ROCK ARMOUR OR RIPRAP
Rock Armour or RIP RAP is an effective solution to protect coastlines and structures from erosion by the sea, rivers, or streams.
Large boulders interlocked together to form rock revetments can be used to control erosion by armouring the beach face and dissipating wave energy. Rock Armour is also used to provide effective scour protection to underwater structures
Rock Armour absorbs wave energy and reduce the power of the waves
The rocks are piled up along the shoreline to form a type of sea wall and are dumped on top of eachother leaving gaps between them that allow water through. This disperses the energy of the waves and reduces their erosional power. They can be very effective.
The boulders must be large, strong and resistant to erosion. Granite and basalt are often used. Small or weak rocks would not be able to withstand the impact from the waves and would quickly be eroded.