MORPHODYNAMIC COUPLING BETWEEN BEACH AND BARS:RESPONSE TO A SHOREFACE NOURISHMENT

摘要

The nearshore at Terschelling (Netherlands) is characterised by the presence of netrnseaward cyclic migrating sand bars generated near the shoreline. The interaction of beach andrnnearshore bars was analysed based on nearly four decades of morphological surveys of beachrnand nearshore profiles. The analysis revealed a behavioural coupling between thernmorphodynamics of the intertidal beach and the inner nearshore subtidal bars. On a decadalrnscale, beach behaviour correlated with the recurrence frequency of the migratory bar system.rnInner bars formed concurrently with sediment being eroded from the beach implying that thernintertidal beach supplies sediment to the bars as they move offshore through the surf zone. Onrna seasonal scale, beach erosion/accretion cycles correlated with the crest depths of the innerrnnearshore bars. A beach shoreward of a high inner bar accretes while an exposed beachrnshoreward of a low inner bar erodes.