Extracting Optimal Policies of Hydropower Multi-Reservoir Systems Utilizing Enhanced Differential Evolution Algorithm Iman Ahmadianfar 1 & Arvin Samadi-Koucheksaraee 1 & Omid Bozorg-Haddad 2 Received: 28 October 2016 / Accepted: 12 June 2017 # Springer Science+Business Media B.V. 2017 Abstract Deriving the optimal policies of hydropower multi-reservoir systems is a nonlinear and high-dimensional problem which makes it difficult to achieve the global or near global optimal solution. In order to optimally solve the problem effectively, development of optimi- zation methods with the purpose of optimizing reservoir operation is indispensable as well as inevitable. This paper introduces an enhanced differential evolution (EDE) algorithm to enhance the exploration and exploitation abilities of the original differential evolution (DE) algorithm. The EDE algorithm is first applied to minimize two benchmark functions (Ackley and Shifted Schwefel). In addition, a real world two-reservoir hydropower optimization problem and a large scale benchmark problem, namely ten-reservoir problem, were considered to indicate the effectiveness of the EDE. The performance of the EDE was compared with the original DE to solve the three optimization problems. The results demonstrate that the EDE would have a powerful global ability and faster convergence than the original DE to solve the two benchmark functions. In the 10-reservoir optimization problem, the EDE proved to be much more functional to reach optimal or near optimal solution and to be effective in terms of convergence rate, standard deviation, the best, average and worst values of objective function than the original DE. Also, In the case of two-reservoir system, the best values of the objective function obtained 93.86 and 101.09 for EDE and DE respectively. Based on the results, it can Water Resour Manage DOI 10.1007/s11269-017-1753-z * Arvin Samadi-Koucheksaraee arvinsamadi.k@gmail.com Iman Ahmadianfar i.ahmadianfar@bkatu.ac.ir Omid Bozorg-Haddad OBHaddad@ut.ac.ir 1 Department of Civil Engineering, Behbahan Khatam Alanbia University of Technology, Behbahan, Iran 2 Department of Irrigation and Reclamation Engineering, Faculty of Agricultural Engineering and Technology, College of Agriculture and Natural Resources, University of Tehran, Karaj, Tehran, Iran