FIELD INVESTIGATION OF WAVE-PROPAGATION OVER A BAR AND THE CONSEQUENTGENERATION OF SECONDARY WAVES

field experiment was conducted to monitor the generation of secondary waves on a barred beach. The results show the decomposition of breakin g incident swell into 4-6 smaller and shorter waves upon entering the deeper water landward of the bar. The consequent blue-shifting of the wave spectrum results in a decrease in the significant wave period and may further delay the dissipation of wave energy. It is inferred that secondary waves are a common phenomenon on barred benches, in particu lar when the incident wave period is large and the seaward slope of th e bar is gentle. (C) 1998 Elsevier Science B.V.