Nowadays, novel water resources management strategies have been developed and applied by borrowing new concepts to overcome the water shortage crisis and balance the distribution of water resources. Therefore, this book has been categorized in four main sections as follows. 1- Perspective, which consists of Climate change, New water resources, Inter-basin water transfer, Nanotechnology, Best management practices by low impact development strategies, Land use, Land planning, and Overland production chapters. 2- Challenges, which consists of Water and sustainable development and Comprehensive and integrated water management chapters. 3- Concepts, which consists of Virtual water, Water footprint, and Water-Food-Energy-Environment nexus chapters, and 4- Necessities which consists of Water security, Food security, Inactive (passive) defense, Water conflicts and water war, Forensic engineering, and Citizen sciences chapters. It should be added that all of these concepts have been integrated into this unique reference, which can help students, academics and practitioners professors who are interested to know more about the new concepts in water resources.