environmental geography

INDIAPHYSICAL ENVIRONMENT

TEXTBOOK IN GEOGRAPHY FOR CLASS XI

First EditionMarch 2006 Phalguna 1927

ReprintedNovember 2006 Kartika 1928December 2007 Pausa 1929December 2008 Pausa 1930

PD 50T RNB

National Council of EducationalResearch and Training, 2006

Rs 35.00

Printed on 70 GSM paper with NCERTwatermark

Published at the Publication Departmentby the Secretary, National Council ofEducational Research and Training,Sri Aurobindo Marg, New Delhi 110 016and printed at Nutan Printers, F-89/12,Okhla Industrial Area, Phase-I,New Delhi 110 020

ISBN 81-7450-538-5

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FOREWORD

The National Curriculum Framework (NCF), 2005, recommends that childrenslife at school must be linked to their life outside the school. This principle marksa departure from the legacy of bookish learning which continues to shape oursystem and causes a gap between the school, home and community. The syllabiand textbooks developed on the basis of NCF signify an attempt to implementthis basic idea. They also attempt to discourage rote learning and themaintenance of sharp boundaries between different subject areas. We hope thesemeasures will take us significantly further in the direction of a child-centredsystem of education outlined in the National Policy on Education (1986).

The success of this effort depends on the steps that school principals andteachers will take to encourage children to reflect on their own learning and topursue imaginative activities and questions. We must recognise that, given space,time and freedom, children generate new knowledge by engaging with theinformation passed on to them by adults. Treating the prescribed textbook asthe sole basis of examination is one of the key reasons why other resources andsites of learning are ignored. Inculcating creativity and initiative is possible if weperceive and treat children as participants in learning, not as receivers of a fixedbody of knowledge.

These aims imply considerable change in school routines and mode offunctioning. Flexibility in the daily time-table is as necessary as rigour inimplementing the annual calendar so that the required number of teachingdays are actually devoted to teaching. The methods used for teaching andevaluation will also determine how effective this textbook proves for makingchildrens life at school a happy experience, rather than a source of stress orboredom. Syllabus designers have tried to address the problem of curricularburden by restructuring and reorienting knowledge at different stages withgreater consideration for child psychology and the time available for teaching.The textbook attempts to enhance this endeavour by giving higher priority andspace to opportunities for contemplation and wondering, discussion in smallgroups, and activities requiring hands-on experience.

The National Council of Educational Research and Training (NCERT)appreciates the hard work done by the textbook development committeeresponsible for this book. We wish to thank the Chairperson of the advisorycommittee for textbooks in Social Sciences, at the higher secondarylevel, Professor Hari Vasudevan and the Chief Advisor for this book,Professor M.H. Qureshi for guiding the work of this committee. Several teacherscontributed to the development of this textbook; we are grateful to their principalsfor making this possible. We are indebted to the institutions and organisations

which have generously permitted us to draw upon their resources, material andpersonnel. We are especially grateful to the members of the National MonitoringCommittee, appointed by the Department of Secondary and Higher Education,Ministry of Human Resource Development under the Chairpersonship ofProfessor Mrinal Miri and Professor G.P. Deshpande, for their valuable time andcontribution. As an organisation committed to systemic reform and continuousimprovement in the quality of its products, NCERT welcomes comments andsuggestions which will enable us to undertake further revision and refinement.

DirectorNew Delhi National Council of Educational20 December 2005 Research and Training

iv

TEXTBOOK DEVELOPMENT COMMITTEE

CHAIRPERSON, ADVISORY COMMITTEE FOR TEXTBOOKS IN SOCIAL SCIENCES AT THE HIGHERSECONDARY LEVEL

Hari Vasudevan, Professor, Department of History, University of Calcutta,Kolkata

CHIEF ADVISOR

M. H. Qureshi, Professor, Centre for the Study of Regional Development,Jawaharlal Nehru University, New Delhi

MEMBERS

Aparna Pandey, Lecturer, DESSH, NCERT, New Delhi

Ashok Diwakar, Lecturer, Government P.G College, Sector 9, Gurgaon

B. S. Butola, Professor, Centre for the Study of Regional Development, JawaharlalNehru University, New Delhi

Beena Srikumar, PGT, CRPF Public School, New Delhi

Noor Mohammad, Professor, Delhi School of Economics, Delhi University, Delhi

MEMBER-COORDINATOR

Tannu Malik, Lecturer, DESSH, NCERT, New Delhi

ACKNOWLEDGEMENTS

The National Council of Educational Research and Training acknowledges thecontribution of Bhagirathy Jhingran, Teacher, Pathways World School, Gurgaonin the development of this textbook; the National Bureau of Soil Survey and LandusePlanning (under ICAR), Government of India, for providing input for the chapteron Soils. Special thanks are due to Savita Sinha, Professor and Head, Departmentof Education in Social Sciences and Humanties for her valuable support at everystage of preparation of this textbook.

The Council is thankful to the Survey of India for Certification of Maps givenin the textbook. It also gratefully acknowledges the support of individuals andorganisations as listed below for providing various photographs used in thistextbook M.H. Qureshi, Professor, CSRD, JNU for Figure 2.4, 5.4, 5.5, 6.1 and6.4; B.S. Butola, Professor, CSRD, JNU for Figure 7.1, 7.5, 7.7 and 7.9; M.V.Srinivasan, Lecturer, DESSH, NCERT for Figure 7.3; ITDC/Ministry of Tourism,Government of India for Figure 2.1, 2.3, 2.8, 2.11, 2.12, 2.13, 2.14, 3.1, 3.3, 4.4,5.7 and 6.6; Ministry of Environment and Forest, Government of Indiafor Figure 2.9, 5.1 and 5.6; Social Science Textbook for Class VII, Part II(NCERT, 2005), for Figure 5.3 and Social Science Textbook for Class VIII, Part II(NCERT, 2005), for Figure 2.10 and 6.5.

The Council also gratefully acknowledges the contributions of Anil Sharmaand Arvind Sharma, DTP Operators; Sameer Khatana and Amar Kumar Prusty,Copy Editors; Bharat Sanwaria, Shreshtha and Deepti Sharma, Proof Readers;Dinesh Kumar, Computer Incharge, who have helped in giving a final shape tothis book. The contribution of the Publication Department, NCERT is also dulyacknowledged.

The following are applicable to all the maps of India used in this book

Government of India, Copyright 20061. The responsibility for the correctness of internal details rests with the publisher.

2. The territorial waters of India extend into the sea to a distance of twelve nautical miles measuredfrom the appropriate base line.

3. The administrative headquarters of Chandigarh, Haryana and Punjab are at Chandigarh.

4. The interstate boundaries amongst Arunachal Pradesh, Assam and Meghalaya shown on this mapare as interpreted from the North-Eastern Areas (Reorganisation) Act.1971, but have yet to beverified.

5. The external boundaries and coastlines of India agree with the Record/Master Copy certified bySurvey of India.

6. The State boundaries between Uttaranchal and Uttar Pradesh, Bihar and Jharkhand, andChhattisgarh and Madhya Pradesh have not been verified by the Governments concerned.

7. The spellings of names in this map, have been taken from various sources.

CONTENTS

FOREWORD iii

UNIT I : INTRODUCTION 1-6

1. India Location 2

UNIT II : PHYSIOGRAPHY 7-31

2. Structure and Physiography 8

3. Drainage System 21

UNIT III : CLIMATE, VEGETATION AND SOIL 32-75

4. Climate 33

5. Natural Vegetation 57

6. Soils 68

UNIT IV : NATURAL HAZARDS AND DISASTERS: CAUSES, 76-93

CONSEQUENCES AND MANAGEMENT

7. Natural Hazards and Disasters 77

APPENDICES 94-98

I. STATES, THEIR CAPITALS, NUMBER OF DISTRICTS, AREA AND POPULATION 94

II. UNION TERRITORIES, THEIR CAPITALS, AREA AND POPULATION 95

III. IMPORTANT RIVER BASINS 96

IV. STATE/UNION TERRITORY WISE FOREST COVER 97

V. NATIONAL PARKS OF INDIA 98

GLOSSARY 99-100

CONSTITUTION OF INDIAPart III (Articles 12 35)

(Subject to certain conditions, some exceptionsand reasonable restrictions)

guarantees these

Fundamental Rights

Right to Equality before law and equal protection of laws; irrespective of religion, race, caste, sex or place of birth; of opportunity in public employment; by abolition of untouchability and titles.

Right to Freedom of expression, assembly, association, movement, residence and profession; of certain protections in respect of conviction for offences; of protection of life and personal liberty; of free and compulsory education for children between the age of six and fourteen years; of protection against arrest and detention in certain cases.

Right against Exploitation for prohibition of traffic in human beings and forced labour; for prohibition of employment of children in hazardous jobs.

Right to Freedom of Religion freedom of conscience and free profession, practice and propagation of religion; freedom to manage religious affairs; freedom as to payment of taxes for promotion of any particular religion; freedom as to attendance at religious instruction or religious worship in educational

institutions wholly maintained by the State.

Cultural and Educational Rights for protection of interests of minorities to conserve their language, script and culture; for minorities to establish and administer educational institutions of their choice.

Right to Constitutional Remedies by issuance of directions or orders or writs by the Supreme Court and High

Courts for enforcement of these Fundamental Rights.

INTRODUCTIONThis unit deals with

Location space relations and Indias place in the world

UNITI

You have already seen the map of Indiain the previous classes. Now you closelyexamine the map of India (Figure 1.1).Mark the southernmost and northernmostlatitudes and the easternmost andwesternmost longitudes.

The mainland of India, extends fromKashmir in the north to Kanniyakumari in thesouth and Arunachal Pradesh in the east toGujarat in the west. Indias territorial limitfurther extends towards the sea upto 12nautical miles (about 21.9 km) from the coast.(See the box for conversion).

Statute mile = 63,360 inchesNautical mile = 72,960 inches1 Statute mile = about 1.6 km (1.584 km)1 Nautical mile = about 1.8 km (1.852 km)

Our southern boundary extends upto645' N latitude in the Bay of Bengal. Let ustry to analyse the implications of having sucha vast longitudinal and latitudinal extent.

If you work out the latitudinal andlongitudinal extent of India, they are roughlyabout 30 degrees, whereas the actual distancemeasured from north to south extremity is3,214 km, and that from east to west is only2,933 km. What is the reason for thisdifference? Consult Chapter 3 on the topicLatitude, Longitude and Time in the book

Practical Work in Geography Part I (NCERT,2006) to find out.

This difference is based on the fact that thedistance between two longitudes decreasestowards the poles whereas the distancebetween two latitudes remains the sameeverywhere. Find out the distance between twolatitudes?

From the values of latitude, it is understoodthat the southern part of the country lieswithin the tropics and the northern part lies inthe sub-tropical zone or the warm temperatezone. This location is responsible for largevariations in land forms, climate, soil types andnatural vegetation in the country.

Now, let us observe the longitudinal extentand its implications on the Indian people. Fromthe values of longitude, it is quite discerniblethat there is a variation of nearly 30 degrees,which causes a time difference of nearly twohours between the easternmost and thewesternmost parts of our country. You arefamiliar with the concept of Indian StandardTime (IST). What is the use of the standardmeridian? While the sun rises in thenortheastern states about two hours earlier ascompared to Jaisalmer, the watches inDibrugarh, Imphal in the east and Jaisalmer,Bhopal or Chennai in the other parts of Indiashow the same time. Why does this happen?

INDIA LOCATION

C H A P T E R

There is a general understanding among the countries of the world to select the standardmeridian in multiples of 730' of longitude. That is why 8230' E has been selected as thestandard meridian of India. Indian Standard Time is ahead of Greenwich Mean Time by5 hours and 30 minutes.

There are some countries where there are more than one standard meridian due totheir vast east-to-west extent. For example, the USA has seven time zones.

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3INDIA LOCATION

Figure 1.1 : India : Administrative Divisions

4 INDIA : PHYSICAL ENVIRONMENT

Fig

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5INDIA LOCATION

1. Choose the right answer from the four alternatives given below.

(i) Which one of the following latitudinal extent is relevant for the extent ofIndias area?(a) 841'N - 357'N (c) 84'N - 356'N(b) 84'N - 376'N (d) 645'N - 376'N

(ii) Which one of the following countries shares the longest land frontier withIndia?

(a) Bangladesh (c) Pakistan(b) China (d) Myanmar

EXERCISES

Name a few place in India through which thestandard meridian passes?

India with its area of 3.28 million sq. kmaccounts for 2.4 per cent of the worlds landsurface area and stands as the seventhlargest country in the world. Find out thenames of the countries which are larger thanIndia.

SIZE

The size of India has endowed her with greatphysical diversity. Thus, you may appreciatethe presence of lofty mountains in the north;large rivers such as Ganga, Brahmaputra,Mahanadi, Krishna, Godavari and Kaveri;green forested hills in northeast and southIndia; and the vast sandy expanse ofMarusthali. You may further appreciate thatbounded by the Himalayas in the north,Hindukush and Sulaiman ranges in the north-west, Purvachal hills in the north-east and bythe large expanse of the Indian ocean in thesouth, it forms a great geographic entity knownas the Indian subcontinent. It includes thecountries Pakistan, Nepal, Bhutan,Bangladesh and India. The Himalayas,together with other ranges, have acted as aformidable physical barrier in the past. Exceptfor a few mountain passes such as the Khyber,the Bolan, the Shipkila, the Nathula, theBomdila, etc. it was difficult to cross it. It hascontributed towards the evolving of a uniqueregional identity of the Indian subcontinent.

By referring to the physical map of Indiayou can now describe the physical variationswhich you would come across while travelling

from Kashmir to Kanniyakumari and fromJaisalmer in Rajasthan to Imphal in Manipur.

Peninsular part of India extends towardsthe Indian Ocean. This has provided thecountry with a coastline of 6,100 km in themainland and 7,517 km in the entiregeographical coast of the mainland plus theisland groups Andaman and Nicobar locatedin the Bay of Bengal and the Lakshadweep inthe Arabian Sea. Thus India, as a country, isa physically diverse land providing occurrenceof varied resources.

INDIA AND ITS NEIGHBOURS

Examine the location map of India (Figure 1.2).You will notice that India is located in thesouth-central part of the continent of Asia,bordering the Indian ocean and its two armsextending in the form of Bay of Bengal and theArabian Sea. This maritime location ofPeninsular India has provided links to itsneighbouring regions through the sea and airroutes.

Prepare a list of Indias neighbouringcountries by consulting the map.

Sri Lanka and Maldives are the two islandcountries located in the Indian Ocean, whichare our neighbours. Sri Lanka is separated fromIndia by the Gulf of Mannar and Palk Strait.

Differentiate between a Gulf and a Strait

Do you think that physical barrier is ahindrance in interaction with our neighbouringcountries in modern times? Give someexamples how we have overcome thesedifficulties in the present day.

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(iii) Which one of the following countries is larger in area than India?(a) China (c) France(b) Egypt (d) Iran

(iv) Which one of the following longitudes is the standard meridian for India?(a) 6930'E (c) 7530'E(b) 8230'E (d) 9030'E

2. Answer the following questions in about 30 words.(i) Does India need to have more than one standard time? If yes, why do you

think so?(ii) What are the implications of India having a long coastline?(iii) How is the latitudinal spread of India advantageous to her?(iv) While the sun rises earlier in the east, say Nagaland and also sets earlier,

how do the watches at Kohima and New Delhi show the same time?

Project/ActivityActivity based on Appendix I (Teachers may help in the exercises by explainingand getting it done by the students).

(i) On a graph paper, plot the number of districts in Madhya Pradesh,Karnataka, Meghalaya, Goa, Kerala, Haryana. Do the number of districtshave some relationship with the area of the state?

(ii) Which state amongst Uttar Pradesh, West Bengal, Gujarat, ArunachalPradesh, Tamil Nadu, Tripura, Rajasthan and Jammu and Kashmir isthe most thickly populated and which one is the least densely populated?

(iii) Find out the relationship between the area of the state and the number ofdistricts.

(iv) Identify the states with coastal boundaries.(v) Arrange the states from west to east which have only land boundary.

Activity based on Appendix II

(i) List the Union Territories which have coastal location.(ii) How do you explain the variation in the area and population of NCT Delhi

and the Andaman and Nicobar Islands?(iii) On a graph paper, draw a bar diagram to show the area and population of

all the Union Territories.

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PHYSIOGRAPHYThis unit deals with

Structure and Relief; physiographic divisions

Drainage systems: concept of water sheds the Himalayanand the Peninsular

UNITII

Do you know that our earth also has ahistory. The earth and its landformsthat we see today have evolved over avery long time. Current estimation shows thatthe earth is approximately 460 million years old.Over these long years, it has undergone manychanges brought about primarily by theendogenic and exogenic forces. These forces haveplayed a significant role in giving shape to varioussurface and subsurface features of the earth. Youhave already studied about the Plate Tectonicsand the movement of the Earths plates in thebook Fundamentals of Physical Geography(NCERT, 2006). Do you know that the Indianplate was to the south of the equator millions ofyears ago? Do you also know that it was muchlarger in size and the Australian plate was a partof it? Over millions of years, this plate broke intomany parts and the Australian plate movedtowards the southeastern direction and theIndian plate to the north. Can you map differentphases in the movement of the Indian plate? Thisnorthward movement of the Indian plate is stillcontinuing and it has significant consequenceson the physical environment of the Indiansubcontinent. Can you name some importantconsequences of the northward movement of theIndian plate?

It is primarily through the interplay of theseendogenic and exogenic forces and lateralmovements of the plates that the present geologicalstructure and geomorphologic processes activein the Indian subcontinent came into existence.Based on the variations in its geological structureand formations, India can be divided into threegeological divisions. These geological regionsbroadly follow the physical features:

(i) The Penisular Block(ii) The Himalayas and other Peninuslar

Mountains(iii) Indo-Ganga-Brahmaputra Plain.

THE PENINSULAR BLOCK

The northern boundary of the PeninsularBlock may be taken as an irregular linerunning from Kachchh along the western flankof the Aravali Range near Delhi and thenroughly parallel to the Yamuna and the Gangaas far as the Rajmahal Hills and the Gangadelta. Apart from these, the Karbi Anglong andthe Meghalaya Plateau in the northeast andRajasthan in the west are also extensions ofthis block. The northeastern parts areseparated by the Malda fault in West Bengalfrom the Chotanagpur plateau. In Rajasthan,the desert and other desertlike featuresoverlay this block.

The Peninsula is formed essentially by agreat complex of very ancient gneisses andgranites, which constitutes a major part of it.Since the Cambrian period, the Peninsula hasbeen standing like a rigid block with theexception of some of its western coast whichis submerged beneath the sea and some otherparts changed due to tectonic activity withoutaffecting the original basement. As a part ofthe Indo-Australian Plate, it has been subjectedto various vertical movements and blockfaulting. The rift valleys of the Narmada, theTapi and the Mahanadi and the Satpura blockmountains are some examples of it. ThePeninsula mostly consists of relict and residualmountains like the Aravali hills, the Nallamalahills, the Javadi hills, the Veliconda hills, the

STRUCTURE AND PHYSIOGRAPHY

C H A P T E R

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9STRUCTURE AND PHYSIOGRAPHY

Palkonda range and the Mahendragiri hills, etc.The river valleys here are shallow with lowgradients.

You are aware of the method of calculatingthe gradient as a part of your study of the bookPractical Work in Geography Part I (NCERT,2006). Can you calculate the gradient of theHimalayan and the Peninsular rivers and drawthe comparisons?

Most of the east flowing rivers form deltasbefore entering into the Bay of Bengal. Thedeltas formed by the Mahanadi, the Krishna,the Kaveri and the Godavari are importantexamples.

THE HIMALAYAS AND OTHERPENINSULAR MOUNTAINS

The Himalayas along with other Peninsularmountains are young, weak and flexible in theirgeological structure unlike the rigid and stablePeninsular Block. Consequently, they are stillsubjected to the interplay of exogenic andendogenic forces, resulting in the development offaults, folds and thrust plains. These mountainsare tectonic in origin, dissected by fast-flowingrivers which are in their youthful stage. Variouslandforms like gorges, V-shaped valleys, rapids,waterfalls, etc. are indicative of this stage.

INDO-GANGA-BRAHMAPUTRA PLAIN

The third geological division of Indiacomprises the plains formed by the riverIndus, the Ganga and the Brahmaputra.Originally, it was a geo-synclinal depressionwhich attained its maximum development

during the third phase of the Himalayanmountain formation approximately about 64million years ago. Since then, it has beengradually filled by the sediments brought bythe Himalayan and Peninsular rivers. Averagedepth of alluvial deposits in these plainsranges from 1,000-2,000 m.

It is evident from the above discussion thatthere are significant variations among thedifferent regions of India in terms of theirgeological structure, which has far-reachingimpact upon other related aspects. Variationsin the physiography and relief are importantamong these. The relief and physiography ofIndia has been greatly influenced by thegeological and geomorphological processesactive in the Indian subcontinent.

PHYSIOGRAPHY

Physiography of an area is the outcome ofstructure, process and the stage ofdevelopment. The land of India is characterisedby great diversity in its physical features. Thenorth has a vast expanse of rugged topographyconsisting of a series of mountain ranges withvaried peaks, beautiful valleys and deep gorges.The south consists of stable table land withhighly dissected plateaus, denuded rocks anddeveloped series of scarps. In between thesetwo lies the vast north Indian plain.

Based on these macro variations, India canbe divided into the following physiographicdivisions:

(1) The Northern and North-easternMountains

(2) The Northern Plain(3) The Peninsular Plateau(4) The Indian Desert(5) The Coastal Plains(6) The Islands.

The North and Northeastern Mountains

The North and Northeastern Mountains consistof the Himalayas and the Northeastern hills.The Himalayas consist of a series of parallelmountain ranges. Some of the importantranges are the Greater Himalayan range,which includes the Great Himalayas and

Figure 2.1 : A Gorge

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Figure 2.2 : India : Physical


the Trans-Himalayan range, the MiddleHimalayas and the Shiwalik. The generalorientation of these ranges is from northwest tothe southeast direction in the northwestern partof India. Himalayas in the Darjiling and Sikkimregions lie in an eastwest direction, while inArunachal Pradesh they are from southwest tothe northwest direction. In Nagaland, Manipurand Mizoram, they are in the northsouthdirection. The approximate length of the GreatHimalayan range, also known as the centralaxial range, is 2,500 km from east to west, andtheir width varies between 160-400 km fromnorth to south. It is also evident from the mapthat the Himalayas stand almost like a strong

and long wall between the Indian subcontinentand the Central and East Asian countries.

Himalayas are not only the physical barrier,they are also a climatic, drainage and culturaldivide. Can you identify the impact of Himalayason the geoenvironment of the countries of SouthAsia? Can you find some other examples ofsimilar geoenvironmental divide in the world?

There are large-scale regional variationswithin the Himalayas. On the basis of relief,alignment of ranges and other geomorphologicalfeatures, the Himalayas can be divided into thefollowing sub-divisions:

(i) Kashmir or Northwestern Himalayas(ii) Himachal and Uttaranchal Himalayas(iii) Darjiling and Sikkim Himalayas(iv) Arunachal Himalayas(v) Eastern Hills and Mountains.

Kashmir or Northwestern Himalayas

It comprise a series of ranges such as theKarakoram, Ladakh, Zaskar and Pir Panjal. The

northeastern part of the Kashmir Himalayas is acold desert, which lies between the GreaterHimalayas and the Karakoram ranges. Betweenthe Great Himalayas and the Pir Panjal range,lies the world famous valley of Kashmir and the

famous Dal Lake. Importantglaciers of South Asia suchas the Baltoro and Siachenare also found in this region.The Kashmir Himalayas arealso famous for Karewaformations, which are usefulfor the cultivation of Zafran,

a local variety of saffron. Some of the importantpasses of the region are Zoji La on the GreatHimalayas, Banihal on the Pir Panjal, Photu Laon the Zaskar and Khardung La on the Ladakhrange. Some of the important fresh lakes suchas Dal and Wular and salt water lakes such asPangong Tso and Tso Moriri are also in thisregion. This region is drained by the river Indus,and its tributaries such as the Jhelum and theChenab. The Kashmir and northwesternHimalayas are well-known for their scenicbeauty and picturesque landscape. Thelandscape of Himalayas is a major source ofattraction for adventure tourists. Do you knowthat some famous places of pilgrimage such asVaishno Devi, Amarnath Cave, Charar -e-Sharif,etc. are also located here and large number ofpilgrims visit these places every year?

Srinagar, capital city of the state of Jammuand Kashmir is located on the banks of Jhelumriver. Dal Lake in Srinagar presents aninteresting physical feature. Jhelum in the valleyof Kashmir is still in its youth stage and yet formsmeanders a typical feature associated with the

Figure 2.3 : The Himalayas

KarewasKarewas are thethick deposits ofglacial clay andother materialsembedded withmoraines.

Figure 2.4 : Meandering Jhelum

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mature stage in the evolution of fluvial land form(Figure 2.4). Can you name some other fluviallandforms in the mature stage of a river?

The southernmost part of this region consistsof longitudinal valleys known as duns. Jammudun and Pathankot dun are important examples.

The Himachal and Uttarakhand Himalayas

This part lies approximately between the Raviin the west and the Kali (a tributary ofGhaghara) in the east. It is drained by two majorriver systems of India, i.e. the Indus and theGanga. Tributaries of the Indus include the riverRavi, the Beas and the Satluj, and thetributaries of Ganga flowing through this

region include the Yamuna and the Ghaghara.The northernmost part of the HimachalHimalayas is an extension of the Ladakh colddesert, which lies in the Spiti subdivision ofdistrict Lahul and Spiti. All the three ranges ofHimalayas are prominent in this section also.These are the Great Himalayan range, the LesserHimalayas (which is locally known asDhaoladhar in Himachal Pradesh and Nagtibhain Uttarakhand) and the Shiwalik range fromthe North to the South. In this section of LesserHimalayas, the altitude between 1,000-2,000m specially attracted to the British colonialadministration, and subsequently, some of theimportant hill stations such as Dharamshala,Mussoorie, Shimla, Kaosani and thecantonment towns and health resorts such asShimla, Mussoorie, Kasauli, Almora,Lansdowne and Ranikhet, etc. were developedin this region.

The two distinguishing features of this

An Interesting FactIn Kashmir Valley, the meanders in Jhelumriver are caused by the local base levelprovided by the erstwhile larger lake of whichthe present Dal Lake is a small part.

Figure 2.5 : Western Himalayas

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region from the point of view of physiographyare the Shiwalik and Dun formations. Someimportant duns located in this region are theChandigarh-Kalka dun, Nalagarh dun, DehraDun, Harike dun and the Kota dun, etc. DehraDun is the largest of all the duns with anapproximate length of 35-45 km and a widthof 22-25 km. In the Great Himalayan range,the valleys are mostly inhabited by theBhotias. These are nomadic groups whomigrate to Bugyals (the summer glasslandsin the higher reaches) during summer monthsand return to the valleys during winters. Thefamous Valley of flowers is also situated in thisregion. The places of pilgrimage such as theGangotri, Yamunotri, Kedarnath, Badrinathand Hemkund Sahib are also situated in thispart. The region is also known to have fivefamous Prayags (river confluences) asmentiond in Chapter 3 of this book. Can youname some other famous prayags in otherparts of the country?

The Darjiling and Sikkim Himalayas

They are flanked by Nepal Himalayas in thewest and Bhutan Himalayas in the east. It isrelatively small but is a most significant partof the Himalayas. Known for its fast-flowingrivers such as Tista, it is a region of highmountain peaks like Kanchenjunga(Kanchengiri), and deep valleys. The higherreaches of this region are inhabited by Lepchatribes while the southern part, particularly theDarjiling Himalayas, has a mixed populationof Nepalis, Bengalis and tribals from CentralIndia. The British, taking advantage of thephysical conditions such as moderate slope,thick soil cover with high organic content, welldistributed rainfall throughout the year andmild winters, introduced tea plantations in thisregion. As compared to the other sections ofthe Himalayas, these along with the ArunachalHimalayas are conspicuous by the absence ofthe Shiwalik formations. In place of theShiwaliks here, the duar formations areimportant, which have also been used for thedevelopment of tea gardens. Sikkim andDarjiling Himalayas are also known for theirscenic beauty and rich flora and fauna,particularly various types of orchids.

The Arunachal Himalayas

These extend from the east of the BhutanHimalayas up to the Diphu pass in the east.The general direction of the mountain range isfrom southwest to northeast. Some of theimportant mountain peaks of the region are

The ShiwalikThe word shiwalik has its origin in thegeological formation found in and arounda place called Sivawala near Dehra Dunwhich was once a headquarter of theImperial Survey and which subsequentlyestablished its permanent headquartersat Dehra Dun.

Figure 2.6 : Himalayan Mountain Complex : Cross Sectional View from South to North

South North

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Kangtu and Namcha Barwa. These ranges aredissected by fast-flowing rivers from the northto the south, forming deep gorges.Bhramaputra flows through a deep gorge aftercrossing Namcha Barwa. Some of theimportant rivers are the Kameng, theSubansiri, the Dihang, the Dibang and theLohit. These are perennial with the high rate offall, thus, having the highest hydro-electricpower potential in the country. An importantaspect of the Arunachal Himalayas is thenumerous ethnic tribal community inhabitingin these areas. Some of the prominent ones

Figure 2.7 : Eastern Himalayas

from west to east are the Monpa, Daffla, Abor,Mishmi, Nishi and the Nagas. Most of thesecommunities practise Jhumming. It is alsoknown as shifting or slash and burncultivation. This region is rich in biodiversitywhich has been preserved by the indigenouscommunities. Due to rugged topography, theinter-valley transportation linkages arenominal. Hence, most of the interactions arecarried through the duar region along theArunachal-Assam border.

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Figure 2.8 : Mizo Hills

Figure 2.9 : Loktak Lake

The Eastern Hills and Mountains

These are part of the Himalayan mountain

system having their general alignment from thenorth to the south direction. They are knownby different local names. In the north, they areknown as Patkai Bum, Naga hills, the Manipurhills and in the south as Mizo or Lushai hills.These are low hills, inhabited by numeroustribal groups practising Jhum cultivation.Most of these ranges are separated from eachother by numerous small rivers. The Barak isan important river in Manipur and Mizoram.The physiography of Manipur is unique bythe presence of a large lake known as Loktaklake at the centre, surrounded by mountainsfrom all sides. Mizoram which is also knownas the Molassis basin which is made up ofsoft unconsolidated deposits. Most of the rivers

in Nagaland form the tributary of theBrahmaputra. While two rivers of Mizoram andManipur are the tributaries of the Barak river,which in turn is the tributary of Meghna; therivers in the eastern part of Manipur are thetributaries of Chindwin, which in turn is atributary of the Irrawady of Myanmar.

The Northern Plains

The northern plains are formed by thealluvial deposits brought by the rivers theIndus, the Ganga and the Brahmaputra.These plains extend approximately 3,200 kmfrom the east to the west. The average widthof these plains varies between 150-300 km.The maximum depth of alluvium depositsvaries between 1,000-2,000 m. From thenorth to the south, these can be divided intothree major zones: the Bhabar, the Tarai andthe alluvial plains. The alluvial plains can befurther divided into the Khadar and theBhangar.

Bhabar is a narrow belt ranging between8-10 km parallel to the Shiwalik foothills atthe break-up of the slope. As a result of this,the streams and rivers coming from themountains deposit heavy materials of rocksand boulders, and at times, disappear in thiszone. South of the Bhabar is the Tarai belt,with an approximate width of 10-20 km wheremost of the streams and rivers re-emergewithout having any properly demarcatedchannel, thereby, creating marshy andswampy conditions known as the Tarai. Thishas a luxurious growth of natural vegetationand houses a varied wild life.

The south of Tarai is a belt consisting ofold and new alluvial deposits known as theBhangar and Khadar respectively. Theseplains have characteristic features of maturestage of fluvial erosional and depositionallandforms such as sand bars, meanders, ox-bow lakes and braided channels. TheBrahmaputra plains are known for theirriverine islands and sand bars. Most of theseareas are subjected to periodic floods andshifting river courses forming braided streams.

The mouths of these mighty rivers also formsome of the largest deltas of the world, for

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example, the famous Sunderbans delta.Otherwise, this is a featureless plain with ageneral elevation of 50-150 m above the meansea level. The states of Haryana and Delhi forma water divide between the Indus and theGanga river systems. As opposed to this, theBrahmaputra river flows from the northeast tothe southwest direction before it takes analmost 90 southward turn at Dhubri beforeit enters into Bangladesh. These river valleyplains have a fertile alluvial soil cover whichsupports a variety of crops like wheat, rice,sugarcane and jute, and hence, supports alarge population.

The Peninsular Plateau

Rising from the height of 150 m above the riverplains up to an elevation of 600-900 m is theirregular triangle known as the Peninsularplateau. Delhi ridge in the northwest, (extensionof Aravalis), the Rajmahal hills in the east, Girrange in the west and the Cardamom hills in

Figure 2.10 : Northern Plain

Figure 2.11 : A Part of Peninsular Plateau

the south constitute the outer extent of thePeninsular plateau. However, an extension ofthis is also seen in the northeast, in the form ofShillong and Karbi-Anglong plateau. ThePeninsular India is made up of a series ofpatland plateaus such as the Hazaribaghplateau, the Palamu plateau, the Ranchiplateau, the Malwa plateau, the Coimbatoreplateau and the Karnataka plateau, etc. Thisis one of the oldest and the most stablelandmass of India. The general elevation of theplateau is from the west to the east, which isalso proved by the pattern of the flow of rivers.Name some rivers of the Peninsular plateauwhich have their confluence in the Bay ofBengal and the Arabian sea and mention somelandforms which are typical to the east flowingrivers but are absent in the west flowing rivers.Some of the important physiographic featuresof this region are tors, block mountains, riftvalleys, spurs, bare rocky structures, series ofhummocky hills and wall-like quartzite dykesoffering natural sites for water storage. Thewestern and northwestern part of the plateauhas an emphatic presence of black soil.

This Peninsular plateau has undergonerecurrent phases of upliftment andsubmergence accompanied by crustal faultingand fractures. (The Bhima fault needs specialmention, because of its recurrent seismicactivities). These spatial variations havebrought in elements of diversity in the relief ofthe Peninsular plateau. The northwestern partof the plateau has a complex relief of ravinesand gorges. The ravines of Chambal, Bhind andMorena are some of the well-known examples.

On the basis of the prominent relieffeatures, the Peninsular plateau can be dividedinto three broad groups:

(i) The Deccan Plateau(ii) The Central Highlands(iii) The Northeastern Plateau.

The Deccan Plateau

This is bordered by the Western Ghats in thewest, Eastern Ghats in the east and theSatpura, Maikal range and Mahadeo hills inthe north. Western Ghats are locally knownby different names such as Sahyadri in

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Maharashtra, Nilgiri hills in Karnataka andTamil Nadu and Anaimalai hills andCardamom hills in Kerala. Western Ghats arecomparatively higher in elevation and morecontinuous than the Eastern Ghats. Theiraverage elevation is about 1,500 m with theheight increasing from north to south.Anaimudi (2,695 m), the highest peak ofPeninsular plateau is located on the Anaimalaihills of the Western Ghats followed by Dodabetta(2,637 m) on the Nilgiri hills. Most of thePeninsular rivers have their origin in theWestern Ghats. Eastern Ghats comprising thediscontinuous and low hills are highly erodedby the rivers such as the Mahanadi, theGodavari, the Krishna, the Kaveri, etc. Some ofthe important ranges include the Javadi hills,the Palconda range, the Nallamala hills, theMahendragiri hills, etc. The Eastern and theWestern Ghats meet each other at the Nilgiri hills.

The Central Highlands

They are bounded to the west by the Aravalirange. The Satpura range is formed by a seriesof scarped plateaus on the south, generally atan elevation varying between 600-900 m abovethe mean sea level. This forms thenorthernmost boundary of the Deccan plateau.It is a classic example of the relict mountainswhich are highly denuded and formdiscontinuous ranges. The extension of thePeninsular plateau can be seen as far asJaisalmer in the West, where it has beencovered by the longitudinal sand ridges andcrescent-shaped sand dunes called barchans.This region has undergone metamorphicprocesses in its geological history, which canbe corroborated by the presence ofmetamorphic rocks such as marble, slate,gneiss, etc.

The general elevation of the CentralHighlands ranges between 700-1,000 m abovethe mean sea level and it slopes towards thenorth and northeastern directions. Most of thetributaries of the river Yamuna have their originin the Vindhyan and Kaimur ranges. Banas isthe only significant tributary of the riverChambal that originates from the Aravalli inthe west. An eastern extension of the CentralHighland is formed by the Rajmahal hills, to

the south of which lies a large reserve ofmineral resources in the Chotanagpurplateau.

The Northeastern Plateau

In fact it is an extension of the main Peninsularplateau. It is believed that due to the forceexerted by the northeastward movement of theIndian plate at the time of the Himalayanorigin, a huge fault was created between theRajmahal hills and the Meghalaya plateau.Later, this depression got filled up by thedeposition activity of the numerous rivers.Today, the Meghalaya and Karbi Anglongplateau stand detached from the mainPeninsular Block. The Meghalaya plateau isfurther sub-divided into three: (i) The GaroHills; (ii) The Khasi Hills; (iii) The Jaintia Hills,named after the tribal groups inhabiting thisregion. An extension of this is also seen in theKarbi Anglong hills of Assam. Similar to theChotanagpur plateau, the Meghalaya plateauis also rich in mineral resources like coal, ironore, sillimanite, limestone and uranium. Thisarea receives maximum rainfall from the southwest monsoon. As a result, the Meghalayaplateau has a highly eroded surface.Cherrapunji displays a bare rocky surfacedevoid of any permanent vegetation cover.

The Indian Desert

Figure 2.12 : The Indian Desert

Can you identify the type of sand dunesshown in this picture?

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development of ports and harbours. Kandla,Mazagaon, JLN port Navha Sheva, Marmagao,Mangalore, Cochin, etc. are some of theimportant natural ports located along thewest coast. Extending from the Gujarat coastin the north to the Kerala coast in the south,the western coast may be divided intofollowing divisions the Kachchh andKathiawar coast in Gujarat, Konkan coast inMaharashtra, Goan coast and Malabar coastin Karnataka and Kerala respectively. Thewestern coastal plains are narrow in themiddle and get broader towards north andsouth. The rivers flowing through this coastalplain do not form any delta. The Malabarcoast has got certain distinguishing featuresin the form of Kayals (backwaters), whichare used for fishing, inland navigation and alsodue to its special attraction for tourists. Everyyear the famous Nehru Trophy Vallamkali(boat race) is held in Punnamada Kayal inKerala.

As compared to the western coastal plain,the eastern coastal plain is broader and is anexample of an emergent coast. There are well-developed deltas here, formed by the riversflowing eastward in to the Bay of Bengal. Theseinclude the deltas of the Mahanadi, theGodavari, the Krishna and the Kaveri. Becauseof its emergent nature, it has less number ofports and harbours. The continental shelfextends up to 500 km into the sea, whichmakes it difficult for the development of goodports and harbours. Name some ports on theeastern coast.

The Islands

Figure 2.13 : Coastal Plains

To the northwest of the Aravali hills lies theGreat Indian desert. It is a land of undulatingtopography dotted with longitudinal dunesand barchans. This region receives low rainfallbelow 150 mm per year; hence, it has aridclimate with low vegetation cover. It is becauseof these characteristic features that this is alsoknown as Marusthali. It is believed thatduring the Mesozoic era, this region was underthe sea. This can be corroborated by theevidence available at wood fossils park at Aakaland marine deposits around Brahmsar, nearJaisalmer (The approximate age of the wood-fossils is estimated to be 180 million years).Though the underlying rock structure of thedesert is an extension of the Peninsularplateau, yet, due to extreme arid conditions,its surface features have been carved byphysical weathering and wind actions. Someof the well pronounced desert land featurespresent here are mushroom rocks, shiftingdunes and oasis (mostly in its southern part).On the basis of the orientation, the desert canbe divided into two parts: the northern part issloping towards Sindh and the southerntowards the Rann of Kachchh. Most of the riversin this region are ephemeral. The Luni riverflowing in the southern part of the desert is ofsome significance. Low precipitation and highevaporation makes it a water deficit region.There are some streams which disappear afterflowing for some distance and present a typicalcase of inland drainage by joining a lake orplaya. The lakes and the playas have brackishwater which is the main source of obtaining salt.

The Coastal Plains

You have already read that India has a longcoastline . On the basis of the location andactive geomorphological processes, it can bebroadly divided into two: (i) the western coastalplains; (ii) the eastern coastal plains.

The western coastal plains are an exampleof submerged coastal plain. It is believed thatthe city of Dwaraka which was once a part ofthe Indian mainland situated along the westcoast is submerged under water. Because ofthis submergence it is a narrow belt andprovides natural conditions for the

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Figure 2.14 : An Island

There are two major island groups in India one in the Bay of Bengal and the other in theArabian Sea. The Bay of Bengal island groupsconsist of about 572 islands/islets. These aresituated roughly between 6N-14N and92E -94E. The two principal groups of isletsinclude the Ritchies archipelago and theLabrynth island. The entire group of island isdivided into two broad categories theAndaman in the north and the Nicobar in thesouth. They are separated by a water bodywhich is called the Ten degree channel. It isbelieved that these islands are an elevatedportion of submarine mountains. However,some smaller islands are volcanic in origin.Barren island, the only active volcano in Indiais also situated in the Nicobar islands.

Some important mountain peaks inAndaman and Nicobar islands are Saddlepeak (North Andaman 738 m), MountDiavolo (Middle Andaman 515 m), MountKoyob (South Andaman 460 m) andMount Thuiller (Great Nicobar 642 m).

The coastal line has some coral deposits,and beautiful beaches. These islands receiveconvectional rainfall and have an equatorialtype of vegetation.

The islands of the Arabian sea includeLakshadweep and Minicoy. These are scatteredbetween 8N-12N and 71E -74E longitude.These islands are located at a distance of280 km-480 km off the Kerala coast. Theentire island group is built of coral deposits.There are approximately 36 islands of which11 are inhabited. Minicoy is the largest island

with an area of 453 sq. km. The entire groupof islands is broadly divided by the Eleventhdegree channel, north of which is the AminiIsland and to the south of the CanannoreIsland. The Islands of this archipelago havestorm beaches consisting of unconsolidatedpebbles, shingles, cobbles and boulders on theeastern seaboard.

On 26 December 2004, the Andaman and Nicobar islands experienced one of the mostdevasting natural calamity. Can you name the calamity and identify some other areaswhich were adversely affected by the same calamity? What was its major consequence?

1. Choose the right answer from the four alternatives given below.

(i) In which part of Himalayas do we find the Karewa formation?(a) North-eastern Himalayas (c) Eastern Himalayas(b) Himachal-Uttarakhand Himalayas (d) Kashmir Himalayas

(ii) In which of the following states is Loktak lake situated?(a) Kerala (c) Manipur(b) Uttarakhand (d) Rajasthan

(iii) Which one of the water bodies separates the Andaman from the Nicobar?(a) 11 Channel (c) 10 Channel(b) Gulf of Mannar (d) Andaman Sea

(iv) On which of the following hill range is the Dodabeta peak situated?(a) Nilgiri hills (c) Cardamom hills(b) Anaimalai hills (d) Nallamala hills

2. Answer the following questions in about 30 words.(i) If a person is to travel to Lakshadweep, from which coastal plain does he

prefer and why?

EXERCISES

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(ii) Where in India will you find a cold desert? Name some important ranges ofthis region.

(iii) Why is the western coastal plain is devoid of any delta?

3. Answer the following questions in not more than 125 words.(i) Make a comparison of the island groups of the Arabian Sea and the Bay of

Bengal.(ii) What are the important geomorphological features found in the river valley

plains?(iii) If you move from Badrinath to Sunderbans delta along the course of the

river Ganga, what major geomorphological features will you come across?

Project/Activity(i) Make a list of major Himalayan peaks from the west to the east with the help

of an atlas.(ii) Identify the major landforms of your state and analyse the major economic

activity practised by the people in each landform.

You have observed water flowing throughthe rivers, nalas and even channelsduring rainy season which drain theexcess water. Had these channels not beenthere, large-scale flooding would haveoccurred. Wherever channels are ill-defined orchoked, flooding is a common phenomenon.

The flow of water through well-definedchannels is known as drainage and thenetwork of such channels is called adrainage system. The drainage patternof an area is the outcome of the geologicaltime period, nature and structure ofrocks, topography, slope, amount ofwater flowing and the periodicity ofthe flow.

Do you have a river near your village or city?Have you ever been there for boating or bathing?Is it perennial (always with water) or ephemeral(water during rainy season, and dry, otherwise)?Do you know that rivers flow in the samedirection? You have studied about slopes in theother two textbooks of geography (NCERT,

2006) in this class . Can you, then, explain thereason for water flowing from one direction tothe other? Why do the rivers originating from theHimalayas in the northern India and the WesternGhat in the southern India flow towards the eastand discharge their waters in the Bay of Bengal?

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

An area drained by a river and its tributariesis called a drainage basin. The boundary line

DRAINAGE SYSTEM

C H A P T E R

Important Drainage Patterns

(i) The drainage pattern resembling the branches of a tree is known as dendritic the examplesof which are the rivers of northern plain.

(ii) When the rivers originate from a hill and flow in all directions, the drainage pattern is knownas radial. The rivers originating from the Amarkantak range present a good example of it.

(iii) When the primary tributaries of rivers flow parallel to each other and secondary tributariesjoin them at right angles, the pattern is known as trellis.

(iv) When the rivers discharge their waters from all directions in a lake or depression, thepattern is know as centripetal.

Find out some of the patterns in the topo sheet given in Chapter 5 of Practical Work inGeography Part I (NCERT, 2006).

Figure 3.1 : A River in the Mountainous Region


Figure 3.2 : Major Rivers of India

23DRAINAGE SYSTEM

separating one drainage basin from the otheris known as the watershed. The catchments oflarge rivers are called river basins while thoseof small rivulets and rills are often referred toas watersheds. There is, however, a slightdifference between a river basin and awatershed. Watersheds are small in area whilethe basins cover larger areas.

River basins and watersheds are markedby unity. What happens in one part of thebasin or watershed directly affects the otherparts and the unit as a whole. That is why, theyare accepted as the most appropriate micro,meso or macro planning regions.

Indian drainage system may be divided onvarious bases. On the basis of discharge of water(orientations to the sea), it may be grouped into:(i) the Arabian Sea drainage; and (ii) the Bay ofBengal drainage. They are separated from eachother through the Delhi ridge, the Aravalis andthe Sahyadris (water divide is shown by a linein Figure 3.1). Nearly 77 per cent of the drainagearea consisting of the Ganga, the Brahmaputra,the Mahanadi, the Krishna, etc. is orientedtowards the Bay of Bengal while 23 per centcomprising the Indus, the Narmada, the Tapi,the Mahi and the Periyar systems dischargetheir waters in the Arabian Sea.

On the basis of the size of the watershed,the drainage basins of India are grouped intothree categories: (i) Major river basins withmore than 20,000 sq. km of catchment area.It includes 14 drainage basins such as theGanga, the Brahmaputra, the Krishna, theTapi, the Narmada, the Mahi, the Pennar, theSabarmati, the Barak, etc. (Appendix III). (ii)Medium river basins with catchment areabetween 2,000-20,000 sq. km incorporating44 river basins such as the Kalindi, the Periyar,the Meghna, etc. (iii) Minor river basins withcatchment area of less than 2,000 sq. kminclude fairly good number of rivers flowing inthe area of low rainfall.

If you look at the Figure 3.1 you can seethat many rivers have their sources in theHimalayas and discharge their waters either inthe Bay of Bengal or in the Arabian Sea. Identifythese rivers of North India. Large rivers flowingon the Peninsular plateau have their origin inthe Western Ghats and discharge their waters

in the Bay of Bengal. Identify these rivers of theSouth India.

The Narmada and Tapi are two large riverswhich are exceptions. They along with manysmall rivers discharge their waters in theArabian Sea.

Name these rivers of the western coastalregion from the Konkan to the Malabar coast.

On the basis of the mode of origin, natureand characteristics, the Indian drainage mayalso be classified into the Himalayan drainageand the Peninsular drainage. Although it hasthe problem of including the Chambal, theBetwa, the Son, etc. which are much older inage and origin than other rivers that have theirorigin in the Himalayas, it is the most acceptedbasis of classification. Hence, this scheme hasbeen followed in this book.

DRAINAGE SYSTEMS OF INDIA

Indian drainage system consists of a largenumber of small and big rivers. It is the outcomeof the evolutionary process of the three majorphysiographic units and the nature andcharacteristics of precipitation.

THE HIMALAYAN DRAINAGE

The Himalayan drainage system has evolvedthrough a long geological history. It mainlyincludes the Ganga, the Indus and theBrahmaputra river basins. Since these are fedboth by melting of snow and precipitation,rivers of this system are perennial. These riverspass through the giant gorges carved out bythe erosional activity carried on simultaneouslywith the uplift of the Himalayas. Besides deepgorges, these rivers also form V-shaped valleys,rapids and waterfalls in their mountainous

Figure 3.3 : Rapids


course. While entering the plains, they formdepositional features like flat valleys, ox-bowlakes, flood plains, braided channels, anddeltas near the river mouth. In the Himalayanreaches, the course of these rivers is highlytortous, but over the plains they display astrong meandering tendency and shift theircourses frequently. River Kosi, also know asthe sorrow of Bihar, has been notorious forfrequently changing its course. The Kosi bringshuge quantity of sediments from its upperreaches and deposits it in the plains. Thecourse gets blocked, and consequently, theriver changes its course. Why does the Kosiriver bring such huge quantity of sedimentsfrom the upper reaches? Do you think thatthe discharge of the water in the rivers ingeneral and the Kosi in particular, remains thesame, or does it fluctuate? When does the rivercourse receive the maximum quantity of water?What are the positive and negative effects offlooding?

EVOLUTION OF THE HIMALAYAN DRAINAGE

There are difference of opinion about theevolution of the Himalayan rivers. However,geologists believe that a mighty river calledShiwalik or Indo-Brahma traversed the entirelongitudinal extent of the Himalaya from Assamto Punjab and onwards to Sind, and finallydischarged into the Gulf of Sind near lowerPunjab during the Miocene period some 5-24million years ago (See the table of geologicaltimes scale in Chapter 2 of Fundamentals ofPhysical Geography, NCERT, 2006). Theremarkable continuity of the Shiwalik and itslacustrine origin and alluvial depositsconsisting of sands, silt, clay, boulders andconglomerates support this viewpoint.

It is opined that in due course of time IndoBrahma river was dismembered into three maindrainage systems: (i) the Indus and its fivetributaries in the western part; (ii) the Gangaand its Himalayan tributaries in the centralpart; and (iii) the stretch of the Brahmaputrain Assam and its Himalayan tributaries in theeastern part. The dismemberment wasprobably due to the Pleistocene upheaval inthe western Himalayas, including the uplift of

the Potwar Plateau (Delhi Ridge), which actedas the water divide between the Indus andGanga drainage systems. Likewise, the down-thrusting of the Malda gap area between theRajmahal hills and the Meghalaya plateauduring the mid-pleistocene period, diverted theGanga and the Brahmaputra systems to flowtowards the Bay of Bengal.

THE RIVER SYSTEMS OF THEHIMALAYAN DRAINAGE

The Himalayan drainage consists of severalriver systems but the following are the majorriver systems:

The Indus System

It is one of the largest river basins of the world,covering an area of 11,65,000 sq. km (in Indiait is 321, 289 sq. km and a total length of 2,880km (in India 1,114 km). The Indus alsoknown as the Sindhu, is the westernmost ofthe Himalayan rivers in India. It originatesfrom a glacier near Bokhar Chu (3115' Nlatitude and 8140' E longitude) in theTibetan region at an altitude of 4,164 m inthe Kailash Mountain range. In Tibet, it isknown as Singi Khamban; or Lions mouth.After flowing in the northwest directionbetween the Ladakh and Zaskar ranges, itpasses through Ladakh and Baltistan. It cutsacross the Ladakh range, forming aspectacular gorge near Gilgit in Jammu andKashmir. It enters into Pakistan near Chillarin the Dardistan region. Find out the areaknown as Dardistan.

The Indus receives a number of Himalayantributaries such as the Shyok, the Gilgit, theZaskar, the Hunza, the Nubra, the Shigar, theGasting and the Dras. It finally emerges out ofthe hills near Attock where it receives the Kabulriver on its right bank. The other importanttributaries joining the right bank of the Indusare the Khurram, the Tochi, the Gomal, theViboa and the Sangar. They all originate in theSulaiman ranges. The river flows southwardand receives Panjnad a little above Mithankot.The Panjnad is the name given to the five riversof Punjab, namely the Satluj, the Beas, the Ravi,the Chenab and the Jhelum. It finally discharges

25DRAINAGE SYSTEM

into the Arabian Sea, east of Karachi. The Indusflows in India only through the Leh district inJammu and Kashmir.

The Jhelum, an important tributary of theIndus, rises from a spring at Verinag situatedat the foot of the Pir Panjal in the south-easternpart of the valley of Kashmir. It flows throughSrinagar and the Wular lake before enteringPakistan through a deep narrow gorge. It joinsthe Chenab near Jhang in Pakistan.

The Chenab is the largest tributary of theIndus. It is formed by two streams, theChandra and the Bhaga, which join atTandi near Keylong in Himachal Pradesh.Hence, it is also known as Chandrabhaga.The river flows for 1,180 km before enteringinto Pakistan.

The Ravi is another important tributary ofthe Indus. It rises west of the Rohtang pass inthe Kullu hills of Himachal Pradesh and flowsthrough the Chamba valley of the state. Beforeentering Pakistan and joining the Chenab nearSarai Sidhu, it drains the area lying betweenthe southeastern part of the Pir Panjal and theDhauladhar ranges.

The Beas is another important tributary ofthe Indus, originating from the Beas Kund nearthe Rohtang Pass at an elevation of 4,000 mabove the mean sea level. The river flowsthrough the Kullu valley and forms gorges atKati and Largi in the Dhaoladhar range. Itenters the Punjab plains where it meets theSatluj near Harike.

The Satluj originates in the Rakas lake nearMansarovar at an altitude of 4,555 m in Tibetwhere it is known as Langchen Khambab. Itflows almost parallel to the Indus for about 400km before entering India, and comes out of agorge at Rupar. It passes through the ShipkiLa on the Himalayan ranges and enters thePunjab plains. It is an antecedent river. It is avery important tributary as it feeds the canalsystem of the Bhakra Nangal project.

The Ganga System

The Ganga is the most important river of Indiaboth from the point of view of its basin andcultural significance. It rises in the Gangotriglacier near Gaumukh (3,900 m) in the

Uttarkashi district of Uttarakhand. Here, it isknown as the Bhagirathi. It cuts through theCentral and the Lesser Himalayas in narrowgorges. At Devprayag, the Bhagirathi meetsthe Alaknanda; hereafter, it is known as theGanga. The Alaknanda has its source in theSatopanth glacier above Badrinath. TheAlaknanda consists of the Dhauli and theVishnu Ganga which meet at Joshimath orVishnu Prayag. The other tributaries ofAlaknanda such as the Pindar joins it atKarna Prayag while Mandakini or Kali Gangameets it at Rudra Prayag. The Ganga entersthe plains at Haridwar. From here, it flows firstto the south, then to the south-east and eastbefore splitting into two distributaries, namelythe Bhagirathi and the Hugli. The river has alength of 2,525 km. It is shared byUttarakhand (110 km) and Uttar Pradesh(1,450 km), Bihar (445 km) and West Bengal(520 km). The Ganga basin covers about 8.6lakh sq. km area in India alone. The Gangariver system is the largest in India having anumber of perennial and non-perennial riversoriginating in the Himalayas in the north andthe Peninsula in the south, respectively. TheSon is its major right bank tributary. Theimportant left bank tributaries are theRamganga, the Gomati, the Ghaghara, theGandak, the Kosi and the Mahananda. Theriver finally discharges itself into the Bay ofBengal near the Sagar Island.

The Yamuna, the western most and thelongest tributary of the Ganga, has its sourcein the Yamunotri glacier on the western slopesof Banderpunch range (6,316 km). It joins theGanga at Prayag (Allahabad). It is joined bythe Chambal, the Sind, the Betwa and the Kenon its right bank which originates from thePeninsular plateau while the Hindan, the Rind,the Sengar, the Varuna, etc. join it on its leftbank. Much of its water feeds the western andeastern Yamuna and the Agra canals forirrigation purposes.

Name the states which are drained bythe river Yamuna.

The Chambal rises near Mhow in theMalwa plateau of Madhya Pradesh and flowsnorthwards through a gorge up wards of Kota


in Rajasthan, where the Gandhisagar dam hasbeen constructed. From Kota, it traverses downto Bundi, Sawai Madhopur and Dholpur, andfinally joins the Yamuna. The Chambal isfamous for its badland topography called theChambal ravines.

The Gandak comprises two streams,namely Kaligandak and Trishulganga. It risesin the Nepal Himalayas between the Dhaulagiriand Mount Everest and drains the central partof Nepal. It enters the Ganga plain inChamparan district of Bihar and joins theGanga at Sonpur near Patna.

The Ghaghara originates in the glaciers ofMapchachungo. After collecting the waters ofits tributaries Tila, Seti and Beri, it comesout of the mountain, cutting a deep gorge atShishapani. The river Sarda (Kali or KaliGanga) joins it in the plain before it finally meetsthe Ganga at Chhapra.

The Kosi is an antecedent river with itssource to the north of Mount Everest in Tibet,where its main stream Arun rises. Aftercrossing the Central Himalayas in Nepal, it isjoined by the Son Kosi from the West and theTamur Kosi from the east. It forms Sapt Kosiafter uniting with the river Arun.

The Ramganga is comparatively a smallriver rising in the Garhwal hills near Gairsain.It changes its course to the southwest directionafter crossing the Shiwalik and enters into theplains of Uttar Pradesh near Najibabad. Finally,it joins the Ganga near Kannauj.

The Damodar occupies the eastern marginsof the Chotanagpur Plateau where it flowsthrough a rift valley and finally joins the Hugli.The Barakar is its main tributary. Once knownas the sorrow of Bengal, the Damodar hasbeen now tamed by the Damodar Valleycorporation, a multipurpose project.

The Sarda or Saryu river rises in the Milamglacier in the Nepal Himalayas where it isknown as the Goriganga. Along the Indo-Nepalborder, it is called Kali or Chauk, where it joinsthe Ghaghara.

The Mahananda is another importanttributary of the Ganga rising in the Darjilinghills. It joins the Ganga as its last left banktributary in West Bengal.

The Son is a large south bank tributary of

the Ganga, originating in the Amarkantakplateau. After forming a series of waterfalls atthe edge of the plateau, it reaches Arrah, westof Patna, to join the Ganga.

The Brahmaputra System

The Brahmaputra, one of the largest riversof the world, has its origin in theChemayungdung glacier of the Kailash rangenear the Mansarovar lake. From here, ittraverses eastward longitudinally for adistance of nearly 1,200 km in a dry andflat region of southern Tibet, where it isknown as the Tsangpo, which means thepurifier. The Rango Tsangpo is the majorright bank tributary of this river in Tibet. Itemerges as a turbulent and dynamic riverafter carving out a deep gorge in the CentralHimalayas near Namcha Barwa (7,755 m).The river emerges from the foothills underthe name of Siang or Dihang. It enters Indiawest of Sadiya town in Arunachal Pradesh.Flowing southwest, it receives its main leftbank tributaries, viz., Dibang or Sikang andLohit; thereafter, it is known as theBrahmaputra. The Brahmaputra receives numeroustributaries in its 750 km long journey throughthe Assam valley. Its major left banktributaries are the Burhi Dihing and Dhansari(South) whereas the important right banktributaries are the Subansiri, Kameng, Manasand Sankosh. The Subansiri which has itsorigin in Tibet, is an antecedent river. TheBrahmaputra enters into Bangladesh nearDhubri and flows southward. In Bangladesh,the Tista joins it on its right bank from wherethe river is known as the Yamuna. It finallymerges with the river Padma, which falls in theBay of Bengal. The Brahmaputra is well-knownfor floods, channel shifting and bank erosion.This is due to the fact that most of its tributariesare large, and bring large quantity of sedimentsowing to heavy rainfall in its catchment area.

THE PENINSULAR DRAINAGE SYSTEM

The Peninsular drainage system is older thanthe Himalayan one. This is evident from thebroad, largely-graded shallow valleys, and the

27DRAINAGE SYSTEM

maturity of the rivers. The Western Ghatsrunning close to the western coast act as thewater divide between the major Peninsularrivers, discharging their water in the Bay ofBengal and as small rivulets joining theArabian Sea. Most of the major Peninsularrivers except Narmada and Tapi flow from westto east. The Chambal, the Sind, the Betwa, theKen, the Son, originating in the northern partof the Peninsula belong to the Ganga riversystem. The other major river systems of thePeninsular drainage are the Mahanadi theGodavari, the Krishna and the Kaveri.Peninsular rivers are characterised by fixedcourse, absence of meanders and non-perennial flow of water. The Narmada and theTapi which flow through the rift valley are,however, exceptions.

The Evolution of Peninsular DrainageSystem

Three major geological events in the distantpast have shaped the present drainagesystems of Peninsular India: (i) Subsidenceof the western flank of the Peninsula leadingto its submergence below the sea during theearly tertiary period. Generally, it hasdisturbed the symmetrical plan of the riveron either side of the original watershed.(ii) Upheaval of the Himalayas when thenorthern flank of the Peninsular block wassubjected to subsidence and the consequenttrough faulting. The Narmada and The Tapiflow in trough faults and fill the originalcracks with their detritus materials. Hence,there is a lack of alluvial and deltaic depositsin these rivers. (iii) Slight tilting of thePeninsular block from northwest to thesoutheastern direction gave orientation to theentire drainage system towards the Bay ofBengal during the same period.

River Systems of the Peninsular Drainage

There are a large number of river systems inthe Peninsular drainage. A brief account of themajor Peninsular river systems is given below:

The Mahanadi rises near Sihawa in Raipurdistrict of Chhattisgarh and runs throughOrissa to discharge its water into the Bay of

Bengal. It is 851 km long and its catchment areaspreads over 1.42 lakh sq. km. Somenavigation is carried on in the lower course ofthis river. Fifty three per cent of the drainagebasin of this river lies in Madhya Pradesh andChhattisgarh, while 47 per cent lies in Orissa.

The Godavari is the largest Peninsular riversystem. It is also called the Dakshin Ganga. Itrises in the Nasik district of Maharashtra anddischarges its water into the Bay of Bengal. Itstributaries run through the states ofMaharashtra, Madhya Pradesh, Chhattisgarh,Orissa and Andhra Pradesh. It is 1,465 kmlong with a catchment area spreading over 3.13lakh sq. km 49 per cent of this, lies inMaharashtra, 20 per cent in Madhya Pradeshand Chhattisgarh, and the rest in AndhraPradesh. The Penganga, the Indravati, thePranhita, and the Manjra are its principaltributaries. The Godavari is subjected to heavyfloods in its lower reaches to the south ofPolavaram, where it forms a picturesque gorge.It is navigable only in the deltaic stretch. Theriver after Rajamundri splits into severalbranches forming a large delta.

The Krishna is the second largest east-flowing Peninsular river which rises nearMahabaleshwar in Sahyadri. Its total length is1,401 km. The Koyna, the Tungbhadra andthe Bhima are its major tributaries. Of the totalcatchment area of the Krishna, 27 per cent liesin Maharashtra, 44 per cent in Karnataka and29 per cent in Andhra Pradesh.

The Kaveri rises in Brahmagiri hills(1,341m) of Kogadu district in Karnataka. Itslength is 800 km and it drains an area of81,155 sq. km. Since the upper catchmentarea receives rainfall during the southwestmonsoon season (summer) and the lower partduring the northeast monsoon season (winter),the river carries water throughout the year withcomparatively less fluctuation than the otherPeninsular rivers. About 3 per cent of the Kaveribasin falls in Kerala, 41 per cent in Karnatakaand 56 per cent in Tamil Nadu. Its importanttributaries are the Kabini, the Bhavani and theAmravati.

The Narmada originates on the western flankof the Amarkantak plateau at a height of about1,057 m. Flowing in a rift valley between theSatpura in the south and the Vindhyan range


Find out the name of the river on whichthe Gersoppa (Jog) fall is found.

Goa has two important rivers which can bementioned here. One is Mandovi and the otheris Juari. You can locate them on the map.

Kerala has a narrow coastline. The longestriver of Kerala, Bharathapuzha rises nearAnnamalai hills. It is also known as Ponnani.It drains an area of 5,397 sq. km. Compare itscatchment area with that of the Sharavati riverof Karnataka.

The Periyar is the second largest river ofKerala. Its catchment area is 5,243 sq. km.You can see that there is a marginal differencein the catchment area of the Bhartapuzha andthe Periyar rivers.

Another river of Kerala worth mentioning isthe Pamba river which falls in the Vemobanadlake after traversing a course of 177 km.

Teachers may explain the comparativeimportance of west flowing small rivers

River Catchment areasq. km

Sabarmati 21,674Mahi 34,842Dhandhar 2,770Kalinadi 5,179Sharavati 2,029Bharathapuzha 5,397Periyar 5,243

Small Rivers Flowing towards the East

There are a large number of rivers flowingtowards the east along with their tributaries.Can you name some of these rivers? There aresmall rivers which join the Bay of Bengal,though small, these are important in their ownright. The Subarnrekha, the Baitarni, theBrahmani, the Vamsadhara, the Penner, thePalar and the Vaigai are important rivers. Findout these rivers from the atlas.

Teachers may explain the comparativeimportance of east flowing small rivers

River Catchment areasq. km

Subarnarekha 19,296Baitarni 12,789Brahmani 39,033Penner 55,213Palar 17,870

in the north, it forms a picturesque gorge inmarble rocks and Dhuandhar waterfall nearJabalpur. After flowing a distance of about1,312 km, it meets the Arabian sea south ofBharuch, forming a broad 27 km long estuary.Its catchment area is about 98,796 sq. km. TheSardar Sarovar Project has been constructedon this river.

The Tapi is the other important westwardflowing river. It originates from Multai in the Betuldistrict of Madhya Pradesh. It is 724 km longand drains an area of 65,145 sq. km. Nearly 79per cent of its basin lies in Maharashtra, 15 percent in Madhya Pradesh and the remaining6 per cent in Gujarat.

Luni is the largest river system ofRajasthan, west of Aravali. It originates nearPushkar in two branches, i.e. the Saraswatiand the Sabarmati, which join with each otherat Govindgarh. From here, the river comes outof Aravali and is known as Luni. It flowstowards the west till Telwara and then takes asouthwest direction to join the Rann ofKuchchh. The entire river system is ephemeral.

Smaller Rivers Flowing Towards the West

The rivers flowing towards the Arabian seahave short courses. Why do they have shortcourses? Find out the smaller rivers ofGujarat. The Shetruniji is one such riverwhich rises near Dalkahwa in Amreli district.The Bhadra originates near Aniali village inRajkot district. The Dhadhar rises nearGhantar village in Panchmahal district.Sabarmati and Mahi are the two famous riversof Gujarat.

Find out the places of confluence of theserivers. Find out some important westflowing rivers of Maharashtra.

The Vaitarna rises from the Trimbak hillsin Nasik district at an elevation of 670 m. TheKalinadi rises from Belgaum district and fallsin the Karwar Bay. The source of Bedti riverlies in Hubli Dharwar and traverses a courseof 161 km. The Sharavati is another importantriver in Karnataka flowing towards the west.The Sharavati originates in Shimoga districtof Karnataka and drains a catchment area of2,209 sq. km.

29DRAINAGE SYSTEM

RIVER REGIMES

Do you know that the quantity of waterflowing in a river channel is not the samethroughout the year? It varies from seasonto season. In which season do you expect themaximum flow in Ganga and Kaveri? Thepattern of flow of water in a river channel overa year is known as its regime. The north Indianrivers originating from the Himalayas areperennial as they are fed by glaciers throughsnow melt and also receive rainfall water duringrainy season. The rivers of South India do notoriginate from glaciers and their flow patternwitnesses fluctuations. The flow increasesconsiderably during monsoon rains. Thus, theregime of the rivers of South India is controlledby rainfall which also varies from one part ofthe Peninsular plateau to the other.

The discharge is the volume of water flowingin a river measured over time. It is measuredeither in cusecs (cubic feet per second) orcumecs (cubic metres per second).

The Ganga has its minimum flow duringthe January-June period. The maximum flowis attained either in August or in September.After September, there is a steady fall in theflow. The river, thus, has a monsoon regimeduring the rainy season.

There are striking differences in the riverregimes in the eastern and the western partsof the Ganga Basin. The Ganga maintains a

sizeable flow in the early part of summer dueto snow melt before the monsoon rains begin.The mean maximum discharge of the Gangaat Farakka is about 55,000 cusecs while themean minimum is only 1,300 cusecs. Whatfactors are responsible for such a largedifference?

The two Peninsular rivers displayinteresting differences in their regimescompared to the Himalayan rivers. TheNarmada has a very low volume of dischargefrom January to July but it suddenly rises inAugust when the maximum flow is attained.The fall in October is as spectacular as the risein August. The flow of water in the Narmada,as recorded at Garudeshwar, shows that themaximum flow is of the order of 2,300 cusecs,while the minimum flow is only 15 cusecs. TheGodavari has the minimum discharge in May,and the maximum in July-August. AfterAugust, there is a sharp fall in water flowalthough the volume of flow in October andNovember is higher than that in any of themonths from January to May. The meanmaximum discharge of the Godavari atPolavaram is 3,200 cusecs while the meanminimum flow is only 50 cusecs. These figuresgive an idea of the regime of the river.

EXTENT OF USABILITY OF RIVER WATER

The rivers of India carry huge volumes of water

Table 3.1 : Comparison between the Himalayan and the Peninsular River

Sl. No. Aspects Himalayan River Peninsular River

1. Place of origin Peninsular plateau and central highland

2. Nature of flow Seasonal; dependent on monsoonrainfall

3. Type of drainage Super imposed, rejuvenated resultingin trellis, radial and rectangularpatterns

4. Nature of river Smaller, fixed course with well-adjustedvalleys

5. Catchment area Relatively smaller basin

6. Age of the river Old rivers with graded profile, and havealmost reached their base levels

Himalayan mountain covered withglaciers

Perennial; receive water from glacierand rainfall

Antecedent and consequent leading todendritic pattern in plains

Long course, flowing through therugged mountains experiencingheadward erosion and river capturing;In plains meandering and shifting ofcourse

Very large basins

Young and youthful, active anddeepening in the valleys


per year but it is unevenly distributed both intime and space. There are perennial riverscarrying water throughout the year while thenon-perennial rivers have very little water duringthe dry season. During the rainy season, muchof the water is wasted in floods and flows downto the sea. Similarly, when there is a flood in onepart of the country, the other area suffers fromdrought. Why does this happen? Is it theproblem of availability of water resource or thatof its management? Can you suggest somemeasures to mitigate the problems of floods anddroughts simultaneously occuring in differentparts of the country? (See Chapter 7 of the book).

Can these problems be solved or minimisedby trasfering the surplus water from one basinto the water deficit basins? Do we have someschemes of inter-basin linkage?

Teachers may explain the followingexamples

Periyar Diversion Scheme Indira Gandhi Canal Project Kurnool-Cuddapah Canal Beas-Satluj Link Canal Ganga-Kaveri Link Canal

Have you read in the newspapers about thelinking of rivers? Do you think that digging acanal is enough to transfer water from the Gangabasin to the Peninsular river? What is the majorproblem? Consult Chapter 2 of this book and

find out the difficulties posed by theunevenness of the terrain. How can the waterbe lifted from the plain area to the plateau area?Is there sufficient surplus water in the northIndian rivers which can be transferred on aregular basis? Organise a debate on the wholeissue and prepare a write up. How do you rankthe following problems in using river water?

(i) No availability in sufficient quantity(ii) River water pollution(iii) Load of silt in the river water(iv) Uneven seasonal flow of water(v) River water disputes between states(vi) Shrinking of channels due to the extension

of settlements

environmental geography

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