This lecture introduce on Sand Dunes. A “dune field” is an area covered by extensive sand dunes. Some coastal areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach. Sand Dunes are ridges of wind deposited sand. Usually 3 to 15 metres high, but can reach 180 metres. The formation of dunes depends on:- amount of sand; speed and direction of wind; occurrence of vegetation.