Faculty of New Sciences and Technologies, University of TehranIranian journal of Ecohydrology2423-60987420201221Efficiency of the Linear Muskingum Method in Flood Routing of Dual Rockfill Detention DamsEfficiency of the Linear Muskingum Method in Flood Routing of Dual Rockfill Detention Dams106110707903110.22059/ije.2020.307845.1369FAHadiNorouziPh.D. Candidate of Hydraulic Structures, Department of Civil Engineering, Faculty of Engineering, University of Zanjan, Zanjan, IranJalalBazarganAssociate Professor, Department of Civil Engineering, Faculty of Engineering, University of Zanjan, Zanjan, IranJournal Article20200731One of the most important applications of rock-fill dams is to control flood by reducing the peak discharge of inflow. It is of great importance to study how much of the inflow to the rock-fill dam reservoir is transferred to the downstream under unsteady flow conditions. In the present study, flood routing in dual detention rock-fill dams was studied using four experimental data samples, linear Muskingum method, and particle swarm optimization (PSO) algorithm and the effect of rock-fill dam length, distance between two dams, and aggregate size was studied on the K coefficient of linear Muskingum method. The results showed that the mean relative error (MRE) of the four experiments used in the present study were equal to 4.9, 3.4, 4.35 and 3.55%, respectively, and the relative error of the peak discharge (DPO) of the mentioned experiments were calculated as 1.58, 0.47, 2.86 and 1.78%, respectively, which indicates the high accuracy of the linear Muskingum method in estimating the outflow hydrograph. The results also showed that, by increasing the distance between the inflow and outflow hydrographs, the K coefficient increased and by increasing the aggregates size, the flow velocity increased and consequently, the K coefficient decreased.One of the most important applications of rock-fill dams is to control flood by reducing the peak discharge of inflow. It is of great importance to study how much of the inflow to the rock-fill dam reservoir is transferred to the downstream under unsteady flow conditions. In the present study, flood routing in dual detention rock-fill dams was studied using four experimental data samples, linear Muskingum method, and particle swarm optimization (PSO) algorithm and the effect of rock-fill dam length, distance between two dams, and aggregate size was studied on the K coefficient of linear Muskingum method. The results showed that the mean relative error (MRE) of the four experiments used in the present study were equal to 4.9, 3.4, 4.35 and 3.55%, respectively, and the relative error of the peak discharge (DPO) of the mentioned experiments were calculated as 1.58, 0.47, 2.86 and 1.78%, respectively, which indicates the high accuracy of the linear Muskingum method in estimating the outflow hydrograph. The results also showed that, by increasing the distance between the inflow and outflow hydrographs, the K coefficient increased and by increasing the aggregates size, the flow velocity increased and consequently, the K coefficient decreased.https://ije.ut.ac.ir/article_79031_be2f1c5827695dc3c1e7ed9431f969eb.pdf