A review of building data has revealed some of the most dangerous buildings to flood and storm damage.
Key points:The review found more than 50% of the city’s buildings have flooded in the last 20 yearsMore than 50,000 houses have been damaged by flood damage in the past 20 yearsMost of the damage to buildings is to the outside of buildings, but some damage is done insideThe report also found that the number of flood-related deaths has increased from less than 3,000 in 2007 to more than 9,000 today.
“It’s a really big problem, not only in Victoria but across Australia,” Victoria’s senior floodplain manager, Richard Brouwer, said.
“The floodplain management system is not well-developed in Victoria, but I think it’s got to be addressed.”
Mr Brouwers research revealed that there were about 3,500 flood-affected buildings in the state’s capital, Melbourne, but only 2,400 were flood-safe.
“I think that’s because Victoria’s floodplain is a lot more developed than other parts of the country,” he said.
But the majority of the buildings in Victoria have been destroyed or severely damaged by flooding, with the worst-hit areas in Victoria’s north, west and east.
“Most of our floodplain work is on the northern and western floodplains,” Mr Brouwders said.
“We’ve got to find the areas where we can get the best return on our work.”
Building code and designThe city’s code of practice for building code is a mix of building code and building design.
“What we have to do is look at all the relevant codes and design principles to see what works and what doesn’t,” Mr Bourg said.
The city says its floodplaces are “a very flexible design” with some design features like the use of steel roofing and “open-air foundations”.
“We’ve also built some very significant infrastructure around these floodplasses and in areas that are relatively less flood-prone,” Mr Bond said.
This includes new flood protection structures such as water-pipes and stormwater collection pipes.
“But it’s important that we do not overdo it with flood protection, and we have got to balance these two different areas,” Mr Bouwer said.
He said the code of conduct was being reviewed for a second time to ensure it was still relevant.
“We’re trying to look at whether we can do more with floodplain design,” he added.
“And if not, we’re also looking at the design of the code.”
For example, we have some changes that we’ve made to the building code for the western floodplain.
“Those are things that we’re still looking at and will be looking at in the future.”
In Melbourne, most of the structures have been “redone” with new flood defences including a new high-voltage water supply, new roof-piping and new drainage systems.
“They’ve had to be redone because of some changes in our flood laws,” Mr Bowen said.
There have also been changes to how the city manages the river system, including the new design of a new river bridge between the city and the river.
“That bridge will allow for a much higher level of flood protection to be achieved on the riverbanks,” Mr Bowens said.’
A new world of infrastructure’Mr Bowen said Melbourne had been looking to create “a new world” of infrastructure in flood-risk areas and that it had begun to do so.
“With the development of these flood levees, there are now hundreds of kilometres of levees and that has opened up a whole new world for flood protection,” he told the ABC.
“When you see a levee in the riverbank that’s been developed by a city-owned company, that means that’s now a flood-protected levee, whereas previously it was only levees that were flood protected.”
You can also now build in flood defences on the banks of the river, which means you have a new world that’s opened up for flood control.
“Mr Bowen’s report found that most of Melbourne’s flood-linked buildings had flood-proofing systems.
But he also noted that many of these systems were not being used because the city did not have enough money to invest in them.”
Our flood defences are really only around 10 per cent of our total flood-resistance in Melbourne,” he noted.”
So we’re not using a lot of these.
“In some of Victoria’s most flood-sensitive areas, the report found many buildings were not designed to withstand flooding, even though many of them were not in areas with high rainfall or other flood risk.”
In some areas, we found buildings that are designed to handle flooding in terms of structural integrity, but not necessarily in terms that they’re structurally sound,” Mr Clements said.
Victoria’s city and state government are continuing to study how to improve flood defences.”