Directs the Chief of Engineers to revise the Missouri River Mainstem Reservoir System Master Water Control Manual to ensure that the System's flood control storage allocation has been: (1) recalculated so that the flood control storage allocation is based on the vacated space required to control the largest flood experienced in the System and the associated serious downstream flooding; and (2) adjusted, prior to each runoff season, such that the space allocated for flood control purposes in the exclusive flood control zone and the annual flood control and multiple use regulation zone is increased by a quantity necessary to ensure that the storage capacity of the zones is adequate to avoid contributing to serious downstream flooding.