A growing understanding of how nature-based solutions can be used for flood mitigation is changing the way Australian communities are managing flood risks.
Flood mitigation has long relied on traditional engineering infrastructure, such as dams and levees, to control water flow, store excess runoff, and safeguard communities. Now, as flood risks are escalating due to climate change, a new approach is gaining a better understanding.
Nature-based solutions (NbS) to flooding involve applying natural processes to address flood challenges while also delivering environmental, social, and economic benefits beyond flood mitigation.
It is a concept that has gained considerable international recognition in recent years and, unlike traditional engineering approaches, it aims to make landscapes more sustainable and resilient, according to Associate Professor Roslyn Prinsley, Lead, Disaster Solutions at ANU.
Prinsley is leading the team of researchers behind the Australian guidelines for Nature-based Solutions for flood mitigation – funded by the National Emergency Management Authority – which will be released in October this year.
Developed to bridge the gap between support for the concept of NbS and the review and analysis of how these types of solutions actually work, the guidelines demonstrate how researchers, community groups and governments can take a nature-based approach to flood management.
The ANU team is collaborating closely with local council and community experts. This approach recognises that effective flood mitigation strategies using NbS require both scientific understanding, and local knowledge gained through real-world implementation and community engagement.
The core aim of NbS in flood management is to store/retain, divert water, or reduce the energy of floodwaters, Prinsley said. Examples include planting trees, restoring wetlands, reconnecting floodplains, planting riparian vegetation, building leaky weirs, restoring and modifying palaeochannels and developing sustainable diversion channels to redirect water around urban areas, and urban green infrastructure.
A central tenet of NbS is the ability to deliver multiple benefits beyond their primary function, she said.
“The same nature-based solutions that improve flood management generally also improve water quality, for example. Other benefits may include increased biodiversity and habitat creation, carbon capture and sequestration, as well as improved soil fertility, water-holding capacity and reduced erosion and bank stabilisation,” Prinsley said.
Read more: How this construction company mitigated floods in a Tasmanian town
Complementing and replacing
NbS flood mitigation demands not only core engineering expertise in areas such as water resources and flood modelling, but also a broader, systemic view of the entire catchment, and deep interdisciplinary collaboration with experts including ecologists, landscape architects, social scientists and economists, according to Dr Jeremy Smith, Research Team, Nature-based Solutions (ANU School of Engineering) and contributor to the new guidelines.
“Civil engineers, particularly those specialising in water resources engineering, flood engineering, environmental engineering and hydraulic engineering, remain central to flood mitigation projects,” he said.
“But there are broader benefits if you look at multiple interventions, and don’t just rely on engineering solutions. It helps to build robustness and resilience.”
For Ben Patterson, Technical Director & Market Lead for Rivers, Flooding & Water Management at engineering consultancy Haskoning, taking a collaborative approach has been crucial in executing several projects, including the upgrade of a heavily dilapidated concrete drainage stormwater channel at Powell’s Creek in Western Sydney.
“The channel required a lot of maintenance from Sydney Water and it offered effectively zero habitat for local species,” he said.
Instead of a “like-for-like” replacement of concrete with concrete, the project aimed for a rehabilitation using NbS, Patterson said. The bottom of the channel was replaced with a new concrete slab to facilitate maintenance for Sydney Water, but features were incorporated into the slab to allow sediment accumulation, fostering marine invertebrates.
“By removing the steep concrete walls the channel was significantly widened, which offset the slowing of water caused by the naturalised banks. It also improved the visual amenity of the area and transformed a degraded space into a vibrant green corridor, creating habitat for local species like crabs, juvenile fish and even stingrays.”
But the real win was in creating a space that enriched the area and seeing how the community has responded to that project, Patterson adds.
“They absolutely love this channel. It’s no longer a degraded, graffitied, concrete-lined channel. It’s now a beautiful green space for people to interact with the water’s edge, walk their dogs and cycle along the path.”
Explore more flood mitigation strategies at the Engineers Australia Climate Smart Engineering (CSE) 2025 conference in Adelaide from 27-28 August.
Get some engineers from Delft, the Netherland are partly 6 meter under sea level and gets a lot more rain than Australia.
Water can be a very influential medium in erosion and deposition unless it is controlled and slowed. As a road and rail engineer, I have spent part of my work in controlling water by talking to neighbours next to our ribbon developments and developing a wholistic approach to slowing erosion and hence the deposition downstream.