علي محمودي

The access channel to the ports is one of the main components of every port, which is necessary for vessels to access the port. Due to the reduction of the depth of the sea while approaching the coast, for the safe passage of these ships, a specific route called the access channel with the minimum required depth is designed and implemented. Periodic dredging of the channel is necessary to remove the sediments trapped in the access channel to maintain the required depth of the water inlet of the vessels. Dredging costs are acceptable to the extent that they do not account for a significant portion of the port's income. Due to the importance and significant costs of dredging, several methods have been presented to estimate the amount of sedimentation in the access channels. In this research, first, previous studies and solutions to reduce sedimentation in access channels have been reviewed. In the continuation of the qualitative and quantitative review and comparison of periodic hydrographic maps of the access channel of Bushehr port, one of the oldest and most important ports of the country, the statistics of maintenance dredging of the channel and also the determination of the general regime of sedimentation in the critical part of the access channel were presented. After going through the initial stages and getting a detailed knowledge of the studied area, modeling was done to determine the wave and current conditions governing the area. In the next step of modeling, a two-dimensional mathematical model of sticky sediment transfer under the dominant effect of tidal flow and with necessary calibrations, based on the equation governing sediment transfer (diffusion-transfer equation) was presented. In the meantime, the necessary sensitivity measurements for the impact of the wave were also checked. After determining the trend and rate of sedimentation based on the current conditions, suitable options to reduce sedimentation in the access channel of Bushehr port, including solutions based on creating a sediment trap, solutions based on structural protection around the channel and the use of new technologies are investigated and the selected solution is based on the function of reducing the sedimentation rate was presented. Examining the performance of solutions based on creating a sediment trap showed that these solutions will not have much effect on reducing the sedimentation rate of the channel due to the dredging costs of their construction and maintenance. On the other hand, the performance of the options based on the construction of sediment collection structures was eva‎luated as more appropriate in reducing the sedimentation rate of the channel. Due to the reduction of tidal velocities in the outer channel, the construction of a retaining structure around the bend of the channel has the opposite effect on reducing the sedimentation rate and is not recommended. Finally, the construction of two jetties parallel to the external channel with a length shorter than the length of the channel is suggested as a suitable option to reduce the sedimentation rate of the access channel of Bushehr port. It should be mentioned that the proposed option should be eva‎luated and feasible in terms of implementation, economy, interference with exploitation operations and environmental aspects.

رسوب , رسوبگذاري , كانال دسترسي , بوشهر , موج و جريان , مدل مايك

sediment , Siltation , Navigation Channel , Bushehr , Wave and Current , Mike 21

Ali Mahmoodi

Dr. Siadat Moosavi