As Gavin notes, Peter Garrett knocked back a Queensland dam because it might have impacted on the habitat of some endangered frogs and things.
I'm wondering this - how would the impact of the dam compare to the impact of a fucking enormous flood? Do those habitats still exist, or are they now 30 feet under water? What sort of condition will those habitats be in when the waters subside, and will those endangered species ever come back? What if they've all been wiped out by the flood? Can we then start pouring concrete for a new dam?
Of course Garrett and the Federal environmental pubes would never consider such an outcome, as they couldn't conceive of it ever raining again in Australia thanks to climate change.