This edited volume presents a comprehensive exploration of smart and sustainable water management, combining urban hydrology, digital innovation, cybersecurity, and climate resilience. It covers rainwater harvesting, stormwater control, wastewater management, wetlands, aquifer recharge, and field-based environmental investigations alongside advanced themes such as IoT-enabled monitoring, AI-driven predictive modelling, blockchain governance, homomorphic encryption, and SCADA security. Blending practical case studies with emerging technologies, the book offers a multidisciplinary resource that connects engineering, data science, policy, and environmental management within a single reference framework. The book integrates traditional water management practices with cutting-edge tools including smart sensors, machine learning, MNDWI-based impact assessment, bioimpedance water quality systems, and blockchain-enabled governance. Dedicated chapters address cybersecurity risks in water infrastructure and privacy-preserving IoT architectures. Real-world field studies from India provide applied insights, while predictive analytics and climate-resilient strategies support forward planning. Readers gain technical depth, implementation perspectives, and policy alignment guidance in one cohesive volume. This book is designed for environmental engineers, urban planners, water utility professionals, cybersecurity specialists, policymakers, researchers, and postgraduate students in civil engineering, data science, environmental studies, and smart infrastructure domains. It also supports smart city teams and sustainability practitioners seeking integrated digital water solutions.