Revealing how wetland restoration changed the shape of the Grampians bushfire

As we await the arrival of some genuine breaking rains across south-eastern Australia, the cooler weather alone is finally helping to ‘close the door’ on what has been a long and difficult fire season across many of the places where NGT is most active. The lack of rainfall, high temperatures, and regular bouts of dry lightning have created a potent mix of fire weather across southern SA, western Victoria, and parts of Tasmania.

As we reported back in January, NGT experienced large-scale bushfire impacts on one of our reserves for the first time, when the December 2024 Grampians bushfire emerged from the south-eastern corner of the National Park, and travelled through the southern part of the Walker Swamp Restoration Reserve.

Now, with the benefit of hindsight, it is interesting to take a closer look at the pattern of the fire scar in this area, which looks like this…

For those of you not familiar with the fire and its direction of travel, the shaded fire scar above shows how the fire travelled from the Grampians National Park (top left) in a south-easterly direction towards Glenthompson, under the influence of a hot north-westerly wind. Thankfully, firefighters managed to pull up the blaze in farm paddocks before it reached Glenthompson, much to the relief of local residents.

However, if you take a closer look, do you wonder why the fire front narrows where it exits the National Park – before burning through the southern portion of the Walker Swamp Restoration Reserve? Indeed, this is despite the area of the Wannon River alluvial fan north of Brady Swamp having burned intensely hot, as shown below

Well it turns out that the change in fire spread in this area was due to the presence of two wetlands previously restored by NGT: Gooseneck Swamp (labelled 2) within the Grampians National Park, and Brady Swamp (labelled 3), which straddles public and private land. Walker Swamp proper (labelled 1) ended up being just to the north of the path of the fire, but is also marked for reference.

The close-up of the fire scar image, shown above, includes arrows to show the direction of travel of the fire, under north-westerly winds. This clearly shows (a) how the bed of Gooseneck Swamp didn’t burn, which likely slowed the bushfire momentarily, although it did ultimately manage to pass around and leapfrog this smaller wetland, but also (b) how the much larger Brady Swamp ended up providing a very successful natural ‘firebreak’.

At the time of the fire, while there was a small, shallow area of water left in Brady Swamp, the full extent of both wetlands remained lush and green due to the retention of sub-surface moisture in the wetland sediments, which in turn meant that the wetland vegetation had not fully dried off and retained a high moisture content.

I took the oblique image below a couple of weeks after the bushfire passed through, looking north-west towards the National Park, in the direction that the fire travelled from. Here you can see that the green tinge on both Gooseneck and Brady Swamp, which prevented them from burning, is still clearly evident, despite the intense heat of the recent fire nearby. This image also illustrates just how much wider the fire front could have been if the vegetation in Brady Swamp had burned and allowed the fire to carry to the other side, which would have burned a vastly greater area of farmland and increased the risk to the nearby township of Glenthompson.

While every fire is different and there is no guarantee that things would play out exactly the same way next time, it is apparent to us (and also to our farming neighbours who own part of Brady Swamp), that on this occasion wetland restoration was a key ingredient in limiting the impact of this particular bushfire outside of the National Park on private farmland and beyond.

That is because for the last 10 years, since we permanently restored the natural sill level level of both Gooseneck and Brady Swamps back in 2015, we have enabled these wetlands to regularly hold water to their natural full supply level for the first time in several decades – also resulting in retention of soil moisture for longer after every flow season, compared with their previous artificially drained state. So despite 2024 being a poor year for rainfall and flows, both wetlands still managed to enter the summer months with a much greater moisture buffer and in better shape than would have been the case if these wetlands had remained artificially drained.

While we tend to focus on how magnificent restored wetlands look when they are full, at their very best and teeming with life, this story illustrates how restored wetlands can also play an incredibly important bushfire protection role, even in the drier years. In the context of concerns about changing climatic patterns, this is another element of the wetland restoration story that is definitely worth talking about!

PS – by the way, if you would like to be reminded of the work that NGT did all those years ago to restore these wetlands:

• you can click here to see the works that permanently restored Brady Swamp by completely removing the bypass drain parallel to the Wannon River.
• you can click here to learn more about the restoration of Gooseneck Swamp, NGT’s very first restoration project in this neighbourhood, and the catalyst for so many wonderful outcomes that have unfolded over the years since.