Rip-Rap and Storm Beach Rocks at Broughton Bay

Storms battering the coast can drive substantial boulders up-shore where they remain at the top of the beach, frequently above extreme high tide level. By this natural phenomenon, a strong barrier is incidentally formed, that protects the upper shore, the base of dune systems, and cliff strata from the extremes of erosion by undercutting and removal of sediments by the sea.

The knowledge that loose arrangements of weighty boulders, with plenty of space between the individual rocks, can absorb and dissipate the energy of the waves, is used in the construction of artificial sea defence systems such as rip-rap for reducing or preventing coastal erosion.

There is evidence of both kinds of barrier, the accidental and the artificial, at Broughton Bay on the Gower Peninsula in South Wales. The rocks are mostly local with the majority comprised of local Carboniferous Limestone – with the occasional boulder of Old Red Sandstone conglomerate or individual mass of brick-wall debris. Many boulders are beginning to be colonised by lichens of various kinds and colours; and the rip-rap offers the opportunity to get up close to the rocks to study their natural textures and fracture patterns.