Geography Of India

Geography Of India :

Historically, India is an ancient country, known as Bharatvarsh. It is surrounded by the sea on three sides, separated from the rest of Asia by a lofty mountain chain. Hence, it has become an independent entity called the Indian subcontinent. In size, India is the seventh largest country in the world. It is a vast country characterized by great diversity in its physical feature. Therefore, it is necessary to acquire some knowledge about principal physical features. The broad facts regarding the external relief, mountain systems, plateaus, plains, drainage systems, glaciers, volcanoes etc.

LOCATION, EXTENT AND BOUNDARIES OF INDIA :

A huge landmass of South Asia is flanked by new fold towering mountains on the northwest, north and northeast. The Arabian sea lies to its southwest, the Bay of Bengal to its southeast and the Indian Ocean to its south. This well defined South Asian landmass is called Indian sub-continent. This sub-continent consists of the countries of India, Pakistan, Bangladesh, Nepal and Bhutan including Sri Lanka, an island narrowly separated by the Palk Strait. India alone covers about three fourths of the area of this sub-continent and has common frontier with each one of them. She along with her five neighbours, forms a clearly identifiable geographical unit, with certain common cultural parameters. Since old times, the country has been known by various names such as Aryavarta, Bharat, Hindustan and lately India. The Indian Ocean or Hind Mahasagar has also been named after India - the only country to be so. According to the Constitution of India, the country is known as Bharat or India.

India lies wholly in the Northern Hemisphere. The Indian mainland extends between 8°4'N to 37°6' N latitudes and from 68°7' E to 97°25' E longitudes. Thus the latitudinal and longitudinal extent of India is of about 29 degrees. It measures about 3,214 km from north to south, and 2,933 km from east to west. Though the latitudinal and longitudinal extent is almost the same, the actual distances do differ
considerably. Why is it so? This is because the east-west distance between two successive meridians of longitude along the equator is at its maximum - 111 km. This, however, goes on decreasing as one moves from the equator to the poles, where it is zero. This is because all the meridians of longitude merge in a single point at the poles - both North and South. On the other hand, the north-south distance between any two successive parallels of latitude along any meridian of longitude remains almost uniform, i.e., 111 km. The following table may further clarify this point:

A glance at the globe should help to convince this point. The northern most point of the Indian mainland lies in the state of Jammu and Kashmir and the southern most point is Kanyakumari in Tamilnadu. However, the southern most point of the country as a whole lies further south in Andaman and Nicobar Islands. It is now called Indira Point. It is situated at 6°30'N latitude. The westernmost point of lndia lies in Gujarat and the eastern most in Arunachal Pradesh. Let us see the impact of such large latitudinal extent upon the lives of the people of India. The northern parts of the country are quite far off from the equator. Therefore, the rays of the sun strike those parts more obliquely. Consequently, this part of the country receives lesser amount of insolation and has cold climate unlike the southern parts. Secondly, the difference between the length of day and right in

southern most part of India is much less only about 45 minutes as they are situated near the equator, This difference between day and night in the northern parts of India steadily goes on increasing till it becomes as much as 5 hours.

The Tropic of Cancer passes almost halfway through the country. Thus half of the country to the south of the Tropic of Cancer is situated in the Tropical or Torrid zone and the other half lying north of the Tropic of Cancer falls in the Sub-tropical zone.

The earth takes 24 hours to complete one rotation on its axis. The Sun rises first in the east and then in the west because the earth rotates from west to east. The earth’s longitudinal expanse of 360° is thus covered in 24 hours, at the pace of 15° per hour. As the longitudinal extent of India is nearly 29°, the real time difference in India between its eastern and western extremities is roughly of two hours. While at the eastern extremity of India the day may have just broken out, the western extremity would take nearly another two full hours to do so.

To iron out this big chunk of time difference, India, like all other countries of the world, follows the local time of its relatively central meridian as the standard time for the whole country. For the convenience of all, each country chooses its standard meridian in a multiple of 7°30'. Accordingly, the standard meridian of India has been chosen to be 82°30' E.

The north-central part of India is broad while the southern part tapers down towards the Indian Ocean in the south. Thus, the northern part of the Indian Ocean has been divided into two, by the sheer presence of Indian Peninsula. The western part of northern Indian Ocean is called the Arabian Sea while the eastern part is called the Bay of Bengal. The total length of the coastline of India including the island groups is about 7,516.6 km. The Palk Strait separates Indian mainland from Sri Lanka. Structurally, Sri Lanka is an extension of the peninsular block of India.

SIZE :

India accounts for 2.42 per cent of the world’s total land area; whereas it sustains 16 per cent of the world population. You will know more about it in lesson No. 26 on population of India. The land frontiers of India measure 15,200 km. Pakistan, Afghanistan, China, Nepal, Myanmar and Bangladesh share common boundaries with India. The kingdom of Bhutan is situated in the Eastern Himalaya. It is a small country and the responsibility of its defence rests with India. Most of our boundary with Pakistan and Bangladesh is almost man-made. There is no mountain range or river to form a natural boundary. The international boundary of India passes through a variety of landforms - barren desert lands, lush green agricultural fields, gushing rivers, snow clad mountains as well as densely forested mountain ranges. The defence of such an international boundary passing through various kinds of terrains is certainly a difficult job. An Indian soldier is, therefore, exposed to various types of extremely hostile conditions on the course of his duty. Sometime, he is posted on the icy cold glaciers. At times he has to bear the wrath of the burning sun and he has to face in the hot sands of the desert. Often he is posted in the marshy, riverine, rainy and thickly forested tracts of the northeast. Our country has to spend crores of rupees daily for the defence of such a long and inhospitable boundary that passes through various kinds of terrain.

• India stands at the head of the Indian Ocean that spans the continents ofAsia, Africa and Oceania providing further links to other continents through the Pacific Ocean and the Atlantic Ocean.
• In the Indian subcontinent, India is the only country to share its land frontiers with every member country of the subcontinent.
• In area India is the seventh largest country in the world but in population it stands next only to China.
• The variation in local time between the eastern and western extremities of India is of two hours. This has been minimised to a certain extent by adopting 82°30' E longitude as the Standard Meridian of India for calculating Indian standard time which we follow through our watches.

 PHYSIOGRAPHIC DIVISIONS OF INDIA :

India is a land of physical diversities. Almost all types of picturesque and breath taking landforms are found here. According to one estimate, 29.3 per cent of area of India is occupied by mountains and hills, 27.7 per cent by plateaus and 43 percent by plains.

From a physiographical point of view, India can be divided into following four regions:

1. Great Northern Mountains
2. Great Northern Plains
3. Great Indian Plateau and
4. Coastal Plains and Islands.

THE GREAT NORTHERN MOUNTAINS :

They include the mountains and plateaus of northern Kashmir, the Himalayas proper and the hills of Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura and Meghalaya. They are divided into three groups. They are

(i) The Himalayas
(ii) The Trans-Himalayas
(iii) Purvachal or the hills of the North-East.

(i) The Himalayas:

This is the highest mountain range of the world. It extends in the shape of an arc for a distance of about 2500 km from west to east along the northern boundary of India between the Indus gorge in Jammu and Kashmir in the west and Brahmputra gorge in Arunachal Pradesh in the east. The breadth of the Himalayas ranges between 400 km in the west to 150 km in the east. The area covered by this
mountain system is about 5 lakh square km. It has three major ranges. These ranges are separated by deep valleys and plateaus. The southern slopes of Himalayas facing India are steeper and those facing the Tibetan side are generally gentler. In the east, Himalayas rise almost abruptly from the plains of West Bengal and Assam. That is why two of the highest peaks of Himalayas, Mt. Everest (in Nepal) and Kanchenjunga are not very far from the plains. On the other hand, the western part of Himalayas rises rather gradually from the plains. Hence, the higher peaks in this part are farther from the plains and a number of ranges lie between the plains and high peak. The high peaks of this part such as Nanga Parbat, Nanda Devi and Badrinath are very far from the plains.

Three parallel ranges can be identified in the Himalayas. These are
(a) Himadri,
(b) Himachal and
(c) Siwalik

(a) Himadri (Greater Himalaya) :

This is the northern most and the highest range of the Himalayas. This is the only range of the Himalaya which maintains its continuity from west to east. The core of this range is made up of

granite rocks and flanked by metamorphic and sedimentary rocks. The extent of this range is between the Nanga Parbat peak (8126 m.) in the westand Namcha Barva peak (7756 m.) in the east. The average height of this range from sea level is about 6100 metres. Over 100 peaks have a height of
more than the average height of the range. The highest peak of the world, Mount Everest, (8848 m) is situated in this range. Kanchenjunga, Makalu, Dhaulagiri, Annapurna are some of the other peaks having a height of more than 8000 metres. Kanchenjunga is the highest peak of Himalayas in India.
The Himadri range is snow clad throughout the year. There are a number of large and small glaciers. After melting of snow and ice, their water falls in the rivers of northern India making them perennial throughout the year. Gangotri and Yamunotri are good examples of such glaciers.The Himadri range can be crossed through some passes like Zojila, Shipkila, Niti, Nathula etc.

(b) Himachal (Lesser or Middle Himalaya) :

It is located southwards of Himadri. The breadth of Himachal range is 60 to 80 km and the height
varies from 1000 metres to 4500 metres. Some of the peaks of this range have a height of more than 5000 metres. This range is highly dissected and uneven. Rocks in this zone have been metamorphosed due to violent thrusts and compression. Therefore, this range mainly consists of metamorphosed rocks. The gentle slopes of the eastern part of this range are covered with dense forests. The south facing slopes of other parts of this range are very steep and generally devoid of any vegetation. The north facing gentle slopes of this range are covered by dense vegetation. 

Pir Panjal in Jammu and Kashmir and Dhauladhar in Himachal Pradesh are the local names of this range. The beautiful valley of Kashmir extends between the Pir Panjal and Himadri ranges. The famous valley of Kullu and Kangra are also a part of Himachal ranges.

Most of the hill towns or resort towns are located in the Himachal range. Shimla, Nainital, Mussouri, Almora and Darjeeling are some such famous hill towns. There are a number of beautiful lakes around Nainital.

(c) Siwalik (Outer Himalaya) :

The southern most range of Himalayas is known as Siwalik. The Himadri and Himachal ranges of the Himalayas have been formed much before the formation of Siwalik range. The rivers rising in
the Himadri and Himachal ranges brought gravel, sand and mud along with them, which was deposited in the rapidly shrinking Tethys Sea. In course of time, the earth movements caused folding of these relatively fresh deposits of sediments, giving rise to the least consolidated Siwalik range. The average height of the Siwalik range is very low, about 600 metres only. There are some broad valleys in between the Himachal and the Siwalik ranges. These valleys are known as ‘duns’. Dehradun valley is one of the best examples.

(ii) The Trans-Himalayan ranges 

There are some mountain ranges to the north of the Himadri in Jammu and Kashmir. The range extending to the north of the Himadri and running parallel to it is called the Zaskar range. North of Zaskar range is the Ladakh range. The river Indus flows towards northwest between Zaskar and Ladakh range. Many scholars treat Zaskar and Ladakh ranges as parts of the Great Himalayas and include them in Kashmir Himalayas. North of the Ladakh range lie the Karakoram. The name of the Karakoram in Sanskrit literature is Krishnagiri, K2 (8611m) is the highest peak of the Karakoram Mountains. This is the second highest peak of the world, next only to Mt. Everest.
Ladakh plateau is situated in the north eastern part of the state of Jammu and Kashmir. This plateau is a very high and arid. It forms one of the remote areas of our country.

(iii) Purvachal :

Purvachal is the name given to all the hills of north east India beyond Brahmaputra gorge. The average height of these hills from sea level is 500 to 3000 metres. These hills are located in Southern Arunachal Pradesh, Nagaland, Manipur, Mizoram, Tripura and Meghalaya. Mishmi, Patkoi Bum,
Naga, Manipur, Mizo(Lushai) and Tripur are the major hilly ranges of this region. Meghalaya Plateau is also part of these hills of the north eastern region. This plateau includes the hills of Garo, Khasi, and Jaintia. Structurally, however, it is a part of Peninsular India.

THE GREAT NORTHERN PLAINS :

This plain extends from west to east, between Himalayas in the north and Great Indian Plateau in the south. The plain extends from the arid and semi-arid areas of Rajasthan in the west to Brahmputra valley in the east. The area of this plain is more than 7 lakh square km. This plain is very fertile and a very sizeable part of the Indian population lives in innumerable villages and several big cities in this region.

This plain is made up of the soils brought down and deposited by the rivers flowing from the Himalayas in the North and the Great Indian plateau in the South. The rivers have been depositing their sediments in this plain over millions of years. Therefore, the alluvium in this plain is quite a few hundred metres deep. In some of the parts, the depth of the sediments is as much as 2000 to 3000 metres.

This plain is almost dead flat. Its average height is 200 metres above the mean se level. Due to a very gentle slope towards the sea, the rivers in this plain flow very leisurely and at times even sluggishly. The slope from Varanasi upto the mouth ofGanga is only 10 cm. per km. The land around Ambala is a bit more elevated. However, it acts as a water divide between the two major river basins - the Satluj
in the west and the Ganga in the east. Rivers lying eastwards of this water divide flow into the Bay of Bengal while those west of it flow into the Arabian Sea.

The relatively higher part of the plain is called bangar. This area is never covered with flood water of the rivers. Contrary to this, the comparatively lower area is called the khadar. This area is flooded by streams almost every year. Khadar area is know as bet in Punjab. There is a strip of plain about 10-15 km broad along the outer slopes of the Siwaliks in Punjab, Haryana and Uttar Pradesh. This region is known as ‘bhabar’. This strip of bhabar is made of gravel and coarse sand. The smaller streams disappear under ground in the ‘bhabar’ region during the summer season and their water surfaces again after crossing the bhabar. This water accumulates in the strip of plain about 15 to 30 km wide and extends to the south of bhabar. Accumulation of this water makes the land marshy. This marshy land is called the terai. Many parts of the terai have been reclaimed, for agricultural purposes.

The great Northern Plain can be divided into four parts: 

(i) Western plain 

(ii) North Central plain 

(iii) Eastern plain

(iv) Brahmputra plain.

(i) Western Plain :

This region includes the Rajasthan desert and bangar region lying to the west of Aravali ranges. The desert is partly rocky and partly sandy. In the ancient period, the perennial streams - Saraswati and Drishadvati- flowed through this region. This region includes the fertile area of Bikaner. River Luni flows through this bangar region and falls into the Rann of Kutchchh. The famous salt water lake of Sambhar is situated in this part of the plain.

(ii) North Central Plain:

This plain extends over Punjab, Haryana and Uttar Pradesh. The part of this plain extending into Punjab and Haryana has been formed by the alluvium brought by rivers Satluj, Beas and Ravi. This is a very fertile area. The part of this plain lying in Uttar Pradesh is made up ofthe deposits laid down, by the rivers like, Ganga, Yamuna, Ramganga, Gomati, Ghagra and Gandak. This part of plain is highly fertile and has been the cradle of Indian civilization and culture.

(iii) Eastern Plain:

This part of the great plains covers the middle and the lower Ganga valley lying in the states of Bihar and West Bengal. Ganga flows through the middle of this plain in Bihar. Ghagra, Kosi and Gandak join Ganga from the north while Son joins from south. On entering West Bengal the plain widens further extending from the foot hills of the Himalayas upto the Bay of Bengal. The southern part of the plain is delta region. Ganga is divided into several distributaries in the delta region. Hooghly is the best example of a distributary of Ganga. This part of the plain is indeed very fertile and more rainy.

(iv) Brahmputra Plain:

The northeastern part of the Great Indian Plain extends into Assam. This plain has been formed by deposition of alluvium brought down by river Brahmputra and its tributaries. Brahmputra is highly
prone to devastating floods at regular intervals. After the floods, the river generally changes its course. This process has led to the formation of various islands in the river. Majuli (1250 square kilometer) in the Brahmputra river is the world’s largest river island. This part is also very fertile. It is
surrounded by hills from three sides. Bangladesh is situated on this plain and the delta joint ly formed by Ganga and Brahmaputra and their distributaries.

THE GREAT INDIAN PLATEAU :

The Great Indian Plateau lies to the South of the Great Northern Plains. This is the largest physiographic division of our country. It covers an area of about 16 lakh square km, i.e., about half of the total area of the country. It is an old rocky plateau region. The topography consists of a series of plateaus and hill ranges interspersed with river valleys. Aravalli hills mark the north-western boundary of the plateau region. Its northern and north-eastern boundary is marked by the northern edge of the Bundelkhand Plateau,Kaimur and Rajmahal Hills. The Western Ghats (Sahyadry) and the Eastern Ghats mark the western and eastern boundaries respectively of this Great Plateau. Most of the area of the plateau has a height of more than 400 metres above sea level. The highest point of plateau
region is the Anaimudi peak (2965 m). The general slope of this plateau is towards east.

The Great Plateau is the part of very ancient landmass, called Gondwana land. From the earliest time it has been above the level of the sea. Therefore, it has been subjected to large scale denudation. Its mountains are generally of relic type. They are composed of very hard rocks, which have withstood the ravages of denudation more effectively than the surrounding regions. Because of their old age, all the rivers have almost attained their base level and have built up broad and shallow valleys. The dominant rock formations, especially those in the southern parts, are of metamorphic origin with frequent occurrences of granites.

River Narmada divides the peninsular block of India into two parts. The region lying to the north of the Narmada is called the Central Highlands and the region lying to the south of Narmada is called the penninsular plateau, more commonly referred to as the Deccan Plateau.

A glance at the map would point out that barring Narmada and Tapti all the major rivers lying to the south of the Vindhyas flow eastwards to fall into the Bay of Bengal. The westward flow of Narmada and Tapi is assigned to the fact that they have been flowing through faults or rifts which were probably caused when the Himalayas began to emerge from the Tethys Sea of the olden times.

(i) The Central Highlands:

It extends between river Narmada and Great Northern Plains. The Aravallis form the west-northwestern edge of the Central Highlands. These hills extend from Gujarat, through Rajasthan to Delhi in the northeasterly direction for a distance of about 700 km. The height of these hills is about 1500 metres in southwest while near Delhi they are hardly 400 metres high. The highest peak of the Aravalli hills is Gurushikhar (1722 m) near Mt. Abu. Mt. Abu on the border of Gujarat and Rajasthan is a beautiful hill station. The region to the east of Aravallis is the highly dissected and uneven. Malwa plateau forms the dominant part of the Central High lands. It lies to the southeast of Aravallis and to the north of Vindhyachal Range.

River Chambal, Betwa and Ken drain the Malwa Plateau before they join Yamuna. The part of the Central Highlands which extends to the east of Malwa Plateau is known as Bundelkhand and is further followed by Baghelkhand and the well known Chhotanagpur Plateau. Vindhyachal Range
forms the southern edge of Malwa Plateau. The Mahadeo Hills, Kaimur Hills and Maikal Range lie towards further east. The slope of Vindhayachal Range towards Narmada valley is absolutely steep and forms escarpments.

It only confirms that Narmada flows through a rift valley. This range has very few passes. Due to this fact the Vindhyas acted as a barrier between northern and southern parts of India for a long time in the past. The valley of Narmada is situated between the Satpuras and the Vindhyas. River Narmada flows from east to west in this valley and falls into the Arabian Sea. This valley has been formed due to the subsidence of the land mass between the Vindhyas and the Satpuras.

(ii) The Peninsular Plateau (Deccan Plateau) :

This physiographic division is the largest region of the Great Indian Plateau. The shape of this plateau is triangular. One of the sides of this triangle is marked by the line joining Kanya Kumari with Rajmahal Hills and this line passes through the Eastern Ghats. The second arm is marked by the Satpura Range, Mahadeo Hills, Maikal Range and the Rajmahal Hills. The third arm is marked by the
Sahyadris (Western Ghats). The area of this Penninsular Plateau is about 7 lakh square km and the height ranges from 500 to 1000 metres above sea level.

The Sahyadri Range forms the sharp edge of the Penninsular Plateau. Its long escarpments running parallel to the Arabian Sea coast are simply breath taking. Due to its location on the western margin of the Penninsular Plateau, the Sahyadri Range is also called Western Ghats. The word ‘Ghat’ also
means a step like mountain. Therefore, this English name of the Sahyadris is meaningful. The height of the Sahyadris increases from north to south. Anaimudi peak (2695 m) situated in Kerala is the highest peak of southern India. Anaimudi is a sort of tri-junction of the Annamalai Range, the Carda-
mom Hills and the Palani Hills. Kodai Kanal is a beautiful hill resort situated on the Palani Hills.
Eastern Ghats running from southwest to northeast form the eastern edge of the Penninsular Plateau. This range is known as poorvadri also. The Eastern Ghats joins the Sahyadris at the Nilgiri Hills bordering Karnataka and Tamilnadu. Udagamandalam (Ooty) situated on the Nilgiris is the famous hill station of South India and lies in Tamil Nadu. Once it was the summer resort of the Governor of Madras Presidency. The Eastern Ghats are not continuous like the Sahyadris. Mahanadi, Godavari, Krishna, Pennar and Kaveri rivers have dissected this range at many places.

The plateau region between the Sahyadris and the Eastern Ghats is known by numerous local names in different regions. Telangana which extends in Andhra Pradesh is the name of such a plateau. River Damodar flows through the Chhotanagpur Plateau. The valley of this river is famous for its huge coal
deposits. Besides coal, this region is a store house of a number of other minerals.

COASTAL PLAINS :

The Great Plateau of India is surrounded by plains on all sides. In the north lies the Great Northern Plain and in south, along the east and west lie the Coastal Plains.

East Coastal Plain extends along the coast of the Bay of Bengal from Ganga Delta in the north to Kanyakumari in the south. This plain is broader than the western coastal Plains. This plain includes the deltas of the rivers Mahanadi, Godavari, Krishna and Kaveri. Chilka, Pulicat and Koluru lakes are the famous lagoons of this plain. These lakes have been formed by enclosing small parts of the Bay of Bengal behind sand bars. Lake Chilka is situated south of the delta of Mahanadi. The lake measures 75 km in length. Lake Pulicut is situated north of Chennai city. Koluru lake is situated between the deltas of the Godavari and Krishnarivers. The east coastal plain is fertile where rice grows in plenty.

West Coastal Plain extends along the Arabian Sea from the Rann of Kutchch in the north to Kanyakumari in the south. Except for the Gujarat plain, the western coastal plains are narrower than the eastern coastal plain. From southern Gujarat upto Mumbai this plain is comparatively broader, but it narrows southwards of Mumbai. Occasionally rocky domes and hills are visible in the plains of Gujarat, the Rann of Kutchch and the plains of Kathiawar. The plains of Gujarat are made up of black soil. The coastal strip extending for about 500 km between Daman in the north and Goa in the south is called Konkan. This region is highly dissected and the coast line is indented or irregular with several natural harbours. A number of small and seasonal rivers flow through this region. The coast from Goa to Mangalore is called the Karnataka coast. The coast from Mangalore upto Kanyakumari is called the Malabar coast. Here the coastal plain is wider. There are a number of long and narrow lagoons. 80 km. long Vembanad is an example of its kind. Kochi port is situated on one of the lagoons.

INDIAN ISLANDS :

There are two small groups of islands. One of these situated in the Bay of Bengal, off the coast of Myanmar is known as the Andaman and Nicobar Islands. The other is known as Lakshadweep and situated in Arabian Sea, off the coast of Kerala. The Andaman Islands consists of (i) North, (ii) Middle, (iii) South and (iv) Little Andaman Islands. Port Blair is the capital city of the entire Union Territory and is located in South Andaman Island. This island group is separated by the Ten Degree Channel. To its south are situated the Nicobar Islands. They include Car Nicobar, Little Nicobar and Great Nicobar Islands from north to south. The southern most point of the Indian Union lies in Great Nicobar Island and has been named after Indira Gandhi. These islands represent a submerged chain of mountains. The Barren Island in the Andamans is India’s only active volcano. These islands act as
a naval and air outpost of our country in view of its strategic location. This island group faces seven countries - Bangaladesh, Myanmar, Thailand, Malaysia, Singapore, Indonesia and Sri Lanka.

Lakshadweep Islands are situated in the Arabian Sea, off the coast of Kerala. All these islands are of coral origin. They have been built up by corals, the microscopic polyps. All these islands are very small in size. The largest island among these, the Minicoy, has an area of 4.5 square km only. Kavaratti is the capital city of this island group.

DRAINAGE SYSTEM :

The drainage pattern or system of an area refers to the system of flow of surface water mainly through the rivers and basins forms. The drainage system studies streams and the directions in which they carry the surface water of an area. The drainage system is related to a number of factors, for example slope of land, geological structure, amount of volume of water and velocity of water. The surface run off of India is carried by a number of small and large rivers. The drainage system of country can be studied with reference to two parts Northern India and Southern India.

(a) Drainage System of North India :

Himalayas play an important role in the drainage system of the North India. This is because the rivers of North India have their sources in these mountains and beyond. These rivers differ from those of South India as they are still deepening their valleys rather rapidly. The debris eroded by these rivers are carried to the plains and seas and deposited there. This deposition is caused by the reduced velocity of river waters in the plains and deltas for want of necessary slope.

The Great North Indian plain has been formed by the silt brought down by these rivers. Some of the Himalayan rivers are older than the Himalayas themselves. As the ranges of the Himalayas had been rising upwards, these rivers were equally busy in downward cutting forming deep gorges and valleys. Consequently, parts of the valleys of these rivers are very deep and gorges have been formed. The
depth of the Indus gorge near Bunji (Jammu & Kashmir) is 5200 metres. Sutlej and Brahmaputra have also formed such gorges.

The drainage system of Northern India can be further sub-divided into three subsystems Indus System, Ganga System and Brahmaputra System. The major rivers of Indus basin are the Indus, Jhelum, Chenab, Ravi, Beas and Sutlej. The Ganga basin includes Ramganga, Ghaghra, Gomti, Gandak, Kosi, Yamuna along with its southern tributaries, Son and Damodar rivers. The major
rivers of Brahmputra basin are Dibang and Lohit in Arunachal Pradesh and Assam Tista in Sikkim, West Bengal and Bangladesh and Meghna, draining northeastern part of Bangladesh.

(b) Drainage System of Southern India :

The Peninsular India is an ancient landmass. Therefore, the streams flowing through this region are in their old stage. They have almost attained their base level of erosion. Their capacity to erode valleys vertically has almost come to a negligible stage. Now these streams are eroding their sides at a slow pace. This is resulting in broadening of their valleys. Consequently, during flood their waters spread over a large area. It is believed that at the time of Himalayan orogeny, due to the movements associated with the mountain building processes, the Peninsular block had a slight tilt towards east. This is why, barring Narmada and Tapi, all the major rivers of south India flow towards east. Narmada and Tapi, both flow through fault or rift valleys. The major rivers of the drainage system of southern India are Mahanadi, Godavari, Krishna, Pennar, Kaveri and Vaigai.

The slope of the northern part of the southern peninsula is towards north. Consequently, some of the streams originating in the Vindhyas, flow towards north and join Yamuna and Ganga. Among these, Chambal, Ken, Betwa, Sind and Son are more important.

The difference between the Himalayan rivers and Peninsular rivers :

The rivers which have their origin in the Himalayas are perennial. These rivers are fed by the melting of ice and snow lying near the tongue of glaciers of the Great Himalayan Range (Himadri). In the rivers of South India, the flow of water is highly fluctuating. While the rivers are in spate during the monsoons, they are almost dry during the long rainless months. Some of these rivers at many places become totally dry.

DIVERSITY AND COMPLEMENTARITY OF PHYSIOGRAPHIC DIVISIONS :

India possesses a wide variety of landforms and relief features. Its young fold mountains of the north have very bold and sharp features. They include very long as well as tall mountain ranges, towering mountain peaks, high mountain passes and precipitous river valleys. If in one direction lie very steep slopes, on the other there are gentle slopes. If some parts are without thick forests, the others are clad
with varied natural vegetation - from tropical rain forests to Alpine grasslands. They rightly boast of large snowfields, glaciers, picturesque water falls along the hanging valleys and glacial lakes like the Dal in Srinagar. The youthful Himalayan rivers prefer to jump, leap and hop forming water falls, rapids and cascades on their way. Equally awe-inspiring are its deep gorges establishing balance between steadily rising mountian ranges on the one hand and silent down cutting action of weighty trans Himalayan rivers like the Indus, Sutlej and Brahamaputra on the other. Not even a handful of countries can boast of such a magestic and maddening beauty of youthful fold mountains. These highest and largest mountain chains of the world have enabled Indian subcontinent to develop its unique culture by acting itself as a physical barrier between the subcontinent and the rest of Asia. Perhaps even more effective is its role as a climatic divide. This physiographic division acts as a store house of snow and water, giving rise to hundreds of perennial rivers to drain and irrigate one of the world’s largest and most fertile plains. In fact the plains themselves are a gift of these mountains and rivers flowing from them. It is also a store house of hydel power, fuel wood, timber, various forest products and medicinal herbs, no excluding some strange wildlife species. No wonder, if this region is able to attract tourists from far and near, both in summer and winter.

The Northern Plains are matchless in expanse. These flat or dead level plains are mostly well drained and fairly well irrigated through the use of surface and ground water. The meandering rivers, ox-bow lakes, braided river channels and a maze of distributaries help to break the monotony of these extremely level plains. Once a forest land, it has now been brought under the plough almost fully. The lower parts of the deltas are ribbonned with mangrove or tidal forests. These well watered plains, supported by highly fertile soils, produce varied crops year after year sustaining a very large chunk of the world’s population. They have also been supporting equally large bovine population. They are one of the world’s largest food baskets producing cereals, pulses, oil seeds, vegetables, fruits besides industrial or cash crops like cotton, jute, sugarcane and the like.

In sharp contrast with the Northern Mountains and Plains stand the hills of moderate attitude and a highly denuded rocky landscape, representing one of the oldest landmasses of the world - the peninsular block of India. Its rounded hills and flat topped ridges have a beauty of their own. The varied metamorphic and old granite rocks have given rise to hills, plateaus and foliated rocks. Further more, the basalt or Deccan Trap of Western India has its typical flat topped hills and ghat or stairlike

structures. Its steep wall-like escarpments run for miles and miles without interruption overlooking the Arabian Sea. Their beauty need to be seen and to be believed. This physiographic division is known for millets and various industrial crops such as cotton, sugarcane, coffee and groundnut. More importantly, it is a store house of minerals - specially the ferrous ones and mineral fuels like coal and
atomic or radio-active minerals. They have also sizeable hydel power resources. They, thus, provide a sound base to develop both agro-based and mineral-based industries.

The coastal strips are ribonned with a coastline which is partly regular and partly indented. The latter has provided spacious natural harbours like Mumbai and Marmagao. The coastal strips and island groups have ideal conditions to tap deep and shallow water fisheries. The coastal plains in the east have very fertile deltas providing rice-bowls. If it is a coast of emergence in the eastern coast then the
major part of the western coast is that of submergence. The plains are rocky and highly eroded. Rice, coconuts, rubber, tobacco and spices are some of the agricultural produce. Off-shore oil and natural gas fields have also been located. If the Lakshadweep are of coral origin, the Andaman and Nicobar Islands are the peaks of emerging mountain chain. These islands are of great strategic significance to the defence of the mainland. They face seven different countries across the seas washing their shores - Bangladesh, Myanmar, Thailand, Malaysia, Singapore, Indonesia and Sri Lanka. The islands are known for fishing, forestry and tourism.

This is how the great diversity of macro and micro relief features and land forms has contributed to enrich our culture, enhanced agricultural potential to grow almost every crop, lay strong foundations of modern industry making all its physiographic divisions totally inter dependent on one another.