Riprap or rock armour or rock or other material used to armour streambeds, bridge abutments, pilings and other shoreline structures against scour or water erosion.
It is used to protect coastlines and structures from erosion by the sea, rivers, or streams. It can be used on any waterways or water containment where there is potential for water erosion.
Riprap works by absorbing and deflecting the impact of waves before they reach the defended structure. The size and mass of the riprap material absorbs the impact energy of waves, while the gaps between the rocks trap and slow the flow of water, lessening its ability to erode soil or structures on the coast. The mass of riprap also provides protection against impact damage by debris, which is particularly desirable for bridge supports and pilings.