Groundwater is the largest natural resource in the world. The estimation of groundwater resources as well as their sustainable management are challenges for users, practitioners, managers, and decision-makers. These challenges can be solved based on the progress in three domains: (1) data modeling (2) data science, and (3) advanced systems of ground measurement and Earth data. This book contributes to the progress of groundwater characterization by addressing some challenges through applications and discussions of relevant case studies as well as new approaches. It contains six chapters that discuss various approaches and tools used to study and investigate the impacts of climate change and pollution risks. They also present techniques for accessing water that may contribute to sustainable exploitation and management of groundwater resources.