The role of water in our communities, from local to regional and right up to global levels, poses a series of key questions about climate change, about the anthropogenic impact on the environment, and about all the interconnected actions and events that affect the availability and quality of the resource. All these questions share a common demand for more scientific knowledge and information. In this particular context the disciplinary boundaries are fading, and there is a growing need to create broader connections and wider collaborative interdisciplinary groups, aimed at building an integrated knowledge-base to serve not only stakeholders but also the whole of society. Only in this way can we hope to respond effectively to the challenges and changing dynamics of human-hydrologic systems. Following this concept, contributors from multiple disciplinary backgrounds, such as Law Studies, Hydrogeology, Monitoring and Information Technologies, Geophysics, Geochemistry, Environmental Sciences, Systems Engineering, Economics and Social Studies, joined forces and interacted in this workshop. The present book reports the proceedings of this three-day ARW (Advanced Research Workshop), and explores different aspects of the environmental security assessment process, focusing on the assessment, monitoring and management of water resources, and giving an overview of the related scientific knowledge.