Sediment Transport Modeling at the Oued Fodda Watershed Level Using HEC-RAS 1D Software

Abstract

The objective of the current work is to determine the amount of sediments transported upstream and at the level of Oued Fodda dam. The latter is considered one of the first large dams built in Algeria. It’s exposed to a serious siltation problem that reduces its capacity every year. The simulation was executed using the HEC-RAS software, for the period varied from January 01, 2016 to April 30, 2016. The modeledsection consisted of about 9999 m length, subdivided into 141 river stations distant from each other by 70 m. The observation of the studied river section bed-profile was selected as a criterion for comparing the results of the model with the real values observed. A roughness coefficient of 0.031 was used. A quantitative estimate with a determination coefficient, R2, of 0.92 was used to support the validity. The mass and concentration of sediments increased significantly in the cross-sections located at the dam upstream.A total cumulative mass was estimated at approximately 712699 tons, just upstream of the dyke, and a maximum concentration of 22.35 g/l was observed, particularly for three main sections selected upstream of the Fodda wadi. However, at the reservoir level, the concentration variability is observed during flood periods, i.e., only for the most important flows