DamCam: https://www.melbournewater.com.au/water-data-and-education/w...
200KM from Melbourne, the Thomson is the main water storage and holds 1,068,000 megalitres. For comparison, Sydney harbour is 562,000 megalitres.
The Thomson is at 96% full, and in fact most of Melbourne's dams are full or nearly full according to:
https://www.melbournewater.com.au/water-data-and-education/w...
But when the USA droughts we flood due to La Nina.
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.