On assessment of effectiveness of KSO method in minimising the sedimentation in dock – a case study

Most of the ports, docks around the world face the problem of moderate/heavy sedimentation in the berthing/manoeuvring areas which in turn affects navigation safety, operation and also the economic viability of the waterfront structures. Hence, there is a global need to seek for permanent solutions, which will combat the problem of siltation in the navigable areas. The present study investigates the effectiveness of keep sediment out (KSO) method wherein a current deflecting wall (CDW) is proposed to minimize the present rate of heavy sedimentation (maximum rate 3–3.5 m annum−1) in a dock situated near the entrance of a macro-tide dominated creek. Depth-integrated, multi-scaled finite element modelling carried out by coupling hydrodynamic, wave, sediment transport models reveals that during flood tides, due to the typical layout of docks, eddies get formed inside the dock. During the initial hours of ebb, presence of strong tidal currents outside the dock prolongs the retention of sediment-laden water in docks and thereby results in heavy sedimentation. Proposed CDW (300 m length) near the southern end of dock entrance minimises the formation of eddies/trapping of sediment during flood; while CDW (40 m length) on northern end enables smooth existence of sediment-laden water during ebb; thereby overall sedimentation in dock reduces by about 50%.