STUDY OF THE EFFECTS OF HUMAN INTERVENTIONS AND MORPHOLOGICAL CHANGES ON RIVER NAVIGATION - (CASE STUDY: FROM KM 462 TO 498 U.S RODA GAUGE IN THE THIRD REACH IN THE NILE RIVER IN EGYPT)

Rivers are the main source of water and life to humans so all of their activities are located on its banks. River navigation is one of the most important activities in current ages. Navigation bottlenecks are appeared and conventional solution is occurred to try to mitigate this problem. Dredging is currently used as a temporary work but some of bottlenecks are repeated again at most regions and needed to periodic maintenance. This research shows that each zone of bottleneck has special properties. The relationship between morphological changes (such as bends, island form, changes of bed level and river width) and appearance of bottlenecks in Nile Rivers. The human interventions in the study reach are determined and studied its impacts on navigational path. Data are collected and delft 3d model is used to simulate study reach from kilometer 462 to 498 U.S. Roda gauge. Nine zones of navigational bottlenecks were appeared in 1982 in minimum discharge case but eight zones were appeared in 2010 in normal case and after prediction of model for seven year. Four zones are appeared after using dredging process and prediction by delft 3d model, where three of them are determined in last report of observed navigation bottlenecks at 2017-2018 therefore this model can be applied to large area in Nile river and predication of navigation problems in the future. In average discharge case, minimum