Three Geological divisions:

1. The peninsular block
2. The Himalayas and other Peninsular Mountains
3. Indo-Ganga-Brahmaputra Plain

• Peninsualar block is made of gneisses (metamorphic) and granites (igneous).

Six physiographic divisions:

1. The Northern and North-eastern Mountains
2. The Northern Plain
3. The Peninsular Plateau
4. The Indian Desert
5. The Coastal Plains
6. The Islands

Northern and North-Eastern Mountains

Approximate length of the Great Himalayan range: 2500 KM. Width: 160-400 KM

Impact of Himalayas on the climate of India?

It can be divided into five sub-divisions:

1. Kashmir (or Northwestern) Himalayas
2. Himachal and Uttaranchal Himalayas
3. Darjeeling and Sikkim Himalayas
4. Arunachal Himalayas
5. Eastern Hills and Mountains

Kashmir Himalayas

• Ranges: Karakoram, Ladhakh, Zaskar, Pir Pinjal
• Glaciers: Baltoro, Siachen
• Passes: Zoji La (Great Himalayas), Banihal (Pir Pinjal), Photu La (Zaskar) and Khardung La (Ladakh)
• Lakes: (freshwater) Dal and Wular; (saltwater) Pangong Tso and Tso Moriri
• Pilgrimage: Vaishno Devi, Amarnath Cave, Charar-e-Sharif
• They are also famous for Karewa formations which are useful for the cultivation of Zafran (a local variety of Saffron). Karewas are the thick deposits of glacial clay and other materials embedded with moraines.
• Kashmir is located on the banks of Jhelum river.
• Meanders is a typical feature associated with the rivers in this region.
• In South, there are longitudinal valleys called duns; Jammu dun and Pathankot dun

Himachal and Uttarakhand Himalayas

• Lies between rivers Ravi and Kali
• Drained by two major river systems: Indus and Ganga
• Northernmost part is an extension of the Ladakh desert, lies in Spiti.
• Ranges: Great Himalayan Range, Lesser Himalayas (Dhaoladhar in HP and Nagtibha in Uttarakhand), Shivalik range
• Pilgrimage: Gangotri, Yamunotri, Kedarnath, Badrinath, Hemkund Sahib and the five famous prayags (Refer to Panch Prayag)
• Famous for hill stations: Dharamshala, Mussoorie, Shimla, Kaosani; Cantt.: Kasauli, Almora, Lansdowne, Ranikhet
• The important distinguishing features of this area are the ‘Shivalik’ and ‘Dun formations’.
• Important duns: Chandigarh-Kalka, Nalagarh, Dehra, Harike, Kota
• Dehradun is the largest of all duns: Length – 35-45 KM, Width: 22-25 KM
• Inhabited with the Bhotia They migrate to higher reaches (Bugyals) in summer and return to the valleys during winters.

Darjeeling and Sikkim Himalayas

• Between Nepal Himalayas and Bhutan Himalayas.
• Fast flowing rivers such as Tista
• Peaks: Kanchenjunga
• Tribe: Lepcha
• Has a mixed population of Nepalis, Bengalis and tribals from Central India.
• Importance: Due to the moderate slope, it is best suited for tea plantations. <India produces about 26 pc of tea in the world; second after China. Also, accounts for 12 pc of tea exports; fourth in the world.>
• Duar formations are peculiar to this region.

Arunachal Himalayas

• From Bhutan Himalayas to Diphu pass in the east.
• Direction: Southwest to Northeast
• Peaks: Kangtu and Namya Barwa
• Rivers: Brahmaputra, Kameng, Subansiri, Dihang, Dibang and Lohit.
• These rivers are perennial and have the highest hydro-electric power potential in the country.
• Tribes: Monpa, Daffla, Abor, Mishmi, Nishi and Nagas
• These communities practice shifting cultivation known as Jhumming.

Eastern Hills and Mountains

• Direction: North to South
• Ranges: Patkai Bum, Naga hills, Manipur hills, Mizo or Lushai hills
• These are low hills
• Tribes practice Jhum cultivation
• Rivers: Barak. Most of the Nagaland rivers form a tributary of Brahmaputra. Rivers in eastern Manipur are the tributaries of Chindwin, which in turn is a tributary of the Irrawady of Myanmar.
• Lake: Loktak
• Loktak Lake: is an important lake in Manipur which is surrounded by mountains on all sides. It is the largest freshwater lake in northeastern India. Also called the only Floating Lake in the world due to floating masses of organic matter on it. It serves as a source for hydropower generation, irrigation and drinking water supply.
• Keibul Kamjao National Park located in the Bishnupur district of Manipur is the only floating park in the world and is an integral part of the Loktak Lake. Home to the endangered Manipur Eld’s Deer or Brow-antlered Deer or Sangai or Dancing Deer.
• Mizoram is also known as the ‘Molassis basin’ which is made up of soft unconsolidated deposits.

The Northern Plains

• Formed by the alluvial deposits of rivers – Indus, Ganga and Brahmaputra.
• Length: 3200 KM; Width: 150-300 KM

Three main zones:

1. Bhabar
2. Tarai
3. Alluvial Plains (Khadar and Bangar)

Bhabar

• Narrow belt. 8-10 KM wide.
• Paralllel to Shivalik at the break-up of the slope. Hence, streams and rivers deposit heavy rocks (and at times disappear) in this zone.

Tarai

• South of Bhabar. 10-20 KM wide.
• Rivers re-emerge and create marshy and swampy conditions known as Tarai.

Alluvial Belt

• South of Tarai.
• Features of mature stage of fluvial erosional and depositional landforms such as sand bars, meanders, ox-bow lakes and braided channels. Riverine islands in Brahmaputra.
• Brahmaputra takes a turn an almost 90 degree turn at Dhubri (Assam) before entering Bangladesh.

Peninsular Plateau

• Bounded by the Delhi ridge, Rajmahal Hills, Gir range and Cardamom hills.
• Made up of a series of patland plateaus: Hazaribagh, Palamu, Ranchi, Malwa, Coimbatore, Karnataka etc.
• One of the oldest and most stable landmass of India.
• Physiographic Features: Tors, block mountains, rift valleys, spurs, bare rocky structures, hummocky hills and quartzite dykes offering natural sites for water storage.
• Black soil in western and northwestern parts.
• Bhima fault in this region has frequent seismic activity (Lathur earthquake)
• NW part also has ravines and gorges: Chambal, Bhind and Morena.

Three broad regions:

1. Deccan Plateau
2. Central Highlands
3. Northwestern Plateau

Deccan Plateau

• Bordered by Eastern Ghats, Satpura, Maikal range and Mahadeo hills
• Important ranges: WG: Sahyadri, Nilgiri, Anaimalai and Caradamom hills; EG: Javadi hills, Palconda range, Nallamala Hills, Mahendragiri hills
• EG and WG meet at Nilgiri hills.
• Highest peak: Anaimudi (2695 m) on Anaimalai hills; Dodabetta (2637 m) on Nilgiri hills.
• Rivers: Mahanadi, Godavari, Krishna, Kaveri etc.

Central Highlands

• Bounded by the Aravali and Satpura range.
• Relic mountains, highly denuded and form discontinuous ranges.
• Near Jaisalmer it is covered by the longitudinal sand ridges and crescent-shaped sand dunes called barchans.
• Elevation: 700-1000 m
• Banas, a tributary of Chambal, originates in the Aravalli. Other tributaries of Yamuna originate from the Vindhyan and Kaimur ranges.
• Minerals in Chotanagpur plateau.

Northeastern Plateau

• Extension of the main Peninsular plateau.
• Meghalaya and Karbi Anglong plateau.
• Megahalaya plateau: Garo hills, Khasi hills and Jaintia hills (named after the tribals inhabiting the region)
• Rich in minerals like coal, iron, sillimanite, limestone and uranium.
• Receives maximum rainfall from SW monsoon. Hence, Meghalaya plateau has a highly eroded surface. Cherrapuni and Myswarnam.

Indian Desert

• Aka Marusthali
• Northwest of the Aravali hills
• Dotted with longitudinal dunes and barchans.
• Low rainfall: >150 mm per year Low vegetation cover
• Evidence that this area was under the sea during the Mesozoic era.
• Features: mushroom rocks, shifting dunes and oasis.
• Rivers are ephemeral: Luni. Brackish lakes. Inland drainage.

Coastal Plains

Two divisions:

1. Western coastal plains
2. Eastern Coastal Plains

Western Coastal Plains

• Submerged coastal plain. Hence, a narrow belt. Narrow in middle and broader towards north and south.
• Ports: Provides natural conditions for the development of ports and harbours due to submergence. Kandla, Mazagaon (Mumbai), JLN port Navha Sheva, Maramagao, Mangalore, Cochin etc.
• Mumbai has the world’s largest natural harbour.
• May be divided into: Kachchh and Kathiawar coast in Gujarat, Konkan coast, Goan coast and Malabar coast.
• Rivers don’t form delta.
• Kayals (Backwaters): Found in the Malabar coast. Used for fishing and inland navigation. Every year Nehru Trophy Vallamkali (boat race) is held in Punnamada Kayal in Kerala.

Eastern Coastal Plains

• Broader
• Emergent coast. Hence, less number of ports and harbours. Chennai, Vizag, Paradwip, Haldia.
• Delta formation

The Islands

Two major Divisions:

1. Andaman and Nicobar
2. Lakshwadeep & Minicoy

Andaman and Nicobar

• Two major island groups: Ritchie’s archipelago and the Labrynth island.
• The group is divided into: Andaman in the North and Nicobar in the South.
• Andaman and Nicobar separated by the Ten Degree channel.
• Barren Island
• Peaks: Saddle Peak (N.Andaman – 738 m), Mt. Diavolo (Middle Andaman – 515 m), Mt. Koyob (S Andaman – 460 m) and Mt. Thuiller (Great Nicobar – 642 m)
• Coral deposits found
• Convectional rainfalls and equatorial type of vegetation.

Lakshadweep and Minicoy

• Entire group built of coral deposits.
• Total of 36 islands of which 11 are inhabited.
• Smallest UT
• Minicoy is the largest island
• Separated by the 9 Degree Channel, north of which is the Amini Island and to the south Canannore island.
• These islands have storm beaches consisting of unconsolidated pebbles, shingles, cobbles and boulders.

Thermal Power Projects in India

Urban morphology is the study of the form of human settlements and the process of their formation and transformation.Morphological studies often deal with development of forms and
pattern of the present city or other urban areas through time.

Urban morphology is the study of the physical form of a city, which consists of street patterns, building sizes and shapes, architecture, population density and patterns of residential, commercial, industrial and other uses, among other things. Special attention is given to how the physical form of a city changes over time and to how different cities compare with each other.

India exhibits a very stable settlement structure such that much of the urban growth that has occurred has been because of the accretion to existing towns and settlements and only marginally because of the emergence of new towns. As a result, the proportion of urban population residing in towns above a certain population cut-off point continues to increase, but there is little evidence of correlation between city size and rates of population growth.

In other words we can state that the development of new urban centers in India has been minimal and the urban growth has been accredited to the development of existing centers.

Prof. E. Ahmad has identified some of the components of urban morphology as site characteristics, historical background, sky-line, green open spaces, and water bodies, physical and cultural dominants.

For the Census of India 2011, the definition of urban area is as follows;

1. All places with a municipality, corporation, cantonment board or notified town area committee, etc.
2. All other places which satisfied the following criteria: i) A minimum population of 5,000; ii) At least 75 per cent of the male main working population engaged in non-agricultural pursuits; and iii) A density of population of at least 400 persons per sq. km.

Urban centres of India are of 4 types:
1. Those that have grown from ancient town and villages e.g. Varansi, Madurai, Patna

2. Those that have grown from medieval towns such as Lucknow, Delhi, Jaipur. These towns have lot of features of medieval Islamic architecture with palaces, minarates, walled city with Meena bazaars.
3. Cities that have grown from the British administrative centres. Most of them were medieval towns or cantonment areas which retain lot of features of European Victorial architecture.
4. During the post independence period a number of planned cities have been developed. Chandigarh, Bhuvneshwar, Gandhinagar, Dispur and Bokaro are some of the typical examples of planned cities.

City is a complex agglomeration of multiple activities – economic, social, cultural, etc. Its ‘central area’ also known as Central Business District is its distinct section which is identified as the centre of marketing, business and financial activities as well as dense built-up sector where lines of transportation converge from various parts and nearly from all direction.

The rapid pace of population growth has led to the excessive utilization of natural resources. Huge population also leads to huge production of wastes. The resultant outcomes are loss of biodiversity, pollution of air, water and soil and increased pressure on arable land. All these have been putting great stress on the environment. If you take the case of India, it supports 17 percent of world population on just 2.4 per cent of the world land area.

The earth’s carrying capacity in terms of its food resource is approaching its limits. Oceanic supply of fish, rangelands which support livestock, and the hydrological cycle to produce freshwater are strained. The backlog of unused agricultural technology is shrinking in industrial and developing countries alike, slowing the rise in cropland productivity. At the same time, soil erosion, air pollution, soil compaction, aquifer depletion, the loss of soil organic matter, and the waterlogging and salting of irrigated land are all slowing food production. At present, it appears that nothing can reverse the worldwide decline in grain output per person. The bottomline is that the world’s farmers can no longer be counted on to feed the projected additions to the present population. Attaining a humane balance between food production and population growth now depends more on family planners instead of farmers.

Mazor impact of popuatlion growth on Environment are:

• Resource Scarcity:

– Food

– Energy (coal, oil, uranium)

– Raw materials (iron, copper, wood, water)

• Environmental Impacts

– Soil degradation

– Deforestation

– Global Warming

Population growth would not be sustainable if it has important negative impacts that will jeopardize the ability of future generations to meet their needs.

India is the second most populous country in the world next only to China. On March 1, 2011 the total population of India was at 1.247 billion. This accounted for 17.5% of the world’s total population. In other words, about every sixth person in the world there is an Indian. China, the most populous country of the world, is a step ahead of us as every fifth person in the world there is a Chinese. While India possesses only 2.42% of the world’s total land area, she is required to sustain almost 17.5% of the world’s population.

Two components of population growth are: Natural growth: It is analysed by assessing the crude birth and death rates. Induced growth: It is assessed by the volume of inward and outward movement of people in any given area. There are four phases of population growth in India. The period from 1901-1921 is referred to as a period of stagnant growth of India’s population. The high birth rate was counterbalanced by high death rate. The decades 1921-1951 are referred to as the period of steady population growth. The mortality rate started showing downward trend as a result of improvement in general health and sanitation conditions after 1921.

The density of population is expressed as the number of persons per square kilometre. According to 2011 census, the density of population in India is 382 persons per square kilometre. Over the last 100 years density has increased more than four times.

Density and its variation across states can be accessed by the following table:-

The word “monsoon” comes from the Arabic word mausim, meaning season.Monsoons refer to a system of winds in the tropical regions under which the direction of winds is reversed completely between the summer and the winter seasons. Under this system, the winds blow from land to sea in winter and from sea to land in summer. Therefore, most of the rainfall in the regions influenced by the monsoons is received in the summer season while winter season is generally dry.

Due to a higher temperature over the land in summer, a low pressure area develops over the continents and the winds blow from neighbouring oceans towards the land. These winds are of maritime origin and hence cause ample rainfall in summer. On the other hand, the continents become colder than the neighboring oceans in winter. As a result a high pressure area is developed
over the continents. Therefore, winds blow from land to sea in winter. These winds, being of continental origin, are dry and do not cause rain.

Role of Jet streams, Tibet Plateau and atmosphere-ocean circulation is of prime importance for the origin of Indian Monsoon.During this summer season the vertical sun rays at tropic of cancer ,the circum polar whirl along with westerly jet stream weakened and shifted northward of the Himalayas and southern branch of this jet stream disappeared by 6-10 June. This removal of westerly jet stream to the north of Tibet plateau leads to reversal of curvature of flow of free air to the north and northwest of the subcontinent. It further leads to development of dynamic depression overlying the thermal depression already established at the surface of northwest Indian subcontinent which ultimately help to trigger the burst of Indian monsoon along with it vigorous advance over the Indian subcontinent.

As long as the position of upper air jet stream is maintained above the surface low pressure to the south of the Himalayas the dynamic anticyclonic conditions persist in the northwestern part of Indian subcontinent which obstruct the ascent of air from the surface low as the air is continuously descending from the above. This is the reason why the months of April, May and June are dry inspite of high temperature and evaporation while upper air low pressure in the east of the Himalayas over Myanmar, Assam and Bangladesh helps in ascend of air and produce rainfall.

During October and November, the high pressure over northern lndia, the winds start blowing from northeast as retreating monsoons. Clear skies and the increase in mercury northern plains is observed which is termed as ‘October heat’. At this time, the low pressure conditions shift to the Bay of Bengal giving rise to cyclonic depressions. These cyclonic depressions often results in the destruction of life and property generally on the eastern coast and the southern coast. Most of the rainfall of the Coromandel Coast is derived from depressions and cyclones.

• Drainage: Flow of water through well-defined channels. Network of such channels is called a drainage system .
• Drainage basin: An area drained by a river and its tributaries.
• Watershed: Boundary line separating one drainage basin from other.
• River basins are larger watersheds.
• Drainage pattern of an area depends on the geological time period, nature and structure of rocks, topography, rocks, slope, amount of water and periodicity of flow.

Important drainage patterns:

1. Dendritic: Resembling the branches of a tree. Eg. Northern Plain rivers
2. Radial: Originate from a hill and flow in all directions. Eg. Rivers in Amarkantak
3. Trellis: Primary tributaries parallel to each other and secondary tributaries join them at right angles.
4. Centripetal: Rivers discharge waters from all directions in a lake or depression

A river drains the water collected from a specific area, which is called its catchment area.

Nearly 77 pc of drainage is towards the Bay of Bengal while about 23 pc is towards the Arabian Sea.

The Himalayan Drainage System

Mainly includes the Ganga, Indus and Brahmaputra river basins.

Over the plains, rivers of this system change the course often. River Kosi is also known as the ‘sorrow of Bihar’ due to flooding by its frequent change of course by deposition of sediments.

Evolution

Geologists believe that a mighty river called Shivalik or Indo-Brahma traversed the entire length of the Himalayas some 5-24 million years ago. Over time this got dismembered into the present three major river systems.

The Indus System

Indus river originates from a glacier near Bokhar Chu in Tibet in the Kailash Mountain range. Known as Singi Khamban (Lion’s mouth) in Tibet. It forms a spectacular gorge near Gilgit in J&K. Enters Pakistan near Chillar in the Dardistan region. Flows only through the Leh distt of J&K.

Smaller tributaries: Shyok, Gilgit, Zaskar, Nubra, Hunza, Shigar, Gasting, Dras. On right bank: Kabul river, Khurram, Tochi, Gomal, Viboa and hte Sangar.

Major tributaries: Satluj, Beas, Ravi, Chenab, Jhelum

The Ganga System

It is the largest river system in India.

Ganga rises in the Gangotri glacier near Gaumukh in the Uttarkashi district. Here it is known as the Bhagirathi. At Devprayag, Bhagirathi meets Alaknanda and is known as Ganga hereafter.

Panchprayag

• Ganga enters the plains at Haridwar.
• Left Bank tributaries (LBT): Ramganga, Gomati, Ghaghara, Gandak, Kosi and Mahananda.
• Right Bank tributaries (RBT): Son
• Discharges into Bay of Bengal near Sagar island.