WAVE SET-UP AND WAVE GENERATED CURRENTS IN THE LEE OF A BREAKWATER OR HEADLAND

Field and model observations indicate the existence of wave generated currents in the lee of breakwaters and headlands. It is shown by an idealised laboratory experiment that such currents could be produced by an alongshore gradient of breaker height with wave crests parallel to the beach. The mechanism for the generation of the current is explained together with some of its characteristics including its interaction with the wave set-up which causes it„ It is further shown that it is possible to calculate by simple methods the hydraulic conditions causing the current. Currents produced by this mechanism appear to be of practical importance in determining the local plan shape of beaches close to breakwaters and headlands.