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 explores the application of the open-source software OpenGeoSys (OGS) for hydrological numerical simulations concerning conservative and reactive transport modeling. It provides general information on the hydrological and groundwater flow modeling of a real case study and step-by-step model set-up with OGS, while also highlighting related components such as the OGS Data Explorer. The material is based on unpublished manuals and the results of a collaborative project between China and Germany (SUSTAIN H2O). Though the book is primarily intended for graduate students and applied scientists who deal with hydrological modeling, it also offers a valuable source of information for professional geoscientists wishing to expand their knowledge of the numerical modeling of hydrological processes including nitrate reactive transport modeling. This book is the second in a series that showcases further applications of computational modeling in hydrological science.