... Describes and documents USGS groundwater flow modeling activities in support of the US Army National Guard investigations; these models were used to (1) improve understanding of the hydrologic system, (2) simulate advective transport of contaminants, (3) delineate recharge areas to municipal wells, and (4) evaluate how model discretization and time-varying recharge affect simulation results ...

Human society depends on liquid freshwater resources to meet drinking, sanitation and hygiene, agriculture, and industry needs. Improved resource monitoring and better understanding of the anthropogenic threats to freshwater environments are critical to efficient management of freshwater resources and ultimately to the survival and quality of life of the global human population. This book helps address the need for improved freshwater resource monitoring and threat assessment by presenting current reviews and case studies focused on the fate and transport of contaminants in the environment and on the sustainability of groundwater and surface-water resources around the world. It is intended for students and professionals working in hydrology and water resources management.

This second edition is extensively revised throughout with expanded discussion of modeling fundamentals and coverage of advances in model calibration and uncertainty analysis that are revolutionizing the science of groundwater modeling. The text is intended for undergraduate and graduate level courses in applied groundwater modeling and as a comprehensive reference for environmental consultants and scientists/engineers in industry and governmental agencies. - Explains how to formulate a conceptual model of a groundwater system and translate it into a numerical model - Demonstrates how modeling concepts, including boundary conditions, are implemented in two groundwater flow codes-- MODFLOW (for finite differences) and FEFLOW (for finite elements) - Discusses particle tracking methods and codes for flowpath analysis and advective transport of contaminants - Summarizes parameter estimation and uncertainty analysis approaches using the code PEST to illustrate how concepts are implemented - Discusses modeling ethics and preparation of the modeling report - Includes Boxes that amplify and supplement topics covered in the text - Each chapter presents lists of common modeling errors and problem sets that illustrate concepts

This book is the long-awaited successor to Owen M. Phillips's classic textbook, Flow and Reactions in Permeable Rocks, published in 1991. In the intervening eighteen years between the two, significant advances have been made to our understanding of subterranean flow, especially through the vast amount of research into underground storage of nuclear waste and aquifer pollution. This new book integrates and extends these modern ideas and techniques and applies them to the physics and chemistry of sub-surface flows in water-saturated, sandy and rocky media. It describes essential scientific concepts and tools for hydrologists and public health ecologists concerned with present day flow and transport, and also for geologists who interpret present day patterns of mineralization in terms of fluid flow in the distant past. The book is ideal for graduate students and professionals in hydrology, water resources, and aqueous geochemistry.