Most studies on coastal and fluvial hydro-and morpho-dynamics have focused on flow properties and their interactions with sediments. However, it has long been accepted that vegetation is also an important factor that can affect the flow in, and the morphology of, aquatic systems. Vegetation in shallow water systems, such as rivers and coasts, plays an important role in altering flow resistance and turbulence (Nepf & Vivoni, 2000; Ghisalberti & Nepf, 2002) and, consequently, it affects the transport of sediment, nutrients, and contaminants (Kemp et al., 2000; Cundy et al., 2005). Because these factors exert major influences on habitats and biodiversity (Leonard & Luther, 1995), aquatic and riparian vegetation has recently been the subject of important research into the management, preservation and restoration of freshwater and coastal ecosystems, including salt marshes (Deloffre et al., 2007; French et al., 2000) and floodplains (Baptist et al., 2006). Although much of this work is field based there is a growing interest in using laboratory flume experiments to obtain detailed measurements of plant-flow interactions.