich in ferromagnetic materials and give rise to red soils on weathering.
• The red colour of these soils is due to the presence of iron oxide.
Gondwana rocks
• These rocks are also sedimentary in nature and they are much younger.
• On weathering they give rise to comparatively less mature soils.
• The soil is more or less of uniform character but of low fertility.
• Volcanic outburst over a vast area of the Peninsular India many hundred million years ago gave
rise to Deccan Traps.
• Basaltic lava flowed out of fissures covering a vast area of about ten lakh sq km.
• Basalts are rich in titanium, magnetite, aluminium and magnesium.
• Consequently the weathering of these rocks has given rise to soils of darker colour.
• The is fertile with high moisture holding capacity and is popularly known as ‘regur’ or black
cotton soil.
• Rocks of extra peninsular (plains and Himalayas) India have given rise to soils with high porosity.
• These soils are generally immature recent and sub recent rocks, result in alluvial soils on
weathering.
• Alluvial fertile soils consist of fine silts and clay. These soils have little relation with the original
rocks.
• On the other hand, the soils of peninsular plateau are generally coarse-grained and are closely
related to the parent rocks. The peninsular soils are generally less fertile.
Relief
• The relief is the most important factor for soil formation in places with steep slopes like the hilly
regions, edges of plateaus etc.
• Soil erosion on barren slopes is rampant and it hinders soil formation. Example: Chambal ravines,
higher reaches of Himalayas where there is minimal or no forest cover (most on the steep
southern slopes) etc.
• The areas of low relief or gentle slope generally experience deposition and have deep soils.
Example: Indo-Gangetic plain.
• The exceptions in the plateau are river basins where the soil layers are sufficiently deep.
Climate
• Temperature and rainfall are the most important factors in soil formation.
• They determine the effectiveness of weathering of the parent material, the quantity of water
seeping through the soil and the type of micro-organisms present therein.
• Two different parent materials may develop the same soil in the same type of climate. Similarly,
the same parent material may produce two different types of soils in two different types of
climates.
• The crystalline granites produce laterite soil in relatively moist parts of the monsoonal region
and non-laterite soil in drier areas.
• Hot summer and low rainfall develops black soil as is found in some parts of Tamil Nadu
irrespective of the parent rock.
• In Rajasthan, both granite and sandstone give birth to sandy soil under arid climate.
• In arid and semi-arid regions, evaporation always exceeds precipitation. There is little vegetation
and the soils badly lack humus content. Hence the soils are invariably of light colour.
• In Rajasthan and the adjoining arid and semi-arid regions, excess of evaporation makes soils lime
accumulating. Hence the soil is pedocal in nature [Pedocal is a subdivision of the zonal soil order. It
is a class of soil which forms in semiarid and arid regions. It is rich in calcium carbonate and
has low soil organic matter].
In areas of heavy rainfall and high temperature, the soils are red or lateritic. Why?
• Torrential rainfall during the rainy season washes the upper soil and leaches the materials into
deeper horizon.
• During the dry summer season the evaporation exceeds precipitation and through capillary
action iron and aluminium oxides are transported to the surface making the soil red.
• In areas of alternate wet and dry climate, the leached material which goes deep down in the
horizon is brought up and the blazing sun bakes the top soil so hard that it resembles a brick.
Therefore, this soil is called lateritic which literally means brick.
Natural Vegetation
• Geologically, Indian soils can broadly be divided into soils of peninsular India and soils of extra-
peninsular India.
• The soils of Peninsular India are formed by the decomposition of rocks in situ, i.e. directly from the
underlying rocks.
• Soils of Peninsular India are transported and re-deposited to a limited extent and are known
as sedentary soils.
• The soils of the Extra-Peninsula are formed due to the depositional work of rivers and wind. They
are very deep. They are often referred to as transported or azonal soils.
Major groups:
• Alluvial soils,
• Black soils,
• Red soils,
• Laterite and Lateritic soils,
• Forest and Mountain soils,
• Arid and Desert soils,
• Saline and Alkaline soils and
• Peaty and Marshy soils.
Alluvial Soils
• Alluvial soils are formed mainly due to silt deposited by Indo-Gangetic-Brahmaputra rivers. In
coastal regions some alluvial deposits are formed due to wave action.
• Rocks of the Himalayas form the parent material. Thus the parent material of these soils is of
transported origin.
• They are the largest soil group covering about 15 lakh sq km or about 46 per cent of the total area.
• They are immature and have weak profiles due to their recent origin.
• Most of the soil is Sandy and clayey soils are not uncommon.
• Pebbly and gravelly soils are rare. Kankar (calcareous concretions) beds are present in some
regions along the river terraces.
• The soil is porous because of its loamy (equal proportion of sand and clay) nature.
• Porosity and texture provide good drainage and other conditions favorable for agriculture.
• These soils are constantly replenished by the recurrent floods.
• They occur all along the Indo-Gangetic-Brahmaputra plains except in few places where the top
layer is covered by desert sand.
• They also occur in deltas of the Mahanadi, the Godavari, the Krishna and the Cauvery, where they
are called deltaic alluvium (coastal alluvium)
• Some alluvial soils are found in the Narmada, Tapi valleys and Northern parts of Gujarat.
• They are mostly flat and regular soils and are best suited for agriculture.
• They are best suited to irrigation and respond well to canal and well/tube-well irrigation.
• They yield splendid crops of rice, wheat, sugarcane, tobacco, cotton, jute, maize, oilseeds,
vegetables and fruits.
• Geologically, the alluvium of the Great plain of India is divided into newer or younger khadar and
older bhangar soils.
Bhabar
• The bhabar belt is about 8-16 km wide running along the Shiwalik foothills. It is a porous, northern
most stretch of Indo-Gangetic plain.
• Rivers descending from the Himalayas deposit their load along the foothills in the form of alluvial
fans. These alluvial fans (often pebbly soils) have merged together to build up the bhabar belt.
• The porosity of bhabar is the most unique feature. The porosity is due to deposition of huge
number of pebbles and rock debris across the alluvial fans.
• The streams disappear once they reach the bhabar region because of this porosity. Therefore, the
area is marked by dry river courses except in the rainy season.
• The area is not suitable for agriculture and only big trees with large roots thrive in this belt.
• Terai is an ill-drained, damp (marshy) and thickly forested narrow tract (15-30 km wide) to the
south of Bhabar running parallel to it.
• The underground streams of the Bhabar belt re-emerge in this belt. It is a swampy lowland with
silty soils.
• The terai soils are rich in nitrogen and organic matter but are deficient in phosphate.
• These soils are generally covered by tall grasses and forests but are suitable for a number of crops
such as wheat, rice, sugarcane, jute etc..
• This thickly forested region provides shelter to a variety of wild life.
Bhangar
• The Bhangar is the older alluvium along the river beds forming terraces higher than the flood plain
(about 30 metres above the flood level).
• It is of a more clayey composition and is generally dark colored.
• A few metres below the terrace of the bhangar are beds of lime nodules known as “Kankar”.
Khadar
• The Khadar is composed of newer alluvium and forms the flood plains along the river banks.
• The banks are flooded almost every year and a new layer of alluvium is deposited with every flood.
This makes them the most fertile soils of Ganges.
• They are sandy clays and loams, more dry and leached, less calcareous and carbonaceous (less
kankary). A new layer of alluvium is deposited by river flood almost every year.
Black Soils
• The parent material for most of the black soil are the volcanic rocks that were formed in the
Deccan Plateau (Deccan and the Rajmahal trap).
• In Tamil Nadu, gneisses and schists form the parent material. The former are sufficiently deep
while the later are generally shallow.
• These are the region of high temperature and low rainfall. It is, therefore, a soil group typical to
the dry and hot regions of the Peninsula.
• A typical black soil is highly argillaceous [Geology (of rocks or sediment) consisting of or containing
clay] with a large clay factor, 62 per cent or more.
• In general, black soils of uplands are of low fertility while those in the valleys are very fertile.
• The black soil is highly retentive of moisture. It swells greatly on accumulating moisture. Strenuous
effort is required to work on such soil in rainy season as it gets very sticky.
• In summer, the moisture evaporates, the soil shrinks and is seamed with broad and deep cracks.
The lower layers can still retain moisture. The cracks permits oxygenation of the soil to sufficient
depths and the soil has extraordinary fertility.
• The black colour is due to the presence of a small proportion of titaniferous magnetite or iron and
black constituents of the parent rock.
• Spread over 46 lakh sq km (16.6 per cent of the total area) across Maharashtra, Madhya Pradesh,
parts of Karnataka, Telangana, Andhra Pradesh, Gujarat and Tamil Nadu.
• These soils are best suited for cotton crop. Hence these soils are called as regur and black cotton
soils.
• Other major crops grown on the black soils include wheat, jowar, linseed, virginia tobacco, castor,
sunflower and millets.
• Rice and sugarcane are equally important where irrigation facilities are available.
• Large varieties of vegetables and fruits are also successfully grown on the black soils.
• This soil has been used for growing a variety of crops for centuries without adding fertilizers and
manures, with little or no evidence of exhaustion.
Major Soil Types of India: Red Soils, Lateritic Soils & Alkaline Soils
Red Soils
• Red soils along with its minor groups form the largest soil group of India.
• The main parent rocks are crystalline and metamorphic rocks like acid granites, gneisses and
quartzites.
• The texture of these soils can vary from sand to clay, the majority being loams.
• On the uplands, the red soils are poor, gravelly, and porous. But in the lower areas they are rich,
deep dark and fertile.
• They are acidic mainly due to the nature of the parent rocks. The alkali content is fair.
• They are poor in lime, magnesia, phosphates, nitrogen and humus.
• They are fairly rich in potash and potassium.
• The red soils are mostly loamy and hence cannot retain water like the black soils.
• The red soils, with the proper use of fertilizers and irrigation techniques, give good yield of cotton,
wheat, rice, pulses, millets, tobacco, oil seeds, potatoes and fruits.
• These soils occupy about 2.85 lakh sq km or 8.67% of the total land area of India.
• They are mainly heterogeneous soils found on the hill slopes covered by forests.
• The formation of these soils is mainly governed by the characteristic deposition of organic matter
derived from forests and their character changes with parent rocks, ground-configuration and
climate.
• Consequently, they differ greatly even if they occur in close proximity to one another.
• In the Himalayan region, such soils are mainly found in valleys, less steep and north facing slopes.
The south facing slopes are very steep and exposed to denudation and hence do not support soil
formation.
• Forest soils occur in Western and Eastern Ghats also.
• They are suitable for plantations of tea, coffee, spices and tropical fruits in peninsular forest
region.
• Wheat, maize, barley and temperate fruits are grown in the Himalayan forest region.
• The desert soils consist of Aeolian sand (90 to 95 per cent) and clay (5 to 10 per cent).
• They cover a total area of 1.42 lakh sq km (4.32%).
• The presence of sand inhibits soil growth. Desertification of neighboring soils is common due to
intrusion of desert sand under the influence of wind [Aeolian sand].
• Occur in arid and semi-arid regions of Rajasthan, Punjab and Haryana. The sand here is blown from
the Indus basin and the coast by the prevailing south-west monsoon winds.
• Sandy soils without clay factor are also common in coastal regions of Odisha, Tamil Nadu and
Kerala.
• Phosphates and nitrates make these soil fertile wherever moisture is available.
• There is a possibility of reclaiming these soils if proper irrigation facilities are available.
• In large areas, only the drought resistant and salt tolerant crops such as barley, cotton, millets,
maize and pulses are grown.
• In Saline and Alkaline Soils, the top soil is impregnated (soak or saturate with a substance) with
saline and alkaline efflorescences (become covered with salt particles).
• Undecomposed rock fragments, on weathering, give rise to sodium, magnesium and calcium salts
and sulphurous acid.
• Some of the salts are transported in solution by the rivers.
• In regions with low water table, the salts percolate into sub soil and in regions with good drainage,
the salts are wasted away by flowing water.
• But in places where the drainage system is poor, the water with high salt concentration becomes
stagnant and deposits all the salts in the top soil once the water evaporates.
• In regions with high sub-soil water table, injurious salts are transferred from below by the capillary
action as a result of evaporation in dry season.
• Most of the peaty soils are under water during the rainy season but as soon the rains cease, they
are put under paddy cultivation.
• Most soils are old and mature. Soils of the peninsular plateau are much older than the soils of the
great northern plain.
• Indian soils are largely deficient in nitrogen, mineral salts, humus and other organic materials.
• Plains and valleys have thick layers of soils while hilly and plateau areas depict thin soil cover.
• Some soils like alluvial and black soils are fertile while some other soils such as laterite, desert and
alkaline soils lack in fertility and do not yield good harvest.
• Indian soils have been used for cultivation for hundreds of years and have lost much of their
fertility.
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