eChapters

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.

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 : 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 : 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 : 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 : 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 : 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 : 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 : 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.

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 : 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:

34. GEOPHYSICAL METHODS

This chapter gives important and useful methods for measurement of seismic signals.

Firstly a brief introduction of seismic signals is given. The P waves, S waves and L-waves are discussed in short.

The old methods of measuring seismic signals like mechanical geophones are replaced by electronic geophones. The discussion includes Electromagnetic type, Reluctance type, Capacitive type and pressure type of basic geophones. New methods of damping are included. New Recently developed amplifiers and filters are also included. Development in oscillographic elements and cameras are discussed. Other information includes, the recently reported Array Technology and Space Technology for measurement of seismic signals.

33. GEOTECTONICS

Introduction

Geotectonics is the branch of geology which deals with the structure and movements of the earth’s crust. It includes the study of large-scale features like mountain chains, mid-oceanic ridge and oceanic trenches. Investigation regarding the form, pattern and genesis of these, and other tectonic units have enabled geo-scientists to ascertain the important characteristics of earth’s crust and reconstructs its evolution and geological history.

33. GEOTECTONICS

Introduction

Geotectonics is the branch of geology which deals with the structure and movements of the earth’s crust. It includes the study of large-scale features like mountain chains, mid-oceanic ridge and oceanic trenches. Investigation regarding the form, pattern and genesis of these, and other tectonic units have enabled geo-scientists to ascertain the important characteristics of earth’s crust and reconstructs its evolution and geological history.

27. STRIKE AND DIP

Outcrop : A part of the rock formation which crops out or exposed on the surface of the earth is called an outcrop.

The total area over which a particular rock unit occurs at the surface whether visibly exposed or not. The term outcrop is especially used for delination of such an area on a geological map.

Attitude : To study these outcrops their attitude help in better understanding the position of the bed on the ground surface or in field is attitude of a bed can be described with the help of two basic structural elements i.e. strike and dip.

24. IGNEOUS ROCKS

Introduction : Petros = rocks and logos = science

Petrology means the science of rocks. It deals with the mode of occurrence composition, classification and origin of rocks and their relation to geological processes and history of the earth.

Rocks can be studies in two ways : The study of rocks as specimens in the laboratory is called Petrography which places emphasis on the purely descriptive part from textural mineralogical and chemical point of view. Petrogenesis deals with the origin and processes of formation of rocks. Petrology is a broader term which includes both petrography and petrogenesis.

Igneous rocks are formed by cooling and solidification of magma, either underneath the earth’s surface or above the earth’s surface.

19. PHYSICAL PROPERTIES OF MINERALS

Def : The minerals are naturally occurring solid bodies having definite chemical composition and certain atomic arrangement, and are formed by inorganic processes in the nature.

All the minerals possess certain physical properties which are considered as follows.

1.Characters depending upon light such as colour streak, luster, transparency, translucency, phosphorescence and fluorescence.

2.Characters depending upon certain senses such as taste, odour and feel.

3.Characters depending upon the atomic structure and state of aggregation such as form, hardness, tenacity, fracture, cleavage and surface tension effects.

On the basis of these three characteristics, the minerals are identified and distinguished.

9. WEATHERING

The general process of production of rock waste partly by mechanical breaking and partly by chemical decomposition is known as weathering. The resulting products of weathering accumulate in the same place from which they are derived and there is no transport involved in the process.

Agents and types of weathering : The agencies which are involved in the process of weathering are atmosphere, water and organisms. The whole process of weathering may be conveniently divided into two types : mechanical or physical weathering and chemical weathering. Mechanical weathering involves those processes which bring about disintegration of rocks and minerals without any chemical activity. Chemical weathering involves various chemical processes which slowly decompose the rocks and minerals. In nature two processes are intimately associated and only under extreme conditions, they do occur as a separate entities. Mechanical weathering breaks down the rock creating more surface area and facilitates chemical weathering. Chemical weathering weakens the rock and makes it more susceptible to mechanical break down. Thus the two processes are always complementary to each other.

1. GEOLOGY

Geology : Earth Science

 Geo = Earth + Logos = Science

 Def : The science which investigates the history of the earth is known as geology.

 Following are the important branches of geology.

1.Coal Geology : it is related with natural gas, coal deposits and their formation.

2.Crystallography : includes the crystal and atomic structure of the mineral. 3. Drilling Technology : it is related with the cores, core logging and coorelation of the lithology.

4.Engineering Geology and Surveying : it is related with engineering aspects of the earth.

Abstract

The desert environment is one of the most challenging environments for human habitation. Inhabitants have to deal with climatic factors such as high temperature, sandstorms, flash floods and lack of water due to low rainfall. The people of Saudi Arabian desert had developed various traditional adaptation approaches such as living in tents, wearing head dresses, settling close to source of water, using camel for transportation, irrigation farming and traditional land management (hema). In recent times, modern technologies for air conditioning, transportation and housing have replaced the traditional adaptation methods especially in the cities. The modern technologies have reduced the challenges faced by the traditional society but has thrown up new challenges to sustainability. The new issues include urban flooding, depletion of underground water, high energy demand and consumption and loss of natural habitat to urbanization. This chapter reviews the traditional and the modern adaptation techniques in Saudi Arabia especially in the urban areas. It examines the implication of the changes for urban sustainability and explores different approaches for reducing the negative impacts. The chapter also dwells on the role of geospatial techniques in adapting to the desert environment.

Abstract

Before 1960’s, UAE was a poor developing country and almost there were no real signs of civilization. During the 1970’s two important things happened: H. H. Sheikh Zayed Bin Sultan Al Nahyan, the president of UAE, and the other Emirates rulers united together and established the United Arab Emirates and considerable oil findings were discovered. The UAE Leadership has proved to have deep future vision; in three decades the country jumped from a relatively backward scattered emirates to a well developed and civilized country.

Development is very obvious : from tents and sandy tracks to tower buildings and highways, from desert to green belts of palm trees and vegetables in all parts of the country, and most important, education, healthcare and all other services became the best in the region. Urban development was so sharp; someone who left the place 10 years ago can hardly know his location and services in all sectors became the best at the international level. The oil money was properly invested in development.

UAE Air Force Space Reconnaissance, used satellite and aerial images for the past 20 years and successfully utilized images from various sources including aerial photographs, Russian satellites images, SPOT and Landsat

Abstract

Three seepage tests were carried out for an earth canal at Rawakeeb Research Station (RRS)-west of Omdurman and an average seepage rate of 3.4 m/day was obtained. This value suggests that irrigation canal at RRS should be lined. In addition to that preliminary economic evaluation showed that canal lining is imperative in RRS. A concrete slab form was well designed for lining of RRS canal. Precasting technique and construction technique provided the required water tightness. Economic evaluation was done for RRS canal to investigate the extent of occurrence of supposed advantages, and to estimate costs and benefits and rate of return to lining. The capital expenditure (C), net present worth (NPW) and benefit/cost ratio were found to be 2600.4, 1961.9 and 1.3 respectively which offers a good indicator to adopt the technique.

Abstract

The Western Desert covers approximately 700,000 km², which is more than two-thirds of the total area of Egypt. This immense desert, to the west of the Nile, spans the area from the Mediterranean Sea to the Sudanese border. The Great Sand Sea lies within the desert’s plain and extends from Siwa Oasis to Jilf al Kabir plateau. Scarps and deep depressions exist in several parts of the Western Desert. Limited agricultural production, the presence of some natural resources, and permanent settlements are found in the western desert oases (Siwa, Bahariya, Farafra, Dakhla and Kharga), all of which have fresh groundwater. Siwa Oasis, close to the Libyan border, is isolated from the rest of Egypt but has sustained life since ancient times. The Siwa’s cliff-hung Temple of Amun was renowned for its oracles for more than 1,000 years. Herodotus and Alexander the Great visited the temple in the pre-Christian era. The Oasis is a natural depression about 23 meters below sea level. It covers an area of about 1050 km² (2,50,000 acres); of which only 87.95 km² (20,940 acres) are currently cultivated. The total numbers of inhabitants in Siwa were 21,482 in 2006. The main activity in Siwa oasis is agriculture which depends on the groundwater that outflows from about 1199 wells and springs giving a total annual discharge of about 255 million cubic meters from which, about 222 million cubic meters are lost due to evaporation and evapotranspiration, while the remainder goes to the natural lakes of Siwa Oasis. This has led to a continuous rise in the water table level and soil salinity.

Present research paper on land degradation processes relates to the improper management of water and land resources in Siwa Oasis, Egypt.

Abstract

The UAE Space Reconnaissance Center (SRC) is accounted as a major national and regional source of up-to-date geospatial data, with direct reception of IKONOS, IRS and KOMPSAT satellite imagery as well as access to some other satellite and aerial imagery resources; an activity which covers the whole Middle East region. The main concern in monitoring the environment of UAE and surrounding countries is the desertification process, the monitoring of which requires careful watching of the sand movement and some other relevant features.

This paper throws light on the role of various types of satellite images in monitoring desertification, by utilization of IKONOS, IRS Pan and Landsat TM images covering part of Liwa and Alain areas, representing the two main dune regimes; Liwa and Manadir, which constitutes the northeastern edge of the Empty Quarter sand sea.

The availability of high resolution images makes it possible to detect the yearly or even seasonal sand movements, being controlled by the prevailing wind conditions and distance from the main sand source. The results clarify that movements of up to 25m was encountered at some small sand dunes and about 10m for larger sand dunes, towards the SSE and SSW in Liwa area. In Rimah area a movement of up to 30m was noticed at a small sand dune towards the ENE and about 12m shift in the hinge of a larger sand dune towards the NW. Temporary or permanent ? movement of thin sand sheets can reach 100’s of meters, was easily detected on Landsat images; ~ 25km NE of Alain city. The 5m panchromatic images, on the other hand, helped in tracing sand movements measured in few 10’s of meters, and interpretability of such images was enhanced by merging them with Landsat imagery.

Introduction

Definition of ‘urban’ areas varies from country to country. Consequently, it is difficult to provide a universally acceptable meaning of the term. The difficulty has been summarised by UN (1998) as follows: “because of national differences in the characteristics that distinguish urban from rural areas, the distinction between urban and rural population is not amenable to a single definition that would be applicable to all countries” (UN, 1998). In many cases the divide between a rural and an urban area is based on the minimum population, but the number varies widely between the countries, e.g., 200 in Iceland, 2000 in some countries of West Asia, 5000 in India, and 10000 in Italy! Despite this challenge, most towns and cities are historical phenomena and have their defined administrative boundaries for services and other purposes, including municipalities. These places straight away qualify as the urban centres.

In India, the word has been defined by the Census of India (2001) as: “(a) All statutory places with a municipality, corporation, cantonment board or notified town area committee, etc.; (b) A place satisfying the following three criteria simultaneously: (i) a minimum population of 5,000; (ii) at least 75 per cent of male working population engaged in non-agricultural pursuits; and (iii) a density of population of at least 400 per sq. km (1,000 per sq. mile).” This definition was adopted for the 2011 Census.

Why Water Budget?

The reliability of water supply in desert regions is at risk due to a multitude of issues including low rainfall, low snow runoff, court-ordered water transfer restrictions and hence higher price of wholesale water. Agencies in desert regions understand the importance of improving water supply reliability, facilitating better water storage, adapting to changing climate patterns and reduced precipitation, improving Environment and Water Quality.

The Desert regions have always fought back the perpetual water scarcity with infrastructure designed around saving water and utilizing alternative water resources. Off late, not only new construction but also new policies and programs have added to their water conservation activities.

One such program attends to the fair distribution of water by tending to consumers who are price sensitive and hence use water without wasting it and by extra-charging those who do not know where to put a stop to their wasteful water use.

Abstract

Indigenous water saving technologies in arid and semi-arid environment is a local traditional practice for effective use of the limited water supply. These technologies can be used as a base for future development that can be made on these technologies through incorporating the current industry tools. The importance of studying the indigenous knowledge and practices is that it can help to develop enhanced versions of these technologies, and to understand the ability of local communities to adopt the newly developed technology. In Sudan, several indigenous water saving approaches has been used by local societies at various scales. An insight for these technologies, their strength and weaknesses are given here. On “Haffir” (water ponds), Wadi control, and water diversion methods were used for a long time of history for water collection and conservation. At farm scale, terraces, mulching, intercropping, low tillage, fallow, low-water consumption crops and fast maturing crops are common indigenous water saving technologies. Traditional water storage in trees such as Baobab and water-melon is an indigenous proactive along the history in western Sudan to store rain water for long dry season.

Abstract

This chapter highlights the significance of irrigated desert agriculture as a prime cause of the settlement and welfare of nomads and the consequent reduction of conflicts over limited land resources. Um Jawaseer Desert Farm Project is located in Bayouda Desert, the Northern State about 200 km north of the capital Khartoum. The planning and management approaches of such irrigated projects were discussed with special emphasis on the participatory approach. In this respect the roles of the donor (NGO), traditional tribal institutions and the project beneficiaries were illustrated. The project beneficiaries were organized into the farmers, well and women committees. The environmental and socioeconomic impacts of the project were evaluated. The project maintained food security, improved nutritional status, hygiene, housing environment and assisted in the provision of primary education and basic health facilities. Cost/benefit analysis showed the high profitability of the project. Other positive impacts include conservation of the fragile environment and biodiversity and improvement of animal productivity. Consequently, the area which witnessed an out-migration, during the seventies and the eighties, due to drought and desertification is now experiencing incoming migration.

However, adaptation to the sedentary mode of life was a real challenge. The most striking benefits of the project was that of women training for the, involvement in the decision-making process and empowerment, since 20% of the land is allocated for women. In addition to that, problems like build up of salinity, sand encroachment, low organic matter content and increased susceptibility to some water-related diseases due to irrigation were tackled successfully.

Introduction

Thar Desert is unique both from floristic and climatic parameters. Biodiversity in this region survives on a very/ fragile ecosysytem under a highly hostile environment. Major area consists of dry undulating mass of loose sand, thus, leading to shifting sand dunes. The sandy plain is full of sand-hills with serve as low depressions where salt and soda are deposited after drying. The whole area is inhospitable and sterile. Trees are rather a few and far between (Bhandari, 2005).

The Thar Desert of western India is known for its rich and ancient culture system and traditions. The communities have long been part of the Thar Desert ecosystem and have evolved specific strategies to live in harmony with its hostile environment. Orans have remained mainstay in balancing this arid ecosystem. Man of this region has never been greedy as he is today. Orans were repositories of ancient system of gene pool conservation. But, there are unregulated encroachment on the marginal lands and over-exploitation of groundwater resources. Orans has been part and parcel of the lifestyle of the Thar Desert inhabitants. Orans are used to provide vital grazing land for livestock, water, minor forest produce, medicinal plants and green cover for the villages. They were worshipped as devbhumi. Orans preserve the endemic, endangered or threatened species, medicinal plants and wild variety of cultivars found.

Abstract

The area of study extends about 65 km from Gamasa City to Burg El-Burullus. The coastal sand dunes are very near to the shoreline in Baltim and El-Burg and far from the shoreline in Gamasa. It is narrow with relatively steep slope northward near Burg El-Burullus and Baltim, while it increases in width eastward to become wide with gentle slope near Gamasa. The coastal sand dunes are very mobile and move toward the agricultural lands, roads (international coastal road), resorts, and other developmental activities. The sand dunes in the study area are classified into two categories, the old fixed dunes and recent mobile dunes. The main directions of wind blow are N, W, and NW directions. It causes the movement of mobile dunes (Barchan and longitudinal). Several methods have been used for dune fixation like the tar spraying, wind fences and stones. Wind fences are not costly and nonpolluting if compared with stonewall and tar spraying, which prevent the land utilization for agricultural purposes.

Abstract

The balance between resources and population constitute the solid base for drawing the future map of sustainable development in the study area in all developmental sectors such as agriculture, industry, tourism, and commercial sectors. Geoenvironmental hazards such as erosion, sea level changes, sand dune encroachment, siltation of the navigation channel of the Damietta harbor, salinization of the soils, the negative effects of the protective structures and bad management of the coastal areas must be studied in details before making the future planning for any area. The main geomorphologic units in this area are: beaches, sand dunes, wetlands, urban areas, reclamation lands and lagoons.

The rate of erosion from 1984 to 2000 in the Rosetta beach is -117.6 m/yr, while it is -17.6 m/yr in the Damietta beach. On the other hand, the rate of erosion in the period from 1984 to 2005 is -104.6 m/yr and -11.4 m/yr in Rosetta and Damietta beaches, respectively. Since, Nile Delta is a typical wave dominated delta (Coleman et al., 1981) and Tide is a semi-diurnal microtidal regime with a maximum tidal range of 50 cm (UNESCO/UNDP, 1978), the erosion and accretion are very dangerous hazard in the area.

Due to the reclamation of vast areas of the coastal dunes, the lagoons and wetlands, the new reclaimed lands are added to the agricultural deltaic land. Thus, the coastal sand dunes, lagoons and wetlands are decreased. The main urban centers have expanded, and new urban centers (Damietta harbor, the New Damietta city and Mansoura city in near future) have been constructed at the expense of vast areas of lagoons, coastal dunes, and backshore flats. The siltation of the navigation canal of the Damietta harbor, salting of the soil (new and old) and sand dune encroachment are very important hazards in the study area. All the previous geoenvironmental hazards and others threaten the sustainable development in the study area.

Abstract

The arid Kachchh district, located at the western most part of the Gujarat State in India, is known for its large extent of area under wetland habitat, which is represented by numerous seasonal water bodies and coastal habitats. Vast stretch of grasslands also available in the northern border of the district, the Banni (23⁰ 19’ to 23⁰ 52’ N; 68⁰ 56’ to 70⁰ 32’ E), which encompasses an area of 2,617 km². There are many depressions in Banni, locally known as Dhandh (shallow lakes). During monsoon, rainwater gets collected in these depressions and form shallow lakes. About 34 smaller and bigger size Dhandhs are present in the Banni. Banni communities are highly dependent on the Dhandhs for various purposes. Due to the erratic rainfall in arid Kachchh, Maldharis is highly unstable for livestock in search of fodder and water during drought years. During the normal rainfall years, livestock from neighboring talukas of Kachhh and even from other districts depends on this grassland and Dhandhs. During last decade, the Banni grasslands have seen serious environmental changes due to the invasion of an exotic plant Prosopis juliflora and increasing the salinity are the major issues of Dhandh degradation. Thus, the Banni is gradually losing its capacity to sustain human and livestock population.

Main objectives of the present paper is to examine the local perceptions of wetland and grassland change, socio-economic status, and factors that cause degradation of the wetland and vegetation resources in the Banni grassland.

Abstract

Burkina Faso is a landlocked country in West Africa with a dry tropical climate characterised by a short rainy season and a long dry season. The annual rainfall varied between 300mm in the northern part of the country to 1200mm in the meridian part. Since many years, the degradation of climatic conditions is observed. Therefore, the annual rainfalls of the 1971-1981 period were inferior to those of the precedent periods, and also the deterioration of the climatic conditions led the limits of some ishoteques “isohyète” to move southward, more than 50km farther. Furthermore, the decennial rainfalls since 1920 were subjected to a latitudinal displacement to the south. For example the ishoteque “isohyète” 500mm which were located at the North of the 15°N outside Burkina Faso during the years 1950-1960 moved gradually year by year and reached the 14°N during the years 1970-1980 inside Burkina Faso.

We let you know that the type of people in a given region is closely linked to the kind of resources found in the concerned region; and which are necessary for human beings to survive.

In fact, more than 100 countries possess arid lands, where more than 40% of the global population lives. The soils of these regions present too much fragility and they are too degraded that they can’t allow people to survive.

Let’s emphasize that in Africa, two third of the total area are arid zones. Thus, for Africans, the type of their struggle for adaptation to the context of their land, illustrates their ingenious capacity to model their hostile surroundings and to leave marks of their cultures all over prehistory and history.

Social organizations in those arid areas are closely linked to modes of exploitation and valuation of resources (water and land). However, human productions in those areas are doubly menaced; on one side by the action of humans who exploit resources for their immediate needs, and on the other side, by climate adverse effects during long periods of drought. It means that climate change and violent meteorological phenomenon worsen circumstances. That leads to environmental degradation and biodiversity reduction; alarming deterioration of vital conditions; and intensification of poverty, both in rural and urban areas; particularly among women and young. Consequently, there are non durable (viable) agricultural practices, overexploitation, overgrazing, excessive and illegal forestry exploitation; destruction of forests and bushes by non-controlled fires, pillages and conflicts with weapons; reduction of vegetation, due to the scarcity of rain; of water in general and menaces of heaps of sands.

Abstract

Increased human activities such as agriculture, mining, and manufacturing have resulted in rapid increase of green house gases (GHGs) in the atmosphere. Atmospheric accumulation of the GHGs results into global warming and climate variability or change. Climate change due to enhanced greenhouse effect arising as a result of human activity is considered a major global environmental threat to mankind today. Perhaps nowhere in the globe are people more vulnerable to climate change than in Sub-Saharan Africa (SSA). Most livelihoods in SSA are climate-sensitive due to over dependency on land and other natural resources and are thus perched on the brink of disaster due to climate change.

Climate change is now undoubtedly affecting millions of people across Africa and it actually threatens to wipe-out the past and current global efforts made to tackle poverty unless urgent and robust decisions and actions are taken. This is also a wake-up call for the world to adopt alternative development models that would ensure massive cuts in GHG emissions to avoid a potentially irreversible change. Scientists have warned that unless the global community, especially the developed countries, take genuine steps now to reduce their emissions; many more millions of people in the developing world will be negatively impacted by climate change.

Abstract

This paper is the synthesis of researches of quaternary on the Chad lake basin, our field investigations, our previous palaeogeographic research underlined by the sédimentological analyses, ¹⁴C radiocarbon and thermoluninescence dating. The objective is to show that after the effects of geological fluctuation, paleoclimatic oscillations, the Chad lake basin experiences since historical times an increasingly drying up due to the combination of geographic factors such as its close position in the Sahara desert, centre of the climate dynamics and human activities. This situation frequently generates recurrent live conditions to which man has to face.

Introduction

Drylands account for over 40% of the global land surface, or approximately 5.2 billion hectares (de Sherbinin, 2002). They provide home for more than 2 billion people or nearly 40% of the population of the world (White and Nackoney, 2003). Asia alone accounts for about 32% of the World’s drylands. Broadly defined by their modest water supply drylands have many regional names, such as semideserts, grasslands, savannas, steppes, and pampas. Dryland ecosystems are a vital part of the earth’s human and physical environments and play a major role in global biophysical processes. They provide much of the world’s grain and livestock, forming the habitat that supports many vegetable species, fruit trees and micro-organisms. With an exception of Australia and the United States, almost all drylands are situated in developing countries with populations living in extreme poverty. Populations of drylands are frequently some of the poorest in the world. Food security and water availability of these areas has always been unstable due to high variability in both rainfall amounts and intensities and the occurrence of prolonged periods of drought. The increasing pressures caused by the global climate change and massive land-use changes further increase human vulnerability in dry regions. The impacts of climate change in drylands are likely to lead to still larger populations being affected by water scarcity and the risk of declining food security and increase the risk of environmental migrations and violent conflicts caused by the decline of resources, which are important to sustain livelihoods (Barnett and Adger, 2007).

Introduction

Desertification is now accepted as a major environmental issue because of the fact that 69.5 percent area of the world’s dry lands and more than 1.2 billion people in over 110 countries living in this habitat are affected by various land degradation processes. During last 20 years, researchers have focused their discussion either on a condition or a cause or a set of processes to assess different paradigms of desertification. Several studies carried out in arid western part of Rajasthan (Singh et al., 1992, Kar, A. 1993b, Kar, 1995, Dregne, H.E. 2000, Kar et al.2007) show that wind erosion is still a major problem. Though, there are many instances of location specific problems like water erosion, salinity/ alkalinity and water logging, about 75% area in arid western Rajasthan is affected by wind erosion hazard of different intensities (SAC, 2007, Kar et al. 2009). Decreasing rainfall gradient from east to west and increasing wind strength in that direction are responsible for the spatial variability in sand reactivation pattern. Water erosion in the form of sheet, rill and gully erosion is a major problem in areas, where average annual rainfall exceeds 350 mm, the rainfall intensity is high and the topographic and soil characteristics favour high run-off. Destruction of vegetation cover and excessive ploughing of shallow soils, especially on the sloping lands, accelerate the problem.

Introduction

Desertification, which is considered a major threat in the drylands of the world, is not about advancing boundaries of the existing deserts, but about land degradation in the arid, semi-arid and the dry sub-humid regions, which together form the drylands (Anon., 1995). Secular variation in climate that has resulted in periodic expansion and contraction of the desert boundaries and regional-scale changes in vegetation condition (Tucker et al., 1991; Nemani et al., 2003; Hickler et al., 2005) is one of the drivers of desertification. Human activities constitute the other major driver. According to Geist and Lambin (2004) the prominent core variables that drive degradation are climatic, economic, institutional, national policies, population growth and remote influences.

Introduction

Low and erratic precipitation, diurnal fluctuations in temperature and low humidity are the typical characteristics of deserts and their margins. Further, strong winds, sunny and very bright days and unpredictable periods of drought and famines are regular features. These lands are poor in fertility. Uninterrupted increase in human and animal pressures is violating carrying capacity of the natural resources, thus resultant is desertification.

Arid zones are described as a part of the drylands, and have the most severe edapho-climatic conditions. The major distinguishing feature for defining and for planning for the arid zone is the low rainfall (below 500 mm or Aridity Index <0.20) with more than 50% inter-annual variability. This makes a great difference in terms of the nature of the ecosystem, the socio-economic environment and the challenges for sustainability. High wind and solar regimes further increase the effect of rainfall variability and the whole complex makes a fragile ecosystem in which small disturbances may cause great loss to the sustainability, which are sometimes irreversible (Hou’erou, 1996). The hot arid zones of the world are economically and environmentally disadvantaged, with unique problems. The ecosystems of these zones are highly fragile with large risks that cause severe impediments to development programs. Of the total land area in the world, arid zones cover 18.8% and the hyper-arid zones account for 22.3% of the total arid zones (FAO, 1989).

Introduction

The Himalayan Moutains that is relatively a younger formation and geologically a very complex occupies most of the Arunachal Pradesh. The mountain terrain covers an area of about 86000 sq. km with elevation ranging from 400 to 6000 m above mean sea level (Satapathy and Dutta 1999). The wet tropical and sub-tropical climate which prevails in most part of the Arunachal Pradesh, there is usual phenomenon of erosion and land degradation by the action of water. It is estimated by the application of USLE for Arunachal Pradesh that the total amount of about 669.35 million tones of soil is eroded annually with an average rate of 90.7 tonnes /ha/year (Singh, 1999).

Arunachal Pradesh falls under upper Brahamaputra river system constituted by 10 major river basins. They are Tawang, Kameng, Dikrong, Subansiri, Siang, Sesseri, Dibang-Tellu, and Tirap-Tiso. In Arunachal Pradesh, Dikrong river is named after joining of two main rivers Pachin and Para . In the catchments of Dikrong river light textured unstable soils with the prevalent practice of Jhum Cultivation makes the entire catchments susceptible to erosion. In every monsoon the river Dilrong carries tremendous amount of silt, gravel, small boulder and causes flood in some parts of the catchments susceptible to erosion. Singh (1999) observed that loss rate through Dikrong River was 100.98 tones/ha/year. This indicates serious threat to soil resources and there is need for urgent treatment for sediment control in Dikrong river bash.

Introduction

The Rispana river is a order of stream forming a tributary of Ganga. Its watershed covers an area of approximately 53.6 Km in the northern part of Dehradun city lies between 78^º30’ to 78^º15⁰’ longitude and 30^º15’ to 30^º 30’ latitude in top sheet No is 1/3. The area is covered in IRS - IC Pan of 13 Jan 1998 and LISS-III of 7 March 1997.

The Doon Valley is enriched with numerous seasonal and perennial streams. Which forms the lifetime or the inhabitants . The Rispana river is the part of the Ganga system of Drainage of the valley. The river originates from the Mussoorie hills, which are full of natural springs. The droplets from the springs collect and form numerous streamlets and these streamlets are joined to be these and they form the famous Shekhar Falls (north of Shahanshai Ashram about 5 Km away). Then the Rispana flows along Rajpur road over the Doon Gravels and then river passes through the tiny hamlets Nalapani, Raipur, Chanderroad, Defence colony, Amwala, Tapowan, Dandadhoran Adohiwala, Dalanwala, Gujram, Ajabpur and finally its contribute the water to the suswa River which intern joins the Ganga.

Introduction

On 26^th December 2004, the Indian coastline experienced the most devastating tsunami in recorded history. The tsunami was triggered by an earthquake of magnitude Mw 9.3 at 3.316ºN, 95.854°E off the coast of Sumatra in the Indonesian Archipelago at 06:29 hrs making it the most powerful in the world in the last 40 years. In recent years increasing the vulnerability to natural disasters of developing countries is a major reason for concern. The potential loss of human lives and property due to natural hazards is very high in the urban areas of these countries. The Information obtained from conventional tsunami hazard maps does not always provide sufficient data for users .needs. The difficulty in presenting more significant information on tsunami hazard maps in conventional paper format is due to the limited available physical space of that format. Printing more information on such paper maps tends to confuse rather than provide more needed information to users. Furthermore, these kinds of maps provide little opportunity for users to ask for additional information, to determine the relationships between different kinds of information and important quantitative analyses. Furthermore, Tsunami hazards have important temporal attributes. Presenting these attributes on the map; e.g. the sequence of volcanic eruptions in a region or the frequency of tsumani in a particular area during a particular period of time is very difficult.

Introduction

The state of Maharashtra now again reels under the scarcity of water. Geologically, major part of the state is covered by Deccan basaltic flows. This basaltic terrain, as such, has been labelled notorious as far as the availability of groundwater is concerned. Uncertain availability of groundwater in the terrain is due to heterogeneity in the nature of piles of basaltic flows which adversely affects the geohydrological characters of the rocks.

The area understudy is unfortunately, a part of basaltic terrain in which no storage structures like major dams or medium projects have been constructed across the existing rivers. Consequently, the irrigation in the area and domestic needs of the people solely depend on whatever water is available in the existing dug wells. The wells do not suffice the need of the people because the percolation of water in the wells is not adequate in major part.

Introduction

Earthquakes are the most destructive among all the natural hazards. Most of the time, they occur without any warning, which makes them most feared and unpredictable natural phenomena. Globally, on an average two earthquakes of magnitude 8 are known to occur every year. Some of the countries like Japan, China and United States have suffered several damaging earthquakes in the past. India has also experienced a number of high intensity earthquakes in the recent past and more than 650 earthquakes of magnitude >5.0 have been reported in India since 1890. Sixty-nine earthquakes in Delaware (U.S.A.) have been documented or suspected since 1871. Refer to Baxter (2000) for more details about the DGS Seismic Network and for documentation of earthquakes. In the 1930s Charles Richter developed a magnitude scale (Richter scale) which was an objective way of discriminating between large and small shocks using the seismic wave amplitude recorded by seismographs (Richter, 1958).

Introduction

A disaster is the result of an immediate situation or the result of a long, set process, which disrupts normal human life in its established social, traditional and economic system. This is due to the destruction of environment which is caused by extraordinary natural destructive phenomena or human-induced hazards resulting in human hardship and suffering beyond recovery unless external aid is brought in.

Introduction

Disasters are the natural and man made extreme events which exceeds the tolerable magnitude of any event, where adjustment is difficult. These events are catastrophic and results in the loss of life and property on a huge scale. These abnormal events form the headlines to the newspapers and media a world and national level.

These processes are beneficial to the human beings because they form the earth and habitable planet for the evolution of life. However, these processes within a short time limit forms, hazardous and such activities adversely affect the human beings and human related activities on a very large scale.

Amongst the three important types of disasters viz. natural, anthropogenic and technological, the first and the foremost natural disaster mainly includes the geological atmospheric and other related natural types viz. floods, earthquakes, cyclones, tsunamis etc.

Introduction

Natural Disasters are inevitable, and Indian subcontinent is prone to all type of Natural Disaster either it is flood, drought, cyclone, earthquakes, tsunami or forest fires etc. Disasters can be classified in several ways. A possible sub-division of disaster is: (i) Natural Disasters; (ii) Human made disasters; (iii) Human induced disasters. Another sub-division is related to the main controlling factors leading to a disaster. These may be meteorological, geomorphological/geological, ecological, technological, global environmental and extra terrestrial. Another useful distinction that can be made between disasters is regarding their duration of impact and the time of forewarning. Some disaster strikes within a short period with devastating outcomes; others have a slow onset period with equally or more serious repercussions. According to the available statistics 60% of the total area of Indian subcontinent is venerable to seismic activity of varying intensities, 16% of the country’s total area is drought prone. In India 68% of total sown area of the country is drought prone. Coastal areas of India is exposed to tropical cyclones, tsunami in recent years and among all the disaster occur in the country, River floods are the most frequent and often the most devastating.

Introduction

Disaster is defined as a serious disruption of the functioning of a community or a society causing widespread human, material, economic or environmental losses, which exceed the ability of the affected community or society to cope using its own resources (ISDR 2002).

Disaster in Global context - The impact of natural disasters in terms of human and economic losses has risen in recent years, society in general has become more vulnerable to natural disasters. Those usually most affected by natural and other disasters are the poor and socially disadvantaged groups in developing countries as they are least equipped to cope with them (IFRC 2001).

Introduction

The natural hazards like floods, cyclones, droughts, landslides and earthquakes are not rare or unusual phenomenon. India is among the world’s most disaster prone areas and a large part of the country is exposed to such natural hazards, which often turn into disasters causing significant disruption of socio-economic life of communities leading to loss of life and property. It would not be considered as a disaster unless it resulted in actual damage to human life or property. According to data accumulated over past 25 years, natural disasters in Asia accounts for about 40% of the world’s total disasters while the death toll ratio is about 50% and the number of people affected is about 90%. The latter figure is about 2.2 times the ratio of number of occurrences in Asia. The figures vary widely over the decades, a result that can be attributed to a few particularly terrible disasters. Such as the 1976 Tangshan Earthquake in China, which killed about 250,000, and a series of severe cyclones that hit Bangladesh in 1970 with a death toll of about 500,000. The death toll resulting from wind and flood disasters jumped by an order of magnitude in the 1990s. But this sudden increase affected Asia’s ratio to the world total by about 15 percentage points because there was a worldwide surge in this type of disaster. Clearly, there is an extreme concentration of victims of such disasters in Asia, Another substantial increase is clear in the value of damage caused by typhoons and cyclones; it is now running at 10 times the level of the 1980s. Again, however, the ratio has remained almost unchanged, at about 40%, because hurricanes in Central and North America account for more than 50% of the world total (51.2%, 58.5%, and 54.4% in the 1970s, 1980s, and 1990s,respectively). It is sadly worth noting that there has been conspicuous growth in the absolute value of damage in both Asia and the Americas.