Impact evaluation of development plans in the Egyptian harbors on morphological changes using numerical simulation (case study: Damietta harbor, northeastern coast of Egypt)

Abstract

The Egyptian government is grappling with the challenge of sedimentation in Damietta Harbor (DH), leading to expensive and recurring dredging operations for safe vessel navigation. This research examined the changes in the region's coastline, both before and after the port was established between 1977 and 1995. The impact of the government's policy to halt backfilling in the navigation lane on adjacent beaches until 2023 was also assessed using remote sensing (RS) and the Digital Shoreline Analysis System (DSAS) program, revealing varying yearly accretion and erosion rates. Following a shoreline movement tracking procedure, in the period from 1985 to 2023, the total areas undergoing erosion and accretion amounted to −1.36 km² and +2.21 km², respectively.

To address the issue, the research team developed scenarios reflecting regional realities and conducted a numerical simulation using the Coastal Modeling System (CMS). Morphological alterations in the approach channel and pre- and post-port regions were monitored to assess the scenarios. The study also explored how deepening the navigation channel affected the annual sediment volume. Results showed that Scenario 5, involving breakwaters extension and the new western breakwater (NWBW), effectively controlled sediment. However, sedimentation increased with the deepening of the navigation channel. Scenario 7, with a 19 m deepening, exhibited slightly higher sediment volume by 21.75% but stood out for its capacity to handle large vessels. Additionally, the sedimentation in the navigation channel experienced a notable 72.1% decrease in Scenario 8, which portrays the anticipated final state of DH compared to the benchmark case.

The study noted morphological changes from planned coastal constructions on the eastern side, including detached breakwaters (DBW) and Y-groins (Y-gs). Despite significant development costs, these structures were deemed insufficient to stabilize the shoreline. In summary, the research highlights the complexity of addressing sedimentation in DH, emphasizing the need for nuanced approaches in coastal management, and considering the consequences of deepening navigation channels.