Swamps! Incredible places whose soil is regularly wet or even underwater, rich in biodiversity, amazing creatures like giant dragonflies and strange and sometimes unappealing scents (at least to us humans).

The Illawarra is home to swamps in low-lying coastal areas, such as Korrongulla Swamp and Korrongulla Wetland, which would be familiar to most people who live in the area.

Less-known and less visited are the upland swamps that occur in depressions and along waterways on the high sandstone country in the west of the region. It seems almost surprising to know that the area up the top of the escarpment is home to damp, boggy, water-retaining swamps. But they comprise one of the 20+ ecological communities that call the Illawarra home. 

Some of these swamps are included in the Dharawal National Park, where they can be seen adjacent to Maddens Creek on the short and very enjoyable walk from Darkes Forest Road to Maddens Falls.

A raised walkway allows people to wander through without damaging the highly diverse and fragile heathland vegetation. The permanently moist soils of coastal upland swamps are home to some spectacular and interesting plants such as Christmas Bells (Blandfordia nobilis), Red Spider-flower (Grevillea oleoides), Dog Rose (Bauera microphylla) and many more. 

These swamps are part of the catchment for O'Hare's Creek, which is listed in the Directory of Important Wetlands in Australia.

They provide habitat for a wealth of fauna, including several threatened species, such as the Eastern Bristlebird and the Giant Dragonfly (Petalura gigantea), with a wingspan of up to 11cm. Although it is one of the largest dragonflies in the world, it is actually only the third-largest in Australia. It may stay in its larval (non-flying) stage in underground burrows for up to 10 years, while the adults, which emerge in spring, only live for a single summer. It requires permanently swampy or boggy conditions for its survival. Beyond that, the swamps play an important role in safeguarding Sydney's water supply, with the dense soil absorbing huge amounts of rainfall in wet conditions, which are subsequently allowed to flow through the landscape. 

The majority of coastal upland swamps in this region are inaccessible to the general public because they are located in designated 'special areas' for the purpose of protecting the Sydney water catchment. You'll see several signs indicating the boundary of these special areas as you head along Darkes Forest Road towards the Maddens Falls bushwalk. Severe penalties apply for anyone found inside the special areas without permission. 

The upland swamps certainly need protection, because they are classified as endangered under the NSW Biodiversity Conservation Act. And unfortunately some of the threats to their survival are increasing in severity.

Second-listed on the NSW Government's profile for this ecological community is anthropogenic climate change, which is already playing havoc with global and local temperatures, seasons and rainfall regimes. The listing indicates that many species and ecological communities will be unable to adapt unless they are able to move to more suitable conditions; given the topographically unique situation of these swamps, migration seems unlikely.

The first listed threat to upland swamps is "alteration of habitat following subsidence due to longwall mining". The listing reports numerous significant environmental harms resulting from subsidence, including in the Illawarra region, where negative impacts have been recorded for Flying Fox Creek, Wongawilli Creek, Native Dog Creek and Waratah Rivulet.

According to the listing: "The usual sequence of events has been subsidence-induced cracking within the streambed, followed by significant dewatering of permanent pools and in some cases complete absence of surface flow.

"Over time, areas of altered hydrological regime may experience a modification to the vegetation community present, with species being favoured that prefer the new conditions. The timeframe of these changes is likely to be long-term." 

In other words, subsidence caused by longwall mining may lead to the destruction of upland swamps. 

These coastal upland swamps within the Illawarra region are unique and limited in number. And once undermined, there seems to be no reliable way to restore them. Prevention of further ham seems to be the obvious way forward to protect them and their unique biodiversity.

It's just amazing to think that, perched hundreds of metres above the city of Wollongong, hanging swamps hang on. 

References

• NSW Office of Environment and Heritage (2000), Anthropogenic climate change - key threatening process listing, accessed 7 September 2025. 
• NSW Office of Environment and Heritage (2005), Alteration of habitat.
• NSW Office of Environment and Heritage (2024), Coastal Upland Swamp in the Sydney Basin Bioregion - profile, accessed 7 September 2025.
• NSW Office of Environment and Heritage (2025), Giant Dragonfly - profile, accessed 7 September 2025.