During a flood the dam is designed to hold back of additional water for flood mitigation or 225% capacity. Under the water release plan which is defined by law, excess water must be released from the dam within seven days or a week of it reaching 100% capacity. Between April 2004 and September 2008, a wide auxiliary spillway with a three-bay fuse plug was installed on the western portion of the dam to further mitigate flooding. In 2007, a feasibility study concluded that Wivenhoe Dam failed to satisfy the Australian National Committee on Large Dams (ANCOLD) guidelines on acceptable flood capacity.