This book provides an overview of advances in experimental, numerical modelling, and theoretical aspects of environmental hydraulics. By highlighting the latest findings on processes in natural aquatic systems, solutions for civil engineering and water resources management, with a special focus on interdisciplinary cooperation between Earth scientists, ecologists, biologists and hydraulic engineers that have helped to mitigate the impacts of anthropopressure on river habitats, it provides both researchers and practitioners with first-hand information about the latest trends in hydraulic research. The book combines peer-reviewed versions of invited lectures and regular presentations at the 40th International School of Hydraulics, held May 23–26, 2023, in Kąty Rybackie, Poland. With contributions from world-leading experts and young researchers, many areas of environmental hydraulics are addressed here, including recent findings in numerical modelling and laboratory and field studies related to sediment and pollutant transport processes in rivers, fluvial morphodynamics, flow in vegetated channels, hydraulic structures in rivers and estuaries, and freshwater fish protection.