Morphodynamic response of a large river mouth to typhoons

During typhoons, the bare intertidal flat and the subtidal bank are exposed to erosion while the main marsh and the deep channel bed tend to experience accretion. On the average, the thickness of erosion on the medium zone is greater than the thickness of accretion on the marsh but is less than the thickness of accretion on the deep channel bed. The typhoon-induced erosion on the bare flat tends to be recovered within a few days while the disappearance of accretion on the deep channel would need weeks and the rapid deposition on the high marsh could be preserved permanently. The magnitude and spatial pattern of typhoon generated erosion/accretion are influenced by astronomical tidal conditions. The erosion and accretion during typhoons are not balanced due to the influence of river flow and tidal current.