Unsaturated Zone Hydrology

Using a quantitative modeling approach, this volume offers a comprehensive exploration of the movement of water in the unsaturated zone (and associated transport phenomena) – the pathway of many contaminants to the saturated zone where much of the world's potable water is stored. It is the first book to combine research and knowledge on this subject from a wide variety of disciplines into a single source directed toward engineering and environmental training and applications. Deals with contaminant and heat transport in the unsaturated zone; includes a description of soils and their properties and unsaturated soil hydraulic properties; describes unsaturated zone processes; and thoroughly explores numerical modeling and uncertainty in modeling. A text for students in engineering and environmental science, and a reference for practicing engineers and scientists involved in the analysis of unsaturated zone contaminant problems.

Vadose Zone Hydrology describes the elements of the physical processes most often encountered by hydrogeologists and ground-water engineers in their vadose zone projects. It illustrates the application of soil physics to practical problems relevant to the characterization and monitoring of the vadose zone. It includes an introduction to physical processes, including basic flow theory, and provides examples of important field-scale processes that must be recognizable by hydrogeologists. Considerable attention is given to the concepts of recharge, including how it is most accurately evaluated in the vadose zone. Field and laboratory methods for characterizing hydraulic properties in the vadose zone are also covered, and case studies illustrating these methods are provided. New and emerging technologies for monitoring the vadose zone, particularly for the purpose of detecting contaminants, are highlighted. In the last section of the book, additional case studies are presented, demonstrating applications related to seepage detection, landfill monitoring, and soil gas investigations. This book is written from the perspective of hydrogeologists and is designed to be directly applicable and to maintain continuity and consistency between chapters. It will be an invaluable primer for environmental or geotechnical consultants, regulators, or students who have no prior formal academic training in unsaturated flow concepts. Because the text contains some of the latest advances in this field, it will be an excellent reference for geologists and engineers currently working on problems of vadose zone hydrology.

Introduction and bief history; Physical properties and characteristics of soils; Behavior of clay-water systems; Potential and thermodynamics of soil water; Chemical properties and principles of soil water; Principles of water flow in soil; Saturated water flow in soil; Unsaturated water flow in soil; Transport of heat and gas in osil and at the surface; Contaminant transport; Effects of infiltration and drainage on soil-water redistribution; Applied soil physics: modeling water, solute, and vapor movement. Drainage in soil water and ground water; Soil remediation techniques; Saptial variability, scaling, and fractals; Appendix 1: Site characterizaton and monitoring devices; Appendix 2: Mathematics review; Appendix 3: tables; References; Index.

The vadose zone is the region between ground level and the upper limits of soil fully saturated with water. Hydrology in the zone is complex: nonlinear physical, chemical, and biological interactions all affect the transfer of heat, mass, and momentum between the atmosphere and the water table. This book takes an interdisciplinary approach to vadose zone hydrology, bringing together insights from soil science, hydrology, biology, chemistry, physics, and instrumentation design. The chapters present state-of-the-art research, focusing on new frontiers in theory, experiment, and management of soils. The collection addresses the full range of processes, from the pore-scale to field and landscape scales.

Vadose Zone Hydrology describes the elements of the physical processes most often encountered by hydrogeologists and ground-water engineers in their vadose zone projects. It illustrates the application of soil physics to practical problems relevant to the characterization and monitoring of the vadose zone. It includes an introduction to physical processes, including basic flow theory, and provides examples of important field-scale processes that must be recognizable by hydrogeologists. Considerable attention is given to the concepts of recharge, including how it is most accurately evaluated in the vadose zone. Field and laboratory methods for characterizing hydraulic properties in the vadose zone are also covered, and case studies illustrating these methods are provided. New and emerging technologies for monitoring the vadose zone, particularly for the purpose of detecting contaminants, are highlighted. In the last section of the book, additional case studies are presented, demonstrating applications related to seepage detection, landfill monitoring, and soil gas investigations. This book is written from the perspective of hydrogeologists and is designed to be directly applicable and to maintain continuity and consistency between chapters. It will be an invaluable primer for environmental or geotechnical consultants, regulators, or students who have no prior formal academic training in unsaturated flow concepts. Because the text contains some of the latest advances in this field, it will be an excellent reference for geologists and engineers currently working on problems of vadose zone hydrology.

Mankind has manipulated the quantity and quality of soil water for millennia. Food production was massively increased through fertilization, irrigation and drainage. But malpractice also caused degradation of immense areas of once fertile land, rendering it totally unproductive for many generations. In populated areas, the pollutant load ever more often exceeds the soil’s capacity for buffering and retention, and large volumes of potable groundwater have been polluted or are threatened to be polluted in the foreseeable future. In the past decades, the role of soil water in climate patterns has been recognized but not yet fully understood. The soil-science community responded to this diversity of issues by developing numerical models to simulate the behavior of water and solutes in soils. These models helped improve our understanding of unsaturated-zone processes and develop sustainable land-management practices. Aimed at professional soil scientists, soil-water modelers, irrigation engineers etc., this book discusses our progress in soil-water modeling. Top scientists present case studies, overviews and analyses of strengths, weaknesses, opportunities and threats related to soil-water modeling. The contributions cover a wide range of spatial scales, and discuss fundamental aspects of unsaturated-zone modeling as well as issues related to the application of models to real-world problems.

Vadose Zone Processes provides a unified, up-to-date treatment on the movement of water through unsaturated media. In addition to covering the basic equations governing the flow and fate of water in unsaturated media, the text covers the biogeochemistry of vadose environments and the statistical description of vadose processes. The authors emphasize maintaining an intuitive understanding of how the results are derived and how they are appropriately applied. This comprehensive and important book will be useful not only to those in traditional fields such as civil engineering, geology, crop science, chemical engineering, agricultural engineering, and hydrology but also in the newer environmental engineering fields including containment transport, pollution remediation, and waste disposal.