I agree with Alan B that dams are an eventual catastrophe if left as they are. We have so much rubbish that we could mulch, mix with concrete & fill the valleys beyond dam walls so as to eliminate any breaching. It'd make the dam safer & solve our waste disposal problems for a very long time if not forever !

Raising the wall should enable a significant increase in the generation of clean renewable energy.

On a more comical note, and as I have little confidence in the true acumen and technical abilities of the Aussie technocrats, someone suggested we import a ship load of beavers, (no the four legged kind) and let them do what they do better than any human.
The yanks have a hell of a time continually breaking up beaver dams, and I must admit from the ones I've seen, I have been fascinated at how they can stack a bunch of branches, twigs and brush to actually stop the flow of water.
They are truly masters of their craft and master dam builders.

We could start by using less water.

For a simple start let every home water closet have a note near the flush buttons /chain etc.

"Whilst it's yellow, let it mellow
When it's brown, send it down."

This could save billions of litres.

They are truly masters of their craft and master dam builders.
ALTRAV,
Because they didn't go to University ?

Several smaller dams would be better all round than just one or two big ones. Environmentally, the evaporation & ground water recharge from smaller dams is more effective as well as in the event of contamination etc. Also flood mitigation & employment as well as recreation are a major consideration. All up, dams are the way forward.
Greenies who are against everything except their own silliness it'd be gratifying to learn that animals won't drown because they'll simply go up as the water rises because they're smart enough to do so.