Reservoir Operation Optimization Using Imperialist Competitive Algorithm to Balance Sediment Removal and Water Supply Objectives

In the literature, optimization of reservoir operation has been mostly carried out to achieve certain objectives including water and/or energy supply, flood control, and environmental preservation. These objectives can be less important for the reservoirs with high sedimentation. Sefid-Rud Reservoir in Iran has been facing extreme sedimentation rates in the past. A major challenge in operation of this reservoir has been to create a tradeoff between sediment removal and water supply to downstream users. The lack of modeling tools for balancing sediment removal with water supply objectives has been the main driving force behind this study. In this paper, a new approach is proposed for monthly reservoir operation optimization of Sefid-Rud Reservoir considering water supply and sediment removal objectives concurrently. The model minimizes the total deficit in supplying demands and maximizes the total volume of sediments removed from the reservoir. The sediment outflow is determined debased on Tsinghua university flushing equation. A new evolutionary algorithm “Imperialist Competitive Algorithm (ICA)” is used to solve the resulted nonlinear optimization model. Five scenarios were assessed for depending on the relative weights assigned to each of objectives of sediment removal and water supply. Based on the results obtained, the feasibility of increasing efficiency of flushing operation while supplying downstream water demands was illustrated. Moreover, the significance of the improved system’s operation with higher long-term reliability of supplying downstream water demands and sediment removal, compared to historical operation, was investigated.