Thursday, May 30, 2024

After the storm: what the floods have taught us

There is no such thing as a one-size-fits-all solution to the flooding crisis experienced yet again in Australia. But there is a common approach that can help mitigate risk and prepare for the future.

The feedback from water managers around recent flood events has been characterised by
shock and awe. Furthermore, it has been about how can stormwater infrastructure ever
cope with the levels of water that submerged parts of towns and cities such as Byron Bay
and Lismore, Brisbane and Sydney experienced.

Of course, there is no single solution for issues resulting from extreme weather events like
those experienced recently.

Not only are we trying to control unprecedented volumes of water, solutions also depend
heavily on local conditions and challenges.

“It’s a mistake to walk into a council area and assume they all have the same problems and
they all should be taking the same approach,” says John Weaver, Contracts Manager at
leading pipeline infrastructure company, Interflow. “It depends on the age of the area, on
population growth, ground type and much more.”

“Newcastle, for example, is an old city that has had stormwater problems amplified by
earthquakes. That’s very different to a newer area like Camden, or a town like Dubbo where they have problems underneath the highways because of subsidence. Then there are other towns where many stormwater problems are caused by silt building up in the pipes.”

So, do we assume there is no solution? “Absolutely not,” Weaver says.

The secret to success is one that can be shared between water managers everywhere. It
means using recent events to create greater awareness around our stormwater infrastructure and the condition of underground assets. Furthermore, it involves the
utilisation of modelling to plan future developments of water infrastructure and residential
and commercial buildings.

Stormwater management into the future

“Look to New Zealand for an excellent example of preparation for the effects of climate
change on water infrastructure,” Weaver says. “Asset owners and town planners are
focussing management strategies on flood events increasing and rising sea levels.”

“They’re doing a lot of modelling, making sure that if there are future land developments or
growth corridors, they fit into what’s predicted to happen with water in the future,” he says.

“In Australia, our focus has been on water security, on getting ready for the next drought.”

“It’s correct to focus on water security,” Weaver says. “But at the same time, increasingly
regular and extreme rainfall events also deserve attention, as the recent floods proved.”

“Directions filter down from the Commonwealth to the states and on to asset owners
around water security,” he says.

“These are typically mandated and, and they provide an excellent model for us to follow to
successfully manage increasingly challenging stormwater issues.”

Practical solutions for current infrastructure

Outside of emptying dams and preparing communities, there is little that can be done in the way of an emergency response to such dramatic flood events.

The focus should instead be on developing greater awareness around the current state of
existing infrastructure and putting in place a management plan that extends its useful life
and improves its performance.

“There are two sides to innovative and successful asset management,” Weaver says. “One is around building new assets and the other is around what to do with existing assets.”

“For example, a major authority that we work with is about to embark on a huge renewal
program. We’re working with them and a few other contractors to come up with options to
renew their assets without increasing the chances of flooding.”

“That works very well, taking an asset owner’s good ideas and running them through a
review program that includes advice from highly experienced contractors. This ensures the
solutions are as good as they can be.”

“The most powerful insight a water manager can have is into the real-time, current
condition of their infrastructure,” Weaver says.

Gradually, all stormwater assets are deteriorating. If a water manager constantly monitors
those assets they will know exactly when they require maintenance. They will enjoy
certainty around the order projects should be carried out and can engage with specialist
contractors to plan and design solutions that extend the assets’ lives whilst improving their

Such insight means asset owners will know when a swift response is required to ensure
public safety as experienced in the work contracted to Interflow by Ipswich City Council to
restore a failing section of pipeline running beneath a popular and busy outdoor
recreational space.

It also means custom solutions can be designed and developed well in advance of them
becoming catastrophic, such as the bespoke renewal of the stormwater drainage culvert
running beneath the bustling Brisbane Corso. Interflow’s unique structural relining of the
culvert, which was exposed to the Brisbane River’s rising tides, meant costly cofferdam
construction could be avoided whilst all structural requirements were met.

Additionally, more was delivered for less when a 50-year extension of life for a vital culvert
running beneath a busy Sunshine Coast Council street was achieved. Without any traffic,
telecommunications, electrical or water disruptions, the unique solution involving the installation of a glass-reinforced liner eliminated all need for excavation, enabling a 25% cost eduction.

Planning for an ageing infrastructure

Prior to the major flood events of the last several years, many Australian councils were
already facing the realities of water infrastructure assets, built prior to 1970, beginning to
reach the end of their life cycle.

An Infrastructure Australia report identified ageing infrastructure as a critical issue across
Australia. External pressures, the report highlighted, included a growing population, a rise in single-person occupied dwellings and increasingly frequent extreme weather events.

Water managers are facing an infrastructure cliff whilst simultaneously experiencing a dramatic rise in community expectations, driven by flood and associated weather events. A
proactive approach must begin with definitive insight into the condition of all parts of the
infrastructure, informed by advice and input from those who’ve been there before.

Latest Articles