ANALYTICAL STUDY ON THE SEDIMENTATION OCCURRENCE AT THE ENTRANCE OF PORTS AND NAVIGATION CHANNELS (CASE STUDY: ASTARA PORT)

Sedimentation is a common problem in harbors, which reduces the required navigation depth and disturbs vessels passage. In order to provide a safe passage for vessels,frequent maintenance dredging in harbors is needed. The amount of maintenance dredging which is the most expensive item in the running costs of harbors depends onthe rate of sedimentation in harbor basins. For example, the annual dredging costs of marinas of the Netherlands are estimated about €500,000,000, as reported in [1]. Asanother case in point, the average annual dredging costs of federal navigation projects in the United States between 1995 and 2000 were estimated to be about M$500, asreported in [2]. Therefore, minimizing sedimentation in harbors is one of the major considerations in port design. Generally, sediments transported into harbors by currents and waves, are deposited in parts of the harbor where currents and waves are not strong enough to keep sediments in motion and reduce water depth.Recently, many attempts have been made to study sediment transport and measures for the reduction of sedimentation in harbor basins. Winterwerp [3] gives asummary of measures for the reduction of sediment deposition reduction measures in harbors for various environmental conditions. Kuijper et al [4] discussed theeffects of harbor geometry on sediment deposition in harbor basins, together with the application of CDW (Current Deflection Wall) as a type of geometricalmodification to reduce sediment deposition in a harbor basin of the port of Hamburg (Germany). Yüksek [5] conducted an experimental study on the effects of layoutsof breakwaters on sedimentation patterns in harbor basins and suggested some design criteria in the form of dimensionless geometrical parameters of breakwaters.In this paper, current, wave and sediment transport of Astara port has been studied by numerical modeling in MIKE-21 software. Results of simulation have showngood agreements compared with field measurements and numerical results. Then, four variants for reduction of sedimentation are proposed and finally the best solution is determined.