Patterns of nearshore sediment transport along the Nile Delta, Egypt: Fid-Bau Portal

Patterns of nearshore sediment transport along the Nile Delta, Egypt

Frihy, Omran E. / Fanos, Alfy M. / Khafagy, Ahmed A. / Komar, Paul D.

Abstract The nearshore sediment-transport system along the Nile Delta has been determined from the response of beaches to the construction of engineering structures, from the forms of geomorphological shoreline features, from large-scale changes in shoreline orientations due to erosion and accretion, and from longshore variations in beach-sand mineralogy and grain sizes. The analyses reveal local patterns of erosion and accretion that have resulted from the interruption of the longshore sediment transport by jetties and groins as well as the major erosion of the promontories adjacent to the mouths of the Rosetta and Damietta branches of the Nile River, brought about by the cutoff of the supply of river sand by construction of the High Aswan Dam. Major zones of shoreline accretion are positioned to the east of the eroding promontories, demonstrating that there are strong longshore gradients in the quantities of the eastward sand transport. The variation east of the Rosetta Branch has been quantitatively evaluated from the patterns of erosion and accretion, based on sediment-continuity considerations. A similar delta-wide comparison is made between the patterns of longshore sediment movements found in this study and those calculated by others from wave-refraction diagrams. Based on the various lines of evidence for beach erosion, longshore sediment transport and shoreline accretion, four nearly self-contained cells have been identified in the littoral zone of the Nile Delta: Abu Quir Bay, the eastern flanks of the Rosetta and Damietta Promontories, and the Burullus central-delta region.