eChapters

INTRODUCTION

India is endowed with a vast and rich diversity of natural resources particularly soil, water, climate and agro-biodiversity. To realize the optimum potential of the agricultural production system on a sustainable basis, there is a need to bestow a paramount importance in the arena of efficient management of natural resources. India with a geographical area of 329 M ha presently supports 17% of the world’s population on merely 2. 5% of world’s land area and 4% of world’s freshwater resources. India’s economy is predominantly agrarian in nature with about 72. 2% of its 1028 million population (census 2001) living in villages and about 54. 4% people (cultivators) directly depending on agriculture.

INTRODUCTION

Any crop has its own optimal requirements or selective response to the environmental factors such as rainfall/ soil moisture supply, day/night air temperature, soil temperature, duration of sunshine and its intensity. The growth and development of a plant which ultimately governs the agricultural productivity of a region, is closely related with climatic factors. Weather phenomenon has a profound influence on crop growth stage. A moderate wind or a light rain, when the crop growth is near to harvest, may do more damage than even heavy rain and high wind in the vegetative phase. So land use planning by matching crop growth with weather parameters forms a basis for successful agriculture (Samra, 2003) in a particular region. In order to achieve sustainable agricultural productivity in the 21^st century, the climate and weather systems are being recognized as critical agenda and input.

INTRODUCTION

The agriculture in north eastern hill region of India is mainly rainfed in nature and shifting cultivation, known as jhuming, is the dominant farming system. The shifting cultivation is detrimental to both soil and vegetation as it is connected to heavy soil and nutrient losses when practised in steep slopes. The burning and slashing operations are responsible for reduced floral and faunal diversity in the region. It is a well known fact that climate is the main driving factor that governs the sustainability of other natural resources such as land, water and vegetation. So far the NE region gets abundant rainfall for survival of the crops at least during the kharif season. The rainfall starts early March and continues up to the late October. The jhum cultivators follow the rainfall trend and get their field ready for sowing of seeds by early March itself so that vegetative stage of crops gets plenty of rainwater for growth and development. Due to increased population pressure, the hills of NE region are over exploited and the jhum cycle has been reduced from 10-12 years to 4-5 years now-adays. Hence the soils do not get sufficient time to revitalize it and are subjected to more and more exploitation and get degraded permanently.

INTRODUCTION

Of an estimated 142 mha of net cultivated areas in India, about 67 % is rainfed and only 45 mha is irrigated. The NCA (1976) predicted that even when the full irrigation potential of the country is exploited by 2013 AD, over 50% of arable land would continue to remain rainfed in future. It is the rainfed belt where cultivation of 91 % coarse cereals (Sorghum, Pearl millet and Finger millet), 91% pulses (Chickpea and Pigeon pea), 80% oilseeds (Groundnut, Rapeseed, Mustard and Soybean) and 65% cotton have predominated. Even the crop that formed the backbone of green revolution such as rice and wheat, still have 50% and 19% area under rainfed condition, thus emphasing the importance of rainfed agriculture in India. Inadequate resource (soil and rain water) management coupled with traditional farming practices are responsible for subsistence farming. Monocropping, traditional crops and their varieties, low and imbalance nutrients and inadequate crop establishment, in past, had been the major cause for poor development of dryland agriculture in the eastern region.

INTRODUCTION

Rubber cultivation in regions extending from 10°N to 10°S latitude is known as the traditional region and the areas other than its natural climatic origin is termed as the non-traditional region. Northeast India comprises majority of the non-traditional areas in India with major climatic constraints like high seasonal rainfall, excessive precipitation and to some extent dry conditions. These areas extending from 22 to 29^°N latitude, holds promise in extending rubber cultivation because of its exceptional climatic make-up and abundant amount of annual precipitation (2000 mm) distributed over a fair period of time.

This perennial crop generally yields latex rubber at the 7th year after planting (with an economic life span of 20 years), although the period (immaturity period) it requires, is higher in the non-traditional region (Rubber Growers Companion, 2006). This immaturity period has also been shown to reduce with water availability in sub-humid climates (Vijayakumar et al. , 1998). Harvest of this crop is by tapping. Tapping is a process of controlled wounding during which thin shavings of bark are removed, thus opening the latex vessels which exude latex. Dry rubber yield is obtained after the latex is coagulated and rolled into sheets (about 500gm) which is then smoked and dried.

INTRODUCTION

The weather conditions during the growing season of crops influences the onset and development of disease. The relationship between weather and plant disease development is the basis for meteopathological forecasting. On the basis of observed or forecast weather conditions, the incidence of plant disease is likely to be predicted.

Such predictions are designed to warn growers of expected significant developments in the manifestation of a particular plant disease. Such disease forecasts, if sufficiently accurate, permit efficient and competent counter measures to be adopted. A short range or medium range of disease forecast, issued at short intervals during the growing of crops, can give guidance to the farmers on the best remedial measures. Growers can decide whether a chemical control measure is needed or not, and if needed then optimum date on which to be applied and similar day to day decisions to fight against disease to minimize the losses to be caused.

The result, of adopting such a plan of weather based control measures, is to reduce the number of chemical sprays to a well timed few, thus giving an equal or even better protection at a lower cost in chemical and labour, and simultaneously reduces losses caused by phytotoxic and mechanical damage to the crop. The reduction in the use of potentially toxic chemical is a matter to be welcomed in the present world, considering the consequences of the widespread use of toxic chemicals.

INTRODUCTION

Integrated Pest Management (IPM) has been defined as a “system that, in the context of the environment and the population dynamics of the pest species, utilizes all suitable techniques and methods in as compatible manner as possible that maintain the pest populations at levels below those causing economic injury” (Glass 1975). The Inter society Consortium for Plant Protection (ICPP) has defined integrated pest management as “the use of multiple tactics in a compatible manner to maintain pest population at levels below those causing economic injury while providing protection against hazards to humans, domestic animals, plants and the environment”. The term ’integrated’ means it is a broad interdisciplinary approach taken using scientific principles of plant protection of variety of management strategies and tactics to fuse into a single system. The terms ‘pest’ means all biotic agents which adversely affect plant production. This includes insects, mites, nematodes, weeds, bacteria, fungi, viruses, parasitic seed plants and vertebrates. The term ‘management’ indicates to keep the pest population below some level based on economic criteria. It does not mean complete eradication of entire pest population.

INTRODUCTION

Mizoram is a hilly terrain lying in the north eastern part of the country. The total geographical area of the state is 21, 087 sq. km and lies between 92º 15/ to 93º 29/ E longitude and 21º 58/ to 24º 35/ N latitude. Out of six agro climatic zones of the NEH region, Mizoram comes under sub tropical hill zone and posses a sub tropical and humid climate due to high rainfall (Fig. 1). These climatic conditions are very conducive for the cultivation of a large number of agri-horticultural crops. The physiography of the state is divided into hills and valley lands. About 90 % area of the state comes under hills and only 10 % area is under valley. The valley lands are sporadically distributed in small patches except in Champhai district. The slope of the hills in Mizoram is much steep as compared to the other states in the North Eastern region. The land use statistics of the state is presented in Table1.

INTRODUCTION

Several biophysical factors govern the agricultural productivity of a region. Among the key biophysical factors, weather and more particularly rainfall has the over riding impact on agricultural productivity since rainfall is a primary source of water and the first requirement for raising any crop. This element influences various dynamics of crop growth and development and accounts from nearly two thirds of variation in agricultural productivity. The amount of rainfall at a particular place is important; an equal important factor is its temporal distribution, which is uneven, uncertain and erratic in most part of the country. Breaks in monsoon are common phenomenon during the monsoon period. The analysis of rainfall characteristics such as occurrence and distribution of dry or wet spell is essentially required for successful crop planning, development of befitting agro techniques, recommendation of suitable crop variety, designing of water harvesting ponds, earthen dams and other soil conservation structures. It is also an established fact that the crop development will be affected if the dry spell coincides with sensitive phonological stage of the crop and sometimes beneficial if it coincides with the ripening stage. Hence for the purpose of crop planning and to carry out the agricultural practices, it is important to know the sequence of dry and wet periods. An attempt has been made in this paper to analyse the rainfall in standard meteorological week as well as monthly basis at different probability levels for Lembucherra by using computer based forecasting technique.

INTRODUCTION

The state of Manipur is located at the easternmost border of India and is characterized by flat valleys comprising of four valley districts (Bishnupur, Imphal East, Imphal West and Thoubal) surrounded by five mild to steep slope hill districts (Chandel, Churachanpur, Senapati, Tamenglong, and Ukhrul). The state is geographically bordered by Nagaland in the north, Burma in the east, Mizoram in the south and Assam in the west. The total geographical area of the state is 22, 327sq. km divided into 20, 089sq. km in the hills and 2, 238sq. km. in the valley. More than 98% of the population in the hill is in rural areas whereas around 60% of the population in the valley is in rural and around 40% are in the urban areas.

The AAS Unit, Imphal is located at 24045' N latitude, 93054' E longitude at an altitude of 774m above msl. The agro-climatic zone of the state covers sub tropical plain zone, sub tropical hill zone, temperate hill zone and sub temperate zone.

INTRODUCTION

It is well accepted that the climatic changes also influence the geomorphic process efficiency and landform development (Ahamad, 1985). Glaciation, sea level changes, flooding and many other geo- environmental events are related with global and regional climatic changes along with tectonic and other non-tectonic factors like natural vegetation, soil, organic development etc. Considering the role of climate on landform development and dynamics of the Late Quaternary climate, a climato-geomorphic study was conducted on the coastal and paleo-coastal areas of the Bengal Basin namely-lower Western (West Bengal coast) and Eastern (Tripura Paleo-coastal Fold Belt Province) Geo-provences. The main objectives of the study were to investigate (i) Development of the landforms during Late Quaternary period with sea level changes and (ii) Climatological influences on the landform modifications.

INTRODUCTION

India has varied agroclimatic conditions, which favour the cultivation of various horticultural crops. Based on the adaptability and system of cultivation, the horticulture can be grouped into four major class such as Temperate, Sub-tropical, Tropical and Arid. India has become the second largest producer of both fruits and vegetables with a total production of 46. 75 million tonnes of fruits from an area of 4. 56 million ha and 93. 16 million tonnes of vegetables from 6. 30 million ha (2003-2004). Besides, there is a tremendous scope for increasing the production of flowers, spices and condiments, plantation crops and medicinal and aromatic plants. Floriculture has emerged as a viable agribusiness. The commercial cultivation of flowers in open field conditions was much popular than protected cultivation in India. But, now- a-days, the protected cultivation has brought a great revolution in Indian floriculture and it helps for the quality production and export to earn sizeable amount of foreign exchange. India has approximately 350 ha under green house cultivation with export value of approximately Rs. 330 crores during 2003-04(APEDA). On the other hand, the prevailing climatic conditions in India are highly suitable for cultivation of the almost all spices from tropical black pepper to temperate saffron. The major spices are mainly grown in humid tropics like Western Ghats and NE States. Out of 21 agro-ecological sub regions in India, spices are grown in 14 different agro ecological sub regions. Fruits, vegetables, flowers spices and condiments, plantation crops and medicinal plants are widely distributed across the country, while plantation crops are restricted to a few regions.

INTRODUCTION

Edible mushrooms are higher fungi occurring seasonally all over the world in various habitats varying from sandy plains to thick forests. About 2000 fungal species in the world have been identified as edible, of which, only a few (20) are cultivated commercially (Chang and Miles, 1991). These mushrooms are generally considered as the good source of protein, vitamins and minerals in addition to their flavour and condiment value. About 3.

INTRODUCTION

Livestock plays a very important role in the mixed farming system of the country contributing about 25 per cent of Gross Domestic Products (GDP) from agricultural sector. India has the largest population of cattle and buffaloes and the highest producer of milk in the world. India has also the second largest population of goats and one of the leading countries in poultry sector. There has been a tremendous increase in milk, meat and egg production since independence. However, owing to various reasons viz. , low genetic potential, scarcity of feeds and fodders, diseases, poor management practices etc. , the productivity is quite low. Climatic conditions of a place have also an important bearing on livestock production and productivity. Climatic factors like ambient temperature, humidity, solar radiation and wind velocity are the important ones which make up the physical environment of the animal having direct and indirect influences on animal’s responses towards climate. Temperature and humidity are the most crucial with the former being the most researched one. Extremes of hot and cold weather are creating stress to any animal and the effects are more severe under hot and humid climate. The varied effects of undesirable climate on animals are pertaining to feed and water intake, physiological, biochemical and endocrinological aspects, reproduction, health and productivity etc. Thus, the positive and negative effects of the environment on the livestock have been discussed in a way to undertake some protective measures.

INTRODUCTION

Prediction of helminthic infections is impractical. The aim of any control programme must therefore, ensure that parasite populations do not exceed levels compatible with economic production. The parasitological monitoring (e. g. faecal egg counts or pasture sampling) at intervals, forecasting on the basis of meteorological data and computer simulation may provide an alternate approach to control parasitic infection (Brunsdon, R. V. , 1980) in a given geographical area. The most common gastrointestinal parasite prevalent throughout the year in Meghalaya, India is Strongyle infection. This is because of the high rainfall and humidity prevalent in the North-Eastern region.

As the prevalence of this infection is mainly dependent on rainfall and humidity, study was being initiated to identify the relationship between rainfall/temperature and strongyle infection. The study would be also helpful in predicting/ forecasting the disease occurrence based on the prevailing pattern of rainfall in a particular location.

INTRODUCTION

One of the most important changes in the global environment which affects the existence of all living things , is the climate change. The climate change globally and locally also changes the aquatic habitat which, in turn directly and indirectly affects the environment. Anyway, the changes in climate are certain to occur and may be inevitable. The only possible way is to analyze the situation and find out the reasons for such changes and take immediate steps to minimize the impact of these climate changes. Global warming has eventually become synonymous with climate change because almost all the variables of the ecosystem are influenced directly or indirectly at different levels.

Aquatic environment is extremely diverse and influenced by the climate changes to a large extent both locally and globally. The changes in the ocean and its life are well studied at different levels with all possible details compared to the freshwater habitats. Unlike agriculture and animal husbandry, the vast majority of the fish production still comes from the natural habitat or the wild collections. Agriculture and animal husbandry usually focus on few important species but for fisheries, all the species of fishes including most of the aquatic living organisms are commercially important. The media (water) in which the aquatic organisms dwell, is much more important to all living organisms of the earth and so the influence by climate changes on water becomes very much relevant in the present situation. Freshwater habitats are limited and are much more complex to investigate in respect of climate changes due to the variability and diverse micro and macro level interactions. A holistic approach to deal with all these problems has not got much attention both globally and locally even though , it is the need of the hour to address the issues of impact of climate changes in the aquatic environment.

INTRODUCTION

Aquaculture had undergone rapid expansion and intensification in the recent past and has taken the shape of a full-fledged diversified industry. But the risk involved in aquaculture activity has also increased significantly due to the outbreak of diseases which has a devastating effect on the aquaculture crops. Fish are aquatic and poikilothermic, their existence and performance are dominated by the quality of their environment . The aquatic environment is a complex system subject to constant physical and chemical changes brought about by natural and manmade processes. Therefore, choosing the proper site to develop aquaculture facility is paramount to its success.

A disease is an abnormal condition of an organism caused by infection, inherent weakness or environmental stress; it prevents the organism from functioning normally which ultimately leads to death (Avault, 1998). In an aquatic environment, there is a profound balancing of relationship between host (fish), pathogen and the environment existing and this is the fundamental concept to disease susceptibility of fish (Snieszko, 1973). A disease organism may be present in the environment or host, but will not cause disease as long as the host has high natural resistant or the physical condition of the host is strong. Once the imbalance is created to any of the component, opportunistic pathogen invades the host resulting to the outbreak of disease.

Key words : Remote Sensing, Ecosystem, Environmental Pollution, Biodiversity Conservation, Coastal Environmental Degradation, Wetland.

Introduction

National prosperity and human resources development are primarily shaped by the availability of natural resources and their use. None the less, the benefits are quite often negated by the resultant environmental degradation concomitant with their utilisation for economic values. The problems of environmental degradation have assumed critical dimensions in many parts of India due to resources exploitation; industrialisation and urbanisation, unchecked population growth and a never ending quest for energy to meet the increasing demands. Moreover, improper utilisation of resources has resulted in such environmental problems as soil erosion, waterlogging, floods, droughts and pollution of various types besides socio-economic disparity among people.

After the 1972 Stockholm conference on Human Environment and Development, there has been a phenomenal increase in the worldwide interest in the environmental issues associated with development. Consequently, the focus of development has shifted to environment friendly and sustainable developmental planning in recent years. The Rio Summit (June 3-14, 1992) further emphasised the fact that earth is an integral and interdependent system, which require sustainable developmental planning. During deliberations of the Rio Summit (Earth Summit), it was emphasised that satellite imagery will be quite helpful in monitoring earth’s environment.

India has a long tradition of environmental protection and has enacted laws during the last three decades to give further impetus to the conservation of natural resources and protection of environment. Some of the important laws are:

Introduction

Precision Farming (PF) revolves around the idea that any agricultural land contains wide spatial variations in soil types, nutrient availability, and other important factors. If these variations are not taken into account, then there may be a loss in productivity. Precision farming is one of the most scientific and modern approaches to sustainable agriculture that has gained momentum in 21^st century. Consider the situation: ‘A farmer goes to his/her field with his/her Global Positioning System (GPS) guided tractor. The GPS senses the exact location of the tractor within the field. It sends the signal to a computer on the tractor that has a Geographical Information System (GIS), storing the soil nutrient requirements map in it. GIS, in consultation with a Decision Support System, decides what is the exact requirement of the fertilizer for a given location and then commands a variable rate fertilizer applicator, attached with the tractor, to apply the exact dose at that precise location. All this is done within a second, before the tractor moves further.’ This may sound like an excerpt from a scientific fiction, but this is what precision farming means to the large growers of the United States or European countries and day is not far off when it will be feasible for large Indian farmers as well.

PF refers to a developing agricultural management system that promotes variable management practices within a field according to site or soil conditions. Within a short span of time, this concept has been described with various names viz. farming by soil; farming soil, not fields; farming by the foot; spatially prescriptive farming; computer aided farming; farming by computer; farming by satellite; high-tech sustainable agriculture; soil-specific crop management; site-specific farming; and site-specific crop management.

Key words : NRSA, Natural Resource and Disaster Management, Agricultural Drought, Ecosystems, Biodiversity Information System, Water Resources, Sea Surface Temperature.

Introduction

A few decades ago, paper maps were the principal means to synthesize and represent geographic information. Manipulating this information was limited to a manual, non-interactive process. Since then the rapid development of new technologies to collect and digitize geographic data, together with an increasing demand for both interactive manipulation and analysis of this data, has generated a need for dedicated software’s namely geographic information systems (GISs).

A GIS is more than a cartographic tool to produce maps. It stores geographic data, retrieves and combines this data to create new representations of geographic space, provides tools for spatial analysis, and performs simulations to help expert users to organize their work in many areas like public administration, transportation networks, military applications and environmental information systems. These above mentioned are few among many others where we are concerned with geographical locations, their present status, its potential for developmental activities, patterns of change over the years and the processes on the surface of the earth.

Geographic information technology is used to manipulate objects in geographic space, and to acquire knowledge from spatial facts. Spatial information theory provides a basis for GIS by bringing together fields that deal with spatial reasoning, the representation of space, and human understanding of space.

Key words : Horticultural Resource Information System. INARIS.

Introduction

Wide ranging Indian climatic conditions are well suited for boosting production of a variety of horticultural crops (fruits, vegetables, flower/ornamental/medicinal and aromatic crops) which presently hold an important position in the global scenario. Development was at a very low ebb till the Third Five-Year Plan and increased significantly since the Seventh Five Year Plan (Rs.10,000 millions plan outlay). Government of India established National Horticultural Board (NHB) in 1984 and Agriculture and Processed Food Products Export Development Authority (APEDA) in 1986 to facilitate its larger development. The outlay is expected to increase even more in the Tenth Plan. Significant progress has been made in area expansion of different horticultural crops resulting in higher production. Besides, use of modern technologies has also brought about improvement in productivity. More than 50 per cent increase in production is seen in many of the horticulture crops during last one decade.

The efficient planning and implementation of different developmental programs on horticultural crops depends on production parameters like soil suitability, varietals dominance, marketable surplus, marketing channels, post harvest handling practices, cost of cultivation and market availability for sustained production. In addition, information on latest technologies developed by various research organizations on horticultural improvement, production, protection and post-harvest technologies are needed to be collected and made available to the scientists, planners and managers working in the related fields. But the available information on this aspect is scattered and the database is too weak to provide adequate support for developmental strategies. The digitization of comprehensive database on horticultural crops will definitely enhance the pace of increasing the area, production, productivity and promoting industry of horticultural crops that have taken lead in the new millennium with reference to nutritional quality of food and export potential. A strong, well-knit database to support need-based, market-driven and cost-effective horticultural development is imperative. Therefore, under National Agricultural Technology Project (NATP) a Mission Mode Sub-project on “Integrated National Agricultural Resources Information System (INARIS)” has been taken up to evolve a comprehensive computerized data management system on various agricultural resources like crops, animals, fishes and natural resources by harnessing RDBMS and GIS. The Co-operating Center at Indian Institute of Horticultural Research, Bangalore has developed the “Horticultural Resources Information System” with the objectives of (i) integrating existing databases in horticulture, (ii) designing and developing a comprehensive database in horticulture and (iii) developing resource maps of major horticultural crops in the country by integrating attribute and spatial data through GIS. In addition to simple storage and retrieval it will include other functions such as manipulation and dissemination of information to various users. This database will be integrated with 13 other Co-operating Centers dealing with different agricultural resources through a virtual private network (VPN). The Lead Center at Indian Agricultural Statistics Research Institute, New Delhi provide warehouse facility with a capability to analyze the data variously and provide report as cubes, tables and graphs to form a national database to cater to the needs of the users through a website. The facility of retrieving information as value-added maps using GIS will also be built in.

Key words : Wasteland Reclamation, Poverty Indicators, Food Insecurity, Alternate Livelihood Systems, Rural Infrastructure Index.

Introduction

The countries of Asia and the Pacific region accounts for nearly two-thirds of the chronically poor and undernourished in the world. FAO estimates indicate that, by 2010, Asia will still account for about one-half of the world’s malnourished population (FAO 2000). In Asia, poverty has mainly been rural phenomenon and nearly three-fourth of the poor live in rural areas, with large majority of them dependent on natural resources for employment and income. South Asia, which had a poverty incidence of 43 percent (or about 520 million people), contributed about 40 percent of the world’s poor. Development of natural resources thus offers a potentially enormous means of poverty reduction.

In developing countries poverty and environmental deterioration are often viable in proximity to each other, and have led many to infer that a two-way causality exists between human and environmental degradation. Environmental degradation usually occurs when production and consumption activities of growing population irreversibly weaken nature’s recycling capabilities. These economic activities are also attributed to the development of markets, the advent of modern technology, and the spatial integration of inaccessible areas to market systems. In many developing countries, however, environmental degradation such as soil erosion, deforestation and pollution are most visible around poor settlements, leading some policy makers to highlight the direct links between poverty and the environment.

One has to recognize that both poverty and the environment are descriptions of states of human and natural resource attributes and cannot be reduced to simple one-dimensional cause-effect relationships. Apart from conceptual difficulties in modeling linkages, another handicap has been the absence of adequate or reliable data sets on poverty and environment characteristics. The challenge for operational research is exploring how circumstantial evidence and inductive logic can be used to explain the nature of interactions between the two states. Based on nationwide wasteland statistics vis-à-vis state and district wise poverty estimates available with the concerned agencies, this study is one such attempt, and evaluates the incidence of poverty with the backdrop of natural resources degradation and role of institutional interventions with illustrations from India.

Key words : Glaciers, Glacial Lakes, Glacial Lake Outburst Floods (GLOF), Himachal Pradesh, Glacial Inventory, Glacier Recession.

Introduction

Glaciers are large masses of snow, re-crystallized ice and rock debris that accumulate in great quantities and begin to flow outwards and downwards under the pressure of their own weight. Glaciers form when yearly snowfall in a region far exceeds the amount of snow and ice that melts in a given summer. In this way, massive quantities of glacial material accumulate in relatively small periods of geologic time. The glaciers exist in environments of high and low precipitation and in many temperature regimes; they are found on all the continents except Australia and they span the globe from high altitudes in equatorial regions to the polar ice caps. Presently, 10% of the Earth’s land area (5.8 million square miles) is covered with glaciers storing about 75% of the world’s freshwater. However, during the last Ice Age, glaciers covered 32% of the total land area of the planet.

Key words : GPS, GIS, DSS, SDSS, RS, Digital Elevation Model (DEM), Ground Water Exploration, Conjunctive Use of Surface and Ground Water, Digital Terrain Modeling (DTM).

Introduction

Water is one of the most precious gifts of nature to living beings and particularly to the mankind. On account of erratic distribution of rainfall both in time and space, the country is subjected to cycles of floods and droughts. With the increase in demand for water for various purposes and to mitigate the twin problems of floods and droughts faced by the country, a coordinated approach for optimum utilization and proper management of this precious resource is of prime importance. In addition, proper development and management of both irrigation and drainage systems are essential. This would require integrated management of surface water as well as gorund water. All the water related problems whether mitigating droughts or floods or better irrigation management practices, dictate for adoption of state of the art water management practices. Water management deals with the control, distribution and allocation of water flows and the treatment of rivers and catchments, consequently, solutions to many of the problems in water management require the knowledge and expertise from diverse sources.

Key words : Integrated Watershed Management (IWM), GIS, DTM, Watershed Delination, Water Quality Modeling, RS, DSS, Ground Water Information System (GWIS).

Introduction

The availability of land and water resources has a major effect on the economic and ecological aspects of life everywhere around the world. As a result, the need to develop better tools for efficient land and water resources management has become very vital. For quicker, reliable and precise results, it is necessary to use the geospatial tools and techniques such as Global Positioning Systems (GPS), Geographic Information Systems (GIS) and Remote Sensing (RS) image interpretation and analysis techniques to manage the natural resources. The application of these tools and techniques not only facilitates timely and repetitive analysis of all the topological features, but also assists in development of Decision Support Systems (DSS) to generate alternative scenarios for optimal use of the natural resources in the long term. The optimal use of these resources through integrated management of land water and vegetation leads to enhanced production and productivity of food, fodder, fiber, fuel, fish, flower and forest resources. Moreover, the holistic management of the resources to produce these outputs is plausible and manageable within the watershed systems, which are hydro geological units from which the runoff resulting from precipitation flows past through a single outlet to downstream locations. The systematic management of land, water, vegetation and livestock resources within the watershed systems is termed as Integrated Watershed Management (IWM). Broadly, IWM can be defined as a multidisciplinary, holistic way of protecting and managing a watershed’s natural resources to enhance biomass production in an eco-friendly manner. The watershed is viewed as a hydro-geological complex and dynamic ecosystem in which natural and anthropogenic processes occur and interact resulting in generation of runoff at the watershed outlet.

Key words : Flood Plains Agro-ecosystem, GIS, RS, Spatial Cropping Pattern, Radiometric Normalization, NDVI, Agricultural Systems.

Introduction

Of late, evidence is accumulating to suggest that high productivity and growth rates achieved during the Green Revolution era in the well-endowed regions of the country (i.e North West India) are no longer being sustained to meet the needs of still increasing population in the country. Past growth sources have nearly exhausted and there is also no scope for expansion of crop land. Indeed pressure for competing land uses will likely reduce area under food grain crops. Shrinking natural resource base (per capita availability of land and water devoted to agriculture), declining quality of resources and environmental degradation issues will imply increasing threat to our ability to meet the basic needs of the growing population of the region unless we shift our effort to potential regions like flood plains of the country for improving productivity.

The flood plain riverine lands of India covering approximately 42 m.ha though most endowed with natural resources and has all the potential of becoming rich, is still economically backward. The reason behind this paradox of extent of poverty in the midst of richness of resources is that the natural resources of the region are not being productively harnessed into the process of the economic development and thus are not delivering their potential and commensurate benefits to the people. The Green Revolution technologies evolved during of 60’s and 70’s had little or no impact in this region of the country. Undesirable spatio-temporal distribution of flood in these areas keeps agriculture under uncertainty and risks. These are also the areas where the poorest are concentrated and agriculture largely continues to be more of subsistence. The nature of agricultural problems are highly variable due to great diversity in the production system as also in the socio-economic conditions of the communities requiring location specific approaches to address the problems and enhance the productivity.

Key words : Groundwater Modelling, GIS, PMWIN, ArcInfo Interface Con2grid, Interface Programme, ArcMacro Language.

Introduction

Groundwater is an important source of irrigation in India and has played a major role in increasing the food production. About 50 per cent of total irrigated area in the country is dependent on groundwater (Central Water Commission (CWC), 2000). Productivity of groundwater is normally more than the surface water due to the fact that it is available at the point of use, requires minimum conveyance infrastructure, is available on demand and maximizes the application efficiency. However, in past few years, excessive and unplanned groundwater pumping in certain parts of the country has resulted in depletion of groundwater resources. Water table in these region is going down day by day and making it beyond the reach of poor farmers. Therefore, keeping the water table in the desirable range is a major concern. This can be achieved by adopting proper pumping rate and pumping schedule. Groundwater modelling has successfully been used for deciding the pumping rate and pumping schedule. Groundwater modelling refers to simulation of groundwater behaviour under varying pumping and recharge conditions. A groundwater model is simply a set of equations, which describe the physical processes active in the aquifer subjected to certain assumptions. While the model itself obviously lacks the detailed reality of the groundwater systems, the behaviour of the validated model approximates that of the aquifer.

Key words : Participatory GIS (P-GIS), Geo-Participatory Rural Appraisal (Geo-PRA) Social Mapping, Resource Mapping, Seasonality Maps, DGPS.

Participatory GIS

Geographical information System (GIS0 and Geographics Information Technologies (GITS) are no more restricted to the elite group of the society. Planners are busy in searching ways in merging community participation with GIS in the context of urban planning, environment equity, sustainable development etc. (Aitken and Michael, 1995, Craig and Ehwood, 1998; Talen, 2000 and Sieber, 2000). In all the cases, common thing is the linking of community participation and GIS in a diversity of social and environmental contexts. Through development, demonstration and modification of methodologies by academics and practitioners the concept of Participatory GIS (P-GIS) emerges. It is an outcome of a spontaneous fusion of participatory forms of development planning with modern information technologies. Experts gave considerable thoughts on the probing questions like whether a bottom up GIS could be successfully developed, how many community participation could be incorporated into GIS and to what context such participation would serve only to legitimize conventional top-down decision making. From these reflections only the concept of people’s participation GIS arose.

In this chapter, an attempt is made to emphasize the fact that while no country in the World is safe from geohazards, a proper understanding on their causes, ways to mitigate them and surviving techniques would help reduce the life and property loss. Each geohazard has its own characteristic way of potential impact and hence classifying vulnerability of different regions and creating awareness on potential impact is essential. In addition to providing basic information on geohazards, this chapter presents a conceptual model on hazard mitigation, rescue and relief operations.

INTRODUCTION

Every year, thousands of people are killed by volcanic eruptions, earthquakes, landslides and floods. These natural causes damage human settlements and infrastructures (GOI, 2004) inflicting life and economic loss. As human population increases, habitation on hazardous and or vulnerable land becomes more common and the risks posed by these hazards increase. The need to observe their behavior, understand them better and mitigate their effects become ever more urgent (IGOS, 2003). Decades of research may have contributed towards betterment of our understanding on the processes of geohazard formation but still a long way has to be covered to develop better mitigation procedures.

This chapter reviews the published information on tsunami and attempts to characterize tsunamigenic sediments in terms of their microfossil content. Tsunamisare long-period waves generated by vertical displacements of marine watercolumn due to earthquakes, volcanic explosion and landslides. These waves can exceed heights of 25 meters (in shallow water) and lengths upto 100km with a velocity of more than 1000km/hour. Even at this magnitude, they are undetectable in deeper waters owing to very low wave height which in turn reduces significantly the response time, causing sudden havoc along coasts. They can cause flooding of coastal areas and affect areas thousands of kilometers away from their point of origin. These characteristics of tsunami imprint ensuing sediments with unique assemblage of microfossils.

INTRODUCTION

Shallow water progressive waves with very large wavelength and long duration caused by the rapid displacement of ocean water are called “tsunami”. Tsunami is a sudden non-meteorologically induced impulse in water regardless of size. Tsunamis are formed by submarine tectonic activity more often due to earthquakes and less frequently due to volcanic eruption, landslides near the coast, meteor impact and nuclear explosions.

The velocity of the tsunami varies and depends on many parameters such as bathymetry, height of the originating wave, initial pressure changes in the sea, etc. and can travel at a speed of more than 1000 km/hr. At the place of origin (directly above the epicentre of submarine earthquake or any other causative factor), the wavelength may be upto few tens to several hundred kilometres but the wave height is often less than one metre only. Since the velocity is proportional to the depth of the water column, it gets reduced to few tens of kilometres as the tsunami approaches the coast. However, the wave height increases significantly reaching 100 m in extreme cases. As a result, the tsunami strikes the coast with massive force. The effect is colossal in islands with low relief. The tsunami waves appear as flooding with water rushing inside the land more violently and with great force towards a river course. In several cases, when the tsunami arrives, the water level in the sea may drop significantly and the waters receding several hundred metres come back with great speed drubbing the coastal lands doubly from both the directions. Though an event of short duration in terms of geological history, tsunami deposits, owing to their higher rate of deposition and other salient characteristics, find place in stratigraphic records. This chapter is an attempt to review the characteristics of tsunami and tsunamigenic sediments, to find out the ability of microfossil content of such sediments for characterization and to identify tsunami deposits in stratigraphic records.

A review on historic occurrences of tsunamis in the Indian Ocean and their associated characteristics followed by detailed characterization of genetic causes of recent tsunamiarepresented in this chapter. Althoughsubmarineearthquakes occur very frequently, resultant tsunami and its strength relied on many factors including transformation of energy into the ocean water, area of rupturing of ocean floor, duration of rupturing, accompanying submarine slides, kind of material at focus of earthquakes and type of faulting. The direction of tsunami wave propagation plays the decisive role in deciding sites of impacts. Perfect blend of all these parameters is required to make a submarine earthquake to generate devastating tsunami, which is relatively rare in geological history. This is the reason why although there were as many as 77 tsunamis that occurred in the Indian Ocean region during historic past, the recent one of 26th December 2004 is deadly and rare geological occurrence. However, aftermath effects in terms of volcanic eruptions, coastal high wave activities and change in climatic cycles are recorded since then and require constant scientific vigil.

INTRODUCTION

Tsunami is defined as a sea wave of local or distant origin that results from large-scale seafloor displacement associated with major earthquake or submarine slide or submarine volcanic explosion. Many a times it is incorrectly described as tidal wave or seismic sea wave, as both of these terms mislead in regard to its mechanism of generation. In Tamil Sangam literature, tsunami is cited as “Azhipperalai”. In South America, it is termed as “Maremoto”. Other names for tsunami include “Flutwellen”, “Vloedgolven” “raz de mare” “Vagues Sismique” and Kai e’e. Prevalence of specific terms for tsunami in many such regions and languages itself stands testimony to the fact that tsunami is known to ancient human populations and that tsunami occurred frequently the historics past.

Detailed information on tectonic evolutionary history of the Bay of Bengal is presented followed by elucidation of these characteristics towards tsunamigenesis in this chapter. The Andaman-Nicobar Island Arc (ANIA) is situated on a 1000 km long plate margin and represents a key region in the developing oceanic crustal area of Bay of Bengal. Frequent earthquakes including the tsunamigenic earthquake of 26th December 2004 off the coast of Sunda take place in this region. The subduction of Indian plate under Myanmar-Thailand plate drives formation of chain of Andaman-Nicobar group of Islands. These oceanic crust formation, subduction and arc formation are all seismigenic and generate shallow focus earthquakes in the Bay of Bengal. It is also observed that the seismicity is decreasing as the bathymetry increases towards SW of the Bay of Bengal. Thus, in long term, the slow accumulation of stress as tectonic plates converge may result in many more earthquakes in this region. After a dormancy of over 100 years, the Barren Island volcano renewed its activity following recent earthquakes. The seismic activity along the Andaman-Nicobar trench is continuing with earthquakes of magnitude varying from 4.8 to 7.2 Richter scale. All these observations suggest resurgent and intense tectonic and volcanic activities due to which allied hazards such as tsunami may take place in future.

INTRODUCTION

The evolving Earth, depending on its heat flow pattern in the mantle throughout geological time, had passed through stages, which are diagnosed through characteristic geodynamic signatures. This chapter focuses on a very active region in the crust, namely, the Andaman-Nicobar Island Arc (ANIA) to recognize such signatures and decipher relative safety of surrounding regions including east coast of India. As similar active arc systems such as Sunda Arc & Japan Arc generate volcanic, seismic and tsunami hazards, understanding the ANIA would be of help assess safety of surrounding regions. Abundant geoscientific literature exists on the northern part of the Indian plate, which is undergoing compressive stress since collision between the Indian and Eurasian plates about 55-45my. However, the behavior of remaining part of the Indian plate underneath the Indian Ocean is still sparcely studied. Owing to these reasons, this chapter attempts to fill the gap in our understanding as well as to assess the implications of renewed phases of geohazard occurrences including that of catastrophic earthquake and tsunami of 26^th December 2004.

Need for systematic mapping and hazard zonation is emphasized in this chapter. Though prevention of natural disaster is not possible, its destruction could be minimized through implementation of effective hazard management system. With this motive, the coastal region between Tangapatnam and Ovari, Tamilnadu State has been classified into various categories of vulnerability based on its response to the 26th December 2004 tsunami. Based on the extent of seawater inundation and coastal geomorphic features, we have assessed the tsunami impact and estimated the behavior of the beaches in case of similar havoc in future. This study had shown that the maximum seawater inundation recorded in the study area is 750m in Colachel and the minimum is 100m in Kadiapatanam, Mandakadu and Vaniakudy areas. Chinnamuttom, Kanyakumari, Manakudy, Pallam and Colachel areas are under high risk.

INTRODUCTION

On 26^th December 2004, tectonic disturbances happened near Sumatra Island with an intensity of 9.3 in the Richter scale wrecked havoc on southwest part of India. In addition to inflicting life and infrastructure loss, the resultant tsunami event had also eroded severely the coastal region and modified topography of beach and shallow coastal regions. It did raise the concern of scientists and emergency planners about the impact of larger earthquake and consequent tsunami should there be any recurrence of such event. Despite becoming aware of tsunami hazard, there has been confusion about areas at risk and areas of safety. This chapter is an attempt to assess the vulnerability of part of Tamilnadu coast based on its geomorphological conditions and the impact of recent tsunami. The hazard maps have been generated and are intended for educational purposes, to improve awareness of tsunami hazards and to encourage responsible emergency planning efforts by illustrating the range of possible tsunami events.

This chapter is an attempt to introduce basic facts about earthquake generation and the role of earthquakes in triggering secondary geohazards. Earthquake, unlike manyother geohazards is yet to be fully understood towards occurrence and magnitude for better mitigation measures. Though unpredictibility of this hazard makes it dangerous, earthquakes seldom kill lives. Instead, poor ability of man-made structures against ground-shaking waves has been the real cause of life loss and damage to property in most of the earthquake incidences. Furthermore, earthquakes generate secondary geohazards such as landslide, failure of dams and reservoirs, etc. Thus, earthquake, as a natural hazard has its own characteristic way of potential impactand hence classifying vulnerability of different regions and creating awareness on potential impact among common public is essential.

INTRODUCTION

The term “earthquake” denotes “shaking/vibration/trembling/ quivering/shuddering/ wobbling of Earth”. Earthquake is the quickest and most unpredictable natural hazard. It is nothing but a series of suddenly generated elastic waves occurring in the Earth due to internal and/or external causes from shallow (few kilometers) to about 700 kilometers depth. It is a form of motion of wave energy transmitted through the surface layer (crust) of the Earth. One generalization that can be made out of scientific and mainstream media information about earthquakes is that, “earthquakes seldom kill; but the associated phenomena such as landslides, flooding, volcanic eruptions and collapse of natural and man-made structures cause the real damage to lives and property”. This chapter is an attempt to describe the basic elements of earthquakes and few mitigation measures.

This chapter presents a case of Jind region of Haryana State, Northern India which had experienced mild tremors of ~ 3 on Richter scale magnitudes in the recent past with a gap of 1 to 2 years. Rejuvenation of the lineament controlled volcanoseismic process is identified as the probable cause of these tremors. This chapter describes seismotectonic characters, micro and mega seismicity of the area and few mitigation measures.

INTRODUCTION

The Haryana state consists of Delhi Super Group (DSG), Indo- Gangetic alluvial plain in the form of alluvial fan, sand dune, alluvium of Ambala, Yamuna and Ghagghar rivers and Siwalik Super Group (SSG) in the southern, central and northern parts respectively (Fig.1). The study area Jind is located in the central part of Haryana and comprises 200 – 600 m thick Indo-Gangetic alluvium. The alluvium is of Quaternary Period and composes alternating layers of clay, silt, sand and kankar. The Bhiwani and Tosham areas, located south of Jind, show the occurrence of Neoproterozoic granite and rhyolite of Malani Igneous Suite (MIS). The rocks occur in the form of ring structure/ring dyke on the hillocks amidst the alluvium. The metasediments (mica schist and quartzite) of Delhi Super Group are underling MIS at Tosham (located at 70 km southwest of Jind). As Jind region experiences mild tremors and there is no previous published work pertaining to the geology, tectonics and seismicity of the area the chapter records these aspects for better understanding and mitigation of earthquake hazard.

This chapter introduces the readers about volcanoes and associated features and hazards. Volcanic disasters are like any other geohazards in causing dangerous impacts. However, volcanic explosions are preceded by many surficial expressions that can be detected through satellite imageries, thermal sensors, change in magnetic and gravity anomalies, disappearances of vegetation, sudden appearances of anomalous water vapor, thermal springs and abnormal behavior of animals. Hence, unlike other geohazards, volcanic hazards could be forecast with fairly accurate time limits that may allow evacuation and precautionary safety measures. While avoidance is the best mitigation measure, proper land use planning, provision of scientifically designed damming and diversion methods could save lives and infrastructure from lava flows. Though, atmospheric contamination by volcanic gases, ash cloud and pyroclastic materials could not be thwarted and controlled and thus they could cause havoc.

INTRODUCTION

The term “Volcano” is derived from the name of Roman mythical God of fire “Vulcan”. A volcano is an opening of different shapes, through which, molten rock and gas get ejected either violently or simply flow over earth’s surface. The molten rock and gaseous materials are drawn from deep inside of crust or mantle of the Earth. Repeated ejection of molten materials through vent, fissures or plate margins forms volcanic mountains on earth’s continental or submarine regions.

Volcanism is a threat not only to the lives and infrastructure, but it also drastically alters landscape, impacts atmospheric quality and renders forests, cities and villages and cultivation lands useless. In addition, volcanic eruptions are capable of causing changes in global atmospheric cycles. For example, the eruptions of El Chicho’n in Mexico in 1982, Laki volcano in Iceland and Asama Volcano in Japan in the year 1783 and Krakatau volcano of Japan in the year 1883 have all impacted global climate and atmorpheric dynamics.

Readers are introduced through this chapter to a geohazard (Landslide) that is most frequently publicized in mainstream media. Systematic examination of landslides and associated structural, tectonic, geological, geomorphological, meteorological, hydrogeological characteristics and land use pattern of Nilgiri hill area had indicated that steep slope, dipping of rockstowards slope, presence of clay layering in weathered rock types, events of continuous heavy rains, flooding on the slopes and improper land use practices play a major role in the genesis of landslides. Inaddition, ongoing seismotectonic activities in Southern Granulite Terrain of South India and reactivation of hidden blind shear zones were identified to be causative factors of recent increase of landslide occurrences.

INTRODUCTION

The downward movement of consolidated and unconsolidated soils and rock en masse from any geomorphic feature due to natural or manmade causes under the influence of gravity is termed as landslide (GSI, 1982). Nevertheless, presence of water, clay material, weak joints, favorable slope and many other characteristics also act as catalysis for this event. Landslides are one of the common geological hazards that affect countless population in India, especially in hilly terrains. Different reasons have been ascribed to different landslides of various terrains. Among them, reactivation of Bhavani shear zone (Prasannakumar and Llyod, 2007), high anthropo-geomorphic intervention (Basu, 2005), local geology, precipitation and slope (Bhattacharjee, 2005), presence of local vertical faults, triangular facets, abrupt deflection of streams and neotectonism

This chapter provides an introduction to cyclogenesis, nature of cyclone disaster and historic events. The mechanism that is in practice in cyclone mitigation, information dissemination and relief and rescue operations are detailed. As the state of Orissa is being battered more frequently by cyclones than any other state of India, special emphasis on cyclone disaster management system of Orissa is also discussed.

INTRODUCTION

Orissa state with immense natural resources is located between 17⁰27’N and 22⁰34’N latitudes and meridians of 81⁰27’E and 87⁰29’E longitudes. Orissa lies on the eastern coast of India with the waters of the Bay of Bengal swirling along its eastern and southeastern boundaries. It shares its boundaries with West Bengal and Jharkhand on the north, Chattisgarh on the west and Andhra Pradesh on the south. Out of the Indian mainland coastline of 7500 km, it constitutes a coastline of about 480 km. It extends for about 155,707 sq.km accounting about 4.74% of the total area of India. According to the 2001 census, it has 3.57 percent of the total population of India. Administratively, it has 30 districts, 3 Revenue Divisions, 58 Sub- Divisions, 51,061 villages and 127 Urban Centers.

Based on physiography, Orissa can be divided into three broad regions - the coastal plains, the middle mountainous region and the plateaus, and rolling up lands. The coastal plains extend from the River Subarnarekha in the north to the River Rushikulya in the south. The coastal zone covers nine districts namely Ganjam, Puri, Jagatsinghpur, Kendrapara, Jajpur, Khurda, Cuttack, Bhadrak and Balasore. It is narrow in the north, widest in the middle, narrowest in the Chilika coast and broad in the south. The coastal belt of Orissa lacks hills excepting few hillocks and mounds in the northern and southern parts. It has extensive low lands adjacent to the sea, sloping gently towards the shoreline of the Bay of Bengal. The coastline consists of the lakes, lagoons, marshes, bays and islands and natural harbors. The lakes in Orissa are natural and artificial. One of the blazing example of the natural lake is the Chilika lake.There is only one bay in Orissa which is the Hukitola bay. Eventually there are only two islands in Orissa - the Short’s Islands and the Wheeler Islands. Among the natural harbor, there is only one of its type in Orissa i.e. Paradeep which holds its recognition as the deepest natural port in the whole of India. The main drainage system of this area is represented by several rivers at their old stages flowing sluggishly towards the sea, which form topographic features like peneplains, natural levees, deltas, etc. (Fig.1). The major rivers flowing in the coastal belts are the Subarnarekha, the Budhabalanga, the Baitarani, the Brahmani, the Mahanadi and the Rushikulya. This region is the combination of several deltas of varied sizes and shapes formed by these rivers. The coastal belt has an area of 40,166 sq. km with a population of 68,79,379, which is 45 percent of the population of 9 coastal districts of Orissa.

Despite widespread occurrence and its potency to inflict heavy causalities and damage to economy, generalizations could not be made to define “drought” – leave alone characterization, development of predictive model and common mitigation measures. Regional variation, be it definition or symptoms or causative factors or consequences and mitigation measures is the hallmark of drought. This chapter is an attempt to present a review on characteristics of drought for the benefit of devising mitigation and reclamation measures.

INTRODUCTION

“Drought” denotes the meteorological, agricultural, environmental, climatic, social, economic and political consequences of a gap between the water availability and demands for the needs of domestic, irrigational, industrial, commercial and recreational consumption in an area over extended period of time. As these demands vary from region to region and depend on too many parameters such as quantum of rainfall, geological and soil characteristics, land use, population, economic activity, climatic conditions, population and culture, drought conditions of an area may not have characteristics of some other region.

This chapter explains how natural disasters are major catastrophic events, which are often aggravated by human intervention, resulting in adverse conditions affecting both natural resources and human habitats. Though drought is as disastrous as any other geohazard, it differs from other geohazards such that it is a ‘creeping phenomenon’, making its onset and end difficult to determine. Only a continuous monitoring of critical parameters ranging from crop failure to joblessness and shifting population, etc, could indicate drought in an area. In this chapter, we demonstrate a GIS based drought forecasting and monitoring model taking Gubbi Taluk of Karnataka as a case study. The approach includes creation of a spatial database of 17 critical parameters and their integration in GIS environment by developing a suitable rating and ranking scheme for the generation of drought severity map. The results have shown that drought could be monitored with the studied parameters and if suitable remedial measures are implemented, their effectiveness could also be monitored with this GIS model.

INTRODUCTION

India is a large country in terms of geographical area, exhibiting greater agro-climatic variation. The country is susceptible to several natural disasters, which are a major constraint to developmental activities. 

This chapter portrays flooding as a geohazard that can be managed with ease through simple and effective measures. Flooding is a recurrent geohazard that affects vast lands in India and elsewhere. Unlike many other geohazards, flooding event and probable area to be affected could be predicted with fairly accurate levels and hence, proper safety measures could be taken easily. However, as flash floods could not be predicted and the nature of flooding hazard that it brings in added danger of health hazard, crop damage and cutting off of supply and communication networks, flooding is as serious threat as any other geohazard. Scientifically designed urbanization and flood control measures are suggested for minimizing the potential impacts of flooding.

INTRODUCTION

Flooding is defined as a temporary submergence of a large area (that normally remains dry) under water by overflowing rivers and reservoirs as a result of heavy rains, high winds, cyclones, storm surges, tsunami, melting of snow or dam burst (Arya et al. 2005). The term “temporary submergence” denotes a time period ranging from few hours to about few months depending on type and location of flooding. Although flooding is a natural phenomenon that plays a major role in replenishing wetlands, recharging groundwater and supports agriculture, extreme demands on natural resources due to population growth, people and their property move closer to water bodies

Many types of geological hazards namely, tsunami, earthquakes, tsunami, floods and drought affect coastal areas like any other place on the Earth. As coastal regions are thickly populated and have abundant urban, industrial and recreational establishments, impacts of geohazards are always severe along coastal regions. Compliance to coastal zone regulations, with protection of sanddunesandmangroveswillbe the best mechanism to minimizethe damages from such hazards. In future, climate change may result in more hazards such as erratic rainfall and increase the frequency of droughts, floods and storm surges, etc. In this context, proposed coastal management zone for the coastal protection, disaster mitigation and management tools in coastal areas are examined in this chapter. It is suggested that extensive use of GIS and development of Geodatabase for the risk prone areas will serve as efficient tool for planners and policy makers to deal with geological hazards. In addition, it is felt that more efforts are needed in legal and institutional framework for integrated disaster management planning on local as well as national level.

INTRODUCTION

Geologic hazards are natural geological processes that inflict severe damage in areas of their operation if the area is utilized by anthropogenic activity in terms of habitation, industrial, recreational or commercial establishments. Many a times, natural geological processes that operated uninhibited for millions of years turn into geological hazards due to human intervention. These losses – lives and economic are not evenly distributed and are more prevalent in the developing countries due to higher population concentration and low level of economic growth. United Nations had realized the need of reducing these losses due to natural disasters and declared the last decade (1991-2000) as the International Decade for Natural Disaster Reduction. Objective of this proclamation was to reduce, through concerted efforts, the loss of life, property damage and socio-economic disruption caused by the natural disasters particularly in the developing countries (Tewar, 2000).

This chapter documents shoreline changes of the Dakshina Kannada and Udupi districts of Karnataka State for the period between 1967 and 2005 studied by comparing the SOI topographic maps with IRS-1C/1D LISS-III satellite imageries through GIS techniques. Examination of coastal geomorphology, sediment flux and effectiveness of seawalls had indicated that the 130km long coastline of Dakshina Kannada and Udupi districts is essentially stable, but for seasonal variations. It has been estimated that, out of 130km, about 55km long coast is vulnerable to sea erosion, of which, 25km is covered byseawalls and covering another 10km length underway. It is revealed through field examination that protection of coastline through these measures is satisfactory only along few patches while other stretches of seawalls simply shift the zone of erosion to adjacent coastline owing to many reasons including quality of construction, unscientific positioning of seawalls, etc. It is also inferred that same is the case of many other coastlines elsewhere including Kerala coast. These experiences warrant scientific design and implementation of coastline protection measures.

INTRODUCTION

The 130km long coastal zone of Dakshina Kannada and Udupi districts is one of the densely populated coastal zones of India. The coastline is almost straight, regular and oriented towards N22°W, N12°W and N6°W directions at south of Mangalore, north of Mangalore and north of Malpe respectively. Barrier beaches and spits, ancient beach ridges, marshes, swamps and tidal flats characterize this zone. Natural features and man-made structures interrupt the shoreline. The natural features include estuarine mouths of Netravati-Gurpur rivers near Mangalore, Mulki-Pavanje rivers near Mulki, Udyavara river near Malpe, Sita-Swarna rivers near Barkur, Kollur-Chakra-Haladi rivers near Kundapur and rock exposures near Someshwar, Surathkal, Mulur, Kapu and north of Malpe (Fig. 1). The man-made structures include one major and four minor ports; breakwaters at the Netravati-Gurpur estuary, New Mangalore Port and Malpe harbor and a number of seawalls placed at various places along the coastline (Fig. 2). All these structures/features bring about local irregularity and contribute to erosion and accretion along the shoreline to some extent. Apart from these, source of beach material, coastal processes like wave refraction, longshore current, littoral drift etc.

This chapter sheds light on a geohazard namely quicksand. Unlike other geohazards, it waits for its victims to cause hazard. Though discounted as a myth and also as a monster problem in Hollywood film stories, phenomenon of quicksand is real and could inflict life threatening dangers. Analyses of genetic causes, associated properties and locales of its occurrences indicate that more deaths might have resulted due to panic and drowning in waters than by quicksand itself. Based on these inferences, potential mitigation measures are presented in this chapter.

INTRODUCTION

Quicksand, referred as “pudhai manal” in Tamil, is one of the lesser known dangerous natural phenomena that cause death of human and other unsuspecting animals. It is a geohazard of different sort. It is different in a sense that it never “goes” anywhere like tsunami or causes hazard like flood or landslide or any other geohazard; but it waits for hapless victims; that is., it is harmless until human beings or other fauna step into the region of quicksand. It is commonly prevalent in many river beds and other locales near water bodies located amidst dense forests. Many a deaths occur due to quicksand but go unnoticed owing to its “non catastrophic” nature. It is also a geohazard less understood pertaining to causes of formation, potential to cause damage and occurrence (www.mythbuster.com). This chapter is an attempt to review the existing literature on this geohazard for better understanding.

impacts other speheres and that too on a distal place! This chapter explains how global warming affects remote places like highlands of Bhutan. Severe hot summers during the year 1994 led to excessive melting of glaciers in the higher Himalayas. The exceptional melting contributed enormous amount of melt water to the lake basins, which caused breach of the morainic dam and consequent enlargement of the outlet of the Luggye Tsho and the Tshopda Tsho, Bhutan. Floods followed the breach on October 7, 1994. These floods destabilized the slopes on either bank of the Pho Chhu near Tshopda Tsho outlet making them prone to landslides. The flash floods also eroded the left lateral moraine of the Raphstreng Tsho, which had disturbed the original angle of repose. The Raphstrcng area is also prone to ice avalanches, rock glaciers, surge of which can damage the rim and also cause spillover of water. Examination of geological, geomorphological, geotechnical, microclimatic and hydrographic information in and around the glacial lakes led to improved understanding of breach characteristics based on which mitigation measures were suggested and implemented in the years 1996-97. Since then the lakes have remained intact. From this case study and satisfactory performanceof mitigationmeasures suggest that similar integrated studies have to be conducted for thorough understanding of hazard prone areas based on which mitigation measures have to be implemented for successful reduction of impacts.

INTRODUCTION

The Lunana area, situated in the northern district of Gasa, is one of the most extensively glaciated terrains of Bhutan (Fig. 1). In response to the general global warming, these glaciers like those of other parts of the Himalaya are in a state of steady retreat, often leaving behind a chain of lakes. Though the glacial lakes endow scenic beauty, they also pose environmental hazards, due to frequent bursting of their morainic dams and consequent flash floods. The last lake-burst occurred on 7^th October 1994, leading to floods in the Pho Chhu River. Following floods, the Geological Survey of India in collaboration with the Royal Government of Bhutan, investigated the Lunana area to identify the causes and effects of the floods and suggest remedial measures. More than a decade had passed since the implementation of mitigation measures and there has been no such breach and flood despite continued Glacial Vetreat during to Global Warming. This chapter describes the characteristics of these glacial lakes, nature and results of the study and mitigation efforts.

reach out their fingers it is gone” - Chinese Philosopher Lao Tzu Tao Te Ching. True to his verses, geohazards are phenomena regulated by the law of natureand it is beyond the human intellect to understand thoroughly and capability to conquer. This is the lesson learnt by us from so many incidences that geohazards cause greatest havoc wherein natural processes are going on and are inhabited by humans. Greed for natural resources and population pressures on the earth’s resources are the causes of many a catastrophic event. Examples in this regard are galore including, damning river courses and location of urban centers along rivers and coasts – flooding, cyclonic storms, tsunami hazards; alteration and deforestation hill slopes for agricultural and construction activities – landslides; unscrupulous utilization of ground water resources – drought, etc. This chapter is an attempt to draw the attention of human communityasa whole toturn towards learning to live with the nature without alterning the natural processes to get rid of impacts of geohazards as a best ever mitigation measure. In other words, this chapter attempts to emphasize the need to change our attitude to escape from natural hazards instead of attempting to tinker around natural processes only to get battered at the end.

INTRODUCTION

Oxford English dictionary states that the word ‘disaster’ is derived from the 16^th century French word ‘disastre’, which is a combination of two terms namely, ‘Des’ meaning bad or evil and ‘astre’ means star. Thus “desastre” signifies a ‘bad star’ or ‘evil star’. Disaster, therefore, implies loss or damage occurring due to some unfavorable star. However, in terms of modern knowledge, the word ‘disaster’ denotes any odd event, whether natural or man made, which can bring about sudden and great miseries to humanity in the form of loss of life or/ and property.

1.1 Geomorphology

Geomorphology is the scientific study of the origin and evolution of topographic and bathymetric features created by physical or chemical processes operating at or near the earth's surface.

The surface of the earth is unstable and affected by a combination of surface and geologic processes that cause tectonic uplift and subsidence. Surface processes are mainly physical and chemical action of water, wind, ice, igneous activity and activities of living organisms on the surface of the earth. Upliftment of mountain ranges, the growth of volcanoes, isostatic changes in surface elevation and formation of deep sedimentary basins are categorized under Geological processes.

Main geomorphological processes occurring in nature are as follows:

1.1.1 Aeolian processes

Aeolian processes include activities of the winds, its ability to shape the surface of the earth. Wind acts as an effective agent of erosion, transportation and deposition materials, and large supply of fine, unconsolidated sediments. Aeolian processes are important in desert (arid) environments.

1.1.2 Fluvial processes

Moving water in a river channel, is able to mobilize sediment and transport it downstream. The rate of sediment transport depends on the availability of sediment itself and the discharge by river.

River originates from mountain with V shaped valley, which later increases in size, merging with other rivers. The network of rivers thus formed is known as drainage system. These systems show four general patterns viz. dendritic, radial, rectangular, and trellis etc. In the mature stage, the river form alluvial flood plains, meanders and ox-bow lakes. Finally when it merges to ocean, forms delta.

2.1 Introduction

Topographic expression is the replica of geological structures present within the earths surface. When various types of rocks of an area are displayed on a map (sheet of paper), it is known as Geological Map. Normally geological maps prepared on topographic maps. Surface topography is best presented by contour lines on a plain paper.

The importance of geological maps is to understand the nature of structure and distribution of surface outcrops with their relation to contour lines. Horizontal and dipping beds are easily identified on map because, horizontal beds runs parallel to contour lines while inclined beds cut through different contours. The angle and direction of dip can be calculated from geological maps. Geological maps are of great importance to civil engineers, after studying geological maps and consultation with geologists, civil engineers can advice for construction of engineering structures like excavation of road cuttings and construction of canal, bridges, dams and tunnels etc. Geologists get vital clues about the geological history of an area, and can draw a cross section of an area and know the structure present underground.

3.1 Introduction

Crystallography is the science of crystals. The term crystal is derived from the Greek word “Crystallos” which means “ice”. The term was used for colorless quartz which was believed to be “fossilized” ice. Crystals are bodies bounded by flat surface, arranged on a definite plan which is an expression of the internal arrangement of the atoms. They are formed by consolidation of magma which is also considered as crystallization.

3.2 Terms in Use to Describe a "Crystal"

3.2.1 Faces

Faces are the plane surface in a crystal. The common faces are usually parallel to net planes containing the greatest number of lattice points or ions. Wide spacing between the net planes leads to development of faces in these planes. Faces are two types like and unlike faces.

The earth's crust is made up of minerals and rocks. Minerals are inorganic substances with a definite chemical composition, whereas rocks are mixture or aggregates of minerals. Each mineral is composed of certain elements present in fixed proportion. For example, mineral quartz, SiO₂ is a compound of the elements silicon (Si) and oxygen (O) combined in the proportion of 1:2, so its chemical formula is SiO₂, whereas rock granite is a mixture of several minerals like quartz, feldspar etc. Nature has provided unique physical properties to different minerals that can be used to identify them.

4.1 Physical Properties of Minerals

Majority of minerals contain following properties that can be used to identify them in field and in laboratory: crystal habit, cleavage, hardness, density, luster, streak, color, tenacity, magnetism, and taste.

4.1.1 Crystal habit

The faces that develop on a crystal depend on the space available for the crystals to grow. If crystals grow into one another or in a restricted environment, it is possible that no well-formed crystal faces will be developed. However, crystals sometimes develop certain forms more commonly than others, although the symmetry may not be readily apparent from these common forms. The term used to describe general shape of a crystal is habit.

Some common crystal habits are as follows: