Volume 4 covers fresh water and watersheds, their health and conservation, protection, and management. Organized for ease of reference, it provides fundamental information on groundwater storage, water quality, supply and balance, and water resource vulnerability. New in this edition are discussions on water footprint assessment, water surface dynamics, and water management on a global scale. Understanding the conditions of watersheds is crucial for restoring areas with degraded water quality as well as protecting healthy waters from emerging problems. This volume demonstrates the key processes, methods, and models used through several practical case studies from around the world.