INVESTIGATION OF EBB DELTA DEVELOPMENT AND RESPONSE USING AMOVABLE BED PHYSICAL MODEL

摘要

Tidal inlets are a complex system of wave and current interactions that react andrninteract with sediment to create a challenge for coastal managers, in maintaining adjacent beachrnamenity and navigational access. An experimental study has been undertaken to gain betterrnunderstanding of tidal inlet processes and through this, develop better predictive tools. A scaledrnphysical model of an idealised tidal inlet was tested to investigate some of the dominatingrnparameters influencing the development of the ebb tidal delta and its relationship with thernadjacent beaches. Results were obtained for four cases of ebb-delta development under thernfollowing conditions: Wave-dominated, Current-dominated, Bypassed and Un-bypassed. Resultsrnshowed that for the Current-dominated case, there was little difference in the growth rate of thernebb delta between the bypassed and un-bypassed cases. This result is due to the erosion from therninlet bed in the bypassed case matching the sediment fed to the delta from the updrift beach inrnthe un-bypassed case. The model demonstrated that artificial bypassing of material effectivelyrnmaintained updrift and downdrift beach alignment. Results for the Wave-dominated case,rnshowed that the growth rate of the ebb delta was retarded by artificial bypassing however it wasrndifficult to confirm whether the ebb delta equilibrium volume would be reduced.