How could Australia transform its approach to building in flood-prone areas?

By Bethany Hooper, School of Architecture, Design and Planning

The increase of flooding events across Australia necessitates a probe into the current approach to building, designing, and developing in flood-prone areas. A common knee-jerk reaction when these events occur is to prevent future building in such areas, but the severity, unpredictability, and intensity of flooding events due to climate change demands a more nuanced design response.  

Whilst the issue is front of mind for those directly affected by the current events, research reveals that by 2030, one million homes across Australia will be at risk of flooding. In these instances the issue itself is not the abundance of water; the issue is the way in which the water engages with ill-prepared buildings in our regional and urban towns.

In NSW, it is interesting to compare the approach of building in flood-prone areas to bushfire prone areas. In places where bushfires are highly probable, the system aims to ensure built forms are resilient through their design, materiality, construction, siting, and mitigation measures. Whilst bushfires are an occurrence that the Australian psyche has come to expect, and as such the industry’s approach is one of designing and planning appropriately, flooding does not have a similar reputation. This was clear in the aftermath of the 2019-20 bushfires where the building industry came together en masse to help rebuild destroyed homes through the establishment of Architects Assist, a response on this scale has not been seen in the aftermath of recent flooding.

Global examples help to demonstrate how our infrastructure, from entire towns to localised urban design and individual buildings, can help mitigate the effects of flooding. These examples present an ideology of living alongside nature and in preparedness for its uncertainties, not in opposition to it. The following examples present different scales of intervention, encompassing approaches of temporality, adaptability, and resilience.

01.  The Fluctuating City
Room for the River Project, Rotterdam, Netherlands by the Dutch Government

After severe flooding in the 1990s, the Dutch government overhauled its flood management by introducing Room for the River in 2006. This project is an example of both an innovative planning methodology and philosophy, in that interventions provide the space and infrastructure for the rivers to expand during times of heavy rainfall. The Dutch government allocated 2.3 billion euros to the project, and by 2016 had completed 34 projects selected from key interventions including dike relocation, flood bypasses, lowering floodplains, green rivers, lowering groynes and removing obstacles (such as redundant pipes, ferry lines, and bridges).

This program strayed from the traditional preventative measures that aim to slow down and stop the water from entering the river systems, which has been seen in Australia in the recent proposal to increase the walls of the Warragamba Dam. The Room for the River program provided space for increased water loads and planned for the safe distribution of it. Not only did this approach consider planning and engineering perspectives, urban designers and landscape architects were engaged to create landscapes of high quality and useability around the river for the surrounding communities. In some ways the Netherlands shares similarities to Sydney in that development on floodplains is somewhat unavoidable as developable land in areas of growing populations can be scarce. As such, many lessons can be learnt from this project, in both process and approach.

02.  The Porous Block
Chulalongkorn University Centenary Park, Bangkok, Thailand by Landprocess

Whilst large-scale municipal interventions may suggest the most impactful effects, mitigation measures can extend to individual developments. As a result of concreting over natural landscapes and removing trees, stormwater run-off can no longer seep into the earth and is exponentially redirected to the rivers in many cities.

A project by Landprocess in Bangkok aims to respond to this issue by developing an innovative park to reinstate the porosity of the once agricultural city. Bangkok has a long history of flooding, once co-existing with water through a network of canals, stilt houses and floating markets. However, in recent decades these networks have been replaced with concrete buildings, carparks, and roads, increasing the severity of flooding (the most recent example seen recently).

In response to this, Landprocess designed a combined building-park for the Chulalongkorn University campus with a raised green roof that redirects stormwater runoff through a series of rain gardens and wetlands. The park acts as one huge retention pond slowing the flow of stormwater into the surrounding river systems, whilst also functioning as a socially occupiable space. This example of green infrastructure was one of the first in Thailand to actively contribute to disaster risk reduction in a highly flood-prone, low-lying area. It is an example of both a resilient and adaptable infrastructure where at the city-block scale, interventions can start to reduce the effects of flooding.

Urban areas in Australia, such as Brisbane which has experienced major flooding, can learn from such examples in planning and development models.

3. The Resilient Home
Homes for all Seasons, Competition Entry in England by JTP and The Environmental Design Studio

Beyond the municipal and city scale, floodplains are current and future homes for many people. In western Sydney, many new suburbs are being built on the floodplain, but individual homes and apartment buildings could be better suited for flooding resilience. The previous NSW Minister for Planning, Rob Stokes, introduced resilient design principles for sustainable development, that were unfortunately scrapped by the new Minister Anthony Roberts weeks later.

The project Homes for All Seasons, submitted by JTP and The Environmental Design Studio in the 2016 Sunday Times British Homes Awards Resilient Homes Design Competition, suggests several design principles that are extremely relevant to current NSW developments on floodplains. The designs include strategically positioning all habitable zones on the first floor and above, allowing the ground floor to become a multi-use space that can be adapted and easily cleaned post flooding. With all habitable rooms raised to a high datum level, an elevated causeway at the first floor provides safe access and egress during a flood. When these houses form an entire block or street, swales become integrated into the roadside to aid in the slowing down of stormwater run-off. The principles contained within this project can already be seen in the rare homes being appropriately designed for its floodplain location such as the Graceville Flood House by JDA Co.

These three examples are not presented as simply transferable from one place to the other, rather they successfully promote and encourage an approach to building, designing, and developing in flood-prone areas that is resilient and proactive, rather than vulnerable and reactive. As Australian cities, urban and regional, start to urgently grapple with these concerns, approaches of adaptability, temporality and resilience can aid in creating a future-proofed built environment.

This article is part of the SEI Student Series on Climate Futures.

Bethany Hooper is studying a Master of Architecture at the University of Sydney and currently holds a Bachelor of Design in Architecture and Bachelor of Creative Intelligence and Innovation from the University of Technology, Sydney. Throughout her studies and professional life, she has developed a passion for environmental design, working on certified Passivhaus and bushfire prone projects. She sees a resilient response to climate change-induced concerns as integral to a sustainable built environment.

Header image: Chao Phraya Sky park, Bangkok by Kritsaroot Udkwae via Shutterstock, ID: 1867833910