Increasing the efficiency of the river Nile western branch at Warrak island

الملخص EN

Regulated rivers usually subjected to continuous morphological changes due to human interventions and the variation of the flow rates released through them.

these changes sometimes affect island banks causing bank failure and deformation.

on the other hand, the morphological changes cause the riverbed to aggrade/degrade.

this, in turn, may affect the carrying capacity and conveyance of the river channel.

to keep the channel conveyance as efficient as possible, bed aggradation should be minimized.

this paper basically aims at increasing the efficiency of the river Nile western branch at Warrak island.

eight scenarios are proposed to achieve this goal, which includes removing the unmanaged human intervention at the island southern nose, dredging the western branch to the safe navigation elevation (12.66 m) and propose a development plan for canalization of this branch.

a 2-D numerical model (delft 3D) was used to simulate this segment of the river to detect and predict the trend of the morphological changes.

the ratio of flow passes through this branch is calculated for all cases, it was found to be 31.4% for the current case, while the maximum value of 45.52% occurred when removing of the southern part of the island nose and dredging the branch is applied.

the morphological changes were predicted, and it is found that the entrance of the west branch is always subjected to sedimentation due to the general alignment of the river in this region.

results also indicates, for development scenarios, that deposition also occurred in the entrance of the west branch, like before, but the dredging was limited to few locations, which can be handled with dredging.

so, it is recommended, in case of using the west branch for navigation in an emergency case, to follow the development of the west branch as a solution.