A sediment transport capacity index was developed as a part of a program to develop methods of flushing flow analysis. The index can be used to develop reservoir operation strategies that consider the movement of sediment as one of the reservoir management goals. The sedimentation transport capacity index determines the instream flow for the maintenance of the substrate below a reservoir in a condition needed by a desirable ecosystem. It can also be used in investigating the impacts of reservoir on the river channel downstream of the reservoir. The method allows a reservoir operator the flexibility of meeting the streamflow needs with a mix of streamflows.