Preface Desert regions are familiar faces in many pages of history of the world. The earliest civilizations and two of the world’s major religions were born here. Now, deserts are themselves making news. Some of the cultures have made hot deserts their home for thousands of years. Modern technologies, including innovative irrigation systems and agricultural patterns have made deserts much more hospitable now. Despite such improvements, arid zones remain vulnerable to climate change and extremes of climate due to not-so-hospitable climate, poor soil and vegetation. In the wake of global climate changes, the desert ecosystem has again come under scrutiny to become one of the heartthrobs of research. Therefore, desert ecosystems seem to be dwindling between development and degradation. Many of the desert ecosystems like Thar desert in India is well studied by researchers from many parts of the world including its own inhabitants. Information is now available about this region for the rest of the world to explore it more for mankind and its development. There is a radical change in the approach to life by the desert dwellers. Development is now a key word to the desert regions. Water is now available through canals and people have started using scientific approaches to conserve rainwater through improved systems. More information is also available on the state of natural resources, natural hazards and the impact scenario. GIS database is available through satellite remote sensing and thematic maps at different scale for assessing the resources at a given situation like drought and floods.

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 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 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 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).

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.

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.

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 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.

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 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 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.

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 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.

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.

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.

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.

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.

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 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 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 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.