In shallow flows, the study of “natural” bodies such as trees, aquatic plants, debris, islands and fish and their interaction with flow have received little attention, unlike flow around cylinders and prismatic bodies. Natural objects have complex geometries, some flex under flow action, while some have holes and porosity. They interact with both the hydraulic and sedimentary environments, and significantly influence the shape of the physical environment. They can help provide protection in fluvial and coastal flood management schemes by absorbing and dissipating hydrodynamic energy, slowing down and delaying flood flows and reducing erosion. In this talk we will examine the interaction of these natural objects with the hydrodynamics and look at the velocity structure in the vicinity of these bodies in small and very large laboratory experiments. The findings are used to offer insight into flood risk management and fish-friendly hydropower schemes.