Turning water from foe to friendResearch news
As one in 100 year floods become more like one in ten, or one in five year events, blue-green infrastructure could help reduce the impact of flooding on our environment and economy.
The aftermath of floods can be devastating for the environment, the economy and livelihoods. In 2017, Deakin University research funded by the Bushfire and Natural Hazard Cooperative Research Centre found that, in Australia, a state that experienced a flood in a given year encountered, on average, 4.5 per cent lower agricultural production both that year and the next, compared to a state that didn’t experience a flood.
Now, research from Deakin’s Centre for Regional and Rural Futures (CeRRF) proposes a way to mitigate the negative environmental and economic impacts of flood while making it possible to benefit from the positives such as increased soil fertility and biodiversity, recharged groundwater and water flow to arid and semi-arid areas.
Blue-green infrastructure, or BGI, is an interconnected network of natural and semi-natural landscape components, including water bodies and open spaces, that have multiple functions such as water storage for irrigation and industry, stormwater control, water purification, and providing wetlands for wildlife habitat.
It can be applied in rural and urban areas or river catchments and is significantly different to conventional infrastructure for preventing floods, such as levies.
The concept has been successfully implemented in the Netherlands, the US, Japan and Belgium as the most effective solution to mitigate the impacts of climate change and flooding. CeRRF PhD student and civil engineer Zahra Ghofrani believes it could be particularly useful in Australia’s climatic conditions of periods of intense rainfall and drought.
“Australia faces a variety of natural disasters – cyclone, bushfire, landslide, drought and flood – but research shows that flood is the most destructive and most costly natural disaster,” Ms Ghofrani explained.
“Floods can’t be prevented, but we can do something to protect the environment, people and infrastructure.
“My research focuses on the feasibility of implementing BGI in the Australian context considering the costs and benefits in terms of biophysical environment, socio-economic systems and infrastructure to increase the resilience and sustainability of regional and rural Australia.”
Ms Ghofrani is working with local government in South Gippsland to examine the feasibility of implementing BGI in the area.
“I chose the Tarwin River Catchment in the South Gippsland Shire as my case study because it’s one of the most important regional parts of Victoria,” she explained.
“The area is very important for its farming and tourism. But, it has experienced destructive recent floods, with the most significant occurring in 2007 and 2012.”
Ms Ghofrani discovered that, like many other regional areas, South Gippsland’s system of ageing levies were not designed to face the increased volume and frequency of floods occurring under climate change.
“The levies are effective for small floods but they are often overtopped by larger, more destructive floods which, due to global warming, are happening every ten to five years, instead of once in one hundred years,” she said.
Ms Ghofrani compared the costs and benefits of upgrading the levy system to implementing BGI in the region and found that BGI was the better option.
“Reconstructing the levies would be more expensive, have a negative impact on the surrounding environment and can be used for only one purpose – to prevent floods, or mitigate their impact. BGI can provide multiple functions, from flood mitigation to water storage to protecting native vegetation and wetlands,” she explained.
“BGI is an integral component of sustainable development and an example of how working with nature, instead of against it, can maximise the positive impacts of flood and stormwater while minimising the negative impacts.”
Ms Ghofrani, who is in the final stages of completing her PhD, hopes her initial research will lead to BGI being implemented in Gippsland and other parts of Australia as real projects.
“BGI is a very new idea in Australia, so my PhD has been about demonstrating the benefits in terms of rainfall run-off reduction, water quality improvement, health and recreation. Once we show people it can work as a real application in their community, I hope to drive implementation projects that will save regional communities from the damage associated with the next major flood.”
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CeRRF PhD student Zahra Ghofrani with an example of a blue-green infrastructure (BGI) system at Deakin's Waurn Ponds Campus.