INDIA LOCATION AND PHYSIOGRAPHY
- India is a large country located in South Asia with a rich civilization.
- It has often amazed and intrigued the rest of the world for its capacity for survival and maintenance of its timeless traditions.
- Its cultural influences had crossed its borders and reached East Asia and South East Asia.
- It acts as a bridge between developed and developing countries of the world and between the East and the West.
- India’s strength lies in its geography as much as in its culture.
- In historical times, India was known as ‘Bharat’ and ‘Hindustan’ The name ‘Bharat’ refers to the ancient, mighty king Bharat and the name ‘Hindustan’ is given after the river Sindhu.
- The Europeans afterwards started referring to this country as ‘India’ a derivative of the word ‘Sindhu’.
- Today, the officially recognized name of the country is India.
India – A subcontinent
- Continent possesses distinct characteristics of diverse
- Physical features
- Climatic conditions
- Natural vegetation
- Cultural norms
- Ancient ethnic and linguistic groups
- Huge area
- Latitudes and Longitudes help us to locate a place.
- India extends from 8o4’ N to 37o6’ N latitudes and 68o7’ E to 97o25’ E longitudes.
- The Tropic of Cancer 231/2oN runes across the country and divides it into two equal halves.
Tropical Temperate regions
- It covers an area of 32,87,263 sq.km, with 1210 million population (2011 Census).
- It stretches from Kashmir in the north to Kanyakumari in the South for about 3,214 Km and from Gujarat in the west to Arunachal Pradesh in the northeast for about 2,933Km.
- Length of Coastline of the Indian mainland is 6000 Km.
- It has a coastline of about 7,516 km inclusive of the mainland, Lakshadweep and Andaman and the Nicobar Islands.
- India’s position is favourable for trade, commerce and economic activities by connecting India with Europe through Suez Cana and also with China, Japan and Australia through Malaccan strait.
The size of India
- India is the second-largest country in Asia
- it is 4 times larger than Pakistan
- 8 times larger than Japan
- 12 times larger than the U.K.
- 3 times smaller than the USA.
India Standard Time
- Longitudes help us to calculate the time of a place.
- The 82o30’ E longitude is taken as Indian Standard Time Meridian (IST), as it passes through the middle of India near Allahabad.
- This is 5 hours 30 minutes ahead of the Greenwich Mean Time (0olongitude)
- After independence in 1947, the Indian Government established IST as the official time for the whole country.
- The east-west extent of India is about 30 degrees of longitude.
- Due to this great longitudinal extent, the sun rises or sets almost two hours earlier in the eastern-most than in the western-most part.
- To avoid confusion with respect to time at different places in India, the almost centrally located longitude 82o30’ E has been selected as standard meridian for the whole country.
- The local time of this longitude is used as the Indian Standard Time (IST)
India and its neighbouring countries
- Palk Strait separates India and Sri Lanka on the south.
- The Himalayas provide a natural boundary on the north.
- Arakanyoma mountain range in the east separates India from Myanmar.
- India’s neighbouring countries. They are:
- Pakistan in the west
- Afghanistan in the north-west
- Nepal, Bhutan and China in the north-east
- Bangladesh and Myanmar on the east.
- India is bounded by the Arabian Sea in the Southwest, by the Bay of Bengal in the east and southeast and the Indian Ocean in the south.
- Kanyakumari or Cape Comorin constitutes the southern tip of the Indian peninsula.
- The Islands of Andaman and Nicobar and Lakshadweep are the parts of India Union situated in the Bay of Bengal and the Arabian Sea respectively.
Unity in Diversity
- India has unique landforms ranging from the highest peaks to the lowest plains.
- In North India, Mount Godwin Austin, otherwise known as mount K2 is the highest peak of India and Malabar coastal plain is the lowest in South India.
- Mount Everest is the highest peak in the Himalayas, which is located in Nepal.
- The height is 8,848 meters. Above the sea level.
- The climate varies from the tropical to the temperate Zone.
- Cherrapunji and Mawsynram in Meghalaya receive the highest amount of rainfall, whereas the Thar Desert receives very low rainfall.
- Mawsynram is the highest rainfall occurs in the world.
- Wet dense tropical forest on the Western Ghats, mangrove trees in the Sundarbans of West Bengal and the Shrubs and sparse vegetation in the Thar Desert.
- The diversity of the physical environment and climate has made India an ideal habitat for varieties of flora and fauna.
- India is a secular country with total freedom of worship.
- People follow Hinduism, Christianity, Islam, Sikhism, Buddhism, Jainism and Zoroastrianism with Cultural diversities.
- In spite of its physical, religious and racial varieties, the ‘Indian Culture’ unites all people. Hence India is known for her “Unity in diversity”.
- People shed all their differences and stand together when there is a crisis.
- The best examples are Kargil invasions and natural calamities floods and Tsunami.
- It is our prime duty to conserve and transmit out cultural values to the future generation of our country and it is our duty to prove ourselves as Indians.
- India has been divided into 28 states and 7 Union Territories on the basis of the language for administrative convenience.
Physiography of India
- Physiography means the description of physical relief features of a country.
- India is a land of great physical contrasts.
- The peninsular plateaus constitute one of the most stable and ancient land blocks on the earth.
- The Himalayas and Great Plains represent the most recent landforms of earth.
Physiographic Divisions of India
- Northern mountains
- Northern Great Plains
- Peninsular Plateaus
- Coastal Plains
- The Northern Mountains are the greatest mountain ranges.
- The upper slopes of many of the ranges are permanently covered with snow and hence they are known as the ‘Abode of snow’ or the ‘Himalayas’.
- Himalaya is the highest mountain range in the world.
- It extends, in the shape of an arc, for a distance of 2,500 km from west to east between the Indus gorge in Jammu and Kashmir in the west and Brahmaputra gorge in Arunachal Pradesh in the east.
- Many of the ranges rise more than up to 8,000 metres above the mean sea level.
- These mountains extend through the states of Jammu and Kashmir, Himachal Pradesh, Uttar Pradesh, Uttaranchal, West Bengal, Sikkim and Arunachal Pradesh.
Formation of Himalayas
- The Himalayas are not a continuous range of mountains but a series of several, more or less parallel or converging ranges separated by valleys and plateaus.
- Millions of years ago, there was only one large and mass on the surface of the Earth and it was surrounded by oceans on all sides.
- The landmass was called ‘Pangea’ surrounded by a water body known as ‘Panthalassa’.
- Large landmass split up into two parts.
- The northern part was known as ‘Angaraland’
- The southern part was known as ‘Gondwana land’.
- The sea separating these two was called the ‘Tethys Sea’.
- Tethys Sea stretched along an east-west direction.
- The river from Angara and Gondwana deposited their silts along the Tethys Sea.
- After a long period, the deposits due to tectonic forces uplifted to form Fold Mountains called the Himalayan ranges.
- The “Aravalli Range” in India is one of the ‘oldest’ mountain ranges of the world.
- The Himalayas is an example of young fold mountains.
- The Himalayas are further subdivided into three parts from west to east. They are:
- Western Himalayas
- Central Himalayas
- Eastern Himalayas
- The Western Himalayas are also known as the Trans Himalayas.
- The lofty Karakoram Mountains extend eastwards from Pamir Knot, which lies in North-West India.
- These ranges in the southwest of Kashmir form India‘s frontier with Afghanistan and China.
- Godwin Austin known as K2 (8,611 metres) the world‘s second-highest peak belongs to this range.
- The ‘Karakoram pass” has acquired special importance now.
- Baltora and Siachin are the two big glaciers found to the south of Karakoram.
- There are two parallel ranges, known as the Ladakh and Zaskar.
- The extension of the Ladakh range is ‘Ladakh plateau’.
- Ladakh plateau’ is the highest plateau in India.
- It lies in the northwest of Kashmir.
- The Himalayas, which radiate from Pamir knot in the Southeast direction is called Central Himalayas.
- The width Varies from 400 km in the west to 150 km in the east.
- The height of the mountains increasing towards east from the west.
- The steep slopes, the high pointed peaks and parallel ranges of the central Himalayas indicate that the Himalayas are young fold mountains.
- These ranges are interspersed by valleys and plateaus.
- There are three parallel ranges found in the central Himalayas from north to south. They are:
- Himadri is the northernmost range of Himalayas.
- The average height of this range is 6,000 metres.
- It extends from Indus valley in the north to the Brahmaputra in the northeast.
- It consists of several peaks in the world.
- Everest is the highest peak in the world with an altitude of 8,848 m.
- The other peaks of Himadri are Kanchan junga (8,598 m), Nanga Parbat (8,126 m), Dhaulagiri (8,167 m) and Nanda Devi (7,817 m), Many Glaciers which are the source of rivers are found in Himadri.
- For example, Gangotri and Yamunotri glaciers are the sources of Ganga and Yamuna rivers respectively.
- ‘Passes’ are the natural gaps across the mountains.
- They provide a route to us with neighbours.
- Zojila pass in Kashmir shipkila in Himachal Pradesh and Nathula and Jelepla in Sikkim are the most important passes across Himadri.
- Himachal lies between the Himadri in the north and Siwaliks in the south.
- It extends over a variable width of 80 km on average.
- The altitude varies from 3,700 m to 4,500 m. it is highly rugged topography consisting of spurs and dissected uplands, ”Pirpanjal” In Kashmir is the longest range of Himachal region.
- ‘Dhauladar ranges’ stretches from Jammu and Kashmir across Himachal Pradesh.
- Kashmir valley, khangra valley and kulu valleys are in between these ranges.
- The popular hill resorts Sri Nagar, Pahalgam, Gulmarg, Mussourie, Shimla and Nainital are located here.
- The places of pilgrim interests such as Amaranth, Kedarnath, Badrinath and Vaishnavidevi temples are the assets of the Himachal ranges.
- Siwaliks is the southernmost range of the Himalayas.
- Its average height is 1,000 m. It is a discontinuous range made up of mud and soft rocks.
- The narrow longitudinal valleys called ‘Duns’ are found in Siwaliks.
- The best example is ‘Dehra Dun’. Along the foothills of Siwaliks, pebbles and gravels are being deposited by the rivers.
- ‘Terai plain’ is made up of deposits of fine slits in the south of Siwalik.
- It supports the Growth of thick forests and marshy lands.
- Brahmaputra River marks the Eastern most geographical limit of the Himalayas.
- These mountains along the Eastern boundary of India is called purvanchal.
- They are of medium height.
- They comprise of Patkai hills and the Naga Hills in the North and the Mizo Hills in the south.
- At the centre, they take a westward turn along the Bangladesh – India border in Meghalaya.
- Here they consist of Jaintia, Khasi and Garo hills from East to west
Northern Great Plains
- The Northern Great Plains are located at the south of Himalayas.
- These are formed by the deposits of Indus, the Ganga and Brahmaputra rivers.
- It extends over a length of 2,400 km.
- It covers an area of over 7 lakh sq.km important characteristics include the soil feature such as Bhabar (Unassorted sediments) Terrai (Terrai (marshy tack) Bhangar (Older Alluvium) and Khaddar (new ever alluvium).
- The Bhabar lies along the foothills at about 8 to 16 km wide.
- The rivers, coming from the mountains, deposit their load along the foothills in the form of alluvial fans.
- The porosity of the deposits is so high that streams sinks and disappears in the Bhabar tract and flow underground.
- The area is marked by dry river courses.
- The Teral is a marshy tract, where most of the underground streams of the Bhabar belt reappear.
- The Terai belt is located towards the south of the Bhabar tract and is about 15 km to 30 km wide.
- It is a zone of excessive dampness.
- It helps to the growth of forests and a variety of wildlife.
- Most of the Terai land has been developed into farmlands.
- The Bhangar represents the alluvial terrace.
- It is formed by the deposition of older alluvium which lies above flood – limit of the plains.
- Bhangar is mainly composed of clay.
- The Khaddar is the newer alluvium brought by the rivers it is deposited in the flood – plains along their banks. it is enriched by fresh deposits of silt every year during the floods.
- Northern plains can be divided into the following regions.
- Rajasthan plain
- Punjab-Haryana plain
- Ganga plain
- Brahmaputra plain
- Rajasthan plain is found located in the west of Aravalli Range and it extends for about 640 kms with an average width of about 300 kms.
- It covers western Rajasthan where two-thirds of this region is desert.
- It is about 300 meters above mean sea level.
- In general, the eastern part of the desert is rocky, while the western part has to shift sand dunes.
- This plain is drained by a number of seasonal streams, originating from the Aravalli ranges.
- Luni is an important river of this region.
- It flows into Rann of Kutch.
- In the north of Luni, there is a large area of inland drainage.
- It has several dry river beds.
How does a river disappear
- Several rivers disappeared during recent geological history.
- Some have disappeared completely.
- He Saraswati was a mighty river in the Vedic and Prevedic time, but disappeared gradually, due to the advancing desert area. Due to the advancing desert area.
- The ‘Ghagra’ is believed to the present-day successor of the Saraswati River.
- There are several Saline lakes in Rajasthan plain.
- The largest is Sambhar Lake, which is located about 65 km west of Jaipur.
Punjab – Haryana Plains
- The fertile plains of Punjab and Haryana lie to the northeast of the Great Indian Desert.
- These plains extend for about 640 km from the northeast to the south-west and labour 300 km from west to east.
- In the east, the Delhi ridge separates the Punjab Hariyan a Plain from the Ganga plain.
- The Punjab- Hariyana plains are formed by depositional activities of the Satluj, Beas, Ravi Rivers.
- The southeastern part of the plains, bordering the Rajasthan plain, is sandy and has shifting sand dunes.
- The areas between Ghaghra and the Yamuna rivers lies in Haryana and forms the Hariyana plain.
- It acts as water – divide (doab) between the Yamuna and the Satluj River.
- The alluvial tract of land between two adjacent rivers. For example, the plains between the Ganga and the Yamuna.
- The Ganga plain is the largest plain.
- It extends from the Yamuna River in the west up to Bangladesh in the east, covering a distance of about 1500 km.
- With an average width of 300 km. It covers the states of Uttar Pradesh, Bihar and West Bengal.
- The Ganga along its large number of tributaries, such as Ramganga, Gomti, Ghaghra, Gandak, Kosi, Yamuna etc.
- From the north and Son, Chambal, Betwa etc.
- From the south, have brought large quantities of sand and silt from the mountains and plateaus respectively and deposited in this vast plain.
- The general slope of the entire Ganga plain in towards the east and the southeast.
- The average elevation of the plain is about 200 m above the sea level.
- Ganga – Yamuna Doab lies in the western part this plain.
- The low lying Rohilkhand is located in the east of the Doab.
- In the middle part, the flow of the rivers is sluggish and most of them keep shifting their courses.
- This has made the region prone to frequent floods.
- The Ganga and the Yamuna rivers are sacred to the followers of the Hinduism.
- Thus many religious places have developed along the bank of the sacred rivers, such as Haridwar, Mathura, Varanasi, Allahabad and so on.
- The religious places have developed into large cultural, educational and tourist centres.
- The Kosi River Known as the “Sorrow of Bihar” has shifted its course by about 100 km in recent times.
- In the lower part, the Ganga and the Brahmaputra rivers divided into several channels in this region to form the largest delta in the world.
- The lower part of the delta called the Sunderbans is covered with thick tidal and mangrove forests.
- The sea-facing region of the delta has a large number of estuaries, mangroves swamps, sandbanks and islands.
- The easternmost part of the northern plains is drained by the Brahmaputra River and its numerous tributaries.
- The Brahmaputra River originates in Tibet and is locally known as Tsangpo (the purifiers).
- Before entering India, it cuts through the Dihang gorge and enters the Assam valley.
- This plain is about 720 km long and about 60 100 km wide.
- The general slope is from the northeast to the southwest.
- The region is surrounded by high mountains except on the west.
- A large number of tributaries coming from the Assam Hills in the north join the main river and form ‘Alluvial fans’. There are large marshy tracts in this area.
- The alluvial fans have led to the formation of Terai.
- The Peninsular plateau is located to the south of northern Great Plains.
- It is triangular in shape and covers an area of about 16 lakh sq. km. it is surrounded by hill ranges on all sides, such as the Aravalli, Vindhya, Satpura and Rajmahal ranges in the north, the Western Ghats in the west and the Eastern Ghats in the east.
- The peninsular plateau extends from north to south for a distance of about 1600 km and from east to west for about 1400 km.
- The average height varies between 600 – 900 mts above the mean sea level.
- The general slope is from west to east, while in the Narmada – Taptiregion it is from east to west.
- The Narmada River divides the peninsular plateau into two unequal parts.
- The northern part is called the ‘Central Highlands’ while the southern part is called the ‘Deccan plateau’.
- Malwa Plateau is bounded by the Aravali range, the Vindhya Range and Bundelkhand.
- It is made up of lava and is covered with black soil. The Chambal River and its tributaries have created ravines in the northern part of the plateau.
- The Bundelkhand is located towards the south of the Yamuna River and is composed of igneous and metamorphic rocks.
- In the northern part, the Ganga and Yamuna system have deposited alluvium.
- The hilly areas are made up of sandstone and granite.
- Some rivers like Betwa and ken have carved out deep gorges.
- The Baghelkhand lies to the east of ‘Malikala Range’.
- It is made up of sandstone and limestone in the west and granite in the east.
- The central part of the plateaus acts as a water divide between the son and the Mahanadhi drainage basins.
- The Chotanagpur Plateau is located towards the northeast.
- It is drained by Damodar, Subarnarekha, koel and Barakar river systems.
- The Damodar River flows from west to east through the middle of this region.
- This region has a series of plateaus and hills, such as the Hazaribagh plateau to the north of the Damodar River, Ranchi Plateau to the south and the Rajmahal Hills in the northeastern part.
- It covers an area of about 5 lakh sq. km.
- It is bounded by the Satpura and the Vindhya ranges in the northwest, the Mahadev and Malikala ranges in the north, the Western Ghats in the west and the Eastern Ghats in the east.
- The Deccan plateau slopes from west to east.
- That is why the rivers like Mahanadi, Godavari and Krishna and Kaveri flow eastward and join the Bay of Bengal.
- The northern part is also known as the Deccan trap is made up the lava rocks and has black Regur soils.
- In the southern part, the Karnataka plateau merges with the Nilgiri Hills.
- The Telangana plateau is drained by the Godavari, Krishna and Penneru rivers.
Hills Ranges of Peninsular India
- Aravalli Ranga is one of the oldest fold mountain systems in the world.
- From northeast to southwest is extent is about 800 km.
- In the north, the average height is about 400 meters, while in the south it is about 900 metres. Guru Shikhar (about 722 metres) in the Abus hills is the highest peak of the Aravalli range.
- The Aravalli ranges are highly eroded and dissected.
- Vindhya Range rises as an escarpment overlooking the Narmada valley and runs parallel to it in the east-west direction for about 1200 km.
- It is composed of sandstone, limestone and shale.
- It acts as a watershed between the Ganga river system and the rivers systems of south India.
- Satpura range lies between the Narmada and the Tapti rivers.
- It is a series of seven hills and stretches for about 900 km.
- A major part of the Satpura Range has a height of more than 900 meters.
- The Western Ghats are running in the north-south direction and form the western edge of the Deccan plateau.
- Its extent is about 1600 km from the Tapti valley in the north up to Kanyakumari in the south.
- The Western Ghats rises abruptly from the western coastal plain.
- That is why on the western side, the rivers flow swiftly and make a number of waterfalls like the Jog falls (270 mts) on the Sharavati River.
- The slope is gentle towards the eastern side of the Western Ghats and the main rivers like the Godavari, Krishna
- Kaveri rises from the eastern slopes and flow eastwards and fall into the Bay of Bengal.
- Thal Ghat, Bhor Ghat, Pal Ghatare the three important passes in the Western Ghats.
- Which provide passage for roads and railways, between the Konkan plains in the west and the Deccan Plateau in the east.
- The Eastern Ghats and the Western Ghats join at the Nilgiris hills and the highest point is Dodda Beta (2637 m). ‘Udhagamandalam’ a hill station lies at the foot of the Doda Beta in the Nilgiris.
- The southern part of the Western Ghats is separated from the main Sahyadri range by Palghat Gap.
- It is used by roads and railways to connect the coastal plain of Kerala with the plains of Tamil Nadu.
- The highest peak of South India is ‘AnaiMudi’ (2695 m) which is the nodal point from which hill ranges, like Anaimalai in the north, Palani in the northeast and cardamom in the south radiate.
- The Western Ghats terminate about 20 km north of Cape Comorin.
- They run almost parallel to the East Coast.
- These are a series of intersected hills, lying between the Mahanadhi River in Orissa and the Vaigai river In Tamilnadu.
- These hills are not continuous and almost disappear between the Godavari and Krishna rivers.
- The Godavari valley divides the Eastern Ghats into the northern and southern parts.
- The northern part is about 200km wide, while the Southern part is only 100 km wide.
- ‘Mahendra Giri’ (1501 m) is the highest peak in the northern part.
- In the southern part the ‘Nallamalai range’ is the most prominent.
- It is composed of quartz and slate.
- The hills and Plateaus in the southern part have low altitude further south the Eastern Ghats merge with the Western Ghats at Nilgiris.
- The peninsular plateau has a number of hill stations such as Udhagamandalam (Ooty), Kodaikanal, Pachaimalai, Mahabaleshwar, Khandala, Matheron and so on.
- The Peninsular Plateau of India is surrounded by coastal plains of variable width.
- It extends from the Rann of Kutch in the west to the Ganga – Brahmaputra delta in the east covering a distance of about 6000 kms.
- The area between the Western Ghats and the Arabian Sea is called the Western coastal plain.
- The area between the Eastern Ghats and the Bay of Bengal is called the Eastern Coastal plain.
- The two coastal plains meet each other at Kanyakumari the southernmost tip of the mainland of India.
Western coastal plains
- It stretches from the Rann of Kutch in the north to Kanyakumari in the south.
- Except in Gujarat, the western coastal plain is quite narrow and has an average width of about 65 km.
- The Gujarat plain, lying towards the east of Kutch and Kathiawar was formed by the Narmada, Tapti, Mali and Sabarmati River.
- It includes the southern part of Gujarat and the coastal areas of the Gulf of Khambhat.
- It has a chain of saline marshes near the coast, which are flooded during high tides.
- The ‘Konkan Plain’ Lying towards the south of Gujarat extends up to Goa for a distance of about 500 km. Its width is about 50 to 80 km.
- It has features of marine erosion like cliffs, reefs and Islands in the south of Mumbai.
- The ‘Konkan coast’ has a series of bays and sandy beaches.
- The northern part of Konkan is sandy while the southern part is rocky and rugged.
- The ‘Karnataka plain’ extends from Goa Mangalore and has an average width of about 30 to 50Km.
- At some places, it descends sharply along the steep slope and makes waterfalls.
- The ‘Malabar plain’ Lies between Mangalore and Kanyakumari.
- It extends for about 50 km and its width varies from 25 to 100 km.
- The main characteristics of the Malabar coastal plain are the existence of lakes, lagoons, backwaters, locally called ‘kayaks’ Vembanad is the largest lake in Kerala.
- Most of the backwaters are parallel to the coastline.
- The logons and backwaters are linked by canals to provide easy navigation with the help of small country boats.
Eastern Coastal Plain
- It stretches from the delta region of West Bengal to Kanyakumari.
- It lies between the Eastern Ghats and the Bay of Bengal.
- The Eastern coastal plain is formed by the alluvial deposits brought by the Mahanadi, Godavari and Krishna and Kaveri rivers.
- The average width is about 120 km and it reaches up to 200 Kms in the deltaic regions.
- The region has a straight shoreline with well – defined beaches of sand, such as the Marina beach in Chennai.
- The coastal plain between Mahanadi and Krishna rivers is known as the ‘Northern Circars’.
- The part laying between Krishna and Kaveri rivers is called the ‘Coromandel Coast’.
- The ‘Utkal plain’ is found along the coast of Orissa and extends for about 400 km and includes the deltaic region of Mahanadhi River.
- The coastline of Utkal plain is smooth and fringed with sand dunes.
- Chilika Lake the Biggest lake in India is located towards the south of the Mahanadi river delta.
- The ‘Andhra Plain’ Lies between the Brahmaputra and Pulicat Lake.
- It has been formed by the deltas of the Godavari and the Krishna rivers.
- The Andhra plain has straight coast and has few sites for good harbours.
- ‘Vishakhapatnam’ and ‘Machilipatnam’ are notable examples.
- Kollerulake is found in Andhra plain.
- The ‘Tamil Nadu’ Plain stretches from the Pulicat Lake to Kanyakumari for a distance of about 100km.
- The fertile soil and well-developed irrigation facilities have made the Kaveri river delta the ‘Granary of South India’.
- There are two main groups of Islands in the Indian Ocean.
- The Andaman and isobar groups in the Bay of Bengal and the Lakshadweep in the Arabian Sea.
- They are located far away from the coast of the Indian Mainland.
- The Andaman and Nicobar group of islands is situated between 60N to 140 N latitudes and between 900 E to 940 E longitudes.
- It consists of about 572 big, small and tiny islands, out of which only 38 are inhabited.
- The total area is about 8249 sq. km The Andaman island groups are separated from the Nicobar island groups by the ‘Ten Degree Channel’ The extreme southernmost point is the ‘Indira point.
- The Andaman is a closely-knit group of islands in which only 25 islands are inhabited.
- In the Nicobar group, only 13 islands are inhabited most of the islands are made up of sandstone, limestone and shale.
- Most of them are of volcanic origin and some are fringed with coral reefs.
- The islands are Mountains with a maximum elevation of about 750 meters.
- Since the Climate is hot and humid the area is covered with thick forests and coconut groves.
- The Lakshadweep groups of islands are located in the Arabian Sea and have only 27 islands out of which only 11 are inhabited.
- The Laccadives, Minicoy and Aminidivi group of islands were renamed as Lakshadweep (literally means one lakh islands) in 1973.
- This islands group is widely scattered over an area of about 110 sq.km south-west of the Kerala coast.
- These islands are of coral origin.
Significance of Indian Physiography
- The presence of the Himalayas in the north prevents southwest monsoon winds and cause rainfall and snowfall.
- If this mountain is absent, a major part of the Indian subcontinent would have been a hot and dry desert.
- The Himalayas forms a natural boundary for the subcontinent.
- It is permanently frozen and is a barrier to invasion.
- The northern plains of India are of great economic and social significance due to their fertile alluvial soils, flat level land, slow-moving perennial rivers and a favourable climate, agriculture and trade have been developed.
- Peninsular Plateau is rich in mineral resources and has huge reserves of Iron, Manganese, Copper, Bauxite mica, Chromium, Limestone etc.
- A large number of big and small ports have been developed all along with the coastal areas. These ports play an important role in the growth of national and international trade.
DISTANCE (Rivers and Lakes)
- Rivers, with their tributary systems, are the main channels of drainage of the land surface.
- Rivers are beneficial to us in many ways.
- Besides providing water for cooking, washing and bathing, they provide water for irrigation, generation of Hydel power, navigation and recreation.
- They also bring down alluvium from the highland areas and deposit it in the flood-plains and deltas.
- Alluvial soils in these areas are, therefore, extremely fertile.
- During each flood, new alluvium is deposited in the lands and fertility of the soil is renewed. Birth of River System
- Usually, mountains receive heavy rainfall and hence a majority of rivers originate in mountainous areas.
- The sheet of water flows down the slope in the form of rills which, after uniting with others, form streams.
The distinction between Himalayan Rivers and Peninsular Rivers
|Himalayan Rivers||Peninsular Rivers|
|The Himalayan rivers like Indus, Ganga and Brahmaputra Originate from the snow-covered mountains.||The Peninsular rivers like Mahanadi, Godavari, Krishna, Kaveri, Narmada and Tapi Originate from the peninsular plateaus.|
|These rivers have large basins and catchment areas.||These rivers have small basins and catchment areas.|
|These rivers flow through deep, nearly I – Shaped valleys.||These rivers flow through broad and shallow valleys.|
|These rivers are perennial in nature and receive water both from the monsoons and the melting of snow.||These rivers are seasonal as they receive water only from the monsoon rains.|
|Due to their perennial nature, these rivers are very useful for irrigation.||Due to the seasonal nature, these rivers are not very useful for irrigation.|
|These rivers are suitable for navigations as they flow over plain areas.||These are not suitable for navigation as they flow over uneven land in the plateau region.|
|These rivers form large deltas near their mouth like the Ganga Brahmaputra delta||The west-flowing rivers mostly form estuaries and the form smaller deltas.|
- Mainstream at different points along its course.
- This mainstream is known as a river and this stream together with its tributaries constitutes a river system.
- The drainage system is related to a number of factors for example slope of the land, Geological structure, amount of volume of water and velocity of the water.
- Inland drainage is found to the west of Aravallis in Rajasthan.
- Luni is the only river that flows through this region.
- The river rises to the south-west of Ajmer in the Aravallis.
- After passing Govindgarh it is joined by the Sarsuti, which has its source in the lake of Pushkar from this point the river is known as Luni.
- The Luni receives two major Tributaries originating from the Aravallis.
- They are Sukri and Jawai.
- After flowing for a distance of about 320 km it is finally lost in the marshy ground at the head of the Rann of Katch.
- The river is a blessing to the arid parts of southern Rajasthan.
- As far as Balotra, the water of Luni is generally sweet, but at the Rann it is Saline.
- The river system of India is tabulated as follows find the name of the rivers in India and their length, area, origin, end and the places benefitted.
The River system of India
|Name||Length (km)||Area||Originates from||Ends in
|Indus||3100||3,21,290 sq. km||In Tibet Kalish Range 5080 mts.||Arabian sea||India and Pakistan|
|Ganga (Bhagirathi)||2480||3,37,000 sq. Km||Gaumukh||Bay of Bengal||Uttar Pradesh, Bihar, West Bengal|
|Tributary||A river or stream which contributes its water to the main river. For example, the Bhavani and Amaravathi are tributaries of river Kaveri|
|Distributary||A branch or outlet which leaves the main river and does not rejoin it, carrying its water to the sea or a lake.|
|Delta||A triangular-shaped alluvial tract, formed at the mouth of a river, For Example, Kaveri Delta, Ganga Delta. Delta of the Ganga is the largest delta in the world|
|Estuary||The mouth of the river where tidal effects are felt and where freshwater and seawater mix; for instance, the Thames Estuary in London and Narmada and Tapti Estuaries in peninsular India.|
- Climate is one of the basic elements in the natural environment.
- It determines the landforms, soil, vegetation and agriculture of a place.
- The sharply contrasting relief features of India create a diverse climate.
- The climate of North India differs from South India with Respect to temperature, rainfall etc.
- Let us have a look at these climatic variations of India with their determining factors.
- Weather is a day to day to day conditions of the atmosphere at any place in regard to temperature, pressure wind, humidity, and rainfall.
- Climate is the average state of weather for a longer period of time at any place.
- Weather records of a minimum period of 35 years are found necessary to obtain a reliable average.
- The climate of a place is determined by the following factors such as
- Distance from the sea
- Position of Mountains
- India lies between 804 to 370 6 N Latitudes. 230 30’ N latitude tropic of cancer passes across the country.
- The parts of the country to the south of tropic of cancer being closer to the Equator, experience high temperature throughout the year.
- The part of the country to the north of tropic of cancer, on the other hand, lies in the warm temperature zone.
- Hence they experience low temperature, particularly in winter.
- For example, New Delhi which is located in 380N experiences 230 C While Kanyakumari at 80 N experiences 320 C During the month of November.
- Temperature decreases with increasing altitude from the earth surface at the rate of 10C for every 165 meters.
- The places situated at the higher altitudes are cooler as compared to places in plains.
- For example
- The mean temperature of New Delhi, which is situated in the plains region at an altitude of 239 meters from the sea level is 40. 20C during the month of June, while the temperature of Shimla, which is located in the higher altitude of 2,205 meters is 23.70 C in the same month.
Distance from the sea
- The places to the north of tropic of cancer experience “Continental climate”, where the summer is extremely hot and the winter is extremely cold.
- The prevalence of the climate is due to the far off location from the sea.
- The Tropical South, which is enclosed on three sides by the Arabian Sea, Indian Ocean and Bay of Bengal, Experiences ‘Equable climate’.
- When the winds blow from sea to the land bring warm temperature while the winds blow across the land bring dry temperature.
- For example
- The westerly winds originated in the Mediterranean Sea and blow into northwest India. They bring rain to Punjab and Haryana.
- The Tropical cyclone wind originates in the Bay of Bengal and blows along the east coast of India.
- It causes heavy loss to life and property.
- Air Currents in the upper layers of the atmosphere is known as the jet stream.
- It could determine the arrival and departure of monsoon winds in India.
Position of Mountains
- Position of the Mountains plays a vital role in determining the climate of any place.
- For example
- The great Himalayan range in North India obstructs the bitterly cold winds from central Asia to India.
- The Himalayan range intercepts the rain-bearing southwest monsoon winds forcing them to shed their moisture resulting in heavy rainfall in the northeast and Indo Gangetic plain
- The Aravalli range intercepts south-west monsoon winds and so western side of this range is a desert and receives very less rainfall.
- El – Nino is a complex weather phenomenon that appears once every five to ten years bringing drought, floods and other weather extremes to different parts of the world.
- It is also a cause for the delay of south-west monsoon onset in India.