To support operation in a water storage facility such that a power selling amount or power generated by water-power generation can be increased.

An operation water level planning part of an optimum storage water level calculation system changes a water storage amount of each unit period t, performs simulation, determines a combination between the water storage amounts wherein a total of generated power amounts or the power selling amount becomes maximum, and outputs it together with a calculated operation water level based on the determined water storage amounts. When a water intake amount Qt of each unit period t is less than an operation limit water intake amount Q0min about the determined combination between the water storage amounts, the operation water level planning part changes the water intake amount Qt into a minimum water intake amount Qmin. The operation water level planning part also changes the water intake amount Qt into the minimum water intake amount Qmin when the water intake amount Qt of each unit period t is less than a lower limit value, and changes the water intake amount Qt into a maximum water intake amount Qmax when the water intake amount Qt is not less than the lower limit value.

COPYRIGHT: (C)2011,JPO&INPIT