Optimizing reservoir operation to include sediment management: A new approach tested for the Roseires Dam, Blue Nile River

Sedimentation poses a challenge for optimal use of reservoirs in the Nile basin. Many reservoirs in the basin have substantially silted up such as Roseires and Sennar dams along the Blue Nile River and Khashm Elgirba dam on the Tekeze-Atbara River. This study develops a new model for optimizing and simulating the operation of multi-objectives reservoir considering sediment management. The model includes three modules: optimization, water allocation and sediment management simulation modules. Genetic Algorithm (GA) is used for optimization. Simulation of reservoir sedimentation is implemented using the trap efficiency method.

The model is applied to the Roseires dam, located at the main stem of the Blue Nile in Sudan. The operation of Roseires dam is optimized for three objective functions; the maximization of the economic return from water released for hydropower generation, irrigation and minimization of the sediment deposition. Four scenarios are studied: the current operation, optimizing the operation for hydropower and irrigation, sediment management only, and the three objectives collectively. The study thus explores different options for dam operation to maximize the economic benefits while maintaining the sustainability of reservoir storage.