Morphology of the Nile River due to a flow rate over the maximum current: Case study Damietta branch

Abstract

Damietta branch is one of the two branches of the Nile River. It is the main source of water for water supply for both domestic and industrial activities, irrigation and navigation purposes in the Nile Delta region and its fringes, Egypt along with the Rosetta branch. Field investigations proved that scour, deposition, and bank erosion occurred along the course of the branch. Also, encroachment by people on the flood plain during the last three decades led to a reduction in its carrying water capacity. Therefore, this chapter aims at presenting the results of a numerical investigation on the effect of passing a higher future discharge more than the maximum current flowing discharge. Two-dimensional hydrodynamic mathematical model (CCHE2D) was used to simulate the morphological changes in Damietta branch due to an additional excess flow of 20 Mm3/day. Also, the CCHE2D was used to predict the effect of high flows on water velocities and geometrical changes at different cross sections. Comparisons between cross sections under the scenario of increasing the discharge from 60 to 80 million m3/day were carried out. Moreover, the side effects on the navigational channel and overtopping problems had been investigated. Consequently different solutions were suggested to increase the ability of Damietta branch to convey higher discharges.