Reallocation of reservoir storage capacity for different water use purposes is regarded as one of the representative strategies for supplying water for human and environmental needs under the difficult situation of new reservoir construction. However, there are impacts of reservoir storage reallocation on river/reservoir systems because each reservoir in a multiple reservoir system is operated by priority order, not by natural order. Accordingly, this study focuses on evaluating the relative impact of reservoir location on a system of 14 multiple-purpose reservoirs and hydrology characteristics modification. The natural and priority orders are considered for three reallocation strategies. The comparison results of reliability, flood frequency, and economic flood damage indicate that individual reservoir storage reallocation has an impact on nearby reservoirs and river systems at downstream points, which are located directly below the reservoir. The multiple reservoir storage reallocation plans are reliable strategies for lessening the impacts on river/reservoir operating systems.