Abstract. The objective is to present a reservoir management system which is capable of determining optimal operating rules both for flood event based and normal operation while at the same time attempting to achieve ecologically oriented operation. In order to maintain the variability of the natural flow regime, a new dynamic operating policy is introduced for normal operation. Flood event based operation is managed by a two-part step function. Both operating policies are optimized using a state-of-the-art multi-objective evolution strategy algorithm.