This book comprises the select proceedings of the 23rd Congress of the International Association for Hydraulic Environmental Engineering and Research-Asia Pacific Division (IAHR-APD 2022). The book focuses on remote sensing and GIS applications, inter-basin transfer, flood modeling, water quality modeling, leak detection, contaminant transport modeling, recycling and reuse, micro pollutants, coastal erosion and protection, smart coastal cities, integrated coastal zone management, blue economy, risk assessment, climate modeling, and eco system-based design, etc. The book can be a valuable reference for researchers and professionals interested in the fields of hydraulic and environmental engineering. .