Hydrodynamic modeling of outlet stability case study Rosetta promontory in Nile delta

Abstract

The hydrodynamic features of Rosetta promontory are simulated numerically to minimize the outlet siltation problems. Many coastal structures (i.e. revetments, groins) are used to solve the erosion of the shoreline and siltation in the outlet. However, the shoreline along the promontory is still unstable and these structures did not achieve the expected results to reduce the problem where the erosion problem is shifted down drift. In this research three potential solutions were investigated. The first solution is to apply a soft approach in term of re-establishment of natural hydrologic conditions such as providing additional water discharge processes through diverting Burullus drains to the end of the estuary to achieve the nature and stable condition for the promontory. The second proposed solution is to reach the equilibrium cross section of the outlet by dividing the Rosetta outlet into two parts by constructing two 500 m separated jetties. The third solution is to control the sedimentation in the outlet by constructing 450 m length jetty attached to the eastern bank of the estuary. Numerical Coastal Modeling System (CMS) was used after tuning the model parameters to check the feasibility of the different proposed solutions on the stability of outlet channel. The study shows that an additional discharge of 47 m3/s in the first scenario results in a stable outlet cross section suitable for navigation purposes but with limited effect on the erosion problem.