Some weird attitudes on here 
Of course Aust have better resources than Pakistan, but even 1st world countries don't usually have a lazy few billion dollars sitting around for this sort of unprecedented disaster. It is needed all at once too, or very quickly - not over 20 years. The Dam was designed to protect Brisbane (and did actually - things could have been far, far worse without it), but this sort of flooding is well beyond the usual seasonal rains. As others have said, it is at 200% capacity. How big should we build our infrastructure - 4 times bigger than nessesary - "just in case"?
Remember also that Australia is a very smallc ountry population wise, with a small(stable, yes) economy. There are 25 million inhabitants - probably fewer than 15 million tax payers - who will fund this clean up. The UK has about 60 million inhabitants does it not?
Some may have have been uninsured by choice, some may not have been able to afford it, others were uninsurable because of proximity to the river. But who cares anyway? There are people who have lost everything - their homes, posessions, businesses, cars, children - its a horrible tradgedy in itself, does it have te be worse than someone elses tradgedy to be worthy of sympathy?
The stories that are coming out are just heart wrenching. Did you read about the 13 year old lad who said "save my little brother first" and then was swept away with his mother before they could rescue him?
Donate or don't donate as you see fit, but I don't think theres any call for comparing this tradgedy with other 'worse' or 'more deserving' ones.