In this paper a new and efficient control method based on fuzzy logic is proposed for real-time operation of spillway gates of a reservoir during any flood of any magnitude up to the probable maximum flood. Artificial neural networks are used to model the non-linear relationship among the main variables of the reservoir under consideration. In order to demonstrate the performance of the proposed method, we simulate the control system using different probable overflow hydrographs. The results of the proposed control method are compared with the results of the conventional control methods. The results obtained from the simulations indicate that the proposed method exhibits superior performance over the conventional reservoir flood operation, with much more flexible results. Copyright (C) 2004 John Wiley Sons, Ltd.