Date of Award

Fall 2018

Document Type

Open Access Dissertation

Department

Civil and Environmental Engineering

First Advisor

Enrica Viparelli

Second Advisor

Ahmed Moussa

Abstract

The construction of the High Aswan Dam significantly reduced the flood flows and the sediment supply to the Egyptian portion of the Nile River. Consequences of this changes in river hydrology are diffuse channel bed erosion in the upstream part of the river, in- channel sedimentation in the downstream part of the system, delta recession, habitat deterioration, wetlands loss, water pollution, and environmental problems. The feasibility of a Nile River-Delta restoration project with controlled flow releases and sediment augmentations at Aswan is here investigated with the aid of site-specific one-dimensional morphodynamic models. The water source for the restoration project, based on previous estimates of water availability in Egypt, is an average annual volume of ~10 billion cubic meters that can be saved by improving the Egyptian irrigation system. Sediment can be mined from High Aswan Dam Reservoir upstream of the High Aswan Dam, where a delta is naturally forming and gradually reducing the volume of the reservoir. The mined sediment can be transported at Aswan with slurry pipes. The design of the pipeline goes beyond the scope of this study. This work is organized in two parts, river modeling, and delta modeling. The river modeling aims to quantitatively characterize the morphodynamic impact of the controlled flow releases and sediment augmentations at Aswan on the Nile River in terms of navigation and flood control. The results of the river modeling show that the ongoing erosion of the Nile River channel in the upstream part of the model reach can be controlled with the proposed sand augmentations, the controlled

flow releases from the Aswan Dam do not represent a threat for navigation and flood control at engineering time scales, and increase in the volumes of water and sediment delivered to the delta. The delta modeling presented herein consists the development of a 1D model to capture delta growth and the associated changes in channel geometry. The model is validated against field data collected in the High Aswan Dam Reservoir delta, and it is then applied to investigate the effects of sea level rise, subsidence, and wave action on the geometry of the channelized portion of the delta top. Future developments of this work, not reported in the present dissertation, consist in the application of the validated delta model to quantify the impacts of the proposed restoration project on the Nile delta in terms of shoreline position and geometry of the delta top.

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