This report takes stock of advances in management practices, and institutional and technological innovations for managing water resources under a changing climate. The focus is on green water defense (GWD) for flood risk management in deltas and other areas vulnerable to flooding in East Asia. The report presents a set of GWD measures and provides a list of best practices that can be used as a guide for developing a management strategy and selecting cost-effective measures for reducing flood risks. Key messages for policymakers about the GWD approach include: water development and management should be right-based, productivity focused and oriented towards multiple functions and wins; well conceived incentive policies and market mechanisms are essential to behaviour change in water use, risk management and in applying the GWD approach; it requires involving stakeholders, combining demand and supply-side management, and balancing structural and non-structural measures.