Temporal Shoreline and Bottom Changes of the Inner Continental Shelf Off the Nile Delta, Egypt
Keywords:
Nile delta, shoreline changes, inner shelf bathymetry, sediment transport, erosion, bathymetric surveyAbstract
Observations of long-term change in the shoreline and bathymetry on the inner continental shelf off the northern Nile delta are based on comparison of two bathymetric maps of closely spaced soundings from 1919/22 and 1986. The changes are depicted after analyses of 40 bathymetric profiles in water depths as great as 30 m and extending about 30 km from the shore. Comparison among these profiles in terms of changes in water depth, shifting in bottom contours and volumetric changes in bottom sediments, identifies areas of erosion (Abu Quir Bay, Rosetta promontory, east of Burullus, and Damietta promontory) and accretion (Abu Khashaba coast, West Burullus inlet, Gamasa and the Damietta spit). These changes are generally due to long-term sediment movement in which most of the accreted sands come from eroded promontory tips as well as from offshore sources. Statistical correlation analysis indicates that areas of potential erosion and accretion are not related to sediment texture, slope gradient and water depth.