The impact of flow reduction on the river morphology during bridge rehabilitation

Abstract

The construction and rehabilitation of bridges are critical infrastructure activities that can significantly impact river morphology and hydrology, particularly during the implementation phase. El Moneab Bridge on El Dahab Island was used as a case study to examine the effects of bridge rehabilitation on the morphology of the Nile River. A numerical model was developed to simulate the river system and assess the impact of various scenarios involving the reduction of the water cross-sectional area due to bridge rehabilitation phases. The model considers multiple scenarios under critical conditions to evaluate the hydrodynamic and morphological changes in the river. Results indicate that reducing the effective water crossing area notably affects both the river’s hydrology and morphology. The study concludes that conducting bridge rehabilitation during periods of minimum discharge can mitigate the negative impacts on riverbed stability and morphology.