In coastal engineering, a tetrapod is a four-legged concrete structure used as armour unit on breakwaters. The Tetrapod’s shape is designed to dissipate the force of incoming waves by allowing water to flow around rather than against it, and to reduce displacement by allowing a random distribution of Tetrapods to mutually interlock.
New shore protection innovations have shown that there are better methods that are less obtrusive and more environmentally friendly than concrete armor structures. Alternate placements of sand and mix sediments and modifications of incident wave conditions through the use of reefs are examples of those.