What are groynes?

Groynes are man-made low walls or sturdy timber barriers built into the sea. They are a form of coastal protection that are built at right angles to the shore to prevent longshore drift. These structures absorb the energy of the sea on the shore, similar to headlands. Their main objective is to reduce the impact of energy on the coast. There are four types of groynes: wooden groynes, steel groynes, rubble-mound groynes and sand-filled bag groynes.