This paper describes the procedures and results of an investigation to evaluate potential increases in nationwide hydropower production that could be achieved by reallocation of flood control storage at existing hydropower reservoirs. One aspect of the investigation considered only the increase in energy that could be achieved by storage reallocation; a second aspect considered potential gains in both energy and capacity that could be achieved by adding to the existing installed capacity as well as storage reallocation. The investigation was performed by the Hydrologic Engineering Center of the U.S. Army Corps of Engineers, and is a component of a technical overview study which is part of the National Hydropower Study. (Author).