Development of a Model for Sediment Evacuation from Reservoirs

Among surface water sources, reservoirs of dams, especially in arid and semi-arid regions of the world, have always faced the problem of sedimentation and storage capacity reduction. In this article, we propose a method to minimize sedimentation in reservoirs. Most studies only consider flushing or long-term operation, but in this study, we propose a long-term optimal operation curve as a combination of long-term plan and periodic flushing. To extract this curve, we have combined an accepted one-dimensional sediment flushing model (Wallingford Model), the area reduction method of calculating lost volume in the reservoir, and Harmony Search (HS) evolutionary optimization algorithm. To evaluate the proposed method, we implemented it in Dez Dam reservoir as one of the most endangered dams in Iran and compared with the recorded statistics. Results indicated that optimization of rule curve during a period of 19 years can evacuate 18% of the sediment entering the reservoir and prevent the loss of 15.5 x 10(6) m(3) of storage capacity.