A flood evacuation and road resilience program is inspiring engineers to devise sustainability solutions that previously may never have been considered.
The Hawkesbury-Nepean Valley suffers one of the highest flood dangers in Australia, with five major tributaries channelling water into its confines during major rain events.
The Warragamba River, Nepean River, Grose River, South Creek and Eastern Creek, as well as several smaller tributaries, all flow fast into the valley and are then slowed at natural choke points.
The water has nowhere to go but across the floodplain, causing further flooding up the valley and along the Hawkesbury River, and swamping populated cities, towns and suburbs such as Emu Plains, Penrith, Richmond, Windsor and McGraths Hill.
The floodplain is around 425 km2 in land area and is home to approximately 135,000 people, a figure that is growing fast. During evacuations, mostly by road, routes can sometimes be flooded.
“In those flood events, people really do need to get out of the valley, because there’s a risk to their lives,” said Jared Crossley, Principal Civil Engineer Urban & Place at AECOM.
Crossley’s co-presentation with colleague Anna Luong at Climate Smart Engineering 2023 will focus on the program which, according to Crossley, is a uniquely inspiring engineering project.
More time to escape danger
The program is about improving the performance and resilience of the flood evacuation road network, so people can get out in the event of a flood.
The NSW government is preparing a concept design and business case to support an investment decision, with joint funding from the Australian government.
“Many of us are excited to work on the program because we come from an engineering environment where the focus is typically on traffic efficiency,” Crossley, who is a Civil Engineer at AECOM in Sydney, explained.
“In this program, we’re looking to improve the performance and resilience of that flood evacuation road network, rather than just improving the general road network performance.”
That translates to maximising the time people have to evacuate, and lowering the risk to life that the flood poses.
AECOM’s team aims to achieve this by: widening road shoulders to increase evacuation capacity away from affected areas; upgrading pinch points such as intersections and roundabouts to cope with the extra evacuation traffic flow; improving drainage culverts and channels; and, in some locations, raising the road and adding bridges.
Formalising sustainability
Why is all of this inspirational? Crossley said there is a formalised process in which the team regularly meets to brainstorm sustainability ideas.
From a decade-long career spanning South Africa, the UK and Australia, this is the first time he has experienced such a sustainability focus in an engineering project.
“We formally sit down and brainstorm potential sustainability solutions and then agree how and when those might be implemented,” he said.
“That might include how we can make the pavement more resilient over its lifetime so that we can not only use more sustainable materials in that pavement, but also so that the pavement lasts longer, which reduces the amount of maintenance you might have to do [and] reduces emissions. “
While sustainability has certainly been considered during past projects, this is the first time he has seen it formalised, documented and given a permanent home in the design workflow.
“It has been quite exciting to feel that you can throw in any sort of idea,” he said. “You have the ability to take pie-in-the sky concepts and throw them in the ring for consideration, whether they get adopted or not.
“When you have a follow-up process, there is encouragement for people to come forward with any ideas they might have.”
The process has left Crossley feeling increasingly engaged in the work he’s doing. It’s that sense he’s hoping to share during his CSE23 presentation.
“We want people to feel inspired that the industry and government is moving in a direction that encourages a different way of thinking about projects,” he said.
“They have the opportunity to work on projects that are more grounded in consideration for the environment and resilience, and that take into consideration future generations.”
Jared Crossley is just one of many engineers who’ll be in attendance at CSE23. There’s still time to secure your place – don’t forget to register.