A NEW LOOK AT BEACH EROSION CONTROL

Abstract

Many methods used previously to reduce or prevent erosion have not worked effectively. It isnow necessary, due to rising costs of construction, to examine old methods and see if Nature hasindicated some direction in which to go. Limitations of groins, seawalls and beach reclamation aredescribed. The most effective natural method of controlling beach erosion by the formation of anoffshore bar is described. The need for normal return of this material to the beach is met by the zetashaped bays sculptured between headlands by persistent swell waves. Man can copy Nature byinstalling offshore breakwaters in order to form stable bays along an eroding coast. The indentationof these is limited and is predictable from the obliquity of the waves or the angle between the down-coast shoreline and the headland alignment. This method has been used successfully in Singaporein spite of the extreme obliquity of the incident swell.