 These inputs and outputs of sediment then equate to the total balance of the system and more than often reflect the amounts of erosion or accretion affecting the morphology of the coast.To assess the sedimentary budget the coast has to be divided into two separate morphologies, commonly known as littoral cells and compartments.Sediment compartments can usually be defined as two rocky barriers which mark the ends of a beach and have a fixed sediment budget, although usually leaky to some extent.