bar

• Longshore drift is lateral movement of the waves. Swash is where waves push material up the beach at an angle due to the prevaling wind. The returning backwash is draged back down the beach at right angles due to gravity.
• Bars form when there is a change in direction on a coastline, which allows a sheltered area for decomposition. Material slowly builds up to appear above the water. The bar develops as long as the suply of deposits is greater than the amount of erosion.
• If a spit reaches the other side of a bay then a sand bar is formed. This happens when there is no strong flow of water fotm a river into the sea, enclosing a sheltered lagoon behind it.
• An example is Chesil Beach, Dorset