The role of numerical model in assessing the waterway restoration for watershed management, the case of BAHR YOUSSEF, Egypt

Abstract

In this study, the role of the numerical models in the river restoration project is discussed. The government of Egypt has a national strategic plan seeking to increase the cultivated area throughout the whole country. This will result in greater water demand for the irrigation sector, which brings attention to the water streams and their existing capacity to carry the new water discharge. Within this national plan, the Ministry of Water Resources and Irrigation intends to increase the discharge capacity of Bahr Youssef waterway from 15 million to 18 million m3/day to cope with the new development projects and the increased population density. Therefore, this work aims to provide the methodology to raise the capacity of Bahr Youssef Waterway to carry the required discharge with least cost. The SOBEK-1D numerical model was used in investigating different rehabilitation scenarios to enhance the waterway capacity to carry 18 million m3/day. The evaluation of the different alternatives considered the socioeconomic aspect as well as the technical and financial aspects. Many settlements exist on the canal bank with different activities depending on the water supplied from Bahr Yousef. The study concluded that it is possible to pass 18 million m3/day in Bahr Youssef. The model results illustrate that this could be happen by dredging only approximately 5,988,684 m3 of sedimentation in the four reaches instead of dredging the whole entire canal with a quantity of 21,150,000 m3. The model succeeded to reduce the required dredging volume by about ¾ of the total deposited material. The model results recommended to dredge only 103.1 km which is about 1/3 of the total length of the whole waterway path, which is approximately 293 km. This resulted in a reduction of the project estimated cost by approximately 72%, with the final dredging cost of approximately 239.5 million EGP for the selected areas.