AGGRADATION AND DEGRADATION IN NILE RIVER REACHES USING HEC-6 MODEL

Abstract

The main objectives of this study are to identify the degradation and aggradation areas along the reaches of Nile River, get the temporal and spatial changes in the resistance of the water course, and predict the changes in water depths along the reaches for water distribution studies as well as for navigation facilities. To reach these objectives, HEC--6 computer model is applied to the second and third reaches of Nile River. Calibration and verification processes give the change of roughness (Manning's n) as a function of the rate of flow and distance. Scenarios for future flow release from the High Aswan Dam were used as an input to the model for prediction of maximum scour and deposition. The results indicate that the maximum scour depths in the second and third reaches after 50 years (1976-2025) are 2.68 and 1.99 meters down stream Esna Barrage and Nag-Hammadi Barrage respectively. The maximum deposition depths are generally found in the area of back water curves tails which are formed up-stream the barrage at the end of any reach. The study showed that, some cross sections have critical water depths that cause problems for navigation therefore it is recommended to apply two dimensional model to these locations.