Field investigation of wave propagation over a bar and the consequent generation of secondary waves

field experiment was conducted to monitor the generation of secondary waves on a barred beach. The results show the decomposition of breaking 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 particular when the incident wave period is large and the seaward slope of the bar is gentle. (C) 1998 Elsevier Science B.V.