The importance of reservoir sedimentation management as a multi criteria problem in practice with multiple decision makers is evident when one considers that the cost of replacing storage lost annually due to sediment deposition throughout the world is in the order of US$13 billion. If sedimentation can be managed successfully, as it has been in some reservoirs, the loss in reservoir storage space due to this phenomenon can be lowered significantly. The purpose of this research is to develop the ordered weighted averaging (OWA) algorithm and apply it and to select the most preferred alternative with different Orness levels for sediment management in dam reservoirs to satisfy the technical and executive requirements, economic factors, social welfare, and environmental impacts. In this way, we present analytic forms of OWA operator weighting functions, each of which has properties of rank-based weights and a constant level of Orness, irrespective of the number of objectives considered. The model are successfully applied to the Dez hydropower reservoir, which has faced serious sedimentation problems. Results of this study provide a general class of parameterized aggregation operators that include the min, max, and average and have shown themselves to be useful for modeling many different kinds of aggregation problems.