Long-shore drift

Long-shore drift is a term used to describe a form of coastal erosion in which waves approach the beach at an angle. The waves effectively carry sand and shingle up the beach at an angle in a particular direction, and this material is then subsequently or later pulled vertically down the beach by backwash and gravity.

The net result is that if the direction is constant then material will be gradually shifted along the beach until the beach is tripped bare.

A common form of resolution of this problem is the introduction of groynes[?], a type of man-made (usually wooden) salient, that are inserted into the beach at intervals and which cause the drifting material to bank up against them and thus reduce or mitigate the effects of long-shore drift.