International Water Technology Journal, IWTJ Vol. 4- No. 3, September 2014 NUMERICAL MODELING OF ROSETTA RIVER MOUTH, EGYPT Ali Masria 1 , Abdelazim Negm 2 , Moheb Iskander 3 , Oliver C. Saavedra 4 1 PhD Student, Energy Resources and Environmental Engineering Department., School of Energy and Environmental Engineering, Egypt-Japan University of Science and Technology, E-JUST, P.O.Box 179, New Borg Al-Arab City, Postal Code 21934, Alexandria, Egypt, E-mail:ali.ali@ejust.edu.eg 2 Chair of Environmental Engineering Department, School of Energy and Environmental Engineering Egypt -Japan University of Science and Technology, E-JUST, (Seconded from Faculty of Engineering, Zagagzig University, amnegm@zu.edu.eg), E-mail: negm@ejust.edu.eg 3 Head of Hydrodynamic Department, Coastal Research Institute, National Water Research Center, Alexandria, Egypt, E-mail: coastal_alex@yahoo.com 4 Dr. of Eng., Associate Professor, Department of Civil Engineering, Tokyo Institute of Technology (2-12-1 Oookayama, Meguro, Tokyo 152-0033, Japan), Also at E-JUST, E-mail: saavedra.o.aa@m.titech.ac.jp ABSTRACT Estuaries play an important role in exchanging water and providing a navigational pathway for ships. These zones are very sensitive and vulnerable to any interventions in coastal dynamics. Almost, the majority of these inlets experience coastal problems such as severe erosion, and accretion. Rosetta promontory, Egypt is an example of this environment. It suffers from many coastal problems as erosion problem along the coastline and siltation problem inside the inlet. It is due to lack of water and sediment resources as a side effect of constructing the Aswan High dam. The shoaling of the inlet leads to hindering the navigation process of fishing boats, negative impacts to estuarine and salt marsh habitat and decrease the efficiency of the cross section to transfer the flow during emergencies to the sea. This paper aims to test numerical several coastal measures (alternative scenarios) in order to search for the optimal alternative that minimizes the erosion and sedimentation problems at Rosetta Promontory (River Mouth). These coastal measures include modifying the inlet cross section by using centered jetties, minimizing or eliminating the coastal dynamic in the entrance using boundary jetties. The objectives of the paper are achieved by using the hydrodynamic modeling tool ( Coastal Modeling System (CMS)). Extensive field data collection (hydrographic surveys, wave data, tide data and bed morphology) is used to build and calibrate the model. Thirteen hard-structures-based scenarios were proposed and tested using CMS to study their effectiveness in reaching suitable solution that mitigates the coastal problems at both the inlet and coastal line. The results show that the 360 m jetty in the eastern bank is better than others in achieving stability conditions but unfortunately, the desired stability conditions were not achieved using any of the 13 tested scenarios. The authors recommend an extension of the study to test more alternatives scenarios which might be combinations of the currently tested ones. Keywords:, Rosetta promontory, erosion, sedimentation, inlet stability, mathematical modeling 1. INTRODUCTION Estuaries are unique water systems; they are interface between fresh river water and saline coastal water (Horrevoets et al. [1]). It provides a link between the coastal ocean and back-barrier bay, exchanging water, sediment, nutrients, and other materials between them (FitzGerald, [2]),(Vila- Concejo et al., [3]), (Pass et al., [4]). They are generally situated in densely populated areas,(Van Leussen and Dronkers, [5]). Inlets play an important role in exchanging water and providing a navigational pathway for ships and small boats to travel between the open oceans and sheltered waters (Lam et al., [6]). The estuarine processes response to both natural and human induced forces requires a sufficient knowledge of the