Bahr Yousef meandering canal management – Hydraulic and morphological assessment

Abstract

Bahr Yousef is a meandering earthen canal and is considered one of the most morphologically active semi-natural streams in the west of River Nile region in Egypt. This stream is usually exposed to periodic changes in cross-sections due to scour, deposition, and improper periodic dredging activities. The objectives of the present study are to assess the morphological behavior and hydraulic performance of Bahr Yousef canal and to identify the flooding areas. Combination of field data, satellite images, and numerical modeling methods is used and achieved to simulate the dynamic behavior of the second reach of Bahr Yousef canal from Dahab regulator (km 77.700) to Saqoula regulator (km 179.450) under different flow scenarios. The designed, actual, and target flows were modeled using HEC-RAS modeling program to evaluate the canal’s hydraulic efficiency. The results showed that in the case of a passing target discharge, the flooded areas increased by 25.8%, and the most significant inundated areas are located between 135 km and 160 km along the studied reach. The canal narrowed by 5.8% from an average of 71.35 m in 2004 to 67.22 m in 2023 due to human activities and natural meandering phenomena. Significant sedimentation (10,671,870 m3) and erosion (4,593,143.67 m3) observed along the studied reach, restricting its capacity to handle target discharge. Recommendations are given to control the scour and sedimentation processes in certain critical curves along Bahr Yousef canal. This is very important to avoid inundation problems that have devastating consequences, including foundation collapses, crop damage, and property loss.