Ecohydrology emerges as a new field of research aiming at furthering our understanding of the earth system through the study of the interactions between the water cycle and vegetation. By combining the analysis of biotic and abiotic components of terrestrial ecosystems, this volume provides a synthesis of material on arid and semiarid landscapes, which is currently spread in a number of books and journal articles. The focus on water-limited ecosystems is motivated by their high sensitivity to daily, seasonal, and decadal perturbations in water availability, and by the ecologic, climatic, and economic significance of most of the drylands around the world. Conceived as a tool for scientists working in the area of the earth and environmental sciences, this book presents the basic principles of eco-hydrology as well as a broad spectrum of topics and advances in this research field. The chapters collected in this book have been contributed by authors with different expertise, who work in several arid areas around the World. They describe the various interactions among the biological and physical dynamics in dryland ecosystems, starting from basic processes in the soil-vegetation-climate system, to landscape-scale hydrologic and geomorphic processes, ecohydrologic controls on soil nutrient dynamics, and multiscale analyses of disturbances and patterns.

This book presents recent lessons learned in the context of research and development for various dryland ecosystems, focusing on water resources management, land and vegetation cover degradation and remediation, and socioeconomic aspects, as well as integrated approaches to ensuring water and land security in view of the current and predicted climate change. As water and land are the essential bases of food production, the management of these natural resources is becoming a cornerstone for the development of dryland populations. The book gathers the peer-reviewed, revised versions of the most outstanding papers on these topics presented at the ILDAC2015 Conference in Djerba, Tunisia.

A large part of the global population lives in arid lands which have low rainfall and often lack the water required for sustainable population and economic growth. This book presents a comprehensive description of the hydrogeology and hydrologic processes at work in arid lands. It describes the techniques that can be used to assess and manage the water resources of these areas with an emphasis on groundwater resources, including recent advances in hydrologic evaluation and the differences between how aquifer systems behave in arid lands versus more humid areas. Water management techniques are described and summarized to show how a more comprehensive approach to water management is required in these areas, including the need to be aware of cultural sensitivities and conditions unique to many arid regions. The integration of existing resources with the addition of new water sources, such as desalination of brackish water and seawater, along with reusing treated wastewater, will be required to meet future water supply needs. Also, changing climatic conditions will force water management systems to be more robust so that future water supply demands can be met as droughts become more intense and rainfall events become more intense. A range of water management techniques are described and discussed in order to illustrate the methods for integrating these measures within the context of arid lands conditions.

This study aims at improving the hydrological process understanding of the semi-arid and transboundary Incomati river basin to enable better water management. Comprehensive statistical and trend analysis of rainfall and streamflow were conducted, and the Indicators of Hydrological Alteration tool was deployed to describe the streamflow regime and trends over time. Land use and land cover change, particularly the conversion of natural vegetation into forest plantation, the expansion of irrigated agriculture and the flow regulation due to dam operation were identified as critical drivers of flow regime alteration. Hydrograph separation using long-term hydrochemical data at seasonal scale, and hydrochemical and isotope data at event scale were performed to quantify runoff components. A novel methodology to calibrate recursive digital filters using routinely collected water quality data was developed and tested in the catchment. This method allows for estimation of daily baseflow from readily available daily streamflow data. Dominant runoff generation zones were mapped using the Height Above Nearest Drainage approach. The hydrological model STREAM was then employed, informed by the runoff generation zones mapping and the process understanding gained in the catchment, as well as remote sensing data. The study provides the basis for better operational water management in the catchment.

Divided into four sections, this book deals with the geography of the arid realm, the water resource problems they face, the methods available for enhancing water supplies, and the management of this resource.