TOPOGRAPHIC RESPONSE TO HIGH WAVES AND SUBSEQUENT BEACH RECOVERY ON CHIGASAKI COAST

Beach topography quickly responds to the action of storm waves, resulting in foreshore erosion and accretion under calm wave conditions after a storm. Field observations were carried out on Chigasaki coast investigate these beach changes. It was found that seabed shallower than 3 m depth rapidly eroded by offshore sand transport during event with deposition zone at depths between 5 m, then recovered within 1–2 years Topographic changes immediately subsequent recovery calculated using BG model (a for predicting three-dimensional based Bagnold’s concept). Given equilibrium slope fine d1 medium-size d2 be 1/120 high numerically reproduced. Moreover, gentle successfully