Many dams (Oriville for example) are important parts of flood mitigation - isn’t having the dams nearly full bad for that? Or is the rainy season over?
100% is full of drinking water. This isn't actually "full" and the dam can hold this amount of water twice again - 300% capacity.
Up to 200% the dam operator can choose to close or open the dam. Above 200% the dam auto-opens and can retain water to 300%. Above 300% means the dam holds no more and all additional water runs downstream.
iirc above 280% the dam wall could be compromised and risk collapse, leading to 0% capacity in a big hurry and the worst natural disaster Queensland would have ever seen.
The dam manual for the dams near you is most likely on the govt water website (like Wivenhoe). Settle in for a long PDF which only an engineer could love.
The first one is the fun one.
But when the USA droughts we flood due to La Nina.