HYDROGEOLOGY Hydrogeology: Principles and Practice provides a comprehensive introduction to the study of hydrogeology to enable the reader to appreciate the significance of groundwater in meeting current and future environmental and sustainable water resource challenges. This new edition has been thoroughly updated to reflect advances in the field since 2014 and includes over 350 new references. The book presents a systematic approach to understanding groundwater starting with new insights into the distribution of groundwater in the Earth's upper continental crust and the role of groundwater as an agent of global material and elemental fluxes. Following chapters explain the fundamental physical and chemical principles of hydrogeology, and later chapters feature groundwater field investigation techniques in the context of catchment processes, as well as chapters on groundwater quality and contaminant hydrogeology, including a section on emerging contamination from microplastic pollution. Unique features of the book are chapters on the application of environmental isotopes and noble gases in the interpretation of aquifer evolution, and a discussion of regional characteristics such as topography, compaction and variable fluid density on geological processes affecting past, present and future groundwater flow regimes. The last chapter discusses future challenges for groundwater governance and management for the long-term sustainability of groundwater resources, including the role of managed aquifer recharge, and examines the linkages between groundwater and climate change, including impacts on cold-region hydrogeology. Given the drive to net-zero carbon emissions by 2050, the interaction of groundwater in the exploitation of energy resources, including renewable resources and shale gas, is reviewed. Throughout the text, boxes and a set of colour plates drawn from the authors' teaching and research experience are used to explain special topics and to illustrate international case studies ranging from transboundary aquifers and submarine groundwater discharge to the hydrogeochemical factors that have influenced the history of malting and brewing in Europe. The appendices provide conversion tables and useful reference material, and include review questions and exercises, with answers, to help develop the reader's knowledge and problem-solving skills in hydrogeology. This highly informative and accessible textbook is essential reading for undergraduate and graduate students primarily in earth sciences, environmental sciences and physical geography with an interest in hydrogeology or groundwater topics. The book will also find use among practitioners in hydrogeology, soil science, civil engineering and landscape planning who are involved in environmental and resource protection issues requiring an understanding of groundwater.