Coastal sediment transport (a subset of sediment transport) is the interaction of coastal land forms to various complex interactions of physical processes. The primary agent in coastal sediment transport is wave activity (see Wind wave), followed by tides and storm surge (see Tide and Storm surge), and near shore currents (see Sea#Currents) . Wind-generated waves play a key role in the transfer of energy from the open ocean to the coastlines. In addition to the physical processes acting upon the shore, the size distribution of the sediment is a critical determination for how the beach will change (see Grain size determination). These various interactions generate a wide variety of beaches. (see Beach). Other than the interactions between coastal land forms and physical processes there is a