Wollongong's inability to manage stormwater run-off through its system of creeks from the escarpment was a "huge problem" the city would have to face up to, Lord Mayor Gordon Bradbery said on Friday.
Monday night's heavy rains exposed once more how vulnerable the city and its suburbs are to flooding caused by storms, as the creeks prove inadequate to effectively drain stormwater from an increasingly built-up area.
Part of the problem lies in geography, with the escarpment funnelling vast amounts of water into a finite number of creeks, some of which flow near houses.
Wollongong City Council says it spends about $5 million a year on flood management and drainage - including $1 million on maintaining and clearing pipes, drains and culverts and creeks, almost $1 million on developing and updating flood risk-management plans and maintaining detention basins.
It also spends more than $3 million on replacing, upgrading or installing new stormwater management infrastructure. But it is becoming increasingly clear that this is nowhere near what is needed, meaning decisions will have to be made about where the money comes from.
"What we spend on stormwater and stormwater management ... is vastly inadequate, as far as I'm concerned," Cr Bradbery said.
"We have these many creeks and stormwater patterns and drainage - it really is a huge problem that we've got to somehow or other get our head around."
Cr Bradbery said the council and citizens would have to decide whether to give the issue the amount needed. He said the council's financial sustainability review was part of the process to find more funds.
"We do not have the adequate funds to replace the ageing infrastructure," he said.
"We're trying to find enough money to do everything, but we don't want to put up rates to such an extent that it hurts people. We've had to put rates up. We've had to find efficiencies here at council.
"But we have some big problems in this city in terms of ageing infrastructure, and this is one of the scenarios and situations where [all] the things that should have been done in the past are now coming home on us.
"Some of these situations are caused by bad planning and bad decisions in the past."
At Woonona, residents live with the effects of the creek being diverted around a soccer field. This turns the edge of the field into an earthen wall, leaving the homes on Lawrence Street caught in a basin.
Cr Bradbery also named the creek diversion around the Innovation Campus as one that could have used more thought.