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International voices fill the pages of Water and Sustainability in Arid Regions, forming an original scientific exploration of current water research and management issues.

In arid regions, agriculture that is ill-adapted to the environment, accelerated urbanization, poverty, and increasing pollution challenge access to and uses of water. Understanding these issues requires incorporating findings from both the physical and social sciences at different temporal and spatial scales.

The chapters in this book were written by hydrologists, remote sensing specialists, ecologists, historians, economists, political scientists, architects, archaeologists, and other experts who live in and study arid lands. The authors present updates, overviews, and analyses of water challenges these areas have faced and are striving to address, from salinization in the fabled Taklimakan Desert in China to land degradation in the northern Mediterranean to groundwater over-exploitation in the southwestern United States.

The book also examines desertification, remote sensing, qanat systems, architecture, arsenic contamination, and other case studies from Iran, the Maghreb region, Argentina and Chile, and Mexico. From this conceptual mosaic of comparative perspectives and research methods emerges a strong assumption: an interdisciplinary approach that combines physical and social sciences is the first step toward globally and comprehensively addressing water and sustainability."This book is a valuable and welcome contribution to the discussion of water and sustainable development. Through the collection of chapters, the book clearly illustrates the contemporary diversity of approaches to water scarcity and presents pertinent and new research findings that readers generally do not find compiled together. The result is a highly relevant, accessible, and timely resource that is unique in its international and interdisciplinary content. This is a must-read for anyone working on environmental and sustainability issues in arid lands."André Mariotti, University Pierre et Marie Curie, and INSU - CNRS (National Institute for Earth Sciences and Astronomy-National Center for Scientific Research/Centre National de la Recherche Scientifique), France "Anyone who reads this book will find himself or herself contemplating the need to rethink how we approach the issue of water and sustainability in arid lands. Drawing on the expertise of both physical and social scientists, the chapters taken as a whole present global, historic, and current perspectives on water scarcity in a multi-layered way that rarely has been done before." Miguel Solanes, Madrid Water Institute, Spain

Inhaltsverzeichnis

Frontmatter

Contemporary Issues

Frontmatter

Chapter 1. Eco-reconstruction in Northwest China

The northwest arid region of China has a long history of economic development. With the emergence of environmental and sustainability concerns in recent years, more attention has been paid to the strategy of developing this region, raising issues of land degradation, the use of water and land resources, and eco-reconstruction. Understanding the complex interactions between land, vegetation, and degradation is necessary to build policies for eco-reconstruction and sustainable water use. Land degradation in arid and semiarid regions is dominated by sandy desertification caused by wind erosion, secondary salinization of soil due to poor drainage and intensified evapotranspiration, and degradation of rangeland by excessive cultivation and overgrazing. This situation intensifies the conflict among humans for land and resources and has serious social, economic, and ecological consequences.

Du Zheng, Yunhe Yin

Chapter 2. Remote Sensing Assessment of Salinization Impacts in the Tarim Basin: The Delta Oasis of the Ugan and Kuqa Rivers

Extracting information about saline soils from remote sensing data can be useful, particularly given the environmental significance and changing nature of these soils in arid environments. One interesting case study is the delta oasis of the Ugan and Kuqa rivers in China’s Xinjiang region, which was studied using a landsat enhanced thematic mapper plus (ETM+) image collected in August 2001. In recent years, decision tree classifiers have been used successfully for land cover classification from remote sensing data. Principal component analysis (PCA) is a popular data reduction technique used to help build a decision tree; it reduces complexity and can help improve the classification precision of a decision tree. A decision tree approach was used to determine the key variables to be used for classification and ultimately extract salinized soil from other cover and soil types within the study area. The third principal component (PC3) is an effective variable in the decision tree classification for salinized soil information extraction. The PC3 was the best band to identify areas of severely salinized soil; the blue spectral band from the ETM+ sensor (TM1) was the best band to identify salinized soil with the salt-tolerant vegetation of tamarisk (

Tamarix chinensis Lour

); and areas comprising mixed water bodies and vegetation can be identified using the spectral indices Modified Normalized Difference Water Index (MNDWI) and Normalized Difference Vegetation Index (NDVI). Based upon this analysis, a decision tree classifier was applied to classify land cover types with different levels of soil saline. The overall accuracy of the classification was 94.80%, which suggests that the decision tree model was a simple and effective method with relatively high precision.

Tashpolat Tiyip, Gregory N. Taff, Hsiang-te Kung, Fei Zhang

Chapter 3. Estimating Net Primary Production in Xinjiang Through Remote Sensing

Land cover components of photosynthetic vegetation (PV) and non-photosynthetic vegetation (NPV) were analyzed with satellite remote sensing technology and knowledge of the typical climate–vegetation characteristics of the arid region of Xinjiang in western China. The objective was to develop a Net Primary Productivity-Geography Processing Ecology Model (NPP-GPEM) of solar energy utilization efficiency based on remote sensing and ecological processes that would fit the arid region with reference to such remote sensing–ecological models as the Global Production Efficiency Model (GLO-PEM), Carbon Exchange between Vegetation, Soil, and Atmosphere (CEVSA), and Carnegie-Ames-Stanford Approach (CASA). The terrestrial ecosystem of Xinjiang was taken as an example for this study. Supported by NOAA/AVHRR (Advanced Very High Resolution Radiometer) meteorological satellite remote sensing data and climate data, the annual NPP of Xinjiang’s mountain–oasis–desert ecosystem from 1981 to 2000 was estimated at 1 km spatial resolution. Detection and analysis of spatio-temporal change also was performed. The results showed there were great differences in NPP spatial–temporal patterns in various regions. NPP increased in most parts of Xinjiang from the 1980s to the 1990s. The west part of the piedmont plain on the north slope of the Tian Shan Mountains had the largest increase in NPP in north Xinjiang, and Kashi-Shache Delta had the largest increase in south Xinjiang. The spatial distribution of NPP was characterized by a general decrease from north to south and from east to west.

Guanghui Lv, Weiguo Liu, Jiangjun Yang, Entao Yu

Chapter 4. The Recent Evolution of the Oasis Environment in the Taklimakan Desert, China

Numerous natural and anthropogenic factors have caused soil salinization, land surface degradation, and desertification in Keriya County in China’s Xinjiang region. Information from multi-temporal remotely sensed data such as the Soil Salinity Index (SSI) has contributed significantly to an understanding of these environmental changes. The approach to calculating SSI is based on the spectral bands of Landsat Thematic Mapper (TM) or Enhanced Thematic Mapper Plus (ETM+). A soil salinity map of the Keriya County area was produced from Landsat ETM+ images, with an overall accuracy of 72.73% and kappa coefficient of 0.6689. The analysis of the recent evolution of the oasis of Keriya County was carried out by coupling climatic and socioeconomic data with information derived from multi-temporal remotely sensed data such as the SSI, Normalized Difference Vegetation Index (NDVI), and different land use classes. Such analysis appeared to be very useful in identifying and monitoring changes occurring in the oasis ecosystem and for understanding the consequences of human-induced land degradation processes.

Yalikun Tashi, Philippe C. Chamard, Marie-Françoise Courel, Tashpolat Tiyip, Yiliminuer Tuerxun, Sam Drake

Chapter 5. High Demand in a Land of Water Scarcity: Iran

Since ancient times, humans have mobilized huge efforts to counter water shortages and meet water demands in arid and semiarid areas. If, however, water issues existed on a local scale in the past, in the present and future these problems occur on national, regional, and global scales and could threaten peace keeping, food security, and eventually sustainable development. In Iran, a nation covering about 1,650,000 km

2

, the supply, transfer, and use of water are major concerns, just as they were in ancient times. At present, about 55% of the water consumed in Iran is provided from groundwater resources and 45% from surface water, and more than 90% of water resources are allocated to the agriculture sector. The freshwater shortage has caused an increase in saltwater consumption, especially in arid and semiarid zones. Misuse and unrestrained water resources and traditional irrigation systems have caused soil salinity, land degradation, and desertification problems. Increasing salinity in most water resources in Iran over the past 10 years has caused an intensive decline of soil and water quality. Therefore, one of the main economical and social strategies of the government of Iran must be management that optimizes the use of water resources to attain sustainable development.

Gholamreza Zehtabian, Hassan Khosravi, Marzieh Ghodsi

Chapter 6. Common Scarcity, Diverse Responses in the Maghreb Region

The Maghreb region faces a large increase in population and water demand for both people and agriculture. At the same time, pollution of the aquifers has reduced hydrological reserves. With a net decrease in rainfall during recent decades and the expansion of rural activities (agriculture and livestock), demand for water in the Maghreb is less and less satisfied. To face this hydric stress, several strategies are required to increase the efficiency of existing resources and develop new ones. Appropriate technical responses call for new equipment to transfer and distribute water and require the mobilization of nonconventional water: implementation of new techniques of seawater desalination, new equipment to treat and recycle wastewater, and the reuse of the foggara system, also known as the khettara. From an “equity of access to water” viewpoint, national solidarity requires the transfer of water from areas of abundance towards areas less well endowed. In order to respond to people’s needs while taking into account the unequal geographic distribution of water, it will become increasingly necessary to seek water from further away to sustain the cities. Coherent interventions require the design of new integrated strategies for the management of available water resources at all levels, including farmers, herders, municipalities, the private sector, and resource managers.

Yamna Djellouli-Tabet

Chapter 7. Changing Water Resources and Food Supply in Arid Zones: Tunisia

The notion of water security in an arid country takes on another dimension when the comprehensive water balance concept is applied to water used by rain-fed agriculture and to the water equivalent of international food exchanges. In the case of Tunisia, this concept expands the prospects for improvements in national food security by optimizing the food balance and the corresponding virtual water flux. It also prompts reconsideration of criteria and indicators classically used to characterize water stress situations. The current situation shows that about 30% of the water used in Tunisia is imported as food (virtual water); that number is likely to reach 40–50% in 2025 due to climate change, diet change, demographic growth, and improved water management. Asia and North Africa will most likely not be self-sufficient in terms of food production and will need to import food from other continents (e.g., South America). Africa, however, could be self-sufficient if its existing water resources are developed. Bioenergy production is likely to be limited to a small fraction of the global energy needs. Major food shortages in cases of severe global droughts (e.g., during very strong El Niño events) may occur, however, with severe consequences in terms of food availability.

Mustapha Besbes, Jamel Chahed, Abdelkader Hamdane, Ghislain De Marsily

Learning from History

Frontmatter

Chapter 8. The Qanat: A Living History in Iran

About 2,500 years ago, Persians invented a number of methods for harnessing groundwater, including a water management system called a qanat. Still used today, qanats are built as a series of underground tunnels and wells that bring groundwater to the surface. They supply about 7.6 billion m

3

, or 15% of the country’s total water needs, and play a major role in advanced water harvesting. However, many of these systems have been abandoned and replaced by other methods over the past few decades, mainly due to socioeconomic conditions and changing technology. In addition, drilling more deep and shallow wells has hurt groundwater quality—especially in the littoral district of Iran’s central plain—which has implications for the environment, people, and economy of Iran. It is necessary therefore to recommend and implement relevant solutions to increase the efficiency of qanats to achieve sustainable development in water resources management.

Hassan Ahmadi, Aliakbar Nazari Samani, Arash Malekian

Chapter 9. Notes from the Turpan Basin: Pioneering Research on the Karez

The karez in China is a unique example of the underground tunnel irrigation systems that were developed by the Persians in ancient times and spread to many regions of the globe. Until relatively recently, it had been difficult for foreign researchers to study the karez in the field because of limited access to the interior of Asia. But in 1981, a Sino-Japanese mission was organized to explore the karez system in the Turpan Basin in China’s Xinjiang province. The author, Iwao Kobori, professor of drylands and desertification at the United Nations University in Japan, was part of that mission and has spent decades studying and documenting the karez system. Today, while the use of the karez is, generally speaking, declining, the research conducted by the mission, as outlined in the chapter, is valuable for conservation and restoration.

Iwao Kobori

Chapter 10. An Introduction to the Khettara in Morocco: Two Contrasting Cases

On each side of the High Atlas in Morocco, various societies have built thousands of tunnel and well networks called khettaras, which are much like the qanats of Iran or the foggara systems of Algeria. Ancient writers have noted the ingenuity of these devices, but in the last 30 years, the use of khettaras has declined. An inventory is necessary to understand the rural zones where groups of khettaras still exist. The contrasting situations of the province of Marrakech (Haouz), where palm groves were irrigated primarily by hundreds of these underground tunnels, and the province of Tafilalet, where an inventory of 500 khettaras recently has been made, highlight the fate of the water management systems. Around Marrakech City, the collapse of the khettara is rapidly impacting water supply. In Tafilalet province, the situation seems more favorable for water supply sustainability and future use of khettaras, with 50% of the khettaras still “alive.” However, the modernization of irrigation and the increase of wells are signs of change. How can these systems be maintained, and how can farmers be allowed to innovate without destroying what made the inhabitants of arid regions relatively prosperous?

Mohammed El Faiz, Thierry Ruf

Chapter 11. Digitally Conserving an Endangered Built Heritage in Kashgar, an Oasis City of the Taklimakan

The ancient oasis city of Kashgar sits at the intersection of caravan routes that once made up the Silk Road. Located west of the Taklimakan Desert in western China, Kashgar has been able to survive due to efficient management of water reserves and maintenance of canals that irrigate crop fields and provide subsistence for local inhabitants. Water has a central role both in the organization of inhabited spaces (urban or rural) and in the distribution of domestic spaces. Indeed, the vernacular architecture of the city is particularly well adapted to the area’s hyperarid environment. Over the last 20 years, however, the city has undergone major urban development and reconstruction, a phenomenon that has threatened its architectural heritage. A digital method has been designed that makes it possible to record images of an architectural ensemble and thereby conserve a particular “culture of construction” that is endangered in Kashgar.

Michel Florenzano, Marie-Françoise Courel, Francesca De Domenico

Chapter 12. The Taklimakan Oases: An Environmental Evolution Shown Through Geoarchaeology

Amid the ocean of sand that is the Taklimakan Desert in China’s Xinjiang province, evidence of human habitation has revealed a rich pastoral and agricultural history along dried-up waterways through which the Keriya River once coursed. The various states of the river, which had connected the north and south oases of the desert but now disappears into the dunes, are visible on satellite images. By confirming the hypothesis of the existence of ancient agricultural settlements on deltas—nowadays totally dry—of this river, research has clarified settlement patterns over the long term by placing them in the evolution of their environment under the influence of natural or anthropic factors. From the current bed of the Keriya River to its fossil courses, several years of pluridisciplinary studies revealed an evolution of the successive deltas of the Keriya River in at least three periods: current, antiquity (third and fourth centuries AD), and protohistory (c. 2,500–1,000 BC: Bronze and Iron ages). These successive deltas correspond to various stages of desertification. In each of them, an oasis and a vast settlement zone are centered on a main village. Studying these settlements and comparing them with those of Central Asia provides an inventory of the interactions between man, water, and the environment and illuminates constants and variables of change.

Corinne Debaine-Francfort, Françoise Debaine, Abduressul Idriss

Management for Sustainability

Frontmatter

Chapter 13. How the Predominance of Water Resources Informs Management

While a number of different kinds of water resources can coexist in a given country, generally speaking, one type in particular predominates based on hydrographical and hydrogeological conditions. Countries or territories located in arid and semiarid zones can therefore fall into three categories, according to their predominant type of water resources: internal renewable resources, external renewable resources, and nonrenewable resources. The types of predominant water resources and the differences in resulting total water resources have a visible impact in terms of explaining current differences in economic development and geopolitical issues in general. In all cases, development and food security seem to be highly dependent on trade with developed countries located in humid zones. In the long term, differences in variously sustainable sources of supply may have the greatest impact on development.

Jean Margat

Chapter 14. Conjunctive Water Management in the US Southwest

Water demands in the US Southwest have been subject to great pressures due to explosive population growth and climate variability that has produced decadal droughts. These pressures have led to unsustainable use of surface water and groundwater, forcing states to adopt conjunctive management of ground and surface water systems. Unfortunately, federal and state laws have not kept pace with the scientific development of management strategies. A series of examples are presented to illustrate some successes and failures of integration of surface water and groundwater management and its accompanying legal implications.

Juan Valdes, Thomas Maddock

Chapter 15. Managing Water Amid Rapid Urbanization: Mexico’s North Borderlands

The arid and semiarid border cities of northern Mexico sit in a region of rapid industrial growth and development, but they face the challenge of supplying water to an ever-increasing number of people with ever-diminishing water supplies. A number of alternatives exist to meet this challenge: improvements in management efficiency, wastewater treatment and reuse, water transfers from agriculture, and seawater desalination. However, several factors within the current institutional framework, such as the turnover of water managers, the criteria used to design water rates, and the lack of effective sanctions for free riders, restrict the implementation of alternative solutions. In view of these constraints, a reform on water laws and a new institutional framework of urban water management are required to face the combination of water scarcity, economic growth, and the prospect of harsher and longer droughts in the near future.

Nicolás Pineda-Pablos, Alejandro Salazar-Adams

Chapter 16. Forecasting Streamflows in the San Juan River Basin in Argentina

San Juan province, located in western Argentina, presents great climate variability with arid characteristics. Mean annual rainfall averages less than 100 mm for the whole province, and snowmelt in the Andean upper basin provides the San Juan River Basin with seasonal streamflow during summer, the period of highest water demand for irrigation. Traditional streamflow forecasts for the San Juan River are based on statistical regression models that are strongly dependent on values of snowpack in winter months (July, August, and September) and streamflow values in the spring months. However, producing forecasts for San Juan River summer streamflow using the Multivariate El Niño Southern Oscillation Index (MEI) data in the preceding June of the water year as an explicative variable can improve reservoir operating system performance for irrigation. To demonstrate this, climate predictors such as the MEI were used to forecast San Juan River streamflows to provide predictability at a six-month lead time. A backpropagation neural model, based on coupled data of snowpack and a climate predictor during the winter period, proved successful in forecasting San Juan River flows during the following summer period.

Juan Carlos Gimenez, Emilio Juan Lentini, Alicia Fernández Cirelli

Chapter 17. Arsenic and Water Quality Challenges in South America

The presence of arsenic in soils and water is a threat to public health and agricultural activities because this toxic element poses contamination risks to plants, animals, and humans. Central Argentina (northern area of department of Union, province of Córdoba) and northern Chile, (El Loa, II Region de Antofagasta) are two of the areas most affected in the world and are representative of the arsenic contamination problem in arid and semiarid regions in South America. In both areas, arsenic levels in water are above the World Health Organization guidelines for human consumption (10 μg/L), and health effects in both sites have different manifestations. Nevertheless, the general trend in epidemiological studies is to find a relationship between chronic arsenic ingestion and cancer occurrence. Scarce data are available in most regions of South America. Environmental monitoring is not a common practice in many countries and should be implemented to verify that current environmental quality norms are met, carry out baseline studies to obtain the necessary data for developing contamination control tools, and estimate the population’s exposure to arsenic. Conveying information to the population about arsenic water contamination and possible solutions is central to overcoming the problem.

Alejo Pérez-Carrera, Alicia Fernández Cirelli

Chapter 18. Evaluating the Restoration of Dryland Ecosystems in the Northern Mediterranean

Drylands in the northern Mediterranean present significant challenges for efforts to preserve ecosystem services. Warming trends combined with declining and more variable summer precipitation have come with more frequent and more intense droughts, exacerbating water shortages. Depopulation from rural uplands towards urban coastal regions, with farmland abandonment, has destabilized agroecological systems. The ensuing land degradation has influenced local hydrology, erosion rates, water quality, and water quantity. Ecological restoration combined with adaptive management can be an effective approach in response to the changing climate and environment. The development of standardized monitoring and evaluation protocols on the EC REACTION project has provided powerful insights and new tools to enhance the potential for successful restoration. The integration of biophysical and socioeconomic indicators and the collaboration between researchers, managers, and decision makers make the approach effective and sustainable. Restoration in drylands can have a marked impact on water budgets through the selection of species and the influence on landscapes and vegetation patterns. Adapting to environmental change and combating land degradation in the northern Mediterranean will require understanding the tradeoffs in ecosystem services and adjusting restoration decisions in response to monitoring and evaluating both biophysical and socioeconomic metrics.

Susana Bautista, Barron J. Orr, José Antonio Alloza, Ramón V. Vallejo

Chapter 19. Old and New: Changing Paradigms in Arid Lands Water Management

Water management paradigms and practices have evolved markedly from the post-World War II years to the twenty-first century. Changes have been particularly urgent and visible in water-limited arid lands. Notable trends include movement from an emphasis on technological, supply-side solutions toward sociological, demand-side management; from rigid top-down state control toward decentralized management; and from local or regional management arenas toward integrated, multilateral formation of water policy from a global perspective. Efforts continue to augment water supplies, but practice has shifted from tactics such as weather modification to energy-efficient desalination, wastewater reuse and, significantly, conservation, which was hardly considered in previous periods of perceived abundance. Overtaking even these efforts in importance is a growing intellectual elaboration of an integrated water management paradigm, which recognizes that each element on both the supply and demand sides of the equation contributes to the total water availability and requires consideration of linkages between urban and rural water use as well as between the domestic, industrial, and agricultural sectors. This awareness has spurred the establishment of “global water initiatives,” marking a shift toward globalization of water management to achieve higher levels of integration.

Charles F. Hutchinson, Robert G. Varady, Sam Drake

Backmatter

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