A drainage issue

Following last weekend's flash flooding around parts of Brisbane, the ABC has this article up:

More wild weather forecast for Queensland raises questions about how Brisbane drains handle intense rainfall

with one guy saying:

"With the bureau forecasting more frequent events, the storm drains across the city simply aren't designed to take in flows of run-off and intense rain," Mr Winders said.

Rather than being flood-resilient, Mr Winders suggests residents need to become "storm-resilient".

"The local council can't do anything about the network, the drains are already in place and there's too much existing development," he said.

"All these things impede the ability of the council to provide any relief from local flooding."

And I suspect he's right.

One thing that isn't mentioned in the article, and that I'm pretty sure would be true, is that Brisbane's drainage system does seems to often handle much higher total rainfall events without flooding, compared to cities such as Melbourne, and probably Sydney too?

I mean, over the years, I have seen many news reports of flash flooding from storms in other cities, and the rainfall totals that caused it often seem to be well under the rainfall we hear about in Brisbane storms or rain events.

So I have always suspected that our drainage system has been engineered to expect higher surges than those of drier cities.   (Melbourne in particular seems to get most of its rain in far less intense events than Brisbane - it's just spread out over drizzly days rather than in 10 or 15 minute bursts like here!)

 But I have never heard an expert confirm that.