The Proceedings of the 4th Symposium on River, Coastal and Estuarine Morphodynamics offers the latest research results concerning quantitative modelling of the interaction of water and sediment and the shapes this interaction makes. Morphodynamics is the study of the evolution of landscape and seascape features, from small scale to large, in response to the erosion and deposition of sediment. The erosion and deposition of sediment is in turn driven by an interaction between the mechanics of flow in a river, debris flow or turbidity current and the mechanics of sediment transport by the flow. Morphodynamics offers an avenue for the explanation of the evolution of consistent, self-adjusting morphologies such as drainage basins, the long profiles of rivers or the shape of shorelines, and the persistence of rhythmic features such as beach cusps, sediment waves and planform meandering. This year's conference proceedings differ from the proceedings of previous conferences in that both large-scale and submarine morphodynamics have been integrated into the scope of the volume. The papers are highly interdisciplinary, covering such diverse areasas geomorphology open-channel hydraulics, sediment transport dynamics, fluid mechanics, ecohydraulics, sedimentology and stratigraphy. The papers include a mix of basic and applied research.