Neshaei - Research Associate, Department of Ocean Civil Engineering, Kagoshima University, ۱-۲۱-۴۰ Korimoto, Kagoshima ۸۹۰, Japan.
Asano - CorrespondinAgu thor, Associate Professor, Department of Ocean Civil Engineering, Kagoshima University, ۱-۲۱-۴۰ Korimoto, Kagoshima ۸۹۰, Japan

Following extensive series of experiments, a model is introduced to calculate the vertical and horizontal distribution of undertow in the surf zone due to random wave attack for reflective beaches. The present model is a modification of the original model presented by Okayasu et a1 (1990) for natural, non-reflective beaches in which the wave set up, radiation stress and mass flux due to breaking waves are modified to include the effect of partially reflected waves. The results of experimental investigation and model development show that existence of reflective conditions on beaches results in a reduction in the magnitude of undertow and modifies its distribution across the beach profile.