J.Murugesan, Dr.P.H.Anand, M.Sc.,M.Phil.,Ph.D

Home , Gudalur block, Nilgiri mountains, Sengottai, Toda people, Torricelli Range

THE NILGIRIS DISTRICT: MODIFICATIONS OF HILL ENVIRONMENT AND IMPLICATIONS USING GEO-SPATIAL TECHNIQUES

Thesis submitted to the Bharathidasan University for the award of degree of Doctor of Philosophy in Geography

Submitted by

J.Murugesan, Assistant Professor and Part – Time Research Scholar,

Research Supervisor Dr.P.H.Anand, M.Sc.,M.Phil.,Ph.D. Associate Professor and Head

Post Graduate and Research Department of Geography, Government Arts College (Autonomous), Kumbakonam – 612 001, Tamil Nadu, India

September – 2013

DECLARATION

I do hereby declare that the thesis entitled “THE NILGIRIS DISTRICT:

MODIFICATIONS OF HILL ENVIRONMENT AND IMPLICATIONS USING

GEO-SPATIAL TECHNIQUES”, which I am submitting for the award of Degree of Doctor of Philosophy in Geography, to the Bharathidasan University, is the original work carried out by me, in the Post Graduate and Research

Department of Geography, Government Arts College (Autonomous),

Kumbakonam 612 001, Tamil Nadu, India, under the guidance and supervision of Dr. P.H. Anand, Associate Professor and Head, PG and Research

Department of Geography, Government Arts College (Autonomous),

Kumbakonam.

I further declare that this work has not been submitted earlier in this or any other University and does not form the basis for the award of any other degree or diploma.

Kumbakonam J.Murugesan 16th September 2013 Part-time Research Scholar

PG and Research Department of Geography (DST-FIST Recognized) Government Arts College (Autonomous), (Accredited by NAAC // AICTE and Affiliated to Bharathidasan University)) Kumbakonam, 612 001, Tamil Nadu

Dr.P.H.Anand,M.Sc.,M.Phil.,Ph.D. 16-09-2013 Associate Professor and Head,

CERTIFICATE

This is to certify that the thesis entitled “THE NILGIRIS DISTRICT:

MODIFICATIONS OF HILL ENVIRONMENT AND IMPLICATIONS USING

GEO-SPATIAL TECHNIQUES”, submitted by Mr. J. Murugesan, for the award of Doctor of Philosophy in Geography, in the Bharathidasan

University was carried out at the Post Graduate and Research

Department of Geography, Government Arts College (Autonomous),

Kumbakonam, 612001 under my guidance and supervision after fulfilling the basic requirements specified by the University.

(P.H. ANAND) Research Advisor

Acknowledgement

The relationship between the natural environment and human culture is a two- way street. Too often, only one part is asserted: that the form of the natural environment influences (or, in extreme cases, determines) the human culture of a place. Mountains may prove obstacles to communication, but transport technology overcomes the barriers. Climate may limit the growth of certain crops, but irrigation or greenhouse protection can extend a plant’s natural limits. That is not to say that the natural environment does not pose risks: hurricanes, earthquakes, volcanic eruptions, or droughts all pose risks to human settlement.

But as human technology expands, people are able to adapt to the constraints once placed by the natural environment.

Besides technological adaptation, human culture has increasingly modified the natural environment, shaping it to its needs. Clearing forests for agriculture, paving surfaces for urban areas, damming rivers, exploiting minerals, polluting air, streams and oceans, are all examples of the permanent changes to the natural world resulting from human culture.Places are the resolution of the forces of nature and adaptations by human culture. Moreover, as this relationship changes over time, so too do places.

Rather than simply comparing the nature of the physical environment with what people do with it, students should consider human perception. Thus, an environment may be considered hazardous by an objective observer, but explaining human adaptation involves knowing how the environment is perceived

4 by those who use it. People might not be expected to settle on the sides of active volcanoes, as in Central America, or build on the shores of hurricane-prone coasts – that they do requires understanding how they perceive the environment and deal with the risk. The present research is focused on the Modifications of

Hill Environment considering the Nilgiris District as a Spatial Unit.

At the outset I thank our Principal Dr. K. Mohanasundaram,

Government Arts College (Autonomous), Kumbakonam, for extending moral and administrative support for the successful completion of this work. I remember the similar support, which was extended to me by the then

Principal-in-charges of this college, during their tenure. I convey my sincere thanks to Prof. I.C. Kamarajand Prof. V. Kumaraswamy, former Heads of the Department of Geography, for consistent encouragement and critical suggestions as and when I approach them.

I wish to express my deepest gratitude to Dr. P.H. Anand, Associate

Professor and Head, P.G and Research Department of Geography,

Government Arts College (Autonomous), Kumbakonam for his unencumbered, exemplary guidance, indefatigable efforts to steer in the right direction, bountiful scholarly advice, undiminished zeal for extracting fruitful information and for his painstaking efforts and deepest understanding of my needs in this research.

I extend my sincere thanks to Dr. P. Thirumalai and Dr. J.Senthil,

Assistant Professors of Geography, P.G and Research Department of

Geography, Government Arts college (Autonomous), Kumbakonam for giving a good shape to this project. I also convey my deep sense of gratitude to my colleagues, Dr. P. Arul, Dr. B. Gobu, Dr. R. Maniyosai,

Thiru. K.K. Jayakumar, and Thiru. A. Senthilvelan. I appreciate the students of M.Sc., Geography, of this college for the assistance during research work.

I convey my deep sense of gratitude to Dr.K.Sekar, the present

Principal of the Periyar EVR College (Autonomous), Tiruchirapalli, for the moral and administrative support, which enabled me to produce this kind of peace of work.

I acknowledge my sincere thanks and regards to my teachers

Professor A. Padmavathy, Professor. M.K.Mariapillai, Professor. M.

Subramanian, Professor. M.RajasekaranRatnakumar, Professor.

N.Nanjundan, Department of Geography, Periyar EVR College

(Autonomous), Tiruchirapalli and Professor SheelaGnanasironmani, then

Principal of the Government Arts College, Tiruvarambur, Professor.

L.Chellappa, then Principal, MannarSerfoji Government Arts College

(Autonomous), Dr.M.Pannerselvam, then Principal, Manar Durisingam

Government Arts College for Men, Sivaganga, for their inspiration and continued support as a teacher and a co-fellow of the teaching faculty.

I thank my colleague Professor T. Kannadhasan, Head of the

Department of Computer Science, Periyar EVR College (Autonomous),

Tiruchirapalli, for the support services rendered during the preparation of the thesis work.

I personally thank my colleagues in the Department of Geography,

Professor. N.HajeeranBeevi, Dr. S.Balaselvakumar, Professor.

P. Dhanalakshmi and Dr. T. Pavendar for their continued encouragement during preparation of this research work. I also convey my sincere thanks to my transferred colleagues Professor P .Ravikumar and Professor K. Sumesh, presently working at Government

Arts College (Autonomous), Coimbatore for their continued support and guidance.

I register my sincere thanks and gratitude to Shri. P. Alaguraja,

Research Scholar, Department of Geology of the Bharathidasan

University, Tiruchirapalli for his timely help and logistic support during the preparation of this research work.

Finally I thank my parents for their whole-hearted support and my grateful thanks and deepest appreciation to my sister Mrs.

D.Palaniyammal, for her devotion, sacrifice and continual encouragement throughout the long years of my education.

J.Murugesan

Sl. No. Contents Page No.

Chapter One Conceptual Development of the Problem

1.1 The Nilgiris: A Prologue 12 1.2 Literature Review 12 1.3 Natural hazards and geomorphology 15 1.4 Natural disasters and geomorphology 18 1.5 Geomorphology, vulnerability and disasters 22 1.6 Remote Sensing 33 1.7 Medical and Public Health 35 1.8 Present Study 36 1.9 Objectives 37 1.10 Methodology 37 1.11 Organisation of the thesis 38

Chapter Two Nilgiris Environment: Profile of the Study Area

2.1 The Nilgiris - A Profile 39 2.2 Administrative Set-up 40 2.3 Historical Development of Nilgiris 41 2.4 Geomorphology 43 2.5 Climate 44 2.5.1 Rainfall 44 2.5.2 Minor Irrigation 45 2.6 Demography 46 2.6.1 Literacy 46 2.6.2 Occupational Structure 46 2.6.3 Birth Rate and Death Rate 47 2.7 Land Holding Pattern 47 2.8 Eco-regions 48 2.9 Flora and Fauna 49 2.10 Forests 50 2.11 Agriculture 51 2.12 Industries 52 2.13 Trade and Commerce 53 2.13.1 Transport and Communication 53 2.13.2 Transport Network 53 2.14 Hill Area Development Programme in the Nilgiris 55 2.14.1 Approach of Implementation 56 2.14.2 Major Thrust 57 2.14.3 Integrated Watershed Management in the Nilgiris 58 2.14.4 Implementation Strategy 59

2.14.5 Soil Conservation 60 2.15 Beneficiary Contribution 61 2.15.1 Forestry 62 2.15.2 Horticulture 64 2.15.3 Sericulture 65 2.15.4 Animal Husbandry and Dairy Development 66 2.15.5 Energy Conservation 67 2.16 Development of Local Bodies 68 2.17 Human Resources Development 69 2.18 Scheduled Tribes 70 2.19 Tourism 72 2.19.2 Tourism Potential 72

Chapter Three The Slope Instability due to Natural Hazard

3.1 Introduction 73 3.2 Environmental Issues 76 3.3 Remote Sensing for Landslide Location and Causes 79 3.3.1 Detection and Classification of Landslides 79 3.3.2 Monitoring Landslide Movement 80 3.3.3 Landslide Hazard Analysis Mapping 80 3.3.4 Analysis and Prediction of Landslides in GIS 80 3.4 GIS Modeling Approach 82 3.4.1 Terrain Factors 82 3.4.2 Vegetation Factors 82 3.4.3 Disturbance Factors 83 3.4.4 Hydrological Factors 83 3.4.5 Climate Factors 83 3.4.6 Historical Factors 84 3.5 Risk Based Approach 86 3.6 Spatial Distribution and Severity of Landslides 86 3.7 Damage caused by November 2009 Landslides 89 3.8 Large-scale Landslide Hazard Zonation 89 3.9 Need for Landslide Risk Maps 91 3.10 Landslide Vulnerability Mapping 92 3.11 Generation of GIS databases 93 3.11.1 Lithology 93 3.11.2 Geomorphology 94 3.11.3 Geological structures 96 3.11.4 Soils 98 3.11.5 Slope 98 3.11.6 Tectonic Implications 99 3.11.7 Landuse / Land cover Analysis 101 3.12 Landslide Vulnerability Assessment 102 3.13 Discussions and Conclusions 105

Chapter Four Modifications of Hill Environment

4.1 Man Made Hazard 108 4.2 Impacts on Morphology of the Earth’s Surface 109 4.3 Morphologic impacts of large sub aerial landslides 110 4.4 Rate of slope recession due to landslide activity 112 4.5 Loss of Soil Resources 113 4.6 Valley Morphology 114 4.6.1 Effects of Landslide Damien 114 4.6.2 Effects on Streams of Sediment Derived from Landslides 115 4.7 Effects of Landslides on Forests and Grasslands 117 4.7.1 Forest Destruction 117 4.7.2 Destruction of Grasslands 120 4.7.3 Destruction of Marine Plant Life 121 4.7.4 Re-vegetation of Forests and Grasslands 121 4.7.5 Landslide Hazard Mitigation through Cost Effective 125 Technology 4.8 Use of Soil Bio Engineering for Slope Stabilization 126 4.9 Environmental and Societal Issues 128 4.10 Geology of Nilgiri hills 130 4.11 Nilgiri landslides 132 4.12 Landslide Prone Locations 134 4.13 Rainfall and Slope Failures 135 4.14 Modifications in Hill Environment: The Nilgiris 136 4.14.1 Hill Environment 139 4.15 Mountains of South India 141 4.16 Biodiversity 143 4.17 Indigenous People 144 4.18 Development - Colonial and Post Independence 144 4.19 Impact of population growth on hills environment 146 4.19.1 Urban problems 147 4.19.2 Geological instability 147 4.19.3 Implication of Hill environment 147 4.19.4 Tea Industry 150 4.19.5 Tea Estates in Nilgiri 152 4.19.6 Flora 154 4.20 Effect of Deforestation on Landslides in Nilgiris 154 4.21 Results and discussion 159 4.22 Conclusion 160

Chapter Five Results, Discussion and Conclusion

5.1 Land Use Patterns in the Region: Pre-colonial and Colonial 162 Periods 5.2 The Post-colonial Period 170 5.3 Recommendations to reduce the landslide at Nilgiri hills 177 5.3.1 Railways 177 5.3.2 Electricity and telecommunication 177 5.3.3 Buildings 177 5.4 Conclusions 179

References 180

Tables

4.1 Human Modification of hill environment 1990 to 2010 138 4.2 Land use changes from 1970 to 2010 156 4.3 Land Resource Development plan 158 4.4 Land use changes 159

Figures

2.1 Study area - The Nilgiris District 39 2.2 Transport Network 54 2.3 Watershed and Drainage Network 59 3.1 Lithology 94 3.2 Geomorphology 95 3.3 Geological structures 97 3.4 soil 98 3.5 Land use and land cover 102 3.6 Nilgiri District : Landslide vulnerability map 104 4.1 Landslide zone mapping (Kallar to Ooty Highway) 133 4.2 Human, Social, Cultural Modification 138 4.3 IRS P6 Digital Data (27 Febuary 2006) 155 4.4 Classified Image 156 4.5 Land resources Development Plan 158

Chapter One

Conceptual Development of the Problem 1.1 The Nilgiris: A Prologue

The Nilgiri district in Tamilnadu is home to the splendorous Blue Mountains that are a part of a larger mountain chain known as the Western Ghats, sweeping across the states of Tamilnadu and Kerala. The elevation of this mountain range varies between 2,280 to 2,290 meters, with the highest peak being Doddabetta at

2,623 meters. The Nilgiris have tea cultivation at the height of 1,000 to above

2,500 meters. This also produces eucalyptus oil and temperate zone vegetables.

The Nilgiris have a cool and wet climate and the area is a popular summer retreat, with hordes of tourists from across the country flocking the heights in all excitement. The picturesque rolling hills of the Nilgiris remind one of the Downs in Southern England. The main town in the region is Udhagamandalam, which reflect a colonial aura with several buildings built on British style. The other major towns of the region are Coonoor, Kotagiri, Gudalur and Aruvankadu.

1.2 Literature Review

Before the appearance of Homo sapiens on Earth, the purely natural system ruled our planet. Many geophysical events such as earthquakes, volcanic eruptions, land sliding, and/or flooding took place threatening only the prevailing flora and fauna. Millions of years later, the human presence transformed the geophysical events into natural disasters. The transformation of these geophysical events into natural disasters occurred simultaneously with the appearance of the human system, when human beings began to interact with

12 nature, when fire was discovered and tools were made from the offerings of the natural habitats. The evolution of humans left behind the age in which only nature existed. It provided the starting point of the interrelation of the human system with nature.

The human system itself was subjected to significant transformations, where the concept of work and hence of social division of work, production relations and economical political systems appeared. These transformations and their links to the natural system have served as templates of the dynamics of natural hazards and therefore, of natural disasters. Natural hazards are indeed geophysical events, such as earthquakes, landslide, volcanic activity and flooding. They have the characteristic of posing danger to the different social entities of our planet, nevertheless, this danger is not only the result of the natural vulnerability, it is the result of the human systems and their associated vulnerabilities towards them (human vulnerability). When both types of vulnerability have the same coordinates in space and time, natural disasters can occur.

Natural disasters occur worldwide however; their impact is greater in developing countries, where they occur very often. In most cases, the occurrence of natural disasters in these countries is due to two main factors. First, there is a relation with geographical location and geological – geomorphological settings.

Developing or poor countries are located to a great extent in zones largely affected by volcanic activity, seismicity, flooding, etc. The second reason is linked to the historical development of these poor countries, where the economic,

13 social, political and cultural conditions are not good, and consequently act as factors of high vulnerability to natural disasters (economic, social political and cultural vulnerability).

Recently, attention has been paid to the prevention, reduction and mitigation of natural disasters by creating a Scientific and Technical Committee of the International Decade for Natural Disaster Reduction (IDNDR). Efforts within this international framework have been taken worldwide however, since natural disasters continue to devastate developing countries (e.g. Hurricane

Mitch in Central America), a major emphasis on prevention should be addressed by institutions at all levels, namely international, national, regional, local, etc.

Strategies for prevention of natural disasters are universal, yet, their applicability needs to take into account the particular characteristics of the threatened entity, in such a way that a better understanding of the vulnerability of a specified social entity (natural + human) could lead to the development of adequate disaster prevention strategies. Understanding and reducing vulnerability is undoubtedly the task of multi-disciplinary teams. Amongst geoscientists, geomorphologists with a geography background might be best equipped to undertake research related to the prevention of natural disasters given the understanding not only of the natural processes, but also of their interactions with the human system. In this sense, geomorphology has contributed enormously to the understanding and assessment of different natural hazards (such as flooding, landslides, volcanic activity and seismicity), and to a lesser extent, geomorphologists have started moving into the natural disaster field.

This research addresses the significance of the incorporation of geomorphologists into the national/regional/local groups of experts to establish adequate strategies of risk assessment and management. These strategies should be based on an understanding of the necessities derived from the vulnerability, both natural and human of the threatened social entities. Given the existence of differential vulnerabilities, this task is even more relevant in developing countries, located in areas prone to natural hazards and where the character of marginalization and economical, political, social and cultural issues reduce the opportunities to prevent and cope with natural disasters.

1.3 Natural hazards and geomorphology

The term natural hazard implies the occurrence of a natural condition or phenomenon, which threatens or acts hazardously in a defined space and time.

Different conceptualizations of natural hazards have not only evolved in time, they also reflect the approach of the different disciplines involved in their study. In this sense, a natural hazard has been expressed as the elements in the physical environment harmful to man (Burton and Kates, 1964); an interaction of people and nature (White, 1973); the probability of occurrence of a potentially damaging phenomenon (UNDRO, 1982); and as a physical event which makes an impact on human beings and their environment (Alexander, 1993).

Natural hazards are threatening events, capable of producing damage to the physical and social space where they take place not only at the moment of their occurrence, but on a long-term basis due to their associated consequences.

When these consequences have a major impact on society and/or infrastructure,

15 they become natural disasters. The term hazard is often associated with different agents or processes. Some of those include atmospheric, hydrologic, geologic, biologic and technologic. Specifically, natural hazards are considered within a geological and hydro-meteorological conception, where earthquakes, volcanoes, floods, landslides, storms, droughts and tsunamis are the main types. These hazards are strongly related to geomorphology since they are important ingredients of the Earth’s surface dynamics. Hazards are the result of sudden changes in long-term behavior caused by minute changes in the initial conditions

(Scheidegger, 1994). In this sense, geomorphic hazards can be categorized as endogenous (volcanism and neotectonics), exogenous (floods, karst collapse, snow avalanche, channel erosion, sedimentation, mass movement, tsunamis, coastal erosion), and those induced by climate and land-use change

(desertification, permafrost, degradation, soil erosion, sanitization, floods)

(Slaymaker, 1996).

According to Gares et al. (1994) geomorphic hazards can be regarded as the group of threats to human resources resulting from the instability of the

Earth’s surface features. The importance of these features is concentrated on the response of the landforms to the processes, rather than on their original source.

Notwithstanding the lack of the use of the concept geomorphic hazard (Gares et al., 1994; Slay- maker, 1996), geomorphology has an important task to fulfill in terms of natural hazards research. Magnitude and frequency, as well as temporal and spatial scale, are key geomorphic concepts strongly correlated to natural hazards.

Indeed, many contributions by geomorphologists or within the geomorphology field have been directed towards the analysis and understanding of natural hazards. Based on their observations of fluvial processes, Wolman and

Miller (1960) introduced the importance of magnitude and frequency of different events and their significance on the landscape as a result of the total work performed by them. Therefore, the importance of extreme events and high- frequency, low-magnitude events within geomorphic processes is determined by the relation of the work done on the landscape to the particular landforms resulting from it. For a given event, such as a natural hazard, magnitude and frequency exert a very important control on the impact of geomorphic processes since they have an influence on landform change and therefore, on the dynamic equilibrium in geomorphological systems. The concepts of magnitude and frequency are essential for the assessment of natural hazards. For example, the consequences of a flood are measured using return periods; giving an idea of the characteristics the flood may have (magnitude) and how often it is likely to occur

(frequency). Although flooding can be regarded as the typical example to represent the magnitude and frequency duality, it also can be well typified by processes such as mass movement, volcanic activity, neotectonics and erosion.

For instance, the significance of magnitude and frequency on mass movement has been demonstrated by the occurrence of slope failures under different conditions and on a great variety of materials. These events included storms with

50 years of recurrence intervals in Scotland (Jenkins et al., 1988), winter floods and their associated failures in humid temperate catchments (Dowdeswell et al.,

1988), in the Pyrenees (Corominas and Moya, 1996), in Mediterranean environments (Montgomery and Dietrich, 1994; Thornes and Alcantara-Ayala,

1998) and in Colombia (Terlien, 1996) to mention a few.

The dynamism of the Earth’s surface is enclosed within a temporal and spatial scale. The response of the landform to the changes caused by the processes corresponds to the magnitude and frequency of the events, the resistance of the involved materials and the size of the concerned landform

(Summerfield, 1991). Natural hazards take place in a certain place and during a specific time, but their occurrence is not instantaneous. Time is always involved in the development of such phenomena. For example, flooding triggered by hurricanes or tropical storms is developed on a time basis. Atmospheric perturbations lead to the formation of tropical storms, which may evolve into hurricanes, taking from a few hours to some days. Hence, the intensity and duration of rainfall in conjunction with the nature of the fluvial system, developed also on a time basis, would determine the characteristics of the flooding

1.4 Natural disasters and geomorphology

Little has been done to associate geomorphology and natural disasters directly.

Few publications in geomorphology deal specifically with this issue (e.g. Okuda,

1970; Verstappen, 1989; Rosenfeld, 1994). However, innumerable works related to natural hazards have represented the significance of geomorphology to the natural disaster field. Geomorphologists have been concerned with the understanding, analysis and forecast of hazards such as flooding, mass

18 movement, earthquakes and volcanism. Flooding associated with hydro- meteorological phenomenon namely tropical storms, hurricanes, monsoons (Kale et al., 1994), El Nin ̃ o or La Nin ̃ a is regarded as one of the most dangerous natural hazards and principal trigger of disasters. Fluvial geomorphologists have paid considerable, attention to flooding. Approaches to understand this process include the study of past events or palaeo-flood geomorphology and flood hydrology (Enzel et al., 1993; Baker, 1994; Kale et al., 1997). Furthermore, flood simulations (Enzel and Wells, 1997; Bates and De Roo, 2000; Chang et al.,

2000), forecasting (Chowdhury, 2000) and flood maps elaborated by using

Geographical Information Systems (GIS) (Merzi and Aktas, 2000), radar imagery

(Zhou et al., 2000) and remote sensing (Islam and Sado, 2000; Siegel and Gerth,

2000) have been a crucial aspect in the development of hazard and risk assessment and management. Based on different approaches such as mapping

(Canuti et al., 1987; Leroi, 1997; Yin, 1994), the elaboration of inventories (Al-

Homoud and Tubeileh, 1997; Chaco ́n et al., 1996; Guzzetti et al., 1994), analysis of historical archives (Brunsden, 1993; Ibsen and Brunsden, 1996;

Dom ́ınguez-Cuesta et al., 1999), field observations, sampling, laboratory testing, monitoring (Gili et al., 2000), modeling (Brunsden, 1999; Sousa and Voight,

1992), the use of photogrammetry (Chandler and Cooper, 1989; Chandler and

Moore, 1989; Chandler and Brunsden, 1995), GIS (Carrara et al., 1990; Dikau and Jaeger, 1993; Dikau et al., 1992; Proske, 1996) and remote sensing

(Mantovani et al., 1996; Singhroy et al., 1998), geomorphologists have focused on the different aspects of mass movement, including landslide hazard analysis

(Hansen, 1984) and assessment (Hutchinson, 1992; Petley, 1998). In addition, there is a tendency to integrate hydrological modeling into mass movement investigations (Ander- son et al., 1996; Brooks and Collison, 1996; Collison et al.,

1995; Collison and Anderson, 1996; Montgomery and Dietrich, 1994; Van Asch and Buma, 1997). This integrative approach, where hydrological models are coupled to mass failure models, has improved the understanding of mass movement and yield better and more precise predictions of mass failure.

Geomorphology has also contributed in the fields of volcanic (Thouret,

1999) and seismic hazards (Panizza, 1991). Geomorphologic surveys have been used as the base for volcanic hazard zoning (Verstap- pen, 1988, 1992), risk

(Pareschi et al., 2000), volcanic management crisis (Go ́mez-Ferna ́ndez, 2000), and to promote natural disaster reduction (Elsinga and Verstappen, 1988).

Furthermore, the analysis of tectonic activity has been used as a key element for seismic hazard assessment (Galadini and Galli, 2000), and such earthquake assessment has also been applied to environmental planning (Panizza, 1981).

Earthquake hazard zonation of the most vulnerable areas such as Mexico (Ordaz and Reyes, 1999) and Turkey (Erdik et al., 1999) has been performed to have a better panorama of the occurrence of such events and their consequences. In the geomorphological dimensions of natural disasters, Rosenfeld (1994) examined the contributions of different geomorphological projects to inter- disciplinary research, including rainfall-induced landsliding, cyclonic storms, flooding, etc. Certainly, the use of remote sensing, Global Positioning System

(GPS) and GIS, has led to the incorporation of geomorphologists into the

20 mapping, analysis and modeling of such geophysical, hydrological and geomorphological processes within the natural and human hazards approach.

Rosenfeld illustrated the relationship between the natural and human sides of the extent of natural hazards by using a pyramid-form graph, where the faces represent the duration and areal extents of different hazards in terms of casualties and hazard severity according to the different degree of development of the countries, and based on the level response needed to cope with the disasters as a function of economic development.

By analyzing the EM-DAT database, which includes phenomena such as slides, floods, earthquakes, volcanoes, wind storms, extreme temperatures, droughts, wild fires, and epidemics as natural disasters, it can be noticed that with exception of extreme temperatures and epidemics, all the other phenomena are geomorphology related presents the percentage of those disasters related to geomorphology by type and region from 1900 to 1999. Between 1990 and 1999,

2008 disasters were recorded worldwide. Eighty four percent of them were related to geomorphology. The total amount of estimated damage in relation to the global natural disasters registered within the same period of time, and the number of people reported killed and affected give a good indication of the significance of geomorphology for the prevention of natural disasters.

The contribution of geomorphology to the field of natural disasters is mainly through the elaboration of hazard assessments. In general, such assessments comprise stages like mapping, modeling, prediction and management proposals, using field observations, photogrammetry, geographical

21 information systems and remote sensing the zonation and mapping of different hazards is done. Modeling approaches consider not only the understanding of present, but past events, leading to accurate predictions of the consequences a geomorphic hazard may have on a determined landscape under a given conditions. Hazard assessment is a key part within the risk analysis process.

Certainly, geomorphologically a greater progress would be achieved if vulnerability analysis were also taken into account.

1.5 Geomorphology, vulnerability and disasters

By examining the different definitions of natural hazards and natural disasters, it is clear that the conceptualization has changed from a perspective of a merely physical or natural event, towards the integration of the human system. Initially, the uncontrollable character of natural hazards directed efforts towards coping with their impacts and also towards the prediction of these events. Technological advances and the development of prediction models for volcanic activity, hurricanes, tsunamis, flooding, landsliding, etc. were developed seeking a better understanding of the phenomena and to some extent to offer possibilities to cope with the impact of natural hazards, but mainly in ‘developed countries’. Later, in the 1960s, the idea of the devastation by natural disasters as a result of the social and economic characteristics of the regions where natural hazards took place was introduced (White, 1961, 1964; Kates, 1962; Burton et. al., 1968;

Hewitt and Burton, 1971). However, it was not until the 1970s that the role of economic and social conditions as factors of vulnerability to natural disasters was acknowledged.

The interest of understanding not only the natural events per se, but the characteristics of risk in the areas prone to these phenomena, has moved the attention of many social scientists towards the study of risk and vulnerability

(e.g., Albala-Bertrand, 1993; Blaikie et al., 1994; Cannon, 1993; Varley, 1991;

Winchester, 1992). Previous investigations have shown the need for defining and measuring hazard events in a non-scientific (physical) view. This includes the description and analyses of different perceptions of hazard (Burton et al., 1968) based on the concept of differential perception of risk, a very important factor in the development of risk management approaches.

At the present time, not only social scientistsbut, geoscientists are considering the socio-economic character of some regions prone to natural hazards, as one of the main factors of vulnerability to natural disasters. For instance, Cardona (1997) considered the social, economic and institutional aspects within the management geomorphologists have contributed enormously on this matter. Dibben and Chester (1999) proposed a framework to analyze human vulnerability in the case of Furnas volcano in the Azores. They recognized that people’s vulnerability to volcanic hazards implies an interaction of different elements related to the social context and the corresponding physiological and psychological characteristics. In his overview of volcanic geomorphology, Thouret (1999) pointed out that in order to cope with the consequences of natural hazards and their interaction with people living around the volcanoes, geomorphology is an essential part to undertake risk assessment based on geomorphic hazard and risk zonation.

The study of vulnerability related to natural disasters has been the focus of different investigations and hence, of several definitions. Westgate and O’Keefe

(1976) defined vulnerability as the degree to which a community is at risk from the occurrence of extreme physical or natural phenomena, where risk refers to the probability of occurrence and the degree to which socio-economic and socio- political factors affect the community’s capacity to absorb and recover from extreme phenomena. For Varley (1991), vulnerability is a function of the degree of social and self-protection available to potential victims. It is clearly related to the ability of households or communities to cope with and recover from outside events and particularly to shocks and sudden changes (Maskey, 1993). It also concerns the predisposition of a society to experience substantial damage as a result of natural hazards (Clarke and Munasinghe, 1995).

These definitions imply that vulnerability is the result of the socio- economic and political systems of the entity in danger. However, it is the definition of Cannon (1993), which considers different factors affecting or producing the vulnerability of individuals or groups, that is most germane.

According to him, vulnerability ‘‘is a characteristic of individuals and groups of people who inhabit a given natural, social and economic space, within which they are differentiated according to their varying position in society into more or less vulnerable individuals and groups. It is a complex characteristics produced by a combination of factors derived especially (but not entirely) from class, gender, or ethnicity.’’ Cannon divided vulnerability into three parts:

(a) Livelihood resilience: the degree of resilience of the particular livelihood system of an individual or group, and their capacity for resisting the

24 impact of hazard.

(b) Health: including both the robustness of individuals, and the operation of various social measures.

(c) Preparedness: determined by the protection available for a given hazard, something that depends on people acting on their own behalf, and social factors.

These three aspects cover a great proportion of the different kinds of vulnerabilities. Nevertheless, each aspect has different components and the combinations of them can be so numerous that it is necessary to specify the particular types of vulnerability of each threatened entity. The latter will provide an adequate understanding of the total vulnerability to natural disasters so that prevention can be effectively accomplished. This insight strengthens the contribution of Aysan (1993), who recognizes different kinds of vulnerability, as follows:

a. Lack of access to resources (materials/economic vulnerability) b. Disintegration of social patterns (social vulnerability) c. Lack of strong national and local institutional structures (organizational vulnerability) d. Lack of access to information and knowledge (educational vulnerability) e. Lack of public awareness (attitudinal and motivational vulnerability) f. Limited access to political power and representation (political vulnerability) g. Certain beliefs and customs (cultural vulnerability)

Weak buildings of weak individuals (physical vulnerability)there are indeed many other kinds of vulnerability. However, all of them can be inserted within four main types of vulnerability: social, economic, political and cultural. This

25 classification indicates that each social entity has different types of vulnerability, and it is not only the result of the human actions, decisions and choices, it is the result of the interaction of the natural, economic, social, cultural and political contexts where people live.

Vulnerability cannot be treated as a homogeneous and general term; its dynamism is given by each society, and it is both a universal and particular concept. There is certainly a differential character of vulnerability. Vulnerability is given by the coupling between the natural and human systems. In this sense, vulnerability can be divided into natural vulnerability and human vulnerability.

Natural vulnerability depends on the threatening natural hazard (very much related to geographical location), thus, there is volcanic vulnerability, flooding vulnerability, landslide vulnerability, tsunamis vulnerability, hurricane vulnerability and so on. On contrast, human vulnerability is based on the social, economical, political and cultural systems.

Hence, vulnerability can be defined as the propensity of an endangered element due to any kind of natural hazard to suffer different degrees of loss or amount of damage depending on its particular social, economic, cultural, and political weaknesses. Total vulnerability is a function of the individual types of vulnerability present in a given area. Such vulnerability determines the magnitude of the disaster, the level of resilience and the recovery process.

Remote sensing provides a systematic, synoptic view of earth cover at regular time intervals and useful for changes in land cover and to revels aspect of biological diversity directly (Hall et al., 1988; Roughgarden et al., 1991; Turner et

26 al., 2003; Cohen and Goward, 2004; Kumar et al., 2010). Satellite image classification, change analysis (Armenteras et al., 2004) and econometric modeling are extensively used to identify the rates and drivers of deforestation in global hotspots of biodiversity and tropical ecosystems. Recently, a joint collaborative efforts between NASA (National Aeronautics and Space

Administration) and World Conservation Union, IUCN (International Union for

Conservation of Nature) for conserving the biological diversity in terms of driver of changes in forest cover and rate of deforestation in overall 34 global hotspots has been signed (Millington et al., 2003).

However, many airborne and satellite sensors with high spatial and spectral resolution, are currently available, to study land cover changes for over the last decades such as Landsat (approximately 30 m pixel size). Landsat is a series of US satellites launched between 1972 and 1999 (Goward et al., 2001;

USGS, 2003; Arvidson et al., 2006; Trigg et al., 2006) for monitoring the temporal and spatial changes in land cover (Kumar et al., 2010). The satellites main sensors have been the Multispectral Scanner (MSS) carried by Landsat 1-5, the

Thematic Mapper (TM) carried on Landsat 4-5 and Enhanced Thematic Mapper

Plus (ETM+) carried on current Landsat 7 satellite. Landsat data have relied on to perform detailed assessments of changes in tropical forests worldwide (Foody,

2003; Kumar et al., 2010). Combination of the three Landsat sensors, MSS, TM and ETM+, have provided the longest time series of images suitable for monitoring changes in the earth’s vegetation at high spatial resolution. A part of the Landsat satellite images, several sensors have the potential tool to provide

27 useful data to monitor the forest cover loss in different parts of the world. The

Moderate Resolution Imaging Spectroradiometer (MODIS) sensor carried on

NASA’s Aqua and Terra satellite provides global map of percent tree cover, vegetation fires and land cover changes (Savtchenko et al., 2004). However,

MODIS data has capacity for global monitoring and forest loss is limited by its

250 m spatial resolution. Advanced Spaceborne Thermal Emission and

Reflection Radiometer (ASTER) is a high spatial resolution (15 to 90 m) multispectral imager with along-track stereo capabilities (Abrams, 2000). The

Indian Multisensor ResourceSat’s Advanced Wide Field Sensor (AWiFS) uses twin cameras to provide a spatial resolution (56 m) of forest cover loss. The high resolution instrument SPOT (European sensor) can provide images at spatial resolution from 5 to 20 m and a useful complement to Landsat for mapping changes in land cover (King, 2002).

In several studies, the satellite remote sensing at regional scale have been used to monitoring the changes in forest cover on the basis of spatial and temporal remote sensed data, throughout worldwide. Fine resolution, spatially explicit data on landscape fragmentation were required to understand the impact of forest cover changes on biological diversity (Liu et al., 2003; Kumar et al.,

2010a). Satellites data have became a major application in change detection because of the repetitive coverage of the satellites at short time intervals (Mas,

2005). Using remote sensing, spatially explicit time series of environmental data can be quickly obtained and update (Dewan and Yamaguchi, 2009), with GIS

(Geographical Information System) techniques provide information about

28 landscape history, topography, soil, rainfall, temperature and factors on which the distribution of species depends (Noss, 2001).

Anthropogenically modified landscapes are natural complexes that have been significantly altered as a result of direct management impact. The landscapes have been controlled, actively exploited, and utterly changed by human. Agricultural lands, including farmland and pastures, are the most common examples of anthropogenic landscapes; together with forests they make up 80 to 90 per cent of the area in some regions (Holzel 1998). More extreme changes by humans result in "technological landscapes," which have undergone the most severe degree of man- induced transformation, including urban landscapes and mining centers (Holzel 1998). The amount of land use intensity can vary, and so the problem arises of measuring levels of landscapes modification. The rate of disturbance and other types of anthropogenic modifications are studied using a variety of tools, more recently including remote sensing data and Geographic Information Systems (GIS). These tools, when combined with local level knowledge, can document features of landscapes at a regional level, allowing for a more in depth-study. Anthropologists' focus on fieldwork and cultural knowledge allows for an added dimension to the final analysis.

Anthropocentric perspectives of environmental degradation use human consequences of change for measuring criticality (Kasperson 1995). It is where the long-term sustainability of the human- environment relationship is threatened most that regions of criticality exist. Remote sensing data is gathered from the

29 landscapes under study in spatial and temporal scales. GIS can play an important role in analyzing the data, it can efficiently storing and extracting data parameters for ecosystem modeling (Stow 1993). Case material from examples of field research incorporating remote sensing and GIS in analysis of critical environments will be presented. The review will show how GIS is used to create spatial models from regional to global scales that are then used in updating environmental policies.

Dr. Alexander Kirsanov, of St. Petersburg, Russia, designed a long-term field study to collect information to make recommendations for sustainable land management in various regions of Russia (Kirsanov 1998). Spatial monitoring was done using remote sensed data, focusing on the changes in the environmental state under influences of natural and technological factors. Along with the remote sensed data, important information from multi-spectral satellites, including LANDSAT, become the basis of and integrated Geographical

Information Systems. Other GIS data includes vector layers such as geological, mineral resources, soils, vegetation, economic, and medical-biological. Finally, statistical data on the environment, economy, natural resources, and infrastructure was collected. Using ARC- INFO, GIS software, the collected geographic and landscape data is processed and compiled. Later, the anthropogenic changes are processed and overlaid into the GIS.

The results of Kirsanov's work on the Kola Peninsula in Russia identified desertification around industrial centers, growing 1-2 km each year. The study also showed industrial waste from several plants leaking into the nearby lake-

30 also the main source of drinking water for the region. Additionally, dust from construction of large dumps, quarries, and reservoirs were shown to have transferred over a large distance by wind (Kirsanov 1998). High-resolution imagery along with aerial photography aided in the analysis.

The importance of the study is in the data reflecting the possible permanent ecological damage. Kirsanov, after the completion of the GIS project, outlined stages of the study, which could apply to any research using GIS. Stage

I involves the planning and creation of the topographic database utilizing spatial geographic and remote sensed data, along with the input of attribute data. Stage

II is the interpretation of the remote sensed data and completion of the preliminary "initial state" map. Stage III, analysis and preparation of cartographic data in the form of GIS spatial modeling are completed.

Finally, during Stage IV the graphic documents are presented and recommendations for environmental monitoring, planning and projects are compiled and presented to government planning commissions. These stages summarize the important parts of an integrated GIS study, but when designing a model for sustainable land management. Kirsanov (1998) also stresses the need for a long-term data collection and continued analysis.

Rita Gardner, Martin Frost and John Gerrard used GIS applications in

"Managing Mountain Soil Erosion" in the Middle Hills of Nepal (Gardner et al.

1995), of this study it is understood that soil erosion has become an increasingly critical environmental problem both scientifically and politically, especially for developed lands in temperate zones. This case study evaluates the

31 appropriateness for the application of GIS to the problem of soil management by using the distinctive environment of the Middle Hills of Nepal. The GIS allows one to pinpoint where specific land use patterns and slope formations coincide, and where roads and pathways create areas at high risk for erosion. This approach lacked in giving quantitative estimates of soil losses, but rather predicted levels of sensitivity to various erosion processes, and responds to simulated changes in land use (Gardner et al. 1995). Additionally, including remote sensing data would extend the GIS use to broader regions for use as a tool in identifying high-risk locations.Despite the usefulness of GIS software technology, an adequate evaluation of the erosion could not be made because a model to represent the transport and storage of sediments in the mountainous terrain of Nepal does not exist. Julie Cox (1995) established a project to monitor the semi-arid rangelands of Botswana utilizing GIS and remote sensing. In the field (Northern Botswana) the data collection should emphasize monitoring of grassland biomass change over periods of several days using NOAA NDVI, remote sensing technology (Cox

1995). The information could therefore be used in the management of the rangeland. The most urgent issue is the distribution of boreholes for the pumped water supply. These wells must meet the demand of water for both wild animals and the domestic cattle herds. Left uncontrolled, soil and vegetation degradation can occur. Cox's prototype for an integrated GIS and remote sensing project for rangeland management includes the input of satellite images (NOAA,AVHRR,

NDVI), rangeland thematic overlay information, and field data; rangeland thematic overlay information includes: rivers, pans, swamps, boreholes, soils,

32 fences, vegetation, land tenure, cattle and wildlife distribution (Cox 1995). Field research stations collect the field data to be stored in a regional database for livestock numbers and productivity, rangeland condition, vegetation quality and quantity, soil moisture and drinking water availability. By first using the carrying capacity model to establish the carrying capacity number, the GIS data could then aid in creating a policy of environmental monitoring to help maintain the stability. This case study involves an integrated ecology approach to rangeland management, an anthropogenically modified landscape.

1.6 Remote Sensing

Nilgiris district is endowed with rich natural resources, which pose an imperative need to check the uncontrolled urban growth and denudation of forests to maintain the fragile ecosystem. To regulate the urban development in consonance with desirable ecological parameters and as well as to guide and monitor the spatial growth of the towns in the district and regulate the landuse pattern in a conservative outlook to protect the ecology of the district, which is fragile in nature, the need for special techniques for planning and suggesting the corrective measures was felt absolute.

Accordingly, Remote Sensing was found to be appropriate head to plan and monitor the implementation strategy being adopted by the core sectoral activities. During the previous plan periods, funds were allocated from Hill Area

Development Programme towards preparation of aerial photographs,

Orthophotomaps and Thematic Maps for the entire district to have a detailed study on the natural resources apart from studying the present landuse, drainage

33 pattern, slope percentage/contours, settlement pointing etc., inorder to suggest corrective measures and enact policies towards conserving the distinct ecology of the district.

The delineated 75 Macro Watersheds needs to be prioritised in order to ensure the saturation of the developmental works especially in respect of the core departmental activities. Action plans are being prepared by using Remote

Sensing techniques by building up Watershed Resources Information System in

1:5000 scale, which is a unique attempt made only in Nilgiris District of the State, which will produce the expected results in the attempt of saturating the high priority watersheds with all the developmental activities by taking up corrective measures in all the possible ecological view.

Planning for hill areas, especially the “Nilgiris” with fragile ecological system, needs specialised training. Training is an essential component of any programme. All special programmes like HADP certainly require training of officials and the stakeholders involved. As envisaged in the strategy, the programme is being implemented on watershed basis and it is also expected to follow the watershed guidelines as prescribed by the Government of India for special programmes. There is the need to keep constant pace with the fast growing technology and scientific advancements. It is also essential to conduct seminars, lectures on innovative methods of planning, implementation and monitoring and for effective exchange of ideas.

For imparting training, institutions have been identified and the services of these and other reputed institutions and resource persons would be utilised for

34 training. The services of reputed NGOs like MYRADA, RDO TRUST, USSS will be availed for community organisation and training of officials and people involved using PRA techniques.

1.7 Medical and Public Health

The success of any programme hinges on the general health conditions of the people and also on the health infrastructure available. Special emphasis has to be laid in this direction.

Although facilities are made available in the Hospitals in Towns, the people in remote areas are relatively beyond the reach of such facility due to inaccessibility. If proper infrastructural facilities are made available in remote areas, the health cover programmes implemented will be highly effective. Hence there is necessity to provide adequate infrastructural facilities to upkeep the health condition in remote areas, especially the tribals, who are in remote areas inside Reserved Forest, are the worst sufferers.

Therefore, priority has been given to such remote areas for construction of

Primary Health Centres, Health Sub Centres. At present, out of 28 Primary

Health Centres and 194 Health Sub-entres 25 Primary Health Centres and 132

Health Sub-Centres have their own buildings.Several Immunisation Programmes,

Health Cover Programmes, Medical Camps are being conducted out of State

Funds. To supplement the efforts taken up under State Plan, funds are proposed to be provided under Hill Area Development Programme.

1.8 Present Study

The study is to assess the human influence on the modifications as well as the natures’ impact on hill environment. Increasing pressure on land for agriculture and monoculture plantations displaced an alarmingly high proportion of natural forests and grasslands leading to an extensive loss of biodiversity and turning the

Nilgiris into a biodiversity “hotspot”. In many hill areas, intensive human and livestock pressures along with indiscriminate felling of trees for commercial purposes have already led to loss of soil and rapid depletion and destruction of forest cover. In addition to this, water retention capacity and productivity of land have been adversely affected. These factors have impaired the ecology significantly, resulting in difficult economic condition for the hill people.

Traditional agricultural practices, especially shifting cultivation, have also contributed to the destruction of forests and soil erosion. The unrestrained spread of monoculture (tea, coffee, eucalyptus etc) destroyed priceless tropical rain forests, mountain forests and grasslands, which have evolved over millions of years. Increasing pressure on urban amenities led to widespread and persisting water scarcity, congestion, and environmental pollution. This zone is a catchment area and during the northeast and southwest monsoon seasons, this region received heavy rainfall, which is followed by intermittent landslides, rock fall and other debris fall and the like. Due to the impact of heavy rainfall this is a common phenomenon affecting many inhabitants who lives along the slopes/ valley regions. This more often affects the road and rail network due to heavy landslides along the roadways disrupting traffic flow. This necessitates a land

36 slide risk and vulnerability map of this so as to demarcate the most vulnerable zones for further gross-root level study.

1.9 Objectives

a. To survey the landslide occurrence zones along the road traffic between Kallar and Ooty using GPS,

b. To determine the human influence on the modification of hills environment using ISO Toposheet and remote sensing data

c. A comparative study between topographical sheet and IRS-P6 Digital data using ENVI to determine the changes in land use and land cover with particular reference to tea and coffee estates and forest cover.

d. To design a map of risk and vulnerability to study the land slide incidence zones and how this can be protected in future.

1.10 Methodology

To study the human influence on the hill environment, the topographical information of the district, which covers 58 A/6, 58 A/10 and 58 A/11 have been converted into digital map formats. The control points were taken using GPS for georeferencing. The individual top sheets were merged to get the overall district physical and cultural landscape. Different shape files were created using

ArcCatalogue. To find the changing hill environment in Nilgiris district, Indian

Remote Sensing Digital Data for IRS-P6 for the time period 27th February 2010 has been obtained for the Digital Image analysis technique using ENVI 4.0.

The processed image results were converted into raster to vector transformations and different shape files were derived. The results were downloaded to ArcMap. To study the landslides, the Indian topographical maps of the entire Nilgiris district (13 topo sheets) have been converted into digital

37 maps with the incorporation of necessary physical features. In the present problem, the road link connecting from foothill (Kallar) to Ooty has been taken and the occurrence of landslides was tracked using GIS 20 Global Positioning

System (GPS). All the landslide occurrences were transferred on to the digital map and re-registered all the points surveyed using GPS. Using this information, two types of maps like risk and vulnerability have been prepared using the classification from Low to very high zonation pattern has been derived and mapped. The study also involves in risk and vulnerability of the high altitude region of the Nilgiris district a detailed field level survey using GPS was carried out along the road link from Kallar to Ooty to physically survey the landslide zones and study empirically about the impact.

1.11 Organisation of the thesis

The thesis has been orgaised into five major chapters: The first chapter deals with the Concptual development of the problem in the hilly terrain. Second chapter is about a detailed study area description of the Nilgiris. The third chapter explains the slope instability due to Natural Hazards in this region. The fourth chapter exclusively deals with the Modifications in Hill environment for the past years. The final chapter is the summary and conclusion with few recommendations.

Chapter Two

Nilgiris Environment: Profile of the Study Area 2.1 The Nilgiris - A Profile

The Nilgiris, popularly known as the “Blue Mountains” is a tiny district, with an area of 2545 sq.km, forms an integral part of the Western Ghats. It is located between 11° 10’N to 11° 45’ N latitude and 76° 14’E to 77° 2’ E longitude and its climate has aptly been described as “the cold tropical island rising above the warm tropical sea of South India”. It is bounded on the north by Karnataka State,

North West by Kerala State, on the South East by Coimbatore District and the

North East by Erode District of Tamilnadu. The entire district is hilly and is divided into two natural zones namely the Nilgiris plateau and the Wynad tableland. (Figure-2.1)

The Nilgiris Plateau is located at the junction of the Eastern and Western

Ghats and has an average elevation of 2000 Meters above the Mean Sea Level, the highest peak being Doddabetta at 2640 Meters the natural boundary of the plateau along much of its Southern side is the Bhavani River and the Northern frontiers are bounded by Moyar River. These tworivers i.e Bhavani and Moyar are the main river streams that drain the Nilgiri hills, Pykarariver, Sigur River,

Kavithole halla, Kedirayar halla, Kalavahalla, Madukadu halla and other streamlets originating from northern parts of the Nilgiri hills flow northward to join

Moyar River. Kundah River, Katteri River, Coonoor River, Neeralipallam and other streams flow in the South Easterly and Easterly directions to join the

Bhavani River. Many manmade reservoirs for Kundah Hydro Electric Project schemes are located in the Nilgiris plateau, important among them being Pykara,

Sandynallah & Parsons Valley.

2.2 Administrative Set-up

The District Head quarters is Udhagamandalam, which is one of the finest tourist destinations, often referred to as the “Queen of Hill Stations”, For the purpose of administration, the district has been divided into four blocks viz.

Udhagamandalam, Coonoor, Kotagiri and Gudalur with the District Head

Quarters at Udhagamandalam. The district is divided into two revenue divisions viz. Udhagai and Gudalur with 4 taluks and 2 taluks respectively.For local administration, the district has two Municipalities, one Cantonment, four

Panchayat Unions, thirteen Town Panchayats and thirty-five Village Panchayats.

2.3 Historical Development of Nilgiris

The Nilgiri hills have a history going back a good many centuries. It is not known why they were called the Blue Mountains. Several sources cite the reason as the smoky haze enveloping the area, while other sources say it is because of the kurunji flower, which blooms every twelve years giving the slopes a bluish tinge.

It was originally tribal land and was occupied by the Todas around what is now the Ooty area, and by the Kotas around what is now the Kotagiri(Kothar

Keri) area. The Badagas are one of the major non tribal OBC (other backward community) populations in the district who reside in the mountain. Although the

Nilgiri hills are mentioned in the Ramayana of Valmiki (estimated by Western scholars to have been recorded in the second century BCE), they remained all but undiscovered by Europeans until 1602. This was when the first European set foot into the jungles. A Portuguese priest going by the name of Ferreiri resolved to explore the hills and succeeded. He came upon a community of people themselvescalling "Toda." This priest seems to have been the only European to have explored this area. The Europeans in India more or less seem to have ignored the ghats for some two hundred or more years.

It was only around the beginning of the 1800s that the English unsuccessfully considered surveying this area. Around 1810 or so the East India

Company decided to delve into the jungles here. An Englishman Francis

Buchanan made a failed expedition. John Sullivan who was then the Collector of

Coimbatore, just south of the Nilgiris, sent two surveyors to make a comprehensive study of the hills. They went as far as the lower level of Ooty, but

41 failed to see the complete valley. The two men were Keys and Macmohan (their first names seem to be lost to the annals of history) and their mission was significant because they were the first Englishmen to set foot in the Nilgiri hills which soon led to the complete opening up of the area.

The original discovery however, is attributed to J.C. Whish and N.W.

Kindersley, working for the Madras Civil Service, who made a journey in 1819 and who reported back to their superiors that they had discovered "the existence of a tableland possessing a European climate."The first European resident of the hills was John Sullivan, the Collector of Coimbatore, who went up the same year and built himself a home. He also reported to the Madras Government the appropriateness of the climate; Europeans soon started settling down here or using the valley for summer stays. The complete valley became a summer resort.

Later on the practice of moving the government to the hills during summer months also started. By the end of the 19th century, the Nilgiri hills were completely accessible with the laying of roads and the railway line.

In Nilgiris district the topography is rolling and steep. About 60 per cent of the cultivable land falls under the slopes ranging from 16 to 35 per cent.The altitude of the Nilgiris results in a much cooler and wetter climate than the surrounding plains, so the area is popular as a retreat from the summer heat.

During summer the temperature remains to the maximum of 25°C and reaches a minimum of 10°C. During winter the temperature reaches a maximum of 20°C and a minimum of 0°C.The rolling hills of the Downs look very similar to the

Downs in Southern England, and were used for similar activities such as hunting.

The district usually receives rain both during South West Monsoon and

North East Monsoon. The entire Gudalur and Pandalaur, Kundah Taluks and portion of Udhagamandalam Taluk receive rain by the South West Monsoon and some portion of Udhagamandalam Taluk and the entire Coonoor and Kotagiri

Taluks are benefited by the rains of North East Monsoon. There are 16 rainfall registering stations in the district the average annual rainfall of the district is

1,920.80 mm.

The principal town of the area is Ootacamund, or Udhagamandalam, which is the district capital. The town also has several buildings which look very

"British", particularly the Churches. There is even a road junction known as

Charing Cross. The other main towns in the Nilgiris are Coonoor, Kotagiri,

Gudalur and Aruvankadu. The famous tourist spot in Coonoor are Lambsrock and Sims Park. In Sims Park, a "Fruit Show" is conducted during summer. All the varieties of fruit are displayed during that time. This park is situated on the way to

Kotagiri.

2.4 Geomorphology

Nilgiris district is a mountainous district of Tamilnadu with many hill ranges and broad valleys with slopping towards plain. The prominent geomorphic units were identified in the district through interpretation of satellite imagery are Crust line, debris slope, alluvial fills, colluvial fills, gullied valley, vegetation filled valley, fractured filled valley, intermountain valley, bazada zone, escarpments, pediments, deep pediments, shallow pediments, undissected plateau, dissected plateau, erosional plateau, flood plain, pediplain, moderate pediplain, residual

43 hill. The Nilgiris hills rise abruptly from the plains (300 m above MSL) to an average elevation of 1370 m above MSL. Some of the prominent peaks are the

Doddabetta (2634 m), the highest peak in Tamilnadu, Kolari (2625 m), Mukurthi

(2554 m), Kudikadu (2590 m), Devabetta (2552 m), the conical grass covered

Bear hill (2531 m) and Nilgiris peak.

2.5 Climate

Although situated in the tropical zone this region enjoys a sub-tropical to temperate climate by virtue of its altitude. The region experiences an average maximum and minimum temperature of 23.1 and 5.1 respectively. The coldest month is December and the hottest month is April during which a dry wind blows from the North - East. Frosty nights are common during January and February.

Thunderstorms are frequent throughout April and May and the monsoon brings in heavy rainfall. Wind velocity of this region ranges between 13.4 Km/Hour and 4.4

Km/Hour. Humidity also ranges from 70 per cent (December) to 94 per cent

(July).

2.5.1 Rainfall

There has been a significant decrease in the number of rainy days over the years. The first three months of the year are almost without any rain. February shows no rainfalland the driest month recorded in this region. The mean amount of rainfall recorded during 2002-2003 was 1616.8 mm. The normal average rainfall in this region varies from place to place and is somewhere between 1500 mm – 3000 mm. It is observed that storm rainfall values in excess of 12.5 mm occurring for more than five minutes duration can cause run off and soil

44 detachment. Normally 70 percent of such storms occur in the months of October,

July, May and November in that order. Erosion intensity is high in May, October and July. The incidence of drought is also common in the Nilgiris. From soil and water conservation point of view, high incidence of drought during April and

December, excess rainfall noticed during July and October.

2.5.2 Minor Irrigation

Even though the average rainfall in this district is quite high when compared with other districts of the state, the retention of water is very low due to its topographic nature. While studying the drainage pattern of Nilgiris, the studies revealed that most of the sources of the water are drained in the low level reservoirs in the plains and hence the ground water table is very low.With the advent of new eco- friendly horticultural practices, studies have revealed that more and more area has been brought under agriculture/horticulture. As a result of this, the demand for water for both irrigation and drinking has increased.

Keeping in mind of the above problems, the Water Resources

Organisation of Public Works Department has proposed the following works with the financial assistance of Hill Area Development Programme under Minor

Irrigation Sector.

The main objectives of the programme are;

a. Construction of Checkdams nearby the river/stream course to meet the demand of land irrigability / drinking water during pinch seasons b. LiftIrrigationworks c. Desilting/ repairing the feeder channels and main channels of Irrigation and d. Special repairs/ maintenance of the damaged checkdams already constructed under HADP

2.6 Demography

The total population of Nilgiris District is 7.65 lakhsas per 2001 census, forming

1.23 per cent of total population of Tamilnadu. The population of this district has registered a decadal growth rate of 7.69 from 1991 to 2001 census. The distribution of male and female population with rural and urban character is as follows:

Female population is marginally more than fifty percent of the total population of 50.37 per cent corresponding to the State average of 49.66 per cent. Rural population constitutes marginally less than fifty percent of the total population of 40.49 per cent.

Total Scheduled Caste population is 145,860, representing nearly 20 per cent of the population. The Scheduled Tribe population is 23,206 representing nearly 3 per cent of the total district population. The Scheduled Caste population is distributed equally in rural and semi- urban areas, whereas three fourth of the

Scheduled Tribes are living in rural areas. Todas, Kothas, Kurumbas, Paniyas and Irulas are the important tribes in the Nilgiris District.

2.6.1 Literacy

The level of literacy is 89.11 per cent, which is higher than the State's average of

84.81 per cent, probably because of higher urban population in the district. The level of literacy among men is 94 per cent while it is 84.15 per cent among women.

2.6.2 Occupational Structure

Agricultural workers engaged in agricultural sector have increased. In the year

1981 total agriculture workers numbered 19,812 and in 2011 this has increased to 24,992. Similarly non- agriculture workers increased from 218,486 to 415,958.

The percentage of increase is higher in non-agriculture workers.

2.6.3 Birth Rate and Death Rate

Birth rate shows a declining trend in this district between the years 1985 and

1999. The percentage of birth rate during the year 1985 was 20.3 per cent and it has come down to 18.1 per cent in 2001.Death rate has decreased to 5.1 per cent in year 2011 as against 5.48 per cent recorded during the year 1995.

2.7 Land Holding Pattern

The holding size is small in the district, averaging 1.94 hectares. Roughly 78 per cent of the holdings are less than 1 hectare each in size. Total Individual

Holdings in respect of Marginal/Small farmers are given below: Below 0.2

Hectare to 0.4 hectares; Marginal: 0.4 to 0.81hectares; Small:0.81 to 1.21. As per the latest survey conducted, forests accounted for about 56 per cent of the total area as against the State average of 16.6 per cent there is an increase of

13.6 per cent in the composition of forests in the last 10 years. The Nilgiris

District occupies the first position among the 31 Districts in the forest share of the

State. The increase constitutes only the barren and uncultivable land. The gross cropped area is maintained almost at the same level of about 31 per cent.

The soil formation in this district may be classified into four types viz, the black soil, brown soil, the yellow soil and red soil. The black soil is best suited for agriculture, followed by brown soil, the yellow soil. Red soil category is unsuitable for agriculture. The main forest products are sandalwood, bamboo, teak,

47 hardwood, eucalyptus, grandies, bluegum and wattle. The net-cropped area is maintained at nearly one fourth of the total area. With the limited scope for irrigation only about 7.8 per cent of the area is irrigated, the rest being rainfed.

The net area sown under important crops are as follows: Tea: 51,303 hectares;

Coffee: 7,431 hectares and Potato: 3,357 hectares.

In Nilgiris District there has been appreciable change in the cropping pattern after the Hill Area Development Programme was introduced. The main emphasis under Hill Area Development Programme is to increase the perennial crops to reduce soil erosion problem and to increase the vegetative cover for eco-development.

2.8 Eco-regions

Two eco-regions cover portions of the Nilgiris. The South Western Ghats moist deciduous forests lies between 250 and1000 meters elevation. These forests extend south along the Western Ghats range to the southern tip of India. The forest are dominated by a diverse assemblage of trees, many of them are deciduous during the winter and spring dry season. These forests are home to the largest herd of Asian Elephants in India, who range from the Nilgiris across to the Eastern Ghats. The Nilgiris and the South Western Ghats is also one of the most important tiger habitats left in India.

The South Western Ghats montane rain forests ecoregion covers the portion of the range above 1000 meters elevation. These evergreen rain forests are among the most diverse on the planet. Above 1500 meters elevation, the evergreen forests begin to give way to stunted forests, called sholas, which are

48 interspersed with open grassland. These grasslands are the home to the endangered Nilgiri Tahr, which resembles a stocky goat with curved horns. The

Nilgiri Tahrs are found only in the montane grasslands of the South Western

Ghats, and number only about 2000 individuals.

Three national parks protect portions of the Nilgiris. Mudumalai National

Park lies in the northern part of the range where Kerala, Karnataka, and Tamil

Nadu meet, and covers an area of 321 km². Mukurthi National Park lies in the southwest of the range, in Kerala, and covers an area of 78.5 km², which includes intact shola-grassland mosaic, habitat for the Nilgiri tahr. Silent Valley

National Park is just to the south and contiguous with these two parks, and covers an area of 89.52 km². Outside of these parks much of the native forest has been cleared for grazing cattle, or has been encroached upon or replaced by plantations of tea, Eucalyptus, Cinchona and Acacia. The entire range, together with portions of the Western Ghats to the northwest and southwest, was included in the Nilgiri Biosphere Reserve in 1986, India's first biosphere reserve.In

January 2010, the Nilgiri Declaration setout a wide range environmental and sustainable development goals to be reached by 2015.

2.9 Flora and Fauna

The natural vegetation of the valley is typically a dense and rather low forest with much undergrowth and many epiphytes, mosses and ferns. Both tropical and temperate flora occurs, vegetation being mostly tropical in character at lower elevations and temperate at higher elevations. Botanically as well as zoologically and ethnologically, the Nilgiris forms a distinct ecological realm of its own; the

49 typical forests of the Nilgiris are called "Sholas".

The different types of vegetation are:

a.The Shola grassland vegetation of the Nilgiris plateau, The open sandal bearing scrub of the Sigur plateau, The moist deciduous and the dry deciduous teak forest of theNilgiris - Wynad andthe forests of South Eastern outer slopes b. The forests are inhabited by elephants, spotted deer, wild bears, Nilgiri langoors, Wood pecker etc. Tigers and Panthers are also not uncommon to sight. 2.10 Forests

The forests occupy about 22 per cent in Coonoor taluk and 66 per cent in

Udhagamandalam taluk with an average of 56 per centfor the Nilgiris District.

The next major land use is under cropped area ranging from 12.7 per cent in

Ooty taluk to 50.3 per cent in Coonoor Taluk with the average of 22.4 per cent

2 The man-made forests comprising of Eucalyptus globulus (95.5 Km ), E.Grandis

2 2 2 (37.2 Km ), E.Citridora (0.8 Km ), Acacia mearnsil (140.8 Km ), Pinus Patula

2 (11.8 Km ) and other miscellaneous plantations like Gravellia robusta; Tectona of

2 70 Km . According to Champion’s classification of forest types of India (1935), these native “Shola” forests conform to the ‘The Southern Wet (Mountane) temperate forests (Group 10A)’. It has been attracting the attention of ecologists for a long time, because of two distinct plant communities namelygrasslands and evergreen “Shola” forests which exist side by side. Mostof the tree species in the

“Shola” belongs to the family Bricaceae, Lauraceae, Myrtaceae, Rosaceae and

Styraceae represented by general species like Litsea, Phoebe, Rhododendron,

Sideroxylon, Syzygium etc. They have top storey, under storey, undergrowth, dense leaf litter and humus along with good growth of epiphytes, lichens, mosses

50 and lianes. A good number of perennial streams originate from these “Sholas”. A botanical study of the “Shola” reveals that no single species predominates. The

“Shola” adds greatly to the beauty of the country side, and is of immense use in protecting the “perennial source of water supply in the streams” and for the general maintenance of ecological balance.”

2.11 Agriculture

Of the total area of the district only one fourth is cultivated. The non-food crops are cultivated in nearly 65 per cent of the area and food crops in the balance 35 per cent. Tea and Coffee are major non-food crops grown and tea is grown in over 50 per cent of the total area, which is mainly located in Coonoor and

Kotagiri. Next is Coffee, which is grown in nearly 9,000 hectares mainly in

Gudalur and Coonoor areas. Cinchona and lemon grass are the other major non- food crops grown. Among the food crops potato is grown on a large scale, paddy and cereals are grown in Gudalur area, which is the only plain terrain suitable for this type of cultivation. Eucalyptus is also grown substantially. The declining and unseasonal rainfall is affecting standing crops to a large extent. Only 6 per cent is covered under irrigation, the rest is dependent on rainfall. Potato, Carrot, Beans,

Beetroot, Radish, Cauliflower are the major vegetables grown in this district.

As per the recent survey vegetables are grown in over 7,500 hectares of the total cultivated area. Cabbage is grown mainly in Udhagamandalam block.

Vegetables grown in Nilgiris are transported to other centres in the State for sale.

Fruits are also grown in this district on limited scale. The area under fruit crops is

612 hectares as per the recent survey. Orange, Jack fruits, Plums, Peaches,

Bananas, Pears, Applesand Mangoes are the fruits grown in a limited scale in the Nilgiris District.Plums of Udhagamandalam area and Mandarine oranges of the Kookal valley of Udhagamandalam block are the well known varieties grown here. The horticulture department is actively engaged in popularising fruits cultivation.

In Gudalur block, Paddy is grown on a modest scale, the total area covered by paddy is around 3,000 hectares. In Nilgiris District, paddy is grown only in Kotagiri and Gudalur block. Other than this, Ginger, Cardamom, lemon grass, garlic, rubber, cinchona and pepper are also grown in a limited scale in

Gudalur block. Eucalyptus and Geranium are grown substantially in

Udhagamandalam block. There is a number of Eucalyptus andGeranium oil extracting units functioning in this area. The extracted Eucalyptus oil and

Geranium oil is sold thoroughout the country.

2.12 Industries

The main industry of the Nilgiris District is processing of Tea. There are about 80

Tea Factories spread throughout the district. Coffee is also grown but the Coffee produced in the district is cured either at Kallar or Coimbatore. As vast area is under Eucalyptus plantation, the manufacturing of the oil is pursued as a cottage industry. The important industry in the public sector is the Hindustan Photo Films

Manufacturing Company Ltd., located in Indunagar, other being the Cordite

Factory, Food/Specialities Ltd., Protein Products of India Ltd., Needle Industries

(India) Private Ltd., and Ponds(India) Private Ltd.,

2.13 Trade and Commerce

The Chief articles of trade in the district are tea, coffee, vegetables, fruits, timber eucalyptus oil, garlic and pepper. The products grown here are marketed both at

Udhagamandalam and Mettupalayam.

2.13.1 Transport and Communication

The Nilgiris District has a good network of roads running in all directions connecting various centres of the district. Numerous Ghat roads have been opened for traffic. The Coonoor ghat road, which connects Mettupalayam and

Coonoor forms the main artery of transport from plains to Udhagamandalam.

However, it is prone to landslides during 1994 and 1995. The Siriyiur ghat road start from Northern crest of the plateau and passes through Masinagudi and

Theppakadu and joins the Gudalur by a State Highway passing through

Cherambadi. As per the data available the total length of roads is 1625 kms, out of which 1071 kms are surfaced and 554 kms remains unsurfaced.

2.13.2 Transport Network

The Road Network is the most important economic lifeline especially in Hilly

Areas. Lack of partially proper road networks, hampers the overall economic progress. Since the Hill economy cannot exist as a progressive economy without adequate and sufficient road network, as all the manufactured goods/ cultivated materials have to be marketed down in the plains. Hence, the importance of the roads in an overall development strategy especially in a hilly area like Nilgiris deserves adequate importance (Figure – 2.2).

The importance of a good road network in Nilgiris cannot be over emphasise for transportation of agricultural producers from the rural areas to the chilling and processing centres in the plain for marketing. As more and more area have been brought under Horticultural/ Agricultural crops, the green leaves has to be sent to the Tea Factories for processing, which are at considerable distance from the villages. Apart from the above, other essential commodities have also to be transported from the plains to the district. Besides, being a famous tourist destination the overall inflow of tourists in the district is also increasing year after year. Hence, a good network of roads is highly essential for the mainstay of the economy in the district.

Due to heavy rainfall and due to the topographical conditions, the lifeline roads get damaged frequently; eventhough adequate care has been taken to

54 arrest soil erosion on the road margins and to provide side drains. Keeping in view a number of accidents that take place on the hilly roads of the District, a compound has been added to provide proper signages, especially cat-eyes centralism studs on important and accident prone areas.

2.14 Hill Area Development Programme in the Nilgiris

The Hill Area Development Programme has been implemented in the Nilgiris

District since the year 1975 under financial assistance from Union Planning

Commission, Western Ghats Secretariat with a view to supplement the efforts of the State Government inPreservation, protection and enrichment of bio-diversity.

The Nilgiris District is endowedwith rich bio-diversity due to the existence of wide range of climatic and geological conditions. It receives annual rainfall with a spatial variation ranging from 800 mm to 3000 mm. It is also gifted with thick layer (1 to 1.5 Meters) of fertile soil. This particular region of Western Ghat is the most suitable habitat for all kinds of flora and fauna.

The Centrally Sponsored Programme, HADP, was initiated in the Nilgiris

District during Fifth Five Year Plan. Over the years, the basic objectives, and approach have undergone changes in tune with the emerging needs. At present, the main objectives of the programme are ecological preservation, restoration and overall development of district economy. Specific objectives of the programme are mentioned below.

a. To preserve and conserve extremely fragile tropical eco-system i.e. sholas and grasslands of Nilgiris. b. Development of landuse plan for forest area as well as cultivated areas on the basis of slope levels and other climatic, ecological considerations.

c. Conserve soil and water to increase productivity of the land by predominantly using vegetative methods and changing the cropping pattern. d. Promote non-land based economic activities to uplift the poor people and to ensure environment protection. e. Economicup-liftmentisolatedlocations, settlements. f. Manage the human pressures on eco-system through comprehensive human settlement policy and discourage migration. g."Area based Approach" will be given top priority. Integrated plans shall be prepared for all watersheds and high priority watershed shall be chosen for treatment. H. Use of scientific interventions will be encouraged i.e. application of Remote Sensing, etc., i. Promotion of Non-Conventional Energy sources i.e. Solar, Hydro, Bio- gas, etc. The activities of Hill Area Development Programme are focused not only on Forest, Soil conservation and Horticulture as the core sectors but also for the sectors meeting the socio-economic developmental needs of the district.

2.14.1 Approach of Implementation

The strategy for implementation of the Hill Area Development Programme has evolved through the years. The Advent of Micro Watershed planning signaled an overall change in the implementation strategy and approach of HADP schemes.

The Resources Information of the watersheds were gathered and analysed through Remote Sensing Techniques. The major criteria of the vulnerable watersheds were decided on their landuse pattern, drainage and the net silt yield index observed through the Silt Monitoring Stations.

The corrective land use pattern on scientific terms as per the slope percentage was given top priority. Hence, Soil Conservation, Horticulture and

Forestry continue to be core sectors during this plan period also. Apart from the above three core sectors, the sectors to meet the demand of socio-economic developmental needs like Welfare of SC/ST, Human Resources Development,

Development of Local Bodies, Roads, Tourism, INDCO Tea Factories, Khadi and

Village Industries, Sericulture etc., are also provided with adequate funds.

2.14.2 Major Thrust

The major thrust during this plan period is given for area development. Soil erosion was identified as the major problem deteriorating the area development due to improper drainage pattern, unscientific agricultural practices etc., Due to the problem of exposing of the top soil often without adopting the slope percentage in cultivating practices, the top fertile soil is often washed away during floods and rainy season, posing a major threat of landslides and decreased crop yields. The heavy usage of chemical fertilisers and pesticides constantly threaten the ecology besides heavy expenditure incurred for landslide treatments. When natural disasters are unavoidable, the damages to the fragile ecology of Nilgiris caused should be minimized.Therefore; integration of the activities of the core departments along with other line departments to stabilize the ecology is given prime importance apart from involving the local people along with Non-Governmental agencies.

Soil Conservation works such as River Widening Works, Staggered trenching with vegetative measures, Drainage Line Treatment works with vegetative measures, Water Harvesting Structures, Stream draining Works etc., are the important works taken up during the plan period strictly on watershed

57 basis, so as to ensure the saturation of the watersheds with the soil conservation activities. In respect of Landslide treatment works, adequate care is taken to avoid Masonry works as far as practicable and to take up vegetative barrier based works through Gabion structures, which is more economic than masonry structures.

In respect of Forestry works, taking up afforestation works in the denuded hills, development of shola forests, fuel wood plantations in the village porambokes, second storey firewood plantations, road side avenue plantations are given top priority apart from other regular forestry programmes.

Regarding Horticulture, tea cultivation and eco-friendly vegetable cultivation have been taken up. Schemes such as floriculture, rejuvenation of

Mandarin Oranges, Mushroom cultivation, Development of area under arecanut and other economic plantations are also given adequate importance to provide economic stability. Research and development of infrastructure for development of horticultural are also given importance. An introduction is made to bring maximum area under organic farming.

The programme also lays focus on the other need-based sectors like

Roads, Development of Local Bodies, Welfare of SC/ST, INDCO Tea Factories,

Human Resources Development, Animal Husbandry & Dairy Development,

Medical and Public Health, Minor Irrigation, Tourism etc.

2.14.3 Integrated Watershed Management in the Nilgiris

The entire district has been delineated into 75 major watersheds on the basis of the drainage pattern as given below. Out of these, 14 macro watersheds

58 consisting 96 Micro Watersheds have been taken up for implementation as per prioritisation.The Nilgiris District is drained by major rivers like Bhavani, Moyar and Kabbini, which are the tributaries of Cauvery and Pandiar.(Figure -2.3)

2.14.4 Implementation Strategy

The annual plan for the year 2010-2011 has been prepared on Watershed basis.

The activities of core sectors i.e. Horticulture, Soil Conservation and Forestry along with Animal Husbandry, Human Resources Development, Sericulture,

Rural Energy Conservation, Medical and Public Health, Development of

Infrastructure and Evaluation, Training and Monitoring have also been integrated; wherever necessary on watershed basis with a view to saturate the developmental activities in the selected watersheds.

All the watersheds were arranged in descending order of annual crop

59 coverage and slope aspects and the top ten watersheds were identified as High

Priority Watersheds. While selecting the coverage of annual crops in more than

10 per cent slope area has also beentaken into account. In fact these areas have been given priority in selection of watersheds. The data required for this exercise was collected from the report prepared by Indian Space Research Organisation,

Bangalore under IMSD programme.

For better implementation and close monitoring of the development works proposed, the selected macro watersheds have further been delineated into several micro watersheds based on the criteria that each micro watershed area is not to normally exceed 700 Hectares. In some cases, where the forest cover is high, the area of the watersheds has exceeded this limit. The plans for each micro watershed has been prepared by the Non- Governmental Organisations identified by HADP with the co-ordination and guidance of the implementing departments, action plans have prepared for 4 years.

During the year 2010-2011, 96 Micro Watersheds of the 14 Macro

Watersheds were identified for taking up different works, including the 37 Micro

th Watersheds, for which the works in the final year (4 Year) of implementation.

2.14.5 Soil Conservation

Soil erosion continues to be one of the most serious and endemic problems threatening the ecology of Nilgiris District. It needs no reiteration that the loss of fertile topsoil is irreparable, ultimately resulting in poor agricultural yields and simultaneously silting up the downstream reservoirs in the plains. The most important causes of soil erosion are:

a. Improper agricultural practice

b. Inappropriate drainage pattern and

c. Denudation of tree cover

Hill Area Development Programme has been addressing and tackling the above problems through soil conservation methods besides Forestry and

Horticultural activities.

Agricultural Engineering Department is the nodal department in implementation of the soil conservation measures. The strategy adopted to undertake various Soil and Moisture conservation activities are as follows:

a. Treatment of Landslides with Vegetative Barriers

b. Drainage Line Treatment works in three reaches

c. Provision of Water Harvesting Structures

d. Stream Training Works in the stream courses

e. Dry Stone Pitching works

f. Contour/ Staggered Trenching works

g. Formation of bench terraces

h. Collection Wells etc.,

In consonance with the Common Approach for Watershed Development, the following norms towards collection of contribution from the beneficiaries have been fixed as follows towards the implementation of schemes. All the measures have been taken to ensure that the beneficiary contribution is paid up.

2.15 Beneficiary Contribution

The beneficiary contribution is collected as per Common Approach Guidelines for

Watershed Management at 5 per cent for Common benefit works and at 10 per cent for Individual Benefit works (5 per cent for SC/ST farmers).The contributions collected from the beneficiaries shall be deposited in the respective head of account of the watersheds. The created assets would be handed over to

Watershed Development Team/ Association for future maintenance.The Works proposed in the plan is as per the Watershed Association Resolutions and the work will be executed adopting the Common Approach Watershed guidelines.The Works proposed in all watersheds are essentially needed and necessary resolutions for all the respective Micro Watershed Associations prepared in the plan had been obtained.

2.15.1 Forestry

Almost 56 per cent of the total area in the Nilgiris District is covered under Forest.

But aerial Photographs and Field Surveys reveal that the percentage of area covered by natural and permanent tree cover is comparatively less. Extension of the permanent tree cover through afforestation and regulating man’s interference with nature, especially in the shola forests are the prime and major objectives of the Hill Area Development Programme.In order to maintain the ecological balance as well as to rejuvenate the denuded forests, priority has been given to

Forestry under Hill Area Development Programme.

The strategy adopted by the Forest Department has been to undertake various conservation measures with the people’s participation are as follows:

a. Afforestation in the degraded and denuded hills and their maintenance

b. Shola Afforestation and its maintenance

c. Miscellaneous Forests Afforestation programme and their maintenance

d. Soil and Moisture Conservation activities in the forest areas

e. Protection of shola and endangered species

f. Minor Forest Produces Afforestation and its maintenance

g. Eco-Tourism in Forest Areas without disturbing the nature

h. Urban / Avenue Planting along the road margins

i. Demarcation/Conservation of Forest areas

j. Creation of awareness among local people

k. Schemes for the Tribal Welfare living in remote forest areas

l. Forest Research Works

m. Special works by Wild Life Warden and

n. Construction and Maintenance of Water Harvesting Structures.

The Guidelines prescribed in the Common Approach for Watershed

Development would be strictly followed, towards beneficial/community contribution.

For the works such as Construction of Cairns, Erection of Sign Boards,

Engagement of Fire Protection Watchers, Anti Poaching Watchers, Organising nature camps, awareness camps, providing salt lick to wild animals, that is, 100 per cent assistance would be extended under HADP. Regarding the Soil and

Moisture Conservation works such as Construction of Checkdams, Loose

Checks with Gabion Structure and Gully plugging works, the works will be implemented in consultation and clearance from the Central Soil and Water

Research and Training Institute, Udhagamandalam.

2.15.2 Horticulture

The major portion of the Nilgiris District lies in a high plateau of altitudes above

2000 metres (6600 Feet). The remaining portion also lies on a plateau of about

1000 metres altitude (3300 Feet). Due to this high altitude, the prevailing conditions are ideal for raising horticultural crops such as Potato, Hill Vegetables,

Tea, Coffee, Spices and Fruits. Though the annual crops are highly suitable for this terrain, studies reveal that annual crops are harmful to the ecology, since the topsoil is often exposed. Moreover, the unscientific agricultural practice, without adopting the slope percentage adds more harm to the ecology.

Based on the above problems, Hill Area Development Programme has launched its drive through horticulture department to correct the landuse pattern and introduce crops suitable to the areas by taking into account of various factors like elevation, slope, rainfall pattern etc.

Apart from taking efforts on converting the annual crop area into perennial crop area, sincere efforts are also been taken to introduce economically viable crops such as Medicinal Plants cultivation, Mushroom production and

Floriculture.Adequate care has also been taken to substitute modern Chemical farming practices with eco-friendly organic farming.

The following are the major activities taken up during the Eleventh Five

Year Plan period.

a. CoverageofAreaunderSpices/Fruitandothereconomicplantations b. Encourage organic farming to get optimum yields with quality c.CoverageofAreaunderCoffeeplantations d.Extensionofareaundereconomicplantations

e. Introduction of economically viable horticultural products such as Medicinal Plant cultivation, Mushroom Production, Floriculture etc. f. Development of Infrastructure in horticultural farms to meet the demands of planting programme g. Production of cut flowers in poly houses h. Establishment of Vermicompost Units by Self Help Groups i. Production of Mushrooms by Self Help Groups j. Provision of Infrastructure facilities to Horticultural Farms

In respect of the scheme works proposed under Horticulture sector, most of the beneficiaries are individuals for which the scheme works are proposed to be extended under maximum subsidy at 25 per cent , in tune with the subsidy norm followed by Horticulture Department. The contribution from the farmer, in effect, is 75 per cent, which is by far above the norms set under the Guidelines of

Common Approach for Watershed Management. The beneficiaries would be selected and benefits distributed to the individuals through the Watershed

Associations. In respect of the common benefits schemes, the works will be implemented with the approval of Watershed Associations. Preference would be given to SC/ST and Self Help Groups. The common assets created would be handed over to the User Groups/Self Help Groups/Watershed Associations for future maintenance.

2.15.3 Sericulture

Sericulture activities are of relatively recent origin in Nilgiris District. The prevailing climatic conditions in the low-lying plateau of the district are conducive for rearing the bivoltine variety of Silk Worms. As the generation of employment is limited in this hilly district, financial assistance is being extended under HADP

65 to build up the infrastructure for Sericulture activities, impart training to the

Sericulturists (mainly Tribals) and extension service through the office of the

Assistant Director of Sericulture by way of free supply of saplings, free supply of rearing tools, construction of rearing sheds etc., The strategy adopted by

Sericulture under Hill Area Development Programme has been to undertake the following with 50 per cent beneficiary contribution. a. Establishment of Seed Multiplication Farms Encouraging Mulberry Cultivation. Extension of Technical Service to the Sericulturists. b. Free supply of Training / rearing tools, Encouraging Inter cultivation of Mulberry. 2.15.4 Animal Husbandry and Dairy Development

The Animal Husbandry and Dairy Development sector under Hill Area

Development Programme provides necessary back-up support for the Dairy

Development activities in Nilgiris District. The total cattle population in Nilgiris is roughly around 2 lakhs and out of this breedable cattle population is only around

1 lakh. Besides the cattle population, especially of the better breed, has been on the decrease over a period of time. In order to improve the breed of cattles for augmenting the milk production and to arrest the decrease in cattle population financial assistance is extended under Hill Area Development Programme to

Animal Husbandry and Dairy Development sector.

The strategy adopted by the Animal Husbandry and Dairy Development sector to improve and upgrade the cattle population /breed in the district the following measures has to be taken up. For Animal Breeding cover activities, 50 per cent contribution has been fixed and for the schemes covering the health

66 cover such as Vaccination and Deworming works, the contribution has been fixed at 10 per cent as per Common Approach Guidelines for Watershed

Management.

a. Programmes on Animal Health Cover

d. Programmes on Animal Breeding Cover

e. Development of Infrastructure for the above purposes

f. Popularisation of Frozen Semen Techniques

g. Other Regular works for improving the Milk Yield and maintaining the hygienic conditions for milk processing. Controlling contagious diseases.

h. Upgradation of Cattle breeds

2.15.5 Energy Conservation

The availability and usage of different forms of non-renewable energy sources not only affects the economy and development of human settlements but also affects the policies and strategies relating to Planning and Development. As the conventional energy sources such as Electricity, fuelwood etc., are exhaustible and have become expensive and scarce day by day, the need to shift to non- conventional energy sources become necessary. Hence, tapping the other energy resources like “Solar Energy” has been given special emphasis.

Keeping this in mind, Hill Area Development Programme, in a joint effort with Tamilnadu Energy Development Agency (TEDA), has taken up a study on the usage of non- conventional energy sources (i.e) Solar Energy which suggested taking up the following programmes in order to ensure coverage of all the hamlets, which are inaccessible and unelectrified.

a. Provision of Solar Photovoltaic Street Lights/ House Lights for Remote

Habitations not covered by electrification b. Provision of Solar Photovoltaic pumping systems c. Provision of Solar Water Heaters 2.16 Development of Local Bodies

To supplement the scant resources available for Sanitation, Watersupply and other developmental works mainly in urban local bodies i.e. four Municipalities, four Panchayat Unions and 11 Special Panchayats, fund is proposed to be allocated to these bodies. With a view to simplify the accounting, workload and also to ensure integrated development, it is proposed to merge all the three sectors into one sector that is Development of Local Bodies.

Due to the topography, providing infrastructural facilities such as roads, footpaths, water supply, bridges, culverts, drainages, etc., require considerably higher investment compared to the areas in plains. Added to it, the increasing inflow of tourists to the tourist spots located in Municipalities and Town

Panchayat areas also demands provision of sufficient infrastructural facilities.

Hence, while finalising the works the following criteria were strictly adhered.

In respect of Water supply works proposed under this head, the following major points have been given due importance. a. Uncovered habitations and drought prone areas have been given top priority b. Second priority was given to improve the Watersupply facilities in the Town Panchayats, Village Panchayats and Municipal Areas c. Works that require heavy investment which the local bodies cannot afford to take up by themselves d. SC/ST habitation shave also been given due preference Replacement of pipelines or extension of pipelines has been also been given adequate

68 importance ensuring protected water supply In respect of Eco-sanitation works suggested during the year 2010-2011, the following points have been given due importance and works proposed accordingly:

a. Top priority has been given for construction of drainage which will act as diversion drain so as to prevent landslides in residential areas. In other words, by constructing such drainage, water flow from uphill side will be diverted in such a way that it will not enter into the subsoil in the residential areas. b. Construction of drainage along the main approach roads, especially BT roads has also been given preference as improper drainage results in damage to BT roads. c. Only main drainages along the depression have been proposed. These drainages would ensure connectivity of small drains from individual houses. Community Latrines at places which are frequently visited by people have also been proposed. The concerned Executive Officers of Town panchayats have given assurance that these latrines would be maintained on Pay and Use pattern.

As regards village Panchayats and Panchayat Unions, the focus is to supplement their resources where the need exceeds the fund availability and in areas where the guidelines in other schemes do not permit certain activities, example, provision, replacement of pipelines, etc.

2.17 Human Resources Development

Any area development programme should aim at the development and management of resources available in that area. Apart from the natural resources, the other vital resources to be developed and managed are the

Human Resources.Unless and until the human resources are well utilized by

69 giving adequate training and providing with adequate infrastructure, all the other developmental schemes being implemented will not be a success.

Keeping this above in mind, financial assistance is being extended under

Hill Area Development Programme to develop and manage the vital resources that is Human Resources and development of the infrastructure required for the same. Accordingly, under the head Human Resources Development, funds are being provided under Hill Area Development Programme for the following schemes.

a. Provision of sanitation facilities to the schools

b. Provision of watersupply facilities to the schools

c. Construction of Additional Class rooms to the Schools

d. Construction of Computer Rooms to the Schools

e. Awareness programmes among students on ecology and other topics

f. Provision of adequate and sufficient infrastructure to play grounds

g. Conducting Seminars/Workshops on various needy topics

h. Conducting training programmes etc.,

i. Impartingvocationaltrainingtothestudentsetc.,

2.18 Scheduled Tribes

Nilgiris has the highest concentration of tribals in the state. The tribals population constitute 3 per cent of the district population The Nilgiris is distinct in that it is the origin of the 6 primitive tribes namely, Todas, Kothas, Irulas, Kurumbas and

Paniyas. Apart from the above tribes, the scheduled caste population is also

70 quite high.

Due to the secluded and conservative outlook of the tribes, many of the tribal habitations in the district remain remote and they are hesitant to come forward to have close contact with the modern world. Many of these habitations also lack basic amenities. In respect of the Scheduled Castes, the economic constraints make them to deprive of their amenities and social development.

Provision of adequate basic amenities and development / improvement of infrastructure to the scheduled castes and scheduled tribes for their economic and social uplift have been given adequate importance under Hill Area

Development Programme. Eventhough schemes have been formulated under

State Plan for the above, to substantiate the efforts of the State Government, financial assistance are proposed to be extended under Hill Area Development

Programme for the economic and social uplift of the above community. One of the most felt needs of the tribals in Nilgiris district is proper housing. The situation is acute in tribal settlements in town panchayat areas, hence substantial amount has been proposed therein. The repairs to houses and construction of new house and other small works will be taken up by the beneficiaries themselves for execution with the help of Voluntary Organisations/NGOs/ Village Panchayats and Town Panchayats.

The objectives of the schemes implemented are on the following:

a. Basic amenities to SC/ST Colonies b. Construction of Low Cost Houses c. Maintenance of Tribal Hamlet Roads d. Documentation of Tribal Culture etc.,

e. Appropriate infrastructure to the GTR/ADW Schools 2.19 Tourism

The Nilgiris district is one the main tourist centres in the country and its importance in the lives and economy of the people of this hill district cannot be overemphasized. It still has a tremendous potential for development. The strategy adopted under Hill Area Development Programme in the Nilgiris District is to promote tourism without disturbing the fragile ecological balance.

2.19.2 Tourism Potential

Tourism is an important source of revenue for the Nilgiris. The district is home to many beautiful hill stations popular with tourists who flock to them during summer. Some of the popular hill stations are Udhagamandalam (district headquarters), Coonoor, Gudalur and Kothagiri. The Nilgiri Mountain Train or popularly known as the Toy Train is popular amongst tourists as the journey offers spectacular and breathtaking views of the hills and forests. Mudumalai

National Park is popular with wildlife enthusiasts, campers and backpackers. The annual flower show organized by the Government of Tamil Nadu at the Botanical

Garden in Ooty is a grand event every year, known for its grand display of roses.

Nilgiris is renowned for its Eucalyptus oil and Tea. Tourists are also attracted to study the lifestyles of the various tribes living here and to visit the sprawling tea and vegetable plantations along the hill slopes. Other popular tourist destinations in the district are Pykara Waterfalls and Lake, Avalanche and Doddabetta peak.

Chapter Three

The Slope Instability due to Natural Hazard 3.1 Introduction

The Nilgiris district has a long history of disastrous landslide events. Some of the notable landslides recorded from the year 1865 to 2009 were discussed here.

Generally October to December is the season for landslide in the Nilgiris. Most of the landslides are triggered by heavy intense rainfall in the district. In November

1891 heavy rain caused many landslips on the Coonoor ghat, and did great damage to the Kotagiri - Metuppalayam road. Many people were killed in Ooty on account ofhouses collapses landslides and drowning on 5th November 1978.

There was continuous heavy rainfall during 12th to 19thNovember 1979 and there was heavy rain of 102.2 mm at Coonoor and a heavy landslide at Selas in which a house was completely buried in the debris along with 2 women and 3 children.

th There was another 'cloud burst' on 11 November 1993 in the upper reach of

Marappalam of Coonoor Taluk, about 18 huts situated below the road and washing away Coonoor MTP ghat Road for about 11⁄2km. The road traffic was suspended for more than a fortnight. Twelve persons lost their live and 15 persons missing. It is laid that 21 passengers were washed away with two buses.

An important highway, sheared stretched of rail road for about 300 meters.

Numerous landslides were reported in the early hours on 14 November 2006 killing one and injuring three persons and disrupting traffic in NH - 67 and blocking of mountain rail track between Mettupalayam and Coonoor. In 2009 it there were 1150 landslides/landslips were reported in Nilgiris out of these

73 landslides about 98 per cent are minor slips. Increasing demands from different sections of society as well as the need to bring into the main stream the isolated communities in the remote hill areas, have resulted in an increase of all types of construction activities in these areas. In order to maintain the tempo of developmental activities and also mitigate losses due to landslides, there is need for developing appropriate framework for landslide hazard management.

The Building Materials Technology Promotion Council of the Government of India published small scale landslide hazard map of India in 1:6 million scales.

The Landslide Hazard Zonation Map of India presented in the Landslide Atlas

The Geological Survey of India, in collaboration with the State Geology branch, Government of Tamil Nadu launched detailed geological investigations of the landslides in August 1979. During 1978 and 1979 over 300 landslides/landslips, which occurred in the densely populated and developed area of 200 sq.km between Ooty and Coonoor were studied detail by the team of

GSI and State Geology Branch of Government of Tamil Nadu. The main causes of landslides in different places were identified and the role played by excessive deforestation, obstruction to the normal drainage channels and changes in land use were studies by the team. The geologists have also been able to produce for the first time in the country a zonation map of landslide susceptibility on a regional scale. Also the report gives recommendation for restrictions on changes

74 in land use, roads, urban development, housing colonies and reservoirs. The risk quantification study for part of The Nilgiris district were carried out by Geological

Survey of India, in collaboration with ITC Netherlands.

During the last three decades, the population in the Hills has gone up many folds as a sequel to heavy urbanisation and tourist influx, exerting severe strain on geo-environmental parameters. Under the circumstances, reactivation of the slide could be disastrous. Hence, detailed study will help to identify the potential parameters of slide for monitoring, mitigating and forewarning.

In the said study, the map was prepared on the distribution and the morphology of the landslides on the basis of tonal, vegetational and topographic anomalies using the black and white Panchromatic Aerial Photographs. This was followed by field inventories with GPS to field check the landslides interpreted from the aerial photographs. During the field inventories, few more landslides were also located. In addition, the Palaeoscars mapped by Seshagiri et al (1982) were also incorporated and combining all, the vector GIS database (points, lines and polygons; in this case, the landslide locations which is our feature of interest, were the points and the other lines and polygons were only roads and buildings) was generated showing the distribution of all landslides, using Arc View software product to be used for Arc GIS software application,Then vector GIS data bases showing the features (mostly in the form of polygons) were generated on various important geo system parameters viz: Lithology, Lineament Density,

Geomorphology, Slope and Land use /Land cover, which only dominantly assign the landslide vulnerability grades to the mountain regions.These five vector GIS

75 layers were converted into raster layers having 5, 48,884 pixels (square grids of

23.5x23.5m2) each, using Arc View. Over these five raster GIS layers, the

Landslide Distribution map was independently overlaid using Arc View software and on the basis of number of landslides falling in each sub classes of the five geosystem layers, Landslide per unit area (weightage) was worked out by dividing the number of landslides falling in each subclass with total number of pixels of the corresponding subclass. Thus, the weightages were assigned to each sub class or the polygon class of all the five geosystem GIS layers. Such five weighted raster GIS layers were then added using Raster calculator menu of

Arc View software and thus the finalintegrated GIS layer was generated with each pixel having the cumulative weightage of all the five GIS geosystem layers.

Finally on the basis of the dynamic range of the weightages of the final integrated

GIS layer, these 5,48,884 pixels of the study area were classified into 5 zones of

Landslide vulnerability such as very high, high, moderate, low and very low. This was validated by counting the number of Landslides falling in these five zones of

Landslide Vulnerabilities.

3.2 Environmental Issues

Landslides have wide-ranging impact on the people of the affected area in terms of the devastation caused to material and human resources. The magnitude of destruction depends on the location of the landslide area. In the context of India it is a painful truth that most, if not all, the areas susceptible to landslide hazards are inhabited by the economically weaker section of the population who have neither the resources nor the expertise to organize rehabilitation measures out of

76 their own. One of the most difficult problems concerning landslide hazards in place like Nilgiris is dealing with existing urban areas where buildings are constructed on or close to a landslide. The ideal approach in this situation is to avoid further development in high-risk landslide prone areas, limit existing-use rights to rebuild, and limit the use of buildings. The most realistic approach is to avoid further development and use of buildings (building type) is consistent with the level of risk posed and the district plan maps clearly show landslide hazard zones.

However some of the main issues related to environment and society are discussed here. The lack of awareness is one of the main issues among the public as well as the planners. The Department of Science and Technology,

Government of India has suggested having raise awareness among policy makers & planners at state/district and user institution level through conducting training programmes/workshops. Also awareness should be created among community leaders and general public affected by landslide hazards about the cost-effectiveness and benefits of taking landslide hazard mitigation measures.

The other main issue is communicating the landslide hazard. There is no clear early warning system is readily available for landslides like Likelihood of the occurrence of an event, the size and in a location that would cause casualties, damage, or disruption to an existing standard of safety. There is no warning signs are clear indications of vulnerable slopes are no where designated in the hazard prone areas. The first responder’s (local people) can take initiation in this regard with the help of Government officials to create awareness among the

77 vulnerable community. The elements at risk should be identified and a risk quantification study can be implemented for these vulnerable sites, so that this information’s can become vital in case of emergency response. As suggested by

National Disaster Management Authority (NDMA), Government of India in the

National Disaster Management Guidelines for landslides, from the funds available with the District Planning and Development Council in landslide prone areas, a part will be allocated for the implementation of landslide management schemes in the Nilgiri district.

Landslides are a sudden, short-lived geomorphic event that involves a rapidtoslow descent of soil or rock in sloping terrains. They occur worldwide, often in conjunction with natural hazards like earthquakes, floods, or volcanic eruptions. Landslides can also be caused by excessive precipitation or human activities, such as deforestation or development that disturb natural slope stability.

Landslides in the United States alone cause $1 to $2 billion in property damage and over 25 fatalities per year. Posing threats to settlements and structures, landslides often result in catastrophic damage to highways, railways, waterways, and pipelines. According to the U.S. Transportation Research Board, annual costs for the repair of minor slope failures by state departments of transportation exceed $100 million.

To determine where protective measures are necessary, scientists and technicians produce landslide inventory and risk assessment maps for many areas around the world Landslides unfortunately, do not display a clear

78 relationship between magnitude and frequency as do earthquakes and floods.

Landslide studies are challenging to scientists, due to the difficulty to represent landslide hazards in quantitative terms over large areas.

3.3 Remote Sensing for Landslide Location and Causes

Remote sensing techniques greatly aid in the investigations of landslides, on both a local and regional scale. Remote sensing offers an additional tool from which we can extract information about landslide causes and occurrences. Most importantly, they greatly aid in the prediction of future landslide occurrences, which is very important to those who reside in areas surrounded by unstable slopes. Satellite Imaging Corporation (SIC) offers satellite imagery from Stereo

IKONOS, SPOT-5, ASTER, Pleiades-1A/1B, LiDAR, and SAR, depending on your project needs, location, and terrain condition.

Landslide studies can be organized into three phases:

a. Detection and classification

b. Monitoring activity of existing landslides

c. Analysis and prediction of slope failures in spatial distribution and temporal distribution

Remote sensing techniques can be and are often used in all three stages of a landslide investigation and monitoring.

3.3.1 Detection and Classification of Landslides

To detect and classify the landslide, you need to be able to view the size and contrast of the landslide features and the morphological expression of the topography within and around the landslide. Interests in determining parameters

79 are the type of movement that has occurred, the degree of present activity of the landslide, and the depth to which movement has occurred. The most common remote sensing tools used for the detection and classification of landslides are satellite imagery and aerial photography.

3.3.2 Monitoring Landslide Movement

Monitoring landslide movement involves the comparison of landslide conditions over time, including the aerial extent of the landslide, the speed of movement, and the change in the surface topography. Satellite imagery and aerial photography are commonly used in this stage of a landslide investigation.

3.3.3 Landslide Hazard Analysis Mapping

Landslide hazard maps typically aim to predict where failures are likely to occur without any clear indication of when they are likely to occur. They are useful for providing landslide hazard information needed for planning and protection purposes.

3.3.4 Analysis and Prediction of Landslides in GIS

A large database is necessary for the analysis and prediction of slope failures. It needs to be able to store, manipulate, and apply the data collected in first two stages, which are recognition and monitoring. A Geographical Information

System is ideal for this stage in a landslide investigation because it is capable of handling large amounts of past, present and future data and integrating this data with predictions. It is capable of data storage, visualization and manipulation of the environment within the application it can also has regional databases perform both local and regional modeling. Most landslide potential models determine

80 terrain instability by combining slope maps with soils data, then selecting from the resultant soil/slope categories the combinations that are rated for severe erosion potential. Vegetative cover considerations extend the model. When available, maps showing historic landslide sites are added for both establishing and testing landslide potential.

Available and Desired Base Data (Listed in Order of Importance)

a. Terrain Data (DEM derived from elevation contours) Landform data to include derived factors of slope and flow accumulation are required for the landslide potential model; aspect and roughness

b. Additional Environmental Data Edaphic data to include soil type, depth to bedrock, and parent material

c. Orthorectified Mosaic Stereo IKONOS Satellite Image or Aerial Photo

Vegetation data to include derived factors of vegetation type and vegetation density Disturbance data to include the locations of recent terrain and cover modifications

d. Other Information Hydrography data to include streams would greatly strengthen the model Climate data to include rainfall, snowfall, and mean temperature

e. CultureHistorical landslide data to include location and frequency of occurrence would greatly strengthen the model as a means for evaluating model performance.

3.4 GIS Modeling Approach

SHALSTAB model which is used, frequently by most GIS specialists and

Scientists combines slope steepness with flow accumulation to classify risk of slope failure. Standard soil parameters are employed to redefine the model as the mechanical properties of soils can profoundly affect slope stability. However, much available soil data is at very small scale (1:240,000) and only useful for regional analysis and if available at larger scale requires expert interpretation for regional variants. An extended SHALSTAB model is proposed depending on availability of base and derived data. Promising extensions include by data availability:

3.4.1 Terrain Factors

a. Aspect is computed from DEM data (derived as first derivative of elevation at minimal effort) and depending on regional climate can marginally effect slow stability with south facing slopes susceptible,

b. Terrain Roughness is easily computed from DEM data (derived as coefficient of variations of surrounding slope conditions at minimal effort) and depending on regional climate can marginally effect slope stability with

"smoother" sloped terrain more susceptible.

3.4.2 Vegetation Factors

a. Vegetation Type by broad categories of forest, non-forest, bare, water land cover can be derived (multispectralclassification at moderate effort) with bare vegetation being more susceptible,

b. Vegetation Density by broad categories of dense, moderate and sparse

82 land cover can be derived (multispectral classification at minimal additional effort beyond vegetation type classification) with sparse being more susceptible

3.4.3 Disturbance Factors

Terrain/Cover Modifications such as forest harvesting, wildfire, mining and other activities can be derived (multispectral classification at minimal additional effort beyond vegetation type classification) with disturbed areas more susceptible

3.4.4 Hydrological Factors

Headwaters of streams (if available as mapped data or could be derived through manual image interpretation at considerable effort) in steep terrain can be derived with uphill locations surrounding headwaters more susceptible

3.4.5 Climate Factors

a. Precipitation by broad categories of wet, moderate and dry conditions (if available as mapped data or could be derived from weather station records at moderate effort) with wet conditions more susceptible,

b. Temperature by broad categories of hot temperature and cool conditions (if available as mapped data or could be derived from weather station records at moderate effort) with temperate conditions more susceptible.

c. The District usually receives rain both during South West Monsoon and

North East Monsoon. The entire Gudalur Pandalaur and Kundah taluks and portion of Udhagamandalam Taluk receive rain by the South West Monsoon and some portion of Udhagamandalam Taluk and the entire Coonoor and Kotagiri taluks are benefited by the rain of North East Monsoon. There are 16rainfall

Registering stations in the district. The normal average rainfall in this region varies from place to place and is somewhere between 1500 mm – 3000 mm.

3.4.6 Historical Factors

a. Location/Frequency of previous landslides in the project area (if available as mapped data or could be derived through manual image interpretation at considerable effort) for use evaluating model performance.

b. SHALSTAB landslide potential model works best with detailed elevation data. A Digital Elevation Model (DEM) spatial resolution of 10 meters is desired. Raster-to-Vectorprocedures are used to convert base maps to project grid and raster-to-vector procedures are used to output a model.

The basic SHALSTAB model primarily involves point-by-point processing with its results dependent on the direct coincidence at each map location.

Several of the proposed extensions such as terrain roughness and headwater proximity, address "contextual relationships" of surrounding conditions.

A nine level landslide potential index is proposed: 0 = not susceptible (lakes) 1 = low potential 2-3 = minimal 4-5 = moderate 6-7 = high 8-9 = extreme Salt and pepper smoothing is proposed to eliminate individual outliers of varying classification. Locations of 6 or higher will be isolated to generate a map of high landslide potential and can be converted to a vectormap.Edge match procedures will be used to insure continuous coverage of the final map and might require

84 tiling into manageable processing units depending on the project size and shape.

Hazard zonation map comprises of a map demarcating the stretches or areas of varying degrees of anticipated slope stability or instability. The map has an inbuilt element of forecasting and is hence of probabilistic nature. Depending upon the methodology adopted and the comprehensiveness of the input data used, a landslide hazard zonation map be able to provide the aspects of location of occurrence time of occurrence type of landslide extent of the slope area likely to be affected and rate of mass•movement of the slope mass (Rajarathnam and

Ganapathy, 2006).

Landslide hazard is one of the most significant hazards that affect different parts of India every year during the rainy season. It has been observed that 21

States and Union Territory of Pudducherry, located in hilly tracts of Himalayas,

N.E. India, Nilgiris, Eastern Ghats, and Western Ghats, are affected by this hazard every year and suffer heavy losses in terms of life, infrastructure and property (Sharda,Y.P, 2008). Though the Nilgiri and other mountainous areas are known to be susceptible to landslides, occurrences of such magnitude were unknown earlier (Thanavelu and Chandrasekaran, 2008).

Most of the topographic maps of hilly terrain of Nilgiris which are used as base maps for carrying out various studies including landslide investigation and mapping are available in small scale of 1:50,000 and a very few in 1:25,000.

Small scale maps typically represent extensive areas, but they offer only a gross perspective on details. The potential for accuracy drops as the area mapped grows larger and the scale grows smaller. Such scaled maps are not suitable for

85 in• depth and accurate landslide investigations and instrumented monitoring. A large•scale map, which shows a limited amount of space and provides a considerable amount of detailed information about that space can only be used for detailed landslide investigations, mapping and monitoring.

3.5 Risk Based Approach

The risk•based approach recognises that a different planning approach is needed for an area that has not been developed and for an area that has been developed or subdivided, or where there exists an expectation to build. Each local authority will need to determine the definition of a greenfield site for their own city/ district. The three stages (Risk Analysis, risk Evaluation, risk

Treatment) for the Risk based planning approach is suitable for the Nilgiris district where the landslide hazard is Very high to Severe.

3.6 Spatial Distribution and Severity of Landslides

23rd October 1865: Worst Storm on record occurred around Ooty and Coonoor.

Coonoor Railway station was covered with water up to five feet deep. In Ooty

Lake rose up to top of willow bound and threatened to breach it. November 1891:

Storm caused many landslips on the Coonoor Ghat, and did great damage to the

Kotagiri • Metuppalayam road.

December 1902: Twenty one inches of rain (three times the average amount) fell in that month in Coonoor, and at Kotagiri 24 inches (six times the average amount) was received, of which 8.45 inches fell in a single night. The

Coonoor railway was blocked for a month the old and new Coonoor railway was blocked for a month the old and new Coonoor ghat roads for nearly as long; and

86 all the traffic of the eastern side of the plateau was thrown upon the Kotagiri ghat, which was itself in a perilous condition •slips having occurred throughout and being serious in six places out of its twenty one miles length.

4th October 1905: 6.8 inches of rain fell at Coonoor in three hours and the

Coonoor river and its effluents came down in heavy and sudden floods, the former sweeping right over the parapet of the bridge near the railway•station. The families of the station staff had to be rescued by breaking open the back windows of their quarters with crowbars.

5th November 1978: 323mm of rain was recorded at Ooty of which 243

MM was during the night•between 5.00 pm of 4th and 8.00 am of 5th. Many people were killed in Ooty on account of houses collapses, landslides and drowning. Reports were also received regarding the causalities due to landslides and floods in Kookalthorai; Madithorai; Adashola and Kallatti areas of

Uthagamandalam Taluk and Manthada of Coonoor Taluk.

November 1979: Heavy rainfall started from 12th November 1979 and the highest rain fall was 114.5mm at Kodanad. On 13th it was 149.4mm at Coonoor and 169.9mm at Kodanad. On the 15th night heavy landslide had occurred at

Doddacombai, on 16th night there was heavy rain at Coonoor resulting in washing away of one woman and 2 Children. The rainfall recorded at Coonoor and Kodanad was 145.2 mm and 142.2 mm respectively. On 19th there was heavy landslide of 100 yards in width and about 1.00 km in length in Selas of

Ketti Village of Coonoor Taluk resulting in filling up of a Valley of 30’ 50'. The heaviest rainfall of the day was 187.6mm at Coonoor. On 20.11.1979 also, there

87 was heavy rain of 102.2mm at Coonoor and aheavy landslide at Selas in which a house was completely buried in the debris along with 2 women and 3 children.

The rainfall recorded on that day at Kotagiri, Kodanad and Kundah was 90.4 mm,

99.8 mm and 78.0 mm respectively. There was heavy rainfall of 71.0 mm at

Devala on 21st. On 28.11.79 also there was heavy rain of 144.2 mm at Coonoor.

25th October 1990: The North East Monsoon was heavy and there was a

'cloud burst'. More than 35 families were buried alive in a place called Geddai.

November 1993: There was another 'cloud burst' on 11•11•1993 in the upper reach of Marappalam of Coonoor Taluk, about 18 huts situated below the road and washing away Coonoor MTP ghat Road for about 1 1⁄2 k.m. The Road traffic was suspended for more than a fortnight. 12 persons lost their live and 15 persons missing. It is laid that 21 passengers were washed away with two buses.

An important highway, sheared stretched of rail road for about 300 m.

11th December 1998: Due to continuous rain fall, one big boulder weighing about 20m tonnes fell an the Coonoor Mettupalayam main road and the road was closed for traffic, the rock was blasted and earth slips were removed and traffic was resumed from 14•12•98.

December 2001: Due to continuous rainfall, two massive land slides occurred near pudukadu on the Coonoor•Mettupalayam high way damaging two bridges resulting in the complete closure of traffic. In addition a closer damage was also caused to the railway track between Coonoor • Mettupalayam. Bridge no 55 near hill grove railway station was completely damaged and Bridge No 56 was also damaged. November 2006: Consequent upon continuous heavy rains

88 in the Nilgiri Hills, numerous landslides were reported to have occurred at the early hours on 14.11.2006 killing one and injuring three persons and disrupting traffic in NH • 67 and blocking of Mountain Rail track between Mettupalayam and

Coonoor (nilgiris.nic.in).

3.7 Damage caused by November 2009 Landslides

Heavy rains triggered a series of landslides in Ooty, Coonoor and Kotagiri regions of the Niligiris, killing 42 people within 48 hours. Most of the people were killed after the landslides slammed into their houses. Seven of a family died at

Acchanakal hamlet near Ooty. The slides and uprooted trees also cut off access to Nilgiris via Mettupalayam. The approach road to Ootyfrom Tamil Nadu via

Mettupalayam has been severely damaged. After 1978, this is the biggest rain•related disaster in the district. However, smaller landslides and fallen trees are also blocking parts of the road. Houses and communication infrastructure came down, and roads and rail lines fell apart. The extent of damage caused to infrastructure is without precedent.About 1890 houses fully or partially damaged due to the landside and the total estimated losses are worth about Rs.300 crore by a government report (The Hindu, 2009).

3.8 Large-scale Landslide Hazard Zonation

The earliest landslide studies in the country were carried out by the GSI. This includes the study of the Nainital landslide by Sir R.D. Oldham in 1880 and C.S.

Middlemiss in 1890, and the study of the Gohana landslide in 1893 in the erstwhile Uttar Pradesh Himalayan region that resulted in the formation of a

350m high landslide dam across the Birehiganga (Bhandari R.K , 2006). The first

89 attempt on National level Landslide Hazard zonation was made by

Krishnaswamy in 1980. The first attempt on regional zonation of northeast India was made by Majumdar in 1980. The next major attempt on regional zonation was jointly made by GSI and State Geology Mines in the year 1982 for the Nilgiri

Hills. The Building Materials Technology Promotion Council of the Government of

India published small scale landslide hazard map of India in 1:6 million scale.

The Landslide Hazard Zonation Map of India presented in the Landslide Atlas

2003 is based on a systematic study of the literature, the information available on intensity and spatial distribution of landslides, preparation and processing of thematic maps in small scale 1:6 million on a GIS platform. The maps produced in the Atlas have limitations. This atlas gives a regional picture on the different hazard category in Nilgiris. The author of this atlas is advised to the reader that the small scale landslide hazard maps only provide a mega view of landslide hazard distribution across our country. For projection of the most probable landslide damage scenarios, landslide hazard maps need to be produced preferably at a scale of 1:10,000 or 1:25,000. Only then the development planners, architects and engineers are able to do reliable risk analyses in real life situations. For large scale hazard maps to be produced there is need for large scale base maps, preferably the digital version. (Bhandari, R.K, 2003).

A detailed macro zonation map for the part of Nilgiri district was produced by D.N. Seshagiri et al (1982). Thanavelu and Chandrasekeran (2008) suggested it is necessary to carry out a comprehensive meso/micro zonation studies applying the methods in vogue for the entire stretch of the slope from

Kallar to Coonoor areas. Jaiswal and Van Westen (2009) conducted a studyon

Probabilistic landslide initiation hazard assessment along a transportation corridor in the Nilgiri.

The scale of landslide hazard zonation mapping depends upon the nature of study requirements, availability of base map and resources. The earlier works has brought out the usefulness of the small scale mapping to various users and also emphasise the requirement of systematic large scale landslide hazard mapping to get more reliable information for risk assessment or implementation of suitable mitigation measures.

3.9 Need for Landslide Risk Maps

Strengthening of buildings and infrastructure should lead to reduction in

Vulnerability. The vulnerability of buildings as well as infrastructure in a landslide however is most in cases nearly 100 percent, regardless of the quality of construction. Hence the vulnerability of the structures cannot be reduced. This option therefore is not highly relevant to landslide prone areas (UNDRO, 1991).

The planning principles of a landslide riak studies are: gather accurate hazard information; plan to avoid hazards before development and subdivision occurs; take a risk•based approach in areas likely to be developed or subdivided; and communicate the risk of hazards (Andrew Leventhal and Geoff Withycombe,

2009 and Wendy Saunders and Phil Glassey, 2009).

Landslide Hazard and Risk Mapping (LHRM) is multivariate and complex problem in mountainous environment. Landslide Hazard mapping has been significantly developed over past decades but framework for risk mapping are

91 rarely available (Sharma V.K). The process of landslide risk estimation integrates the hazard levels with specific element or set of elements at risk. He considered three sets of elements viz, Risk to life (Grade•1), Social risk such as lifeline features (Grade•2) and Infrastructure like road, bridges etc. (Grade•3). Sine this is a qualitative approach the out put map will be greatly helpful to the regional users, Community users and as well as the private users.

The Risk map will answer the questions of a. Which areas of the district are, or are likely to be under pressure for development,

b. What infrastructure already exists near a landslide hazard (buildings, network utilities etc.) and the value of that infrastructure?

c. What level of risk the community is prepared to accept or not accept (in practice, it is easier to define what the community will not accept using community reactions to past events as a guide);

d. Consideration of the feasibility (effectiveness versus cost) of possible engineering solutions or other risk reducing mitigation works.

3.10 Landslide Vulnerability Mapping

In the entire Nilgiri Mountains, the highly developed area between Coonoor and

Ootacamund is facing recurring Landslides and so far more than 350 landslides have been reported. Such landslides were mapped by browsing the earlier workand the interpretation of black and white panchromatic aerial photographs on1:10,000 scales, by studying them under stereo models using wild APT2 double scanning stereoscope. In such stereo-models, as the actual relief of the terrain is exhibited, the zones of arcuate breaks, escarpments, depressions with

92 concavity along the slopes with the bulged toes in the down slopes, Crescent shaped vegetation banding, Crescent shaped vegetation blanks, Linear and

Parallel crevasses indicating the traces of the landslide movements etc. were critically mapped and these were field checked. During the process of field checks, few more landslides were also located and all were assembled and the landslide distribution map was prepared. All these lead to the detection and mapping of nearly 350 landslides and palaeoscars in the study area. From amongst these, over 144 landslides and palaeoscars of larger dimension werefiltered out and a GIS layer was prepared using Arc-View software showing these landslides.

3.11 Generation of GIS databases

Subsequent to the generation of GIS data base on the landslides, GIS data bases were generated individually on five geosystem parameters viz: Lithology,

Lineament Density, Geomorphology, Slope and Landuse / Land cover, which only generally assign different landslide vulnerability grades to the mountain areas.

3.11.1 Lithology

Lithologically, the Nilgiri Mountain is predomi-nantly covered by the Charnockites and these Charnockites have undergone different degrees of weathering. So, accordingly using the tone, drainage density, vegetal coverage etc in the satellite data and followed by the field check, the lithology of the study area was classified into highly weathered, moderately weathered and poorly weathered Charnockites. These zones covered by these three classes of

Charnockite were digitized as three polygon classes using on screen digitization technique in Arc-GIS and GIS layer was generated for the lithology

(Figure-3.1).

3.11.2 Geomorphology

The charnockite group of rocks with the enclaves of Satyamangalam Schist

Complex exposes in the Nilgiri district. This group represented by chamcokite and pyroxene granulite and covers a major part of the district in the southern part, which is popularly known as “Nilgiri Massif”. The Bhavani Group (Peninsular

Gneissic complex) comprises fissile hornblende biotite gneiss and occurs in the northern part of the district. The Satyamangalam Schist Complex is represented by quartz•sericite / mica schist, ultramafics and banded magnetite quartzite.

The Nilgiri Massif is capped by aluminous laterite at a number of places

94 indicating the deep zone of weathering (GSI, 2000).Most of the parts of the district rocks are deeply weathered and the soil thickness is found to be upto

40m with lithomarge is a common feature in the district. The low gradient of slope in Ootacamund, promotes stagnation of surface water as bogs and swamps

(GSI, 2000).

The above IRS P6 LISS – III data used for mapping the lineaments was subjected to further variousimage processing techniques, particularly to contrast stretching, false color composites and color composites of principal component images etc. From the same, various geomorphic features were interpreted and these were vectorised as individual polygon classes and GIS data base was generated on geomorphology (Figure. 3.2).

The geomorphic features so interpreted in the study area include crest

95 lines, escarpments, tor cliffs, midslope mounts, conicalhills, slopes with natural vegetations, plantations, settlements and barren rocks, barren valleys, filled valleys, barren fracture valleys, filled fracture valleys etc.

3.11.3 Geological structures

The Nilgiri hills rise abruptly from the surrounding plains to an elevation of 1370m amsl and it is surrounded by the Coimbatore plains in the southeast, Bhavani plains in the northeast, Moyar valley in the north and Gudalur Plateau in the northwest. The prominent hills are Ooty hills, Dodabetta, Kodaibetta, Bhavani

Betta and Devabetta. Dodabetta is the highest peak in Tamil Nadu (GSI, 2000).

Moyar is a prominent river in the district and flows in an easterly direction,along the northern boundary of the district. The drainage is dendritic to radial at places with prominent rapids, cascades and water falls.

On the basis of tonal, textural, topographical, drainage and vegetation linearities and curvi-linearities, the fracture controlled lineaments seen in IRS-P6

LISS III Raw and FCC data and DEM wrapped FCC data were mapped and these were field checked for their tectonic origin. From these lineaments, lineament density diagram was prepared15 by superimposing a grid map having

4687 grids of 250 x 250 m2 each over the lineament map , measuring the total length of lineaments per each grid and plotting them in corresponding grid centers. Based on the plotted values, lineament density contours were drawn.

The same showed the variance of density values from 0 to 400 mts and this was grouped into 5 classes viz; 0 (Very Low), 0 to 100 (Low), 100 to 200 (Moderate),

200 to 300 (High) and more than 300 (Very High) and GIS database was

96 generated digitizing these five classes of lineament densities as five polygon classes using ARC-GIS again under vector mode (with lines and polygons).

The erosional surfaces such as Dodabetta, Ootacamund, Coonoor and

Moyar are recorded in the district. All these erosional surfaces are capped by residual laterite. All Dodabetta surface includes landform such as high peaks, structural hills, and rocky escarpments with or without soil cover around which prominent radial drainage is developed. The Ootacamund and Coonoor surfaces include gentle mounds, with soil cover, stream meanderings and gentle smoothening of the hills. The latter abuts against the former at many places, with break in slope (Figure-3.3).

3.11.4 Soils

The soils of Nilgiri district can be broadly classified into 5 major soils types viz.Lateritic soil, Red sandy soil, Red loam, black soil, Alluvial and Colluvial soil.

Majorpart of the district covered by Lateritic soil. The Red sandy soil and Red loams areoccurring as small patches. Block soil is developed in the valleys; where the waterlogging is also common during the monsoon period. The alluvial and colluvial soilsare seen along the Valleys and major river courses respectively. Figure-3.4 shows the soil map of Nilgiris distric with respect to local place names.

3.11.5 Slope

The slopes of the study area were classified into four categories, such as steep

(>40 degrees), moderate (40 – 20 degrees), shallow (20 - 3 degrees) and rolling

98 slopes (<3degrees) by enlarging the topographic sheets of 1: 50,000 scale to

1:12,500 scale. These four classes of slopeswere prepared from the topo sheet of 1:12,500 scale by interval measuring the distances between the two contours of 20Meters For example, if the distance between the two contours was less than 2mm, the said zone was mapped as steep (>40 degrees), 2mm - 4mm as moderate (40-20 degrees), 4mm to 28mm as shallow (20-3 degrees) and more than 28mm as rolling (<3 degrees) slopes. The vector GIS layer was similarly generated for the same showing these four polygon classes of slopes.

3.11.6 Tectonic Implications

Kilometre scale compound slides of 0.5 to 2 metres slips are observed at Katteri hill site. Both earth material and rocky material were slided from the top of the hills to the bottom. The entire slope was subjected to downwards movements which suggests that theslide might have happened on the hidden blind shear zone preserved beneath the lateritic soil cover. It is possible that the sites of past landslides at Glendale Tea Estate, Elk Hills, Allangy village Slide Yelanathi and also other sites of Nilgiri landslides may represent the locations of palaeo - shearzones.

Tectonically, the Nilgiri granulites are squeezed between E-W dextral

Moyar shear zone in the North and NE-SW sinistral Bhavani Shear zone in the

Southeast. The area is geodynamically active now along the E-W and NE-SW striking palaeo shear zones originally formed during the Moyar as well as

Bhavani Shearing events. Theupliftment characters of Western Ghats and reactivations of lineaments were identified from landscape studies of

Vamanapuram basin of Kerala (Sri Kumar Chattopadya et al 2006). It is well known that earthquakes are also a cause of landslides due to propagation of different directional vibrations. There is a noticeable increase in the events of

Nilgiri landslides especially after Gujarat republic day earthquake on 26.1.01.

Far-field foreshock of the 2001 Gujarat earthquake released at Nanguneri of

Tamil Nadu on January 17, 2001. Since then, the Southern Granulite terrain of

Tamil Nadu and Kerala have been experiencing many micro seismic fracturing events of lands and buildings usually accompanied with either seismic noise or moved utensils (Manimaran and Renuga, 2007); viz. Dharmapuri on 29.1.01,

Krishnagiri on 4.2.2001; Sivakasi on 10.2.01, Kottaiyam on 13.2.01; Kollam on

15.2.01; Tenkasi on 25.02.01; Nagercoil on 27.2.01; Ramanathapuram on

28.2.01; Alangulam 1.3.01; Usilampatti on 9.3.01; Sengottai on 10.4.01;

Ramanathapuram on 5.5.01; Kottaiyam on 7.6.01; Kadalundi on June 2001;

Pondichery on June 2001; Pattukottai on 15.7.2001; Patthanamthitta on June

2001; Pondichery (M 5.6) on 25.9.2001; Bhuvanagiri on 29.12.2001 and also on

20.02.2002; Ramanathapuram on 16.4.2002; Palaghat on July 2002; Thiruvarur on 8.8.02; Kollam on 31.8.02; Idukki on 8.9.02; Nellai Puliyankulam on 6.10.02,

Tuticorin on 22.12.02; Palayamkottai on 8.2.03; Vellaloor (Kovai) on 22.02.03;

Kumbakonam on 24.7.03; Krishnagiri on 19.2.04; Tirunelveli on 15.10.04;

Oothumalai on 21.10.04; Indian Plate Sumatra Earthquake (MW 9.3 on

26.12.2004) which has affected not only the Indian Plate, 2000 KM radial area of the Northern Sumatra Epicentre also; Cuddalore on 30.12.04; Chennai on 4.1.05;

North Chennai on 24.01.05; Dhevarkulam on 24.1.05; Tenkasi Mekkarai on

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17.2.05; Arur (Dharmapuri M 3.8) on 22.3.05; North Sumatra (M 8.7) on 28.3.05;

Kayathar-Tuticorin on 30.03.05; Karisalkulam on 10.4.05; Ottapidaram on

06.05.05; Tuticorin on 7.5.05; Kovilpatti on 22.05.05; Veeravanallur on 10.07.05;

Chennai on 24.07.05; Vaipan Island on 26.7.05; Srivaikundam on 7.8.05;

Thiruvarur on 19.8.05; Pompuhar (TN) and Pakistan (M 7.6) on 8.10.05;

Kottaiyam on 3.2.06; Aravakurichi on20.3.06; Aravakuruchi and Ottanchatiram on

30.03.06; Java (M 7.7) on 17.7.06; Kumbakonam on 23.7.06; Tamil Nadu border

(M 3.4) on 4.8.06; Ramanathapuram on 1.9.06; Palani-Ottanchattiram on

7.10.06; Alangulam (Nellai) and Pavurchatram on 10.11.06; Usilampatti on

14.12.06 and Kadaladi-Ramanathapuram on 29.09.07. These microseismic fracturing events of Southern Granulate Terrain clearly reveal the ongoing transpressive tectonics in Tamilnadu and Kerala region which has initiated the reactivation of different crystal segments bounded by N-S, NW-SE, NE-SW and

E-W running deep shear zones of South India (Manimaran 2007; Manimaran and

Renuga, 2007) which in turn resulted in instability of the slopes and increase of landslides events at Nilgiri Hills. Continuous small scaleseismotectonic activities are also capable of inducing landslides when other conditions are favourable.

3.11.7 Landuse / Land cover Analysis

The Landuse / Land cover of the area is yet another important parameter controlling the landslides as it provides varied degrees of protection and vulnerability to landslides. For example the natural vegetation and the thick forests anchor the soils and protect the slopes from slope failures. Where as, the plantations, settlements, highly developed areas with net work of road Increase

101 the probability of Landslides occurrence. By duly interpreting the raw and digitally processed IRS P6 LISS –III data, land use and land cover features were interpreted. The features so interpreted viz: dense forests, forest blanks, open forests, plantations, reserve forests, scrub forests, settlements, water bodies, water logged areas etc., were digitized and vector GIS layer was generated showing all the features as different polygon classes.(Figure-3.5)

3.12 Landslide Vulnerability Assessment

Subsequent to the generation of raster GIS layers on the above five geosystem parameters, the landslide vulnerability weightages were assigned to each feature class of all the five geosystem layers based on the number of landslides per unit area. As these are now raster layers, the polygon classes are referred to as feature classes. The same was done by overlaying the GIS layer on landslides

102 over the above five raster GIS layers of different geosystems individually, counting the total number of landslides falling in individual feature class of these five raster layers, counting the total number of pixel in each feature class and dividing the number of landslides (LS) falling in each feature class by the total number pixels (A) covered by the corresponding feature class. Such ratios so derived were multiplied by 1000 and the landslide vulnerability weightages (LVW) were thus assigned to each feature class. The above derived landslide vulnerability weightages were assigned to each pixel of the each feature class in all the five raster geosystem layers Such LVW will be same for all the pixels of a particular feature class in the five geosystem layers. For example all the 2,

17,983 pixels of highly weatheredCharnockite will have LVW value of 0.46 and are shown in red colour. Subsequent to the assignment of LV weightages

(LVW) to all the feature classes of the five rasterised geosystem layers, these were all integrated together using Raster Calculator of the Spatial Analyst extension menu of Arc GIS. This has added the LVW value of each pixel of the lithology raster layer with the corresponding pixels of the weighted raster layers of the remaining four Geo systems and the final integrated GIS layer was generated. Such an integrated GIS output had the totally accrued LV weightages in all their 5, 48,884 pixels which ranged from 0.2 to 6. Then , the pixels which were having 0.2 to1.36 LVW in the final integrated layer were marked as very low

, 1.37 to 2.52 as low , 2.53 to 3.68 as moderate, 3.69 to 4.84 as high and 4.85 to

6 as very high, as far as the landslide vulnerability of the area is concerned.

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Figure 3.6 shows the landslide vulnerability was done by superimposing the landslide distribution layer over the final integrated GIS layer on landslide vulnerability. The same has shown final derived weightages, a map on landslide vulnerable zones was prepared showing the five zones viz:

o Very Low Vulnerable Zone o Low Vulnerable Zone o Moderate Vulnerable Zone o High Vulnerable Zone and o Very high Vulnerable Zone

The same map was also validated by superimposing over the past 25 landslide location map and identify the segments having multiple combinations of landslide inducing parameters are identified. By duly considering the controlling or influencing parameters, site specific management plans are suggested to control landslides in the form of afforestation, nailing, retaining walls, etc., to turn for the

104 development of hill area. In the present study, Landslide Vulnerability zonation mapping has been carried out using Landslide per unit area method. As far as the geosystem parameters are concerned, five vital geosystem parameters were used for such vulnerability mapping. The validation showed that this method can be successfully employed for landslide vulnerability mapping.

3.13 Discussions and Conclusions

Before the losses from landslides can be reduced, the hazard must first be recognised and the risk assessed appropriately. A landslide hazard assessment, which is commonly in the form of a map, provides people with a practical and cost•effective way to recognise areas where landslides exist or could occur.

So far landslide hazard zonation mapping for the study area has been attempted for the district only based on Landslide Susceptibility Index (LSI) considering factors like lithology, slope angle, distance from major thrust/faults, land use pattern and drainage density in relation to frequency of existing landslides. These approaches are qualitative and some of then are quantification.

Risk analysis involves assessing the hazard as well as considering the consequences if people and property are affected by these hazards. This paper provided an overview of the risk management processes on landslides.

The district is categorized under severe to very high landslide hazard prone areas. This indicates the area is well known for the danger of landslides, and for the perennial threat to life and property. Restriction on all new constructions and adoption of improved land use and management practices deserve to be encouraged. Investments on landslide remediation measures, on

105 public education and on early warning systems are strongly indicated. One of the most difficult problems concerning landslide hazards in place like Nilgiris is dealing with existing urban areas where buildings are constructed on or close to a landslide. The ideal approach in this situation is to avoid further development in high•risk landslide prone areas, limit existing•use rights to rebuild, and limit the use of buildings. The most realistic approach is to avoid further development and use of buildings (building type) is consistent with the level of risk posed and the district plan maps clearly show landslide hazard zones.

Landslides are one of the natural hazards that affect large parts of India especially the Himalayas, the Northeastern hill ranges, the Western Ghats, the

Nilgiris, the Eastern Ghats and the Vindhyas, in that order. In India the incidence of landslides in Himalayas and other hill ranges is an annual and recurring phenomenon. There is a variation in the degree of landslide incidences in various hill ranges. Increase in population and rapid urbanization has led to expansion of construction activities in hilly terrains and has catapulted frequency of landslides to dramatic proportions in recent decades. Most importantly, there has been paradigm shift in the policy of Government of India towards prevention and mitigation as against the traditional policy of response and relief in post-disaster situation. Vulnerability to landslide hazards is a function of a site’s location

(topography, geology and drainage), type of activity and frequency of past landslides.

The Nilgiris district in Western Ghats part of Tamil Nadu state is one of the severe to very high landslide hazard prone areas of India and the district is well

106 known for landslide threat.Unprecedented rains triggered about a hundred landslides within an area of 250sq.kms in the district during 1978. Nearly 200 landslides were recorded during 1979 and causing loss of life and severe damage to property. Though the Nilgiri and other mountainous areas are known to be susceptible to landslides, occurrences of such magnitude were unknown earlier. A total of 28 landslides of medium to large size occurred on 14

November, 2006.

About 899 small, medium and bigger size landslides were reported within five days from 10 to 15 November, 2009 and took away about 80 human lives, also the vast damage was reported on houses, roads and railway lines. In the recent times causalities and damage due to landslides have increased in the

Nilgiri Hills. A detailed damage survey has been conducted in these areas to estimate loss to the infrastructure, property, human and cattle loss were estimated. These landslides taught the very clear lesson for the need and urgency of landslide planning in Nlgiris among the scientific community and planners.

In the present study, Landslide Vulnerability zonation mapping has been carried out using Landslide per unit area method. As far as the geosystem parameters are concerned, five vital geosystem parameters were used for such vulnerability mapping. The validation showed that this method could be successfully employed for landslide vulnerability mapping.

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Chapter Four

Modifications of Hill Environment 4.1 Man Made Hazard

Landslides impact the Earth’s natural environment, including effects on the morphology of the Earth’s subaerial and submarine surfaces; forests and grasslands, and habitats of native flora and fauna. Morphologic effects are part of a general tendency of surface degradation by mass wasting and erosion. The effects of landslides on vegetation and wildlife are mostly negative; in some cases, they are catastrophic. However, landslide-caused disasters to flora and fauna are generally local in nature, which allows for species recovery with time.

In the long term, landslides may even have positive effects on the habitats of flora and fauna.

Biotechnical approaches to landslide mitigation have much less impact on the environment than traditional concrete and steel retaining structures.

Biotechnical slope protection utilizes mechanical elements (structures) in combination with biological elements (plants) to prevent and correct slope failure and erosion with minimum impact on the environment. Much has been written on the impacts of landslides on the total environment, including effects on people, their homes and possessions, farms and livestock, industrial establishments and other structures, and lifelines. However, few authors have discussed the effects of landslides on the natural environment that is on:

a. Morphology of the Earth’s surface, particularly that of mountain and valley systems, both on the continents and beneath the oceans;

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b. Forests and grasslands that cover much of the continents, and

c. Native wildlife that exist on the Earth’s surface and in its rivers, lakes and seas.

We will use landslide terminology as presented by Varnes (1978) and

Cruden and Varnes (1996). As used, the term “landslide” will include all types of gravity-induced mass movements, ranging from rock falls through slides/slumps, avalanches, and flows, and it includes both subaerial and submarine mass movements triggered mainly by precipitation (including snowmelt), seismic activity, and volcanic eruptions. For simplification, the term “debris flow” will include mud flows, debris torrents, and lahars.

4.2 Impacts on Morphology of the Earth’s Surface

The surface of the Earth, both on the continents and beneath the oceans is continually modified by internal forces and the forces of gravity; both, particularly the latter, produce landslides. The net morphologic effect of landslides is to reduce slopes to angles at which they possess long-term stability. “The processes involved vary enormously from extremely large rapid movements to extremely slow micro-displacement. The result is denudation in the source area, frequent erosion along the transport path, and then deposition, the degree of whose permanence varies widely.” We have made no attempt to quantify the worldwide, or even regional, morphologic significance (i.e., the average rate of down-cutting) of landslides, an amount that is extremely difficult to determine for large areas. However, we do present case histories of some of the world’s largest landslides, which provide useful information on the maximum effects of

109 individual or regional landslide events, and which have provided local information on rates of slope recession and cliff retreat.

4.3 Morphologic impacts of large subaerial landslides

The world’s largest landslides are prehistoric, but their remains are displayed as significant morphologic features on the Earth’s surface. Most very large landslides have been triggered by earthquakes or volcanic eruptions. In a study of 40 major historic earthquakes, Keefer (1984) has shown that landslides can be

2 triggered over an area as large as 500,000 km by M=9.2 earthquake.In 1977,

Wolfe (1977) identified what may be the world’s largest subaerial landslide: an

18x25-km displaced block of limestone on Samar Island, the Philippines. This block was interpreted by Wolfe to be an earthquake-triggered Holocene

3 landslide, possibly as large as 135 km in volume.

Another huge prehistoric landslide that was probably earthquake-induced is the Simareh landslide in southwest Iran (Harrison and Falcon, 1938; Watson and Wright, 1969). Composed of limestone debris, this landslide, which occurred

2 about 10,000-11,000 yrs B.P. (Watson 1982) has a surface area of 166 km and

3 an estimated volume of 24-32 km , making it one of the world’s largest subaerial landslides (Shoaei and Ghayoumian, 2000).

The world’s largest historic landslide is the 1980 Mount St. Helens rock slide debris avalanche in the Cascade Range of southwestern Washington State,

U.S.A., which was triggered by a catastrophic volcanic eruption (Voight et al.,

3 2 1983). This 24-km-long, 2.8- km landslide buried about 60 km of the valley of

110 the North Fork Toutle River under a cover of hummocky-surfaced, poorly sorted debris, ranging in size from clay to blocks of volcanic rocks with individual volumes as large as several thousand cubic meters.

In high-mountain regions, large catastrophic landslides often occur due to failure of valley walls that have been oversteepened by glaciers and debuttressed by de-glaciation. In the Upper Indus Basin of northern Pakistan such activity has had a major effect on the valley morphology of the Karakoram

Range. In a study of this region, Hewitt (2002) has identified 180 large rock- avalanche deposits that have formed cross-valley barriers (that is landslide dams) on Upper Indus streams. More than one half of these individual

2 Karakoram landslides originally covered more than 10 km of valley floor and

3 more than 50 million m in volume. Two of the events covered more than 50

2 9 3 km each and exceeded one billion (10 ) m in volume. Debris thickness ranged from 5 m to more than 500 m (Hewitt, 1998). Roughly one rock avalanche occurred in every 14 km of valley surveyed (Hewitt, 2002). Nearly all of these rock-avalanche dams have been at least partially breached. “Lacustrine deposits were found upstream of almost every example, although most lakes are now drained or filled with sediment. However, though breached, at least 120 of the landslide dams are not completely cut. They persist as local base level and steps in the river profiles.” (Hewitt, 2002, p. 67).

Although they are not commonly as large or catastrophic as the events noted above, landslides caused by precipitation obviously also have major effects on the morphology of the Earth’s surface. Nearly all of the nations of the

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World are subject to some degree of “gravitational leveling” by precipitation- induced mass movements.

4.4 Rate of slope recession due to landslide activity

Landslides obviously are one of the main geomorphic processes that lead to slope retreat. However, as has been noted by Iida and Okunishi (1983, p. 68):

“The geomorphic significance of landslides (or the average rate of denudation) has not been evaluated because they occur irregularly and discontinuously in time and space.” In spite of this, landslide researchers can reasonably estimate the volumes of most individual large landslides, and they know that landslides triggered by major earthquakes or volcanic activity can denude hundreds or even thousands of square kilometers of the Earth’s surface. For example, Keefer

(1994) has modeled the long-term sediment production of earthquake-triggered landslides for 12 seismically active regions. His modeling indicated that rates of sediment production by earthquake-induced landslides have been very high

3 2 (>200 m /km /yr) in four of the studied regions (Island of Hawaii, Irian Jaya, New

Zealand, and the San Francisco Bay Region of northern California) and

3 2 moderately high (20 to 200 m /km /yr) in five others (Peru, Turkey, southern

California, all of onshore California, and central Japan).

Less is known about rates of recession of natural slopes that are affected by many smaller landslides acting over larger areas, particularly those caused by heavy rainfall. Modeling methods for expected slope retreat has been offered by

Mitchell and Bubenzer (1980) and others, but these approaches apply mainly to relatively homogeneous soils and do not separate slope retreat due to landslide

112 activity from that due to erosion and other factors. However, numerous field studies have attempted to predict rates of slope denudation resulting from landslide activity based on extrapolation of observed rates of retreat. Most such studies have been primarily for limited areas and relatively short periods of observation.

4.5 Loss of Soil Resources

In major landslides, all of the soil/colluvium down to bedrock is carried downslope, taking all of the trees and other vegetation with it. Because no soil is left for new plants to grow on, the bare tracks of landslides can remain visible for hundreds of years. There have been a few attempts to quantify losses of soil resources due to landslide activity. Noteworthy is the study by Wright and Mella

(1963) of the affects of the aforementioned 1960 earthquake-induced landslides in south-central Chile on the soil resources of the area. There have been attempts to quantify losses of soil resources due to rainfall-triggered landslide activity in hilly regions in Tanzania. Rapp et al. (1972) estimated that soil losses

3 in the Mogoro River valley averaged between 5000 and 10,000 m /yr, while

Temple and Rapp (1972) noted that an approximately equal catchment in the

3 Mgeta area of the western Uluguru Mountains lost approximately 270,000 m in less than 3 hrs in February 1970.

It should be noted that some of the soil lost from hill slopes because of landslide activity with the passage of time may be reconstituted as usable agricultural soil in the valleys below. This is especially true in the case of debris- flow deposits in the form of debris fans or terraces, which with time may provide

113 excellent agricultural conditions, either for pastureland or for crop production.

4.6 Valley Morphology

Both subaerial and submarine landslides have major long-term effects on valleys

(and canyons) in which they occur. While gravitational mass movements tend to lower the surface of the Earth, landslide deposits in mountain valleys often have the opposite effect on the valley bottoms, particularly when the streams are dammed by the landslides.

4.6.1 Effects of Landslide Damming

Large landslides often completely block river valleys, impounding lakes. Most landslide “dams” fail by overtopping and breaching due to erosion. However, if they don’t fail, the geologic “short-term” effect on morphology is the impoundment of a lake. Landslide dams can affect valley morphology in the following ways:

a. Deposition of lacustrine and deltaic sediments in the lake impounded by the dam, resulting in changes of stream gradient, surface morphology, and surficial geology upstream from the dam.

b. Formation of avulsively-shifting channels downstream from the dam by the introduction of high sediment loads from erosion of the landslide deposits.

c. Secondary landsliding along the shore of the impounded lake due to reservoir filling or to rapid drawdown if the natural dam fails (Schuster, 1995),

d. Most landslide dams fail within relatively short periods of time (Schuster and Costa, 1986; Costa and Schuster, 1988). However, many of today’s large landslide dams and their impounded lakes have existed for hundreds or even thousands of years. Especially noteworthy, are the following:

a1. 2,200-yr-old Waikaremoana landslide dam and lake, New Zealand, a2. Simareh (Seimarreh, Saidmarreh) landslide dam in southwest Iran, which about 10,000 yrs ago impounded a huge lake that later filled with sediment to become a lacustrine plain,

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th a3. 20 century Usoi landslide dam and Lake Sarez, southeastern Tajikistan.

e. An outstanding example of a landslide-dammed lake that exists as a long-term geologic feature is Lake Waikaremoana on the North Island of New Zealand. This 250-m- deep lake with an area of 56 sq.kmis a remarkable natural feature that owes its survival to the erosion-resistant nature of the Tertiary sandstones and siltstones in the landslide dam (Read et al., 1992; Riley and Read, 1992). The lake has reduced the upstream gradient of the Waikaretaheke River to zero for about 15 km. Because the incoming river carries little sediment, Lake Waikaremoana has not been noticeably reduced in size or volume by sediment deposition.

The world’s largest and highest historic landslide dam was formed by the earthquake- triggered Usoi rock slide–rock avalanche, which dammed the

Murgab River in the Pamir Mountains of southeastern Tajikistan in 1911. The resulting 600-m-high dam impounds 53-km-long, 550-m deep Lake Sarez. This natural dam is twice as high as Nurek Dam (also in Tajikistan), the world’s highest man-made dam. The dam has not been overtopped; inflow from the

Murgab River and outflow (seepage) through the dam, in the form of several large outlet springs, appear to be in equilibrium. Thus, this landslide dam will continue to have a major effect on the long-term gradient of the Murgab River.

4.6.2 Effects on Streams of Sediment Derived from Landslides

Sediment liberated from mountain slopes by mass movements is stored on the lower slopes, on the valley bottoms, or in stream channels. Numerous studies have been conducted to determine the amounts of sediment that actually enter streams from landslides. In some cases, this material is in the form of landslide- derived sediment those dams, or partially dams, the streams. In other cases, the

115 sediment is derived by erosion from landslides located near the streams.

Sediment delivery to stream channels from landslides can be significant.

Based on studies of 19 debris flows that entered the Van Duzen River basin in northern California, Kelsey (1978) estimated that the annual yield of sediment to

3 3 the river by debris-flow activity was ~41,000 m , or ~2,200 m per event.

Studies of sediment production in streams in the Rocky Mountains of northern Idaho, U.S.A., have indicated that the amount of sediment reaching stream bottoms is derived from the following sources: 40 percent from rotational landslides, 40 percent from debris avalanches, and 20 percent from overland flow erosion (Wilson et al., 1982). In a similar study in Puerto Rico, Larsen and

2 Torres Sanchez (1992) found that 81 percent of the 300 t/km of sediment transported out of the Mameyes River basin was contributed by mass wasting.

Swanston (1991) has noted the types of channel changes that occur by introduction of materials from the following types of mass movements:

a. Debris avalanches and debris flows – Large, short-term increases in sediment and woody debris; channel scour; large-scale movement and redistribution of bed-load gravels and woody debris; damming and obstruction of channels; accelerated channel bank erosion and undercutting; and alteration of channel shape by flow obstruction.

b. Slumps and earthflows – Low-level, long-term contributions of sediment and large woody debris to channels; partial channel blockage; local channel constriction below point of entry; and shifts in channel configuration.

Debris flows, which often follow the stream channels for great distances,

116 are the main landslide types that affect streams. Debris flows provide important sediment-transport links between hillslopes and stream channels, and thus are an important factor in drainage-basin sediment budgets (Benda and Dunne,

1987). In addition, debris flows influence the spatial and temporal distributions of sediment in stream channels, either because they deposit sediment in the channels or because the deposits themselves provide sources for enhanced transport of sediment farther downstream (Benda, 1990).

4.7 Effects of Landslides on Forests and Grasslands

4.7.1 Forest Destruction

Widespread stripping of natural forests and jungle cover by mass movements has been noted in many parts of the world, but especially in tropical areas as the result of large-scale, earthquake-induced landslide activity. In September 1935, two shallow earthquakes (M=7.9 and 7.0) in the Torricelli Range, north coast of

Papua New Guinea, caused “hillsides to slide away, carrying with them millions of tons of earth and timber, revealing bare rocky ridges completely void of vegetation” (Marshall, 1937). Approximately 130 km2 (8 percent of the region affected) was denuded by the landslides (Simonett, 1967; Garwood et al., 1979).

On the south slope of the Torricelli Range, Montgomery and Eve (1935, p. 14) reported: “Soil and sub-soil with their covering of tropical jungle had disappeared from 60 per cent of the slopes, baring the underlying bedrock.” In November

1970, a M=7.9 earthquake triggered landslidesalong the north coast of Papua

New Guinea that removed shallow soils and tropical forest vegetation from steep slopes in the Adelbert Range (Pain and Bowler, 1973). Vegetation was stripped

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2 from about 25 percent of the slope surfaces in the 240-km area that was affected by landsliding. Similarly, in 1976 two shallow earthquakes (M=6.7 and 7.0) struck the sparsely populated, jungle-covered, southeast coast of Panama, causing huge areas of landsliding. Garwood et al. (1979) estimated that the slides

2 removed approximately 54 km of jungle cover (12 percent of the affected region

2 of 450 km ).

Similar sub-tropical forest devastation due to earthquake-induced landslides occurred in the previously mentioned 1987 Reventador and 1994

Paez events in Ecuador and Colombia, respectively. In both cases, the earthquakes occurred after long periods of rainfall, and the saturated residual soils on steep slopes failed as thin slides that rapidly transformed into debris flows. The Reventador landslides removed the subtropical jungle from more than

75 percent of the southwestern slopes of Reventador volcano (Nieto et al., 1991;

2 Schuster et al., 1996). Figueroa et al. (1987) estimated that 230 km of natural forest were lost in the region. The Paez landslides stripped soil and vegetation

2 (mostly second-growth sub-tropical brush and forest) from 250 km of steep valley walls (Martinez et al., 1995). In Puerto Rico, landslides are triggered by heavy rainstorms, including hurricanes. In the Luquillo Mountains of Puerto Rico, which are especially hard-hit by landslides, Brokaw (2003) has reported that landslides denude between 0.08 per cent and 1.1 per cent of the forest area per century.

The destruction of temperate forests by landslides has also been studied extensively. In their study of the influence of landslides on forest vegetation in the

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Valdivian Andes due to the 1960 M=9.2 Chilean earthquake, Veblen and Ashton

(1978, p. 165) have noted that: “Catastrophic mass movements associated with seismic activity have affected the Andes of south-central Chile several times in the past 400 years and have profoundly influenced theregional vegetation.” They

2 further noted that more than 250 km of temperate forest slopes were denuded in the 1960 event. Many forest areas in New Zealand have been damaged by landslides. Studies of forest losses in the upper drainage basin of the Pohangina

River on the North Island by James (1973) noted hat in 1946 the erosion surface exposed by mass movements in a red beech forest was 1.7 percent of the drainage area. By 1963, the denuded area was 2.7 percent, an increase of 60 percent in 17 years. In another study on the North Island, Eyles (1971, p. 91) found that: “The initiation of rapid hillside erosion was probably connected with the vegetational change from forest to scrub and it may have been enhanced by further change to grass.”

Numerous studies have been made of temperate-forest damage due to landslides in southwestern Canada and the northwestern United States.

Especially noteworthy have been studies of landslide-caused forest damage on the Queen Charlotte Islands off the coast of British Columbia (e.g., Wilford and

Schwab, 1982; Smith et al., 1986). The Queen Charlotte Islands include vast tracts of valuable commercial timber. The coniferous forests of the islands consist primarily of western hemlock, Sitka spruce, Douglas fir, and western red cedar. Gimbarzevsky (1988) has inventoried more than 9,000 rainfall-caused landslides in these forest areas.

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In the northwestern United States, numerous studies on the effects of landslides on forests had been conducted by the U.S. Forest Service (e.g.,

Swanston and Swanson, 1976; Megahan et al., 1978; Swanston, 1991;

McClelland et al., 1999). Most of these studies have dealt with the effects of logging practices on landslide activity.

In rare cases, forests have been destroyed by large water waves caused by landslides. An outstanding example was the catastrophic destruction in 1958 of virgin forest to an elevation of 530 m above Lituya Bay, southeastern Alaska, by a giant wave caused by a high-velocity rock slide that entered the bay (Miller,

1960).

4.7.2 Destruction of Grasslands

There are few references in the literature devoted specifically to the destruction of grassland or non-forested areas by landslides. Noteworthy was the study by

Langenheim (1956) of the effects of the 1923 Gothic earth flow in Colorado,

U.S.A., on subalpine vegetation. In another study in the western United States,

Beatty (1988) noted the effects of mass wasting on natural grasslands on Santa

Cruz Island, California. In a New Zealand study of mass movements that destroyed grasslands in the Tangoio Conservation Reserve, northern Hawkes

Bay, Eyles (1971) noted that landslide activity was significant in areas that had originally been forested, but had been converted to grassland. In another study of landslides on grasslands of the North Island of New Zealand, Trustrum et al.

(1984) studied the relationship between landslide activity and pastureland productivity in the landslide-prone Wairarapa hill country.

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4.7.3 Destruction of Marine Plant Life

Although less is known about destruction of marine plant life by landslides than that which occurs sub-aerially, current studies of California’s Big Sur Coast indicate that coastal landslides can harm habitats for marine plants ranging from macroalgae to kelp forests and other varieties of seaweed (Moss Landing Marine

Laboratories, 1998; Oliver et al., 1999). In the Monterey Bay National Marine

Sanctuary (MBNMS), coastal plant life continually is affected by landslides, especially those that are triggered by the effects of California State Highway.

Disposal of debris from these landslides without harming the habitats of plants and wildlife along this Pristeen coastline poses a continual problem to the

California Department of Transportation (Caltrans). Although not so well- reported, landslides on other coastlines worldwide undoubtedly have similar harmful effects on marine plant life.

4.7.4 Re-vegetation of Forests and Grasslands

Landslides are among the most severe disturbances of the tropical rainforests of

Puerto Rico. Revegetation of the forested landslide areas of the tropical, wet

Luquillos Mountains of northeastern Puerto Rico has received a greater concentration of study than any other landslide area in the world. The following recent ecological papers having been devoted to this study: Guariguata (1990),

Walker and Neris (1993), Walker (1994), Fernandez and Myster (1995), Walker and Boneta (1995), Fetcher et al. (1996), Walker et al. (1996), Myster (1997),

Myster and Walker (1997), Myster et al. (1997), Myster and Everham (1999),

Brokaw (2003), Walker (2003), and Shiels and Walker (in press). As noted by

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Walker (2003, p. 1): “Tropical landslides, including those in Puerto Rico, revegetate within a remarkably short time, provided there exists a stable substrate Whenample nutrients are also available [landslide] forests recover most characteristics of pre-disturbance forests within 100 yr. Plant succession is governed by slope stability and nutrient availability...Biological processes that lead to succession and stabilization include inputs of seeds by wind, gravity and birds, vegetative expansion of neighboring plants; and the competitive and facilitative interactions of colonizing plants...Attempts to stabilize landslides include physical barriers to slow erosion, plantings to stabilize soil surfaces, fertilization to promote plant growth, and artificial perches to encourage bird dispersal of seeds.”

Similarly, in a study of 46 landslides in the Luquillos Mountains,

Guariguata (1990, p. 828) noted that post-landslide forest succession “seems to require at least fifty years before regrowth begins to resemble mature-forest basal area.”Other studies of re-vegetation of landslide areas in tropical forests have been carried out for the following countries/areas: Jamaica (Dalling, 1994); the Caribbean (Walker et al., 1996); Costa Rica (Walker, 1994; Myster, 1997); and Panama (Garwood, 1985).

Studies of revegetation of landslide areas in subtropical montane forests have been conducted in Ecuador (Stern,1995; Myster and Sarmiento, 1998; and

Ohl, 2000), Bolivia (Kessler, 1999), and Tanzania (Lundgren, 1978). Stern (1995) and Kessler (1999) have suggested that landslides are important in tropical mountains for maintaining forest species diversity, particularly in areas with steep

122 topography and humid climate. In her study of re-vegetation of landslides triggered by the 1987 Reventador earthquakes in northeastern Ecuador, Stern

(1995, p. 219) noted that landslides “likely contributed to the large portion of forest dominated by colonizing species that are not able to establish or survive under mature, closed-canopy forests.” In tropical mountain areas of southern

Ecuador, Ohl (2000) has noted that landslides are an important factor in regeneration and diversity of the forest ecosystem. Where landslides occur, diversity of the forest increases dramatically as shown by the fact that most species found on landslides during succession are not elements of the mature forest.

Numerous studies of revegetation of landslide areas have also been conducted in temperate areas. In the United States, Moss and Rosenfeld (1978) have described local destruction of the temperate forest community in a valley in the Niagara escarpment of New York State by “catastrophic” mass wasting. They found that forest and grassland areas destroyed by landslides do not remain permanently blighted. Instead, mass movement is just one of several environmental factors that give rise to “random perturbations” that trigger essential recycling and rejuvenation of biotic systems. They found that “...a whole new series of small isolated communities has been brought into being as a result of mass movements opening up the forest cover enabling enrichment of the flora by providing additional, diverse habitats where the adjacent dominant and subdominant species compete with species from outside the valley.” (Moss and

Rosenfeld, 1978, p. 172).

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Flaccus (1959) discussed rates of revegetation of important “pioneer” tree species – paper and yellow birch, pin cherry, and trembling aspen – on landslide scars and deposits in the White Mountains of New Hampshire, U.S.A. He found that for the harsh climates of New Hampshire, steep scarps, bare till, and talus may remain largely free of forest cover for more than 100 years after landslide activity, but that all such areas recover over sufficient time if the slopes do not continue to be disturbed. Less-steep, more-protected habitats on landslides, and especially landslide deposit areas, may revegetate much more rapidly, commonly within 50 years.Local hardwoods are the first to return, followed by conifers.

[Note that the authors have observed thick, immature stands of the common native hardwood, red alder, on landslides in the U.S. Pacific Northwest within 10 yrs of landslide occurrence.]

Forest recovery following landslide activity has received considerable attention in Fiordland on the South Island of New Zealand (e.g., Poole, 1951;

Holloway, 1954: Mark et al., 1964; Stewart, 1986). Poole (1951) mentioned the importance of landslides in determining plant succession for valley-slope forests in Fiordland. Holloway (1954, p. 399) noted that “communities of kamahi, broadleaf, and mountain ribbonwood occupy temporarily the debris of past landslides.” Mark et al. (1964) suggested that forest species return more quickly to landslide debris deposits than to the denuded main-scarp surface. On the denuded main scarp and slide face, brush species become established soon after the landslide and retain an important place in the canopy for about 50 yrs, after which they are increasingly suppressed by the emerging forest trees.

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In the 1980’s, Smith et al. (1986) conducted a detailed study of revegetation patterns of landslide-destroyed forests in the Queen Charlotte Islands,

British Columbia, Canada. The upper portions of the landslides were partially scoured to bedrock or compact glacial till, whereas the lower parts consisted mainly of chaotic mixtures of logs, rocks, and soil deposited on, or mixed with, the original soil. Two major trends in vegetative development on slide surfaces were observed, one dominated by red alder and one by conifers. The alder was dominant on the lower parts of the slides, while conifers dominated on the middle and upper parts.

4.7.5 Landslide Hazard Mitigation through Cost Effective Technology

Strengthening of buildings and infrastructure should lead to reduction in

a. gather accurate hazard information;

b. plan to avoid hazards before development and subdivision occurs;

c. take a risk-based approach in areas likely to be developed or subdivided; and

d. communicate the risk of hazards.

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4.8 Use of Soil Bio Engineering for Slope Stabilization

Soil bioengineering is the use of plant material, living or dead, to alleviate environmental problems such as shallow, rapid landslides and eroding slopes and stream banks. The effectiveness of vegetative structures is limited to 0.5 to

1.0 meters in general and complements the conventional civil engineering structures. For deep seated failures, bioengineering structures can not stabilize directly but can contribute indirectly to civil engineering structures by protecting the soil surface.

Soil bioengineering most often mimics nature by using locally available materials and a minimum of heavy equipment, and it can offer roadside managers an inexpensive way to resolve local environmental problems. Soil bioengineering can provide an effective means of treating sites where steep slopes and soil instability are resulting in revegetation problems. Soil Bio- engineering is not a substitute for civil engineering. It offers engineers a set of tools to complement those already available in solving range of shallow slope problems. The functions of Soil Bio Engineering work similar way as civil engineering structures. Six major engineering functions that a bio-engineering structures are: Catch (Holding / stopping of falling soil particles over the surface),

Armour (armouring the slope surface against rain splash and erosion), Support

(supporting the soil mass from below), Anchor (anchoringthe loose particle down to a firm ground), Reinforce (reinforce the soil by increasing its shear strength) and Drain (improving drainage capacity of the poorly draining soil).

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Soil bioengineering systems are strong initially and grow stronger as vegetation becomes established. Even if plants die, roots and surface organic litter continues to play an important role during reestablishment of other plants.

Once plants are established, root systems reinforce the soil mantel and remove excess moisture from the soil profile. This is often the key to long-term soil stability. Soil bioengineering provides improved landscape and habitat values.

Soil Bio Engineering systems work by fulfilling the engineering functions required for the protection and stabilization of slopes.

Established vegetation can be vulnerable to drought, soil nutrient and sunlight deficiencies, road maintenance side cast debris, grazing, or trampling, and may require special management measures to ensure long-term project success. The on-going experience of realizing soil bioengineering works an effective tool for the treatment of landslides and unstable slopes. Soil bio

Engineering systems work by fulfilling the engineering functions required for the protection and stabilization of slopes. The difference between re-vegetation and bio engineering is that plants must provide one or more of the roles of catching debris, armouring the surface, reinforcing the soil, anchoring the surface layer, supporting the slope or draining the material. This means serving the engineering functions. For stabilization of slope any one of the following may be used: a) Civil

Engineering on its own, b) vegetative Engineering Alone, c) a combination of the two. The strength of a structure at various stages of its life can be related to maximum strength.

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4.9 Environmental and Societal Issues

Landslides have wide ranging impact on the people of the affected area in terms of the devastation caused to material and human resources. The magnitude of destruction depends on the location of the landslide area. In the context of India it is a painful truth that most, if not all, the areas susceptible to landslide hazards are inhabited by the economically weaker section of the population who have neither the resources nor the expertise to organize rehabilitation measures out of theirown. One of the most difficult problems concerning landslide hazards in place like Nilgiris is dealing with existing urban areas where buildings are constructed on or close to a landslide. The ideal approach in this situation is to avoid further development in high-risk landslide prone areas, limit existing-use rights to rebuild, and limit the use of buildings. The most realistic approach is to avoid further development and use of buildings

(building type) is consistent with the level of risk posed and the district plan maps clearly show landslide hazard zones.

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National Disaster Management Authority (NDMA), Government of India in the

The downward movements of consolidated and unconsolidated soils and rock matter from any geomorphic features due to natural or manmade causes are termed as landslides (GSI, 1982). Such movements or displacements occur under the influence of gravity. Presence of water greatly aids this phenomenon as it makes the rocks and soil more weak and mobile. Different phases of the

Bhavani shear zone reactivations were delineated from crystallographic lattice preferred orientation and seismic properties studies. About 85 per cent of the total area of Darjiling Municipality has crossed the critical value (0.5) of potential

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Anthropo-Geomorphological index (P.A.G.) and immediate Measures should be taken to avoid a major catastropy. The problem of landslides in Sikkim is found to be a function of interaction among geology, precipitation, slopes, Human intervention and time From Geological studies of Itanagar Capital Complex of

Arunachal Himalaya, pointed out that the existence of local vertical faults, fault scraps, triangular facets, active landslides, abrupt deflection in the stream/rivers courses are the indicative features of neotectonism. Using Geo-environmental factors like lithology, slope morphometry, structure, relative relief, land use and land cover and hydro-geological conditions has developed a rapid hazard assessment technique – predicted Landslide Hazard Evaluation Factor (LHEF) through univariate statistical analysis. Manimaran 2008 highlighted the links between reactivation of blind shearzones in weathered zones and landslides in

Nilgiri Hills. The intensity and magnitude of these landslides varies greatly depending upon the extent and amount of slope and size of the rock mass involved. It is very essential to keep a constant watch on the embankments and hill slopes in respect of their stability. Any possibilities of sliding must be foreseen and all necessary measures must be taken o prevent any loss.

4.10 Geology of Niligiri hills

Nilgiri Hills of Tamil Nadu are located at the junction of the Eastern and Western

Ghats, Udhagamandalam, popularly known as Ooty, the Queen of Hills, is a major tourist attractionof South India. The major country rock exposed at Nilgiri

Hills is charnockites (granulites). They are enderbitic natured rocks essentially composed of minerals of quartz, plagioclase, and potash feldspars (less),

130 orthopyroxene, garnet and biotite. The rock is medium to coarse grained, greenish grey coloured rock, polygonal granoblastic texture to foliated banding texture. The general strike of the granulites is N60°-70°E with steep dips (55°-

75°). The Nilgiri charnockities are termed as syn-accretionary granulite was accreted to the Dharwar craton prior to the 2500 Ma granulite event. (Janardhan et al, 1994). The trident shaped Nilgiri granulite terrain of exhumed nature extends for a strike length of about 140 km with a maximum width of about 80 km. The two major shear zones termed as the Moyar shear zone (MSZ) and the

Bhavani Shear Zone (MBSZ) border the Northern and Southeastern margins of

Nilgiri granulites terrain respectively. The original layering structures are well preserved in charnockite. The dark coloured melanocratic layer is with garnet and biotite alternating with quartz and plagioclase rich quartzofeldspathic layer.

On alteration the charnockites are converted into thick brownish weathered skin with clay layers formed from feldspars. Clay layers play catalytic role in causing

Nilgiri landslides, especially during rainy season. The layered charnockite of

Nilgiris was attributed to extensive migmatization followed by granulite high grade metamorphism (Srikantappa, 1996). Apart from charnockites, conformable to regional strikes there are bands of gabbroic anorthosites, anorthosites, mafic granulites, pyroxenites and banded magnetite quartzites and dykes of dolerites.

Soil type of Nilgiri is mainly of residual, lateritic red coloured porous soil. At places buried lignite deposits are also seen in valley portions. Black soil of swelling nature, enriched in montmorillonite clay and Kaolin clay are also present as top regolith in some places, where basic and ultrabasic rock types occur.

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4.11 Nilgiri landslides

Figure -4.1 shows Occurrence of landslides prone areas where collected using gpsalong the road of Kallar to Nilgiris, the recent and past landslide becoming frequent and rather an annually recurring phenomenon in one part or other of the district with the frequency gaining during the northeast monsoon, causing frequent road blocks, breaches of infrastructure, loss of lives and destruction of properties. Landslides were severe during the two consecutive years 1978 and

1979 as well as in 2006, inflicting loss of life and damage to property.

Unprecended rains triggered about a hundred landslides within an area of 250 square kilometers in the district during 1978 while nearly 200 landslides were recorded during 1979 and 30 landslides during 2006 in the Coonoor to

Mettupalayam ghat road. Soil slips, earth slides, rock slips, rock falls, compound slides and land subsidence are common and Nilgiri area is prone to all kinds of landslides.

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Because most of road cutting as well as railway track cutting are with steeply dipping rock formation (charnockite with soil covers) disposed towards the steep geomorphic slopes of the area. As a result there are more unstable conditions of the slopes and sliding may take place along the slope at any time.

When the aerial extend of the steep slope is more, attention should be given for construction of retaining walls at the bottom. The area in which beds dip towards

o the slope with dip amounts more than 45 are unsafe (Arora, 1988) and prone to landslides Nilgiri and Darjiling hills are most affected by landslides due to same side steep slopes and steep dip formations. Whereas Yercaud hills of Salem,

Kothgiri to Mettupalayam of Nilgiri Ghat section and Dehradun to Mussoorie hills track are free of landslides where beds are dipping into the hills and against the slope.

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It is observed that while there were innumerable slides between Coonoor and Mettupalayam and the number of slides on the Kotagiri-Mettupalayam sector was negligible. Along the roads, the natural sholas or forests remain relatively undisturbed and geomorphic slopes are moderate to steep. The Geological reasoning behind these Ghat Sections are geomorphic slope and geological formationare dipping towards road sections and are in same direction in the former case. Whereas in the Kotagiri Section, Geological formations are mostly dipping against (or) oblique to the geomorphic slopes of area and thickness of weathered cover is very low.

Improper land use practices such as heavy tilling, agricultural practices and settlement patterns and withdrawal of toe support have contributed to creep in many cases. A common factor noticed in most of these vulnerable slopes are deforestation in the recent past, cultivation of seasonal crops and increase in settlements.

4.12 Landslide Prone Locations

Numerous and large sized master joints make the rock very weak and unstable and joints act as channel ways for the seepage of water. Sliding may take place along joint planes dipping towards the slope. For example the slided and subsided Kundah dam site is showing 3 sets of joints in Charnockite blocks. It is observed that the enchelon fractures at Nilgiri. To avoid further landslides and subsidence, grouting of jointed block with good quality cementing materials should be done to fill them and make the rock strong and stable.

Nilgiri hill slopes are mostly covered with either red coloured lateritic soil or

134 black coloured soil and are occurring above the steeply dipping, rock types and both soils are prone to landslides. The lateritic soils are intercalated with thin layers of Kaolinite clays (AL2 SI2 O5 (OH4) and black soils are enriched with montmorilonite clays (Ca, Na) 0.2 - 0.4 (Al, MgFe)2 (SiAl)4 O10 (OH)2. n(H2O).

During rainy season, the clay beds acts as smooth gliding surface which can facilitate landslide. Bulging and swelling of the clays during wet season followed by shrinkage of clays during consecutive dry season result in a subsidence of ground. Clay bed present along the fracture surface of rock formation if wet act as a lubricant and greatly enhances the possibilities of rock slips. Vibrations created by heavy vehicular traffic may also accelerate the landslides and solifluction especially during continuous heavy rainy season and flooding on the slopes.

4.13 Rainfall and Slope Failures

In the Nilgri Hills, it has been found that steep as well as gently slopes have failed. A study of steepness of slope vis-à-vis the number of landslides seems to indicate that the slides in 1978 and 2006 occurred on comparatively steeper slopes than those of 1979. The synthesis of this correlation with rainfall data reveals that the intensity of precipitation in 1978 and 2006 were high only for three days, whereas the rainfall in 1979 was distributed in the months of August and December. This indicates that the 1978 and 2006 slides occurred due to heavy precipitation in a short period when there were flash floods and water spreading and consequent soaking on the slopes resulting in mass movement of the material over relatively steeper slopes. On the contrary, during the 1979

135 monsoon the longer duration of rainy period permitted greater infiltration of water into the soil and consequent triggering of landslides in areas as gentle as

o 10 slopes. Many slides have taken place in areas of intense cultural activity. The cultural activities include agricultural operations, construction of buildings and road, removal of earth and rock, leveling of slopes, deforestation and blocking of natural drainage. These steep slopes have failed where the toe had been removed either by stream action or by man. Deforestation has marked effect in rendering the slopes slide prone. In the 1978 landslides, deforested slopes have failed while the adjacent areas with similar topography and geology had withstood slide movement, possibly because of the vegetal cover (Raja, 2006).

4.14 Modifications in Hill Environment: The Nilgiris

2,623 meters. The Nilgiris have tea cultivation at the height of 1,000 to above

2,500 meters. This also produces eucalyptus oil and temperate zone vegetables.

136 two national parks in the Nilgiris. Mudamulai National Park is in the northern part of the range at the junction of Kerala, Karnataka and Tamilnadu covering an area of 321 sq km. Mukurthi National Park lies in the Southwest of the range in Kerala, covering an area of 78.5 sq km The whole sweep of Western Ghats to the

Northwest and Southwest come under the realm of India's first biosphere reserve, which is a home to number of bird species, including the Nilgiri Pipit,

Nilgiri Woodpigeon and Nilgiri Blackbird. Nilgiris is also home to Toda people a tribe that has been living there for ages. High above the sea level, situated at the junction of the two ghat ranges of the Sahayadri Hills, Nilgiri district provides a fascinating view. Kerala on the west, the Mysore State on the north, and

Coimbatore district on the east and south bound it. Headquarters of Nilgiris district is Udhagamandalam (also called as Ooty). Nilgiris means "Blue

Mountains". The entire area of the Blue Mountains constitutes the present district of Nilgiri. The height of the hills in the Blue Mountain range varies between 2,280 and 2,290 metres, the highest peak being Doddabetta at a height of 2,623 metres. (Figure-4.2)

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Table-4.1 depicts the results of modifications made by human on hill environment from 1990 to 2010 using geospatial technology. The changes are vast among the settlements and estates which are given in ha for all the taluks in Nilgiris district.

Table-4.1 Human Modification of Hill Environment (1990 to 2010)

S.No Taulks Name Settlement Estate s s Ha Ha 1 Panthalur 29.2 82.4 2 Gudalur 15.6 74.9 3 Udhagamandlam 15.1 72.6 4 Kothagiri 30.6 29.4 5 Coonoor 12.0 62.1 6 Kundah 10.6 32.1 Source: Data Generated from Analysis

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Nilgiris derives its charm from its natural setting. The steep hills and fantastically narrow valleys with numerous rivers and rivulets running in all directions with a few fine waterfalls here and there provide beautiful scenery. The temperate and most equable climate further heightens the attractiveness of the place.

4.14.1 Hill Environment

A mountain is a landform that extends above the surrounding terrain in a limited area. A mountain is generally steeper than a hill. Mountains cover 54 per cent of

Asia, 36 per cent of North America, 25 per cent of Europe, 22 per cent of

South America, 17 per cent of Australia, and 3 per cent of Africa. As a whole,

24 per cent of the Earth's land mass is mountainous. 10 per cent of people live in mountainous regions. Most of the world's rivers are fed from mountain sources, and more than half of humanity depends on mountains for water.

The fragile balance of plants and animals that share the Earth took millions of years to develop. Some life-forms have persisted in nearly their original state, surviving episodes of mass extinction. Some, like us, are relative newcomers. The ones that have perished will not return. The web of life connects the smallest bacterium to the giant redwood and the whale. When we put that web in peril, we become agents of calamity. Wild life in Nilgiris contributes to a major share in the total wild life in India. One of the major wildlife attractions in

Nilgiri hills is spotting a Nilgiri Tahr (an endangered mountain goat). Elephants, deers, bisons, peacocks, panthers, hynas, bears, wild boars are some of the notable species in Nilgiris.

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Nilgiris has to offer untouched natural mountains and forests which attracts trekkers from all over the world. Trekking is so famous in Nilgiris that it is also known as ‘Trekkers’ Paradise’. A trekking in these mountains will give you an insight into the variety of flora and fauna that this heavenly place has to offer.

Nilgiris is also known for its tea cultivation. The steep mountain sides, the climate, humidity are in right proportion to make the ‘Nilgiri Tea’ have a unique fragrance and flavour. The breathtaking views of the sprawling tea estates along the mountain plateaus look as if there is a green carpet on the hills welcoming the visitors.

The region around Nilgiri Hills is famous for its colorful culture. Every year numerous fairs and festivals are held here. Noted among them are 'Tea and

Tourism Festival' and 'Summer Festival'. The Ministry of Tourism, Governments of the Tamil Nadu and the Government of India jointly organize the 'Tea and

Tourism Festival' during the months of January-February. Held for 3 days, the festival provides you an opportunity to explore and taste wide varieties of tea available there.Shopping in Nilgiris are a real charm and exciting. Ooty, the headquarters of Nilgirs, is a beautiful town with road side flower shops to big shopping malls with exclusive Nilgiri products including Nilgiri tea, Home-made chocolates, Fruits, natural oils like Eucalyptus oil, Toda embroideries, plant nurseries are easily available.

As a tourist destination, the Nilgiris has been favorably compared with famous tropical resorts, including Nuwara Eliya in Sri Lanka, Baguio in

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Philippines, Mount Kilimanjaro in Tanzania, the Blue Mountain resorts of New

South Wales and the lake resorts of Guatemala.

4.15 Mountains of South India

The NilgiriMountains of south India is considered unique by anthropologists, geologists, climatologists, botanists as well as tourists. It has remained a subject of constant study and researchover the last two centuries. Man-nature balance hadcontinued undisturbed in the Nilgiris for thousands of years until the early 19th century when it became a British colony attracting, in due course, various developmental activities. Subsequently, the Nilgiris and its popular hill stations emerged as favourite places for the British population in India for rest andrecuperation, game and for raising commercial plantations. In the process, the traditional indigenous crops were replaced by “English” vegetables and thenatural forests gave way to commercial plantations of coffee, tea and other exoticspecies of trees. After Independence in 1947, the government of India accelerated the developmental process on the same lines as during the colonial period leading to a rapid growth of urbanisation and commercialplantations.

Increasing pressure on land for agriculture and monoculture plantations displaced an alarmingly high proportion of natural forests and grasslands leading to an extensive loss of biodiversityand turning the Nilgiris into a biodiversity

“hotspot”.

Nilgiris entered an anxious era of landslides, which have become more frequent and disastrous in recent decades. The “Report on the study of

Landslides of November 1993 in Nilgiris district” observed that “occurrence of

141 land-slides in Nilgiris, particularly at the onset and during the north-east monsoons, is a ubiquitous, recurring, annual phenomenon”. The colonists simultaneously developed theNilgiris as a tourist resort for the English population. When independence came, the English were replaced by the Indian princely classes, politicians, capitalists and bureaucrats. After the 1970s, tourism became a mass industry for various reasons. Tourist arrivals increased exponentially to cross a million a year since 2000. However, without a proper plan to promote iton desired lines, the lop-sided and haphazard growth of tourism brought more harm than good to the hills. Alongside, unrelenting commercialization and immigration explosion with no corresponding improvements in infrastructures and amenities have begun to strain the carrying capacity of the hills,leading to water famine, pollution, urban congestion and marginalisation of the indigenous people. The Nilgiris is at the cross roads in the

21st century. Its development appears to have reached its limits with the predominant plantation economy collapsing and its tourism industry stagnating.

Any further shifts in land use or cropping pattern appear economically unsound and ecologically catastrophic. Promotion of tourism again may prove counter productive unless there is a radical change in the focus and objectives of the industry in consonance with the overall priorities of the district. The Nilgiris is desperately looking for the best international practices to balance the needs of development and conservation.

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4.16 Biodiversity

About 3000 varieties of plant species are found in this “ecological paradise”.

About eighty plant species, including 36 species of orchids, are endemic to the

Nilgiris. Broadly, two distinctgroups of flora represent the Nilgiris. Up to about

1800 msl, the dominant plants are “megatherm”. Above 1800 msl, there is a distinct groupshowing “European or north temperature affinities (valerians, violets, anemones, pimpernels, barberry etc).” The outstanding floristic peculiarity of the Nilgiris is due to the exceptional amount of endemic plants side by side with introduced “exotic” trees, shrubs, herbs, etc. (Hockings 1989 p46). The

Nilgiris forms part of the Nilgiri Biosphere Reserve, the first of its kind establishd in the country.

There are as many as ten different vegetation types in the Nilgiris, which are classified into the following four major zones. Dry Deciduous Forests of the hills occur below 1100 m and serve as sanctuaries for the extraordinarily rich wildlife. The Mudumalai wildlife sanctuary, one of the oldest in the country, is spread over a 1000 m high plateau. Moist Evergreen Forests occur up to 1800 m. They are now mostly lost to large scale plantations of coffee and tea. Montane

Zone Forests form a cool (average temperature: 10 15 degree centigrade) dark temperate zone spreading out among the numerous clusters of native habitations. Theseforests, called the “Sholas” locally, occur between1800 2000 m. Montane Zone Savannas are grasslandsabove 2200 m. Grasses present here vary in heightfrom less than six inches to eight feet.

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4.17 Indigenous People

There are five indigenous groups in the Nigiris, which also boasts a pre-history dating back to about BC 10,000.The ecological and anthropological significance of the area has rendered it one of the most intensely researched areas in the whole Asia. The latest bibliography of 75 the hills contains 6786 entries

(Hockings 1996).'The people and the terrain of the Nilgiri Plateau have long attracted interest because of their unusual characteristics. Throughout the three principal periods - aboriginal, colonial, national independence - the Nilgiri region has constituted a singular and singularly instructive enclave, and a distinct locale as perceived by observers as well asby its inhabitants. “It is clearly an enclave in the sense of having special natural and human characteristics, markedly distinct from those of the surrounding lower lands”, says Mandelbaum (Hockings 1989: 1

19).

4.18 Development - Colonial and Post Independence

Till about the time the British arrived on the Nilgiri hills at the beginning of the

19th century,the economy of the Nilgiris had been based on a “complicated system of intertribal economic and ritual exchange that was based firmly on trust”. Buffalo-herding, small scale swidden cultivation,tool-manufacture for a semi-pastoral lifestyle and collection of minor forests produce were the mainstay of the harmoniously integrated indigenous people. Their collective needs were limited their lifestyle in tune with nature and their value system steeped in conservation. For instance, at the funeral of the Badagas, the numerically largest of the indigenous people, the elders assembled there seek absolution for a long

144 list of sins on behalf of the dead person. About half of these “sins” pertain to crimes against nature. After the advent of the British, the hills were gradually turned into a “resort heaven” for the British population in India. The colonizers also introduced changes in the traditional cropping pattern of the natives, cleared the forests for plantations and generally set the pace for development on the hills. The British introduced a wide range of vegetables, fruits, plantation crops and exotic trees, which transformed the traditional subsistence economy of the district into a commercial one linked to markets in India and abroad. The size and mix of the population also began to change with the steady inflow of population from the plains for working in the plantations, laying roads and railway tracks, construction of buildings and for manning commercial establishments. In 1821,

100 percent of the population consisted of the indigenous tribe-like communities, but by 1961, in contrast, only 25 per cent of the populations were “not immigrants and descendants of immigrants.” After independence in 1947, governmental policies and programs accelerated the developmental process on the same lines as during the colonial period, giving room for the rapid growth of tourism and plantation industries.Plantations (chiefly coffee, tea, eucalyptus, wattle and cinchona) expanded to cover 90 per cent of the cultivated area displacing, in the process, substantial areas of original forests and attracting huge immigrant labour. Mountain Rivers were dammed at several points flooding natural habitats to produce over 1000 MW of power equivalent to 40 per cent of the hydro- electricity generated in the state. Large and medium industries came up in the district in the 1970s to produce photo films, protein products, etc.

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4.19 Impact of population growth on hills environment

As the following table depicts, Nilgiris has experienced a much sharper growth in population both prior to and after independence. According to the latest census the population of the hills is 764,826 with the livelihood opportunities being limited in hill areas, the growth in population immigration only aggravated the poverty situation and marginalized the indigenous people (SNC Newsletter

1986). Note the continuous surge in population for five decades from 1921 to

1971. Loss of biodiversity: The unrestrained spread of monoculture (tea, coffee, eucalyptus etc) destroyed priceless tropical rain forests, montane forests and grasslands which have evolved over millions of years. The Central Soil and

Water Conservation Training and Research Institute(CSWCRTI) situated in the

Nilgiris explains: “Biodiversity and degradation are related because of the differential abilities of species in utilizing site resources and developing full cover for protection of land and water.The variety of species acts as an agent of soil conservation through proper cover human interference has been instrumental in reducing biodiversity in the Nilgiris leading to the disappearance of natural ecosystem.”

“In broad ecological terms, the Nilgiris district has undergone a drastic and quite irreversible transformation since the advent of the British nearly two centuries ago. Modernization of theNilgiri economy has repeatedly caused chains of ecological reaction that have drastically, and most often irreversibly, changed the life of man, other primates, the flora and other fauna which occupied the relevant ecological niches”.

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The formation of lakes to tap hydropower has substantially altered the hydrological pattern of the western Nilgiris. This interference with nature has without doubt been a great stimulus to the economic development of the district and its inhabitants, but the long-term geo-ecologicalimplications might bring about secondary adverse effects that are not yet fully apprehended.

4.19.1 Urban problems

Increasing pressure on urban amenities led to widespread and persisting water scarcity, congestion, and environmental pollution. “In the urban areas of the

Nilgiris district there is lack of regular drainage system. The quantum of drainage water getting into the soil is substantial.

4.19.2 Geological instability

More disquietingly, geological instability led to an anxious eraof landslides. The report of the Geological Survey of India (GSI) investigated the unprecedented floods and landslides in 1978 said, “The stage of preventing environmental degradation in Nilgiri district has been crossed over. The harm has been done.

The present stage is one of repairing these since then with major slides occurring in 1993, 1995 and 2002. The worst ever landslide occurredin 1993. The total length of the main scrap was 1000 meters and about three million tones of debris were moved down. In 1995 a mini hydropower project under planning for over a decade was withdrawn at geological consequences.

4.19.3 Implication of Hill environment

The Palni Hills, which have lost much of the native flora and fauna owing to

`development' and encroachment, await government action on a proposal to

147 declare the area a national park or a wildlife sanctuary. This stunning terrain was once home to large herds of Nilgiri tahr. In the early 1990s, the Tamil Nadu

Forest Department submitted a proposal to the State government to protect much of the Palni Hills by declaring the area a wildlife sanctuary or a national park. The proposal was the result of a remarkable collaborative effort by the

State Forest Department, the Palni Hills Conservation Council (PHCC) and several concerned individuals. Ten years later, the area still awaits the notification in this regard. In the meantime, mounting pressure on the habitat from encroachment and increased tourist inflow has taken its toll on the hills.

The Palni Hills, an eastern spur of the Western Ghats, are located in central western Tamil Nadu. Spread over 2,068 sq km, the Palni Hills are contiguous with the high range Anamalai and Cardamom Hills and form an imposing range of mountains in Dindigul district. Like other mountain ranges such as the Nilgiris in the southern part of the Western Ghats, the Palni Hills are made up of pre-Cambrian gneisses, charnockites and schists, making them one of the oldest mountain ranges in India. In the southwest, the Palni Hills rise abruptly from the plains to form an elevated plateau around 1,800-2,500 metres high; its eastern half is composed of hills 1,000-1,500 m high.

The Palni Hills sustain four major vegetation types - the scrub forests and dry and moist deciduous forests of the low- and mid-elevations, and montane evergreen forests, known as sholas, and native grasslands, a unique feature of the Western Ghats ecosystem, of the upper Palni Hills. The grasslands-shola ecosystem used to be found at all high-altitude areas in the southern half of the

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Western Ghats. The native grasslands are famous for the Kurinji (Strobilanthes kunthianus) flowers, which blossom once in 12 years. Besides providing habitats to several important species of mammals such as the Nilgiri tahr (Hermitragus hylocrius) and the Grizzled Giant Squirrel (Ratufa macoura) that are endemic to the Western Ghats. The Palni Hills are home to many endemic species of plants, amphibians, butterflies and birds. Of great importance to the people of Tamil

Nadu is the role played by the Palni Hills as a critical watershed; streams in the

Palni Hills flow into the Vaigai and the Amaravathi (a tributary of the Cauvery) rivers.

Historically, the Palni Hills have been an island of biodiversity, little affected by the centuries of human history on the distant plains below. The physical nature of their steep slopes and thick jungles combined with the diseases associated with the lower forests kept most people away from exploring the hills. Dolmens in the mid-altitudes of the hills attest to a group of megalithic- era people who were the first known human inhabitants of the Palni Hills. Much later, two groups of people, the Puliayans and the Paliyans, arrived. Until very recently, their offspring practised shifting cultivation and lived off wild fruits and honey. In the last 500 years, small groups of Tamil-speaking plains people settled in a few pockets in the hills, such as Poombari, Vellagavi and

Mannavanur. However, most of the hills retained an unblemished quality, which survived until the mid-19th century when the upper Kodaikanal plateau was developed as a colonial-era hill station. Thus, the Palni Hills were a veritable

Garden of Eden that remained isolated in a land with an ancient, widespread and

149 well-developed human civilisation. A blanket of non-native vegetation covers the lake basin. The Perumalmalai peak, the distinctive Kodai landmark, looms over the lake area. One hundred and fifty years ago this scene would have looked very different, with undulating hills of wild grasses interspersed with shola forests.

4.19.4 Tea Industry

Tea industry is over 100 years old and is the backbone of the Economy of this

District. It is an agro based export oriented industry. Of the total cultivated area,

Tea is grown in nearly 70per cent of the area. As per the recent data available

Tea is grown in over 45,974 hectaresand the production is around 60,000 tons.

The saga of development of tea in India is fascinating. Tea was reported to be growing inIndia in the early 19th century. The search for tea in Assam was started by the East IndiaCompany as an alternative source of supply to United

Kingdom, which until then was mainly dependent on China. With the emphasis on indigenous tea in Assam, the first commercial effort in organised tea cultivation was started by Assam Tea Company in 1839. Tea plants sent from

Calcutta Botanical gardens were reported to be grown in Nilgiris district in Tamil

Nadu in 1839but was cultivated on a commercial scale by 1853.From a modest beginning in 1839, India today is the world's single largest producer of tea and also one of the largest exporters of tea. The total area under tea in the country increased from0.3 million hectares during 1960-61 to 0.5 million hectares during

2003-04 and the productionwhich was 300 million kgs during 1960-61 has increased to 850.5 million kgs during 2003-04.(Economic Survey, 2004-05). India accounts for about 28 per cent of the global production oftea.In India, tea is

150 grown in Assam, West Bengal, Tamil Nadu, Kerala, Kamataka, and to some extent in Himachal Pradesh and Tripura. South India accounts for nearly 25 per cent of thetotal national production. The exports of tea from this region are of the order of 100 million kg per annum, which constitutes more than half of the total tea exports from the country. Tea plantation is one of the major plantation crops grown in Tamil Nadu. It is cultivated mainly inthe hilly and high rainfall zones of

Nilgiris, Coimbatore, Dindigul, Theni, Kanyakumari andTirunelveli districts. In

South India, Tamil Nadu leads both in terms of area and productionfollowed by

Kerala and Kamataka.Tea has occupied an important place in Indian economy for the last several decades. In fact, tea industry is regarded as one of the most important agro based industries in India. Itprovides direct employment to over one million workers in the country. Unlike other agriculturalcrops, tea provides the highest employment per unit of arable land. In 2002, there were 12.55lakh people employed in tea plantations. Women contributed about 50 per cent of the workforce.Many more are employed by other sectorsrelated to tea and tea trade like tea machinery, packing, ware houses, etc. Tea industry earns foreign exchange for the country and the contribution of tea to the totalagricultural exports eamiiigs was 4.96 per cent during 2003-04 (Handbook of Statistics on theIndian Economy, RBI, 2004-05).The exports of tea from India during 2003-04 was 183.1 millionkgs in quantum and Rs. 1636.9 crore in export earnings as against 211.3 million kgs in quantumand Rs. 2003.2 crore in export earnings during 1997-98 (Economic Survey, 2003-04). It is estimated that more than 16 per cent of total tea exports in the World are from India.

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Besides, it also generates revenue to Cenfral and State Governments through indirect taxes related to tea manufacturing and sale of the finished product. It is estimated that about Rs.10,000 to Rs. 12,000 per ha is paid by the industry as Government revenue in different forms.However, the tea sector in

India is passing through a difficult phase. The productivity hasdeclined from 1865 kg/ha in 1997 to 1625 kg/ha in 2002. There has been a decline in green tealeaves prices, which has affected the farm economics of the tea growers all over the country. The prices of made tea sold at Indian auctions registered a decline during 2002 over 2001 and this hasput the small tea growers into difficulty. Moreover, new and more efficient sources of teasupplies have emerged in different parts of the world. All these have become a cause of concernfor the

Tea industry, Tea Board and Government. Against this background, a study was undertaken to examine the current status and the entire supply chain management of tea sector.

4.19.5 Tea Estates in Nilgiri

A tea tour to south India will take you to the Nilgiris, a picturesque range of hilly landscapes. It is here that you will find tea gardens at elevations ranging from

1000 meters to 2500 meters. The tea estates in Nilgiri produce tea that is mild in taste with a mellow and clean liquor. Moreover, tea is grown all year round in the

Nilgiri region, unlike Assam and Nilgiri where it is but seasonal. Having a lateritic origin, the Nilgiris soils are red and yellow loam. Most tea plantations here get two monsoons owing to which the tea bushes in South India 'flush' all the year round resulting in cropping season throughout the year.

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Tea produced in the tea estates in Nilgiri give a fine and pronounced flavor. The flavor of the tea is derived from the high elevation and prevails throughout the year in the varying degrees. Considered as blender's dream,

Nilgiri teas give the liquor body and strength as well. During a tour of the tea producing areas in the Nilgiri region, the best places to visit are the Kodanad

Estate, Lockhart Tea Estate, Highfield Tea Factory, Glendale Tea Estate and

Vigneshwar Estate Tea Factory. The tranquil ambience, soothing greenery and salubrious climate - everything about the Nilgiri region spells magic. So why don't you experience this magic for yourself with a tea tour that will add up as an experience to cherish for life

The Blue Mountains or the Nilgiris are mountain ranges situated in South

India. Nilgiri tea is grown at elevations ranging from 1000 meters to above 2500 meters. Nilgiri teas are relatively mild with a mellow, light and clean liquor and grow all year round unlike the seasonal Assam and Darjeeling teas. Nilgiri tea is usually auctioned in Coonoor, Coimbatore and Kochi. Oolong and Black teas are produced in large quantities. Most of the tea is grown for domestic consumption, though some of it is exported, particularly the higher grades and green teas.

Most tea plantations get two monsoons here owing to which the tea bushes in

South India 'flush' all the year round. Therefore the cropping season continues all through the year.

The Highfield Tea Factory, Kodanad Estate, Vigneshwar Estate Tea

Factory and Hittakkal Estate Tea Factory, are the most well known tea estates in

Nilgiri. Other noteworthy tea estates in Nilgiri are Ripon Tea Estate, Mayfield Tea

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Estate, Goomankhan Tea Estate, Lockhart Tea Estate, Glendale Tea Estate,

Parkside Tea Estate, and many more.

4.19.6 Flora

Over 2700 species of flowering plants, 160 species of fern and fern allies, countless types of flowerless plants, mosses, fungi, algae, land lichens are found in the sholas of the Nilgiris. No other Hill station has so many exotic species

Much of the Nilgiris natural Montane grasslands and scrublands interspersed with sholas has been much disturbed or destroyed by extensive tea plantations, easy motor vehicle access and extensive commercial planting and harvesting of non-native eucalyptus and wattle plantations (Acacia dealbata, Acacia mearnsii and cattle grazing. In addition there is one large, and several smaller hydro- electric impoundments in the area.

4.20 Effect of Deforestation on Landslides in Nilgiris

Landslides occur as a consequence of various triggering factors. Rainfall is one such factor. But the human intervention like deforestation may cause the soil to lose its capacity and ultimately lead to landslides during heavy rainfall. The

Nilgiris in the Western Ghats entered an anxious era of landslides since the calamitous landslides of 1978. The frequency of landslides has increased in recent years with major slides occurring in 1993, 1995, 2002 and very recently in

November 2007. The Nilgiris landslides have been demonstrated to be the reflection of pore pressure increase during the rainy seasons. The major problem in Nilgiris district is deforestation between 1849 and 1992, the shoals were decreased from 8,600 ha to 4,225 ha (Newspaper article reference). Previous

154 studies on deforestation and land use changes in Western Ghats showed a loss of 25.6 per cent in forest cover between 1973 and 1995 in the southern part.

The present study aims to find the extent of deforestation in Nilgiris district and the increase of landslides due to deforestation.Figure – 4.3 is the IRS P6 digital data for Nilgiris District (cropped)

Table 4.2 shows the Land use changes from 1970 (using the base data generated from ITM) and optical remote sensing digital data for the year 2010.

Figure -4.4 shows the classified image in to ten categories of land use data have been grouped to find the changes between two time periods. They are dense forest cover, open forest cover, scrub, rocky area, grass land, dense tree cover, and plantation cover, urban and built up areas, water bodies and estates. The pixel by pixel change from 1970 to 2010 clearly shows that there had been a

155 decrease of 32 in dense forest cover, 2.38 in open forest, 1-24 in scrub class,

11.54 in grass land, 4.93 in dense tree cover, 5.73 in plantation crops and very meager level of water bodies, all in km2. There has been increased or exposed rocky surface of 16.6 km2 and expansion of urban areas in 14.47 km2 and increase in estates 26 km2. The results indicate there has been a radical change among the built up areas and estate building in the district.

Table-4.2 Land use Changes from 1970 to 2010

S.No Category Topo sheet Km2 2010 Km2 Difference m2 Pixel m2 1 Dense Forest 70630.26 70.63 39143627.58 39.14 -31.49 2 Open Forest 28451.37 28.45 26073497.91 26.07 -02.38 3 Scrub 11668 11.66 10428817.80 10.42 -01.24 4 Rocky area 14572.17 14.57 31188488.63 31.18 +16.61 5 Grass land 32055.77 32.05 20518571.63 20.51 -11.54 6 Dense tree 16400.55 16.40 11472539.30 11.47 -04.93

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cover 7 Plantation cover 27791.36 27.79 24063975.2 24.06 -05.73 8 Urban 5072 05.72 20190534.36 20.19 +14.47 9 Water bodies 6855.17 06.85 6.746553.97 06.74 -0.11 10 Estates 54509.18 54.50 80372356.8 80.37 +25.87 Source: Digital image analysis and Indian Toposheet

The following six classes were identified, namely, the water bodies, dense forests, open forests, degraded forests, grasslands and plantations. The definition for different forest classes used were; Dense forest- having a canopy cover > 40 per cent , Open forest - having a canopy cover between 20 and 40 per cent ; Degraded forest with < 20 per cent canopy cover (this class also includes scrub vegetation and forest blanks). The method of maximum likelihood classification was adopted and the change detection statistics were extracted for different time periods of 1973-1989, 1989-1992 and 1992-1999. The detection of changes from initial state of 1973 to final state of 1999 was also reported to get an exact idea about how much deforestation has taken place over the last 26 years. (Figure –4.5)

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Table-4.3 Land Resource Development plan

S.No Categories Area m2 1 Water bodies 15032.83 2 Afforestation 5072 3 Afforestation/Gap Horti 16400.55 4 Silmpasture forest TPLN 1400.71 5 Sivil pasture/Grass land 2791.36 6 Dense deciduous forest 7930.26 7 Preserve 1666.80 8 Multi layer 32055.77 9 No change 2851.37

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4.21 Results and discussion

As seen from the Table-1, 482.85 km2 of dense forest was drastically reduced over a period of 15 years. This accounts for about 56.87 per cent of reduction of thick dense forest. Not much change was reported for open forest but the amount of degraded forest has been increased to 24.94 per cent which includes the

Udhagamandalam town and the surrounding area. The wattle (Acacia mearnsii/A. dealbata) plantation in the southwest part of Nilgiris district was removed and resulted in an increase of about 482.76km2 grassland. Between

1989 and 1992, the reported changes were less with a maximum 180.39 km2 reduction of open forest. As seen from Table 1, 23.56 per cent of dense forest,

2.94 per cent of open forest, 13.87 per cent of degraded forest has decreased from 1992 to 1999. The overall changes between 1973 and 1999 shows that, about 446.05 km2 of dense forest has been reduced which accounts for about

52.53 per cent nearly 197.4 km2 open forest has been replaced which accounts to 18.57 per cent. This results in increase of grassland toabout 516.33 km2. The loss of dense forest cover is more pronounced between 1973 and 1989, as a result of which the degraded land and grassland increased during the period. The reduction of open forest reached the maximum during 1989-1992. The plantations, especially the tea estateswere observed to be maximum during

1989-1999.

Table-4.4 Land use changes Land Use / *Landuse changes in km2 Land Cover 1973-1989 1989-1992 1992-1999 1973-1999 Dense forest -482.85 161.03 -124.23 -446.05

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Open forest 9.27 -180.39 -26.28 -197.4 Degraded forest 67.06 32.76 -51.16 48.66 Grassland 482.76 -86.28 119.85 516.33 Plantation -93.74 71.47 81.9 59.63 Water bodies 17.5 1.41 -0.08 18.83 *Positive and negative sign indicates increase and decrease in landuse respectively.

To study the impact of deforestation on landslides, the frequent landslide prone area was demarcated with reference to Geological Survey of India map, which includes 5 major slides and 14 other important slides forming an area of

330.56 km2. The landuse/landcover map of 1973, 1989, 1992 and 1999 within that landslide prone area was prepared. Among them 98.47 km2 of dense forest have been reduced drastically within the landslide prone area of 330.56 km2 between 1973 and 1999. As a consequence of the massive reduction, the tea plantations were increased to 55.10 km2 and grassland to 37.19 km2. Also the increase in degraded forest was 11.38 km2 over a period of 26 years. When trees are cut down, their roots are no longer available to hold the soil together. A heavy rainfall is sufficient to make the rocks and boulders come hurtling down. The landslides in Nilgiris are mostly of this nature i.e. rainfall induced landslides.

Though tea plantation is a far better soil binder on the hills, compared to vegetables like potato, tea gardens in the district are prone to frequent landslides because of the lack of proper drainage. All these plantations have short inadequate roots, leading to an increase in the number of landslides.

4.22 Conclusion

The present study of forest cover changes using multi-temporal remote sensing clearly shows the extent of deforestation. The land used for tea estates without

160 considering proper drainage and slope ultimately results in loss of natural ecosystem and ends in massive frequent landslips.

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Chapter Five

Results, Discussion and Conclusion 5.1 Land Use Patterns in the Region: Pre-colonial and Colonial Periods

In the early 1800s the slopes of the Upper Plateau were bought over by the colonizers, chief among them being John Sullivan, from the Todas at one rupee an hectare. The Nilgiri Upper Plateau was the habitation zone of the Toda tribe, who were a semi-nomadic pastoral people. They had herds of semi-wild hill buffalos with different pastures during the dry season from January to June. Their settlements in the midst of shola forests with good surrounding pasture land and running water nearby are called munds (actually mod, which means a herd of cattle). The main source of Toda livelihood was the buffaloes that they bred with great love and care, and indeed worshipped. The buffalo milk was processed into butter, ghee and buttermilk, the surplus of which they bartered with neighbouring tribal groups and visiting merchants from the plains for other necessities. The sholas provided medicinal plants, fruits, and other edibles.

Millets were grown by agriculturalist Badaga people who had migrated in waves from Karnataka to this region centuries back. Badagas also served as traders for goods from the plains together with incoming Chetties. Clothes, grains, jaggery, salt and other commodities including opium derived from poppies grown by the Badagas were obtained from them by the Todas, who also provided them with churning sticks of rattan and cane products like beds and baskets in addition to milk and milk products and their beautifully embroidered shawls for ceremonial occasions. It was a custom for Badaga corpses to be covered with

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Toda shawls. Sometimes a Badaga would entrust his buffaloes to the care of his

Toda partner, who would take the animals along with his own to the pastures.

Todas often approached Badagas for medical help.

The Kota people were the blacksmiths and smiths in gold and silver, artisans and musicians. They live scattered in seven settlements in the Nilgiri district and there is one settlement in Wayanad. Each Kota family serviced a certain number of Toda and Badaga families living at not more than a day’s walking distance. They provided them with pots for the household, metal tools, axes, knives, jewellery, oil lamps, clay smoking pipes and other metal works. In return they got ghee, male buffalo calves and buffalo carcasses for leather work from the Todas. When there was a death in the Toda family the Kota had to provide many of the necessities like arrows, knives, sieves etc., and also play music at the funeral. At a Kota funeral, which the Toda attended, they provided a buffalo to be sacrificed as well as ghee to be poured on the pyre. During the Kota annual ceremony in honour of their god Kambataraya, the Toda supplied ghee made from milk processed at their sacred dairy temples. The Kota also supplied leather goods and did carpentry work for the Badagas. They also helped to thatch the houses and provided ceremonial music. In return the Badagas supplied cloth, grain, jaggery and salt to the Kotas. For the hunting ceremony of

‘bedasami,’ performed by both Badagas and Kotas, the Todas used to bring clarified butter to smear on the weapons.

The Kurumbas were the forest based tribes and they provided forest produce to the others, such as honey, bees wax, herbal plants and therapy,

163 baskets, winnows and large grain storage baskets. From his Alu Kurumba partner who lived in the Upper Plateau, the Toda got forest produce, particularly honey, bamboo and rattan for house building and baskets for a variety of purposes. The short wooden post to which buffaloes were tied for sacrifice and the long wooden pole set up in front of the funeral temple at the second funeral of the Todas were also supplied by the Alu Kurumbas. In return the Toda gave buffalo calves, some ghee and clothes. The Kurumbas because of their deep knowledge of the forests were also feared as sorcerers, particularly by the

Badagas. At the same time, their services were solicited for warding off magical attacks and for protecting their crops and animals from diseases.

The Irulas in the Nilgiris are a forest-based community like the Kurumbas and live mostly on the lower eastern slopes in uni-ethnic settlements or together with Kurumbas, with whom they have economic exchanges and maintain friendly relations. The Irulas also grew millets and fruit trees like lime, jack, orange and bananas in gardens around their settlements. The two ethnic groups helped each other in growing their crops in shifting cultivation. The Irula priest offered priestly services to the Kurumbas in their ceremonies. The Kotas received brooms, bamboo artefacts, honey, resin incense and other forest produce from Irulas. In return, the latter got field and garden implements from the Kotas. As the

Kurumbas, the Irulas also supplied baskets, winnowers and winnowing fans of split bamboo to the other neighbouring communities. Some Todas used to receive bamboo flutes from the Irulas of some villages. They went down to the plains for bartering forest produce for salt, tobacco, clothes and other such items.

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The social symbiotic relationship among the indigenous groups involved economic, cultural and ritual interactions. While each of the tribal groups had their specialization, they also carried out multiple livelihood activities. The Kotas, for example, also herded animals and grew some millets, cereals, garlic, mustard etc. for self-consumption through shifting cultivation. The Kurumbas and Irulas were food gatherers and hunters but they also carried out slash and burn agriculture and domesticated animals such as chickens, goats and sheep. They depended on each other for several necessities of life. This relationship involving not just economic exchange of goods, but with ritual and social dimensions was mostly on a hereditary basis between families of each community.

The Badagas were Hindu (Shaivite) peasant refugees. When Hyder Ali and Tipu Sultan established their kingdom in the Deccan, large numbers of peasants came to the Nilgiris as refugees. They were mainly from the Mysore part of Karnataka, and they are known as Badagas (Northerners). By and large they settled in the Tamil Nadu side of the Nilgiri Hills where some of their compatriots had wandered in and settled down in earlier times after the

Veerashaiva anti-caste Hindu reformist movement faced severe repression in

Karnataka during the 12th and 13th centuries. They continued to come at the time of the fall of the Vijaynagar Empire also around the mid-16th century due to the consequent political instability. At around this time the Mysore State rulers converted to Vaishnavism and made the worship of Vishnu a state cult, which began to be enforced upon the people. This created some conflict between the

Shaivites and Vaishnavites and this could be one of the reasons for the flight of

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Shaivites to the Nilgiri Hills.2 They are there in Kodagu and Wayanad also where they are known as Gounders. They were granted land by a council of men from the indigenous Toda, Kota and Kurumba tribes. In part, they cleared virgin tropical montane forest. In many ways they adapted to the lifestyle and culture of the pre-existing tribes for the sake of their own survival.

These groups were endogamous and their interrelationship resembled that of the Hindu jajmani system, but without its extremes of hierarchy and complete subjugation of some groups by others. Untouchability was unknown. If reciprocity was not adhered to there was a withdrawal from the cooperative arrangement and no other family from the withdrawing group would replace the one who had withdrawn. The need for the other would necessitate the required adjustments and mutual cooperation. In their search for land suitable to millet cultivation the Badagas probably pushed Kurumbas lower down the hills and the

Todas further upwards, but this does not appear to have been done through using any violent means. Rather the methods used earlier were consensual. By and large it was a peaceful and autonomous existence in the hills. Each community had its own priests and council of elders with no overlord. The councils came together for consultations in cases which concerned some or all the groups. Kotas, for e.g., interceded to find solutions to intra-Badaga conflicts and vice versa.

This peaceful and autonomous existence came to an end in the early 17th century when the kings of Mysore became rulers of Wayanad and titular possessors of the Nilgiri Hills. The latter were under the immediate rule of

166 dependents of theirs called Udaiyars or the Rajas of Ummattur. The Plateau became involved in a military struggle between the kings of Mysore and

Maduraifor the control of tribute primarily from the Badagas. A number of fortresses were erected in various parts of the hills. Butthe general way of life of the tribal people was not disturbed as a result of this tussle for overlordship of the region.

It was the British interventions in the region which started the process of massive changes, whereby the hill peoples and the environment, the flora and fauna, came to be at the receiving end. The land revenue farming system of the

British and their transformation of the area into a cash crop cultivation one had repercussions on the indigenous peoples’ livelihoods and interrelationships. The land legislation promulgated by them in the 1860s and ‘70s forbade shifting cultivation and made the forests into state property. Some land had already been bought at throwaway rates from the Todas and vast tracts of grazing land and forests were seized for tea and coffee plantations and exotic tree species without any compensation at all to the concerned Adivasi groups. In place of the native species many water guzzling exotic trees were planted to be used as fuel wood for domestic fires, for use in tea factories that were established, and for industrial use, to some extent in the hills but mostly in the plains (this was the manufacture of quinine, paper and medicinal oils like eucalyptus). The consequent deforestation affected the livelihoods of the indigenous peoples, who lost hunting areas and sources of forest produce.

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Different communities reacted differently to the British encroachment. The

Badagas as agriculturists followed and adapted; the Kurumbas retreated further down the hills. The Toda and Kota adapted slowly and reluctantly under the force of circumstances. The colonial interventions in the economy of the region also disrupted the mutuality between the indigenous groups. It was during this time that conflict between Badagas and Kurumbas over land ownership and control became acute. Periodic massacres of the Kurumbas took place by the Badagas in the 19th century under the charge of witchcraft.

By the time of the first British census in the region in 1812 the Badagas had become the numerically dominant community due to increased migration of peasants from the Mysore plains, and soon they became the local economically dominant one as well. An internal differentiation took place within the community.

Even earlier there had been some caste-class based differentiation but now it grew apace. Those who could not pay the land tax became tenant small holders, landless labourers and plantation workers. Indebtedness grew and much Badaga land was sold to British planters. The invasion of the place by new settlers and a new economy made the 19th century into a traumatic one of droughts, famines, starvation and epidemics (plague, smallpox, cholera) for the indigenous people and their livestock. Having lost the sources of their earlier livelihoods and culture they had perforce to adapt themselves to the new times.

Only some villages near the new towns of Ooty and Coonoor achieved a measure of prosperity. Jakkatala village sold much of its land to the government for the Wellington Barracks and then profited further from contracts for gangs of

168 labourers to build the barracks, the railway line and some other public structures.

By the beginning of the 20th century some Badaga families had become very wealthy as contractors. The value of modern education was also realized by many in this community. Literacy in English and Tamil enabled them to take over high positions in the British administration as karnams (accountants) and managers. Farmers took to commercial farming in imitation of the British and started using fertilizers and pesticides. Money lenders and other middle men made their appearance.

Toda lifestyle was rudely disrupted by the colonial interventions in the region. They were no longer able to pursue their pastoral nomadic way of life as earlier. A large chunk of grassland was now occupied by plantations or exotic tree species. Trees like acacia and eucalyptus dried up much of the marshes and swamps, which had been sources for reeds used to build the warm Toda huts.

The kurinjee along with other plant and shrub species disappeared with the vanishing of the shola grassland landscape. The dark brown honey processed from the nectar of the kurinjee flower by the bees was no longer available.

Diseases brought by the white people into a pristine terrain decimated the Toda population and they were reduced to a few hundred by the 1940s.

With the marketisation of the economy, starting in the early part of the 20th century the cooperative relationships between the indigenous groups more or less came to an end by the 1950s. The market became a means of exchange for all the groups. Many of the products produced by these groups no longer had any takers and became slowly extinct. Kota pottery, which was mainly the work

169 of Kota women, has almost become an extinct art. The demand for Kota blacksmith articles also dwindled drastically because of the British policies of import of goods and lack of support for Indian rural crafts. The Kotas were also not trained to manufacture the implements required in the plantation economy.

So in the end these industrious creative artisans were forced to limit themselves to agricultural activity, mainly on their own lands, but some also do work as skilled or unskilled agricultural labourers and some are engaged in animal husbandry. Loss of land and livelihood transformed many Kurumbas and Irulas of the Upper Nilgiri Plateau into plantation labourers.

The population in this area, hitherto sparse because of its inhospitable climate, grew by leaps and bounds with large-scale immigration from the plains for doing the coolie work on the plantations. The percentage of the population of the indigenous people declined in relation to the total population. Today, the tribal population of the district is only 4.32 per cent of the total population, which stands at 7.35 lakhs as per the 2011 Census. Presently, the Todas, the most ancient tribe of the Nilgiris, total about two thousand including Toda Christians.

The changes in the land use pattern also affected the terrain negatively. Land erosion began to take place and landslips became commonplace.

5.2 The Post-colonial Period

In the post-colonial period the horticultural and plantation economy of the Nilgiri district continues, though now the ownership has been transferred to Indian business houses and to the State government. The region has also developed into a major domestic and to some extent international tourism destination as has

170 happened in the case of most ‘hill stations’ developed under British rule. Every significant bank and big business house within the country has built up its own holiday home here. Hundreds of hotels, small, big, medium and large have come up. Much of the construction activity takes place in gross violation of hill area building rules and the Master Plan. None of this heightened building up was followed by a complementary expansion of civic amenities like proper roads, sanitation and drains, waste and sewage disposal means. Thousands of tourists come to a town like Ooty every day during the tourist seasons. The situation is pregnant with serious dangers for public health. Already incidences of jaundice, typhoid and other such water-borne diseases have spectacularly increased in the last few years.

With every passing year so-called natural calamities are also increasing in scope and frequency. For example, the two principal towns—Coonoor and

Ooty—are often cut off from Coimbatore, which is their life-line. Enormous land slips occur with even a few days of rainfall. It is not that the rainfall is extraordinary, but the reality is that the whole land mass is steadily becoming more and more vulnerable. The frequency of heavy and light vehicular traffic on these roads, unscientific construction activity and agricultural practices have become clearly insupportable for the terrain and contribute considerably to soil erosion and air, soil and water pollution.

The tourism sector is carried out mostly by private players coming from outside the region and by the State and Central governments, for which it is a major source of revenue. Very little benefit accrues to the local indigenous

171 people, apart from some sales of embroidered shawls by Toda women, some pottery items by Kota women, and honey and other products sourced by

Kurumbas. Toda villages are objects of tourist curiosity and the streams of visitors to the village sited above the Botanical Garden (situated on grasslands usurped from them) have misled some of the inhabitants to indulge in begging from the tourists. They have degenerated into objects of tourist curiosity and are victims of flavoured social and cultural anthropological studies by Western scholars.

Roads and highways that are built for trade and tourism purposes have cut into the remaining pasture lands of the Todas endangering whatever buffalo stock they still have with them. Now buffalo herding is done in the vicinity of the settlements and the milk and milk products sold. This remains a source of livelihood for the majority of the Todas. Many Todas have been forced to become agriculturists cultivating potatoes, vegetables and even tea. Some of them do not themselves practice agriculture, but have leased out their land for cultivation. Not all Todas have been able to switch to agriculture. They are poor and are not able to avail of bank loans required for agriculture. They do coolie work; collect eucalyptus leaves, act as extras in the many commercial films shot here, or work as caddies in the golf course.

The change in lifestyle and loss of the traditional buffalo culture, much unemployment or employment not suitable to their educational qualifications among the educated youth, and the free and plentiful availability of IMFL has made a large number of Toda youth and men into alcoholics. Healthy habits like

172 drinking of buttermilk are replaced by tea and coffee drinking. There is clear-cut degeneration of once tremendously healthy people. Toda women are trying to improve their status within a largely patriarchal pastoral culture. While polyandry and infanticide are no longer practiced (which were used to control population growth earlier and maintain clan solidarity), bride price has given way to the dowry system. Full equality is not yet assured to the women, who are still not allowed anywhere near the sacred dairy temple, where the priest is always only a male, and where no ceremonies accompany the name giving function of a female child.

Hydro electric power stations have also destroyed vast stretches of forest, wiped out some endemic flowering plants and broken up older pasture lands of the Todas and destroyed their hamlets. Water pollution due to effluents let out from seven major factories, tea factories and small-scale units, pesticides and fertilizers being used in plantations and for vegetable cultivation, and from municipal wastewater and sewage have affected the local plant species, many of which do not flower now, and fish populations in the water bodies. This pollution also kills many local insect species and birds. Many species of Nilgiri bees have begun to disappear. Chemicals used in agricultural lands adjoining the forests are destroying them. Forest Protection Acts are often violated in connivance with forest officials and trees are cut down. Illegal stone quarrying is going on by stone mafias and road contractors buy stones from these illegal quarries with impunity.

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It is estimated that the Nilgiri sholas have shrunk from 8600 hectares to about 4225 hectares and there is an 85 per cent loss of grasslands. The role of the sholas as ‘overhead tanks’ feeding underground aquifers from which springs the Kaveri many kilometres away in Kodagu is thus undermined creating water shortages crucial for farming in the plains and deltas of Karnataka and Tamil

Nadu. Water shortage is there in many parts of the Nilgiri district too with an unsustainable rise in the settled population and with an enormous floating tourist population. The swamps in the region too have diminished in numbers due to exotics. In addition to sustaining many wetland flora and fauna they also support many streams with water round the year. They too need to be conserved for their role as water catchments. A large chunk of government reserves still remain under exotic plantations in the Upper Nilgiri Plateau, which cater to the industrial demands of companies like South India Viscose and others. The forest departments are making efforts now to remove many ecological predator species that have got introduced into the region. This includes acacia, eucalyptus, lantana and parthenium weeds. Pine trees are also not suited to the grassland terrain; having shallow roots on thin soil strong monsoonal winds are apt to uproot and crash them down causing much damage to overhead electrical power lines, dwellings, and passing vehicles on the roads. Adivasis, particularly the Todas and Kotas have repeatedly complained about the encroachment on their traditional lands by the forest department. Apart from such land losses there is land alienation also due to debts and through engaging in leasing rather than self-cultivation of commercial crops.

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All the three main sub-regions of this biosphere face a severe agrarian crisis pertaining to cash crops like pepper, tea and coffee. Wayanad especially witnessed a spate of suicides of the primary producers resulting from this crisis.

In the Tamil Nadu part the crisis of the cash crops sector is no less severe (for example in the tea sector), but as yet suicides are not common probably because there is the cushion of food crops, mainly vegetables (also mainly market dependent), to fall back upon. In the last several years tea prices had dropped below sustainable levels. As usual, the many small growers (mainly from the

Badaga community) were the worst-affected. Farmers in Nilgiris bitterly point out that in spite of many promises of fixing a minimum support price for green tea leaves nothing concrete has been done to date. Price fluctuations are a part of the globalization process.

Since the beginning of the crisis in the tea sector at the beginning of the new millennium the central government started supporting floriculture in the region. The district was declared an agri-export zone for the purpose of generating revenue. But the small farmers who took to the cultivation of flowers for the domestic market in the big cities of India and for export abroad are again facing a debt crisis due to the imbalance between input and output costs. Input costs—greenhouses, which get damaged very often due to the strong velocity winds, drip irrigation planting materials, costs of fertilisers and pesticides—are more than the prices received, which are not able to cover production and transportation costs. As in the case of tea, manipulation of prices is there by the private traders in collusion with the big farmers. Small farmers who had taken

175 bank loans to support the costs involved have recently been involved in many agitations for the writing-off of the loans, for the formation of a Floriculture Board, co-operative marketing rather than through private dealers. But the government departments or bank officials are not willing to concede any of these demands.

Alienation of the land of small growers to real estate players is a growing reality.

In short, displacement and marginalization of tribal communities has taken place due to an economy based on tourism development, commercial forestry and cash crop cultivation. An agrarian crisis is affecting the small growers hailing mainly from the indigenous Badaga community.

A study conducted by Government of Tamil Nadu reveals that the occurrence of landslide gets accelerated from 1978 onwards and if the present trend continues, the possibility of occurrence of landslide will increase from 70 per cent to 100 per cent in the Next 10 – 20 year’s period. The illiteracy is one of the main causes to move population to highly vulnerable areas. About 3785 huts were damaged during 2009 landslide were belonging to the uneducated and low income people of the district. There was improper drainage system in the urbanized areas is the other cause of landslides. Since most of the drainage were blocked and people constructed houses over the river drainages and diverted the water course abruptly. For the development of road the natural slopes were cut by the agencies without any engineering studies is the major cause of landslide in road side areas. From the study, it has been advised to use soil bio engineering technique for lope stabilization where ever is possible. It offers engineers a set of tools to complement those already available in solving

176 range of shallow slope problems. The cost of implementing this technique also is very much less than the civil engineering measures. Also the natural beauty of the hills would be retained in the hill slopes. The Soil bio-engineering provides improved landscape and habitat values. However the soil bio engineering is not suitable for all sites and situations, it is advised a detailed site-specific study should be carried out before implementing this technique.

5.3 Recommendations to reduce the landslide at Nilgiri hills

Under the Pre disaster Management the following mitigation measures may be followed to minimize landslide harzards in Nilgris (Syed Basheer Ahamed and

Gopikrishnan, 2008; Manimaran, 2008).

5.3.1 Railways

a. In India, the two hill regions namely, Darjiling of West Bengal and Nilgiri of Tamil Nadu are having mountain trains facilities.

b. Desilt all the toe drains, side drains, cross drains and catch water pits all along the railway lines.

c. Trains should be cancelled during the time of heavy rain and flooding.

5.3.2 Electricity and telecommunication

All electric poles including high risk towers and transformers should be erected with strong RCC foundations and the strength of pole concrete should be ensured before monsoon.

5.3.3 Buildings

 Pre monsoon checking of foundation, surfaces and drains, etc.,

 Water dampness should not be allowed around the buildings.

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 Special vigil over buildings situated nearby steep slopes.

 Blockage of surface and sub surface drainage should be avoided.

 Angular retaining walls with weep holes should be constructed to protect

the angular earth cut faces around the building.

 Slanting roof with light weight material for design of houses should be

adopted.

 All buildings should be provided with damp proof course at the basement

level.

 Leak proof sewage and drainage channels should be constructed to avoid

infiltration.

 Vacant land portions around the houses to be protected by cement

plastering (as per the local conditions)

 Man made soil erosion activities should not be carried out in and around

the residential areas.

 Made up soil should not be dumped within the site.

 Buildings should not be designed very near to the cut faces.

 Sufficient distance should be provided between the cut face and the

buildings.

 Over head tanks, bath rooms, latrines and septic tanks should not be

constructed very near the (rear side) cut face.

 All septic tanks should be properly sealed to avoid percolation.

 Rain water harvesting sump should be placed on the surface of the earth.

 Plantation of shallow rooted plants and turfing should be done in the

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residential areas.

 Plantation of trees adjacent to the retaining walls should be avoided.

 Construction should not be carried out in the Geo Technically rejected

areas.

5.4 Conclusions

The pattern and nature of landslides occurrence in the Nilgiri hills are common in both the northeast and southwest monsoons. Irrespective of Vegetated or non- vegetated, steep or gentle slopes, all are prone to landslides during continuous over-saturation of over burden due to heavy rain. Comparatively Ghat slopes with inward dipping lithounits are seems to be safe. Increase in settlements at hill tops, both slope and rock dipping outwards from the ghat sections, continuous flooding on heavy rains, intercalation of clay layering in weathered zone are the characteristic features behind the Nilgiri landslides. The increase in the events of landslides Nilgiri may be due to seisomotectonically active Southern Granulite terrain of South India from the time, before and after 2001 Gujarat Republic day earth quake.

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