The study of the evolution of landscapes and seascapes in response to the erosion and deposition of sediment (Parker (2006) U. Illinois); ‘the interaction between the form and the processes’ (I. Livingstone and A. Warren 1996). See Stephenson (2006) PPG 30, 1 for a review of coastal morphodynamics, and Swart and Zimmerman (2009), Ann. Rev. Fluid Mechs. 41, 203 on the morphodynamics of tidal inlet systems. For morphodynamic modelling, see Abad and García (2004) Wld Water & Env. Resources Congr. and Federici and Seminara (2003) J. Fluid Mechs 487.