In the Netherlands today much attention is paid to the effect of coastal structures on the environment. In the past it was usual to quantify the effect of such a structure on its environment solely with the purpose of deciding whether that effect could imply any hazard to the structure itself (or to structures in the neighbourhood). Nowadays environmental impact studies are mainly carried out to see what possible changes the structure may bring about in the integral coastal system. However, changes in the coastal system can only be studied if information is already available regarding that coastal system. Therefore scientists and engineers from various disciplines, such as hydraulic engineering; sedimentology. geology, physical oceanography and marine biology have joined forces to describe and analyze the long·term and large-scale morphological evolution of the Dutch coastal zone as an integrated system.