Wave tank experiments on erosion of rocky coasts

Abstract

Erodable blocks representing vertical cliffs andshore platforms were exposed to attack by artificiallygenerated waves. Maximum erosion in allblocks occurred above still water level. Verticalcliffs became deeply notched in a form which containedno horizontal portion and which had thelower segment located below still water level.Platform shapes were degraded by cutting on theplatform surface and rounding of the leading edge.No wave-tank evidence was found to support thecontention that high tide shore platforms arepresently being formed by storm wave activity.Notches on the sides of the blocks were caused byaeceleration of waves constricted between the blockand tank sides. Such constrictton and attendantincrease in velocity may also favour rapid erosionin sea arches, caves and closely spaced stacks.Erosion debris moved rapidly from the base ofthe model cliff and was not involved in subsequentblock notching.