This book focuses on scientific and technological aspects of groundwater-resources assessment and surveillance. It describes relevant risks and investigates selected techniques for the monitoring and mitigation of the individuated threats to groundwater quality. The authors discuss the concepts of groundwater-resources protection and offer examples of both geogenic and anthropogenic degradation of groundwater quality, such as heavy metals from mining activities and natural water-rock interactions, as well as risk of contamination due to geological CO storage practices etc. The volume also covers non-invasive monitoring techniques and briefly addresses innovative sensor technologies for the online assessment of water quality. Furthermore, the role played by geochemical techniques, the potential of environmental isotopes and the support provided by physical modelling are highlighted. The chapters guide the reader through various viewpoints, according to the diverse disciplines involved, without aiming to be exhaustive, but instead picking representative topics for their relevance in the context of groundwater protection and control. This book will be of interest to advanced students, researchers, policy-makers and stakeholders at various levels.