الفهرس | Only 14 pages are availabe for public view |
Abstract Sedimentation phenomenon in land harbors navigation channels is one of the most important problems affecting the economy of any harbor that is commonly constructed in many countries around the world, especially Egypt. Damietta harbor navigation channel traps about one million m3 of long shore annual sediment that costs about 50 million pounds every year and erodes the down drift for approximately 2 km. In the present study, littoral transport process in Damietta harbor navigation channel and the neighboring shorelines have been simulated using a 2D Delft-3D model and a 1D Litpack model. The 2D-Model has been calibrated using water levels’ measured data, measured current patterns and magnitudes and morphology measured profiles. Different scenarios have been studied in order to control the sedimentation problem in the navigation channel; jetty extension, using current deflector walls and using sediment traps. Results of the 2D simulation indicate that using of 500,000 m3 offshore trap having geometry of 500 m x 200 m x 5m depth and parallel to the channel away of the western jetty by 50 m with 200 m overlap with the jetty in addition to extension of the western jetty by 100 m hinders the sediment from reaching the jetty. This scenario was found to be the most economic scenario with trapping efficiency 84% and annual channel deposition of 127.000 m3 this increases the periodic dredging time and reduces navigation wasted time by dredging process. In addition, after calibrating the 1D-model using full measured shoreline with the model’s output, the model shows results of applying four scenarios considered as a combination between hard structures such as head lands and sand nourishment. The study indicates that construction of four head lands eastern of the harbor with length of 160m, spacing of 400m with a total nourishment amount of 300,000 m3/year with 150,000 m3 through construction of the head lands are found to be reasonable and easy to be obtained from the annual dredged materials from the suggested sediment trap. Finally, fixed pumping system is recommended to be set-up on the end of the western jetty which regarded as an exchange of dredging process to pump the trapped sediment by the proposed trap into the onshore part of the western jetty to be used to extract the heavy minerals and the black sands then bypass the rest sediment quantities to be nourished on the eastern shores of the harbor. |