Blue Mountains swamps

Blue Mountains Swamps are a biologically diverse plant community that occurs nowhere else in the world. The vegetation in these swamps range from low buttongrass clumps to large shrubs such as Hakea and Grevillea species. The swamps provide essential habitat to several threatened species, such as the Blue Mountains Water Skink (Eulamprus leuraensis) and the Giant Dragonfly (Petalura gigantea).

 

Blue Mountains swamps play a vital part in maintaining the water flows in the Greater Blue Mountains World Heritage Area's creeks and waterfalls, by storing water and slowly releasing it over time. Swamps also act as filters, purifying water prior to the release into creeks. Other threatened species such as Epacris hamiltonii and Pherosphaera fitzgeraldii rely on the continued seepage from hanging swamps for survival in their specialized habitats.

There are less than 3,000 ha of Blue Mountains Swamp in existence. As they predominantly comprise many small areas, they are very susceptible to edge effects.

As the urban footprint expands to the edges of the plateau, the swamps are coming under ever increasing pressure.

The predominant threats to Blue Mountains Swamps are:

  • Channelisation and tunnelling from stormwater discharges
  • Sediment deposition and nutrient enrichment
  • Weed invasion
  • Clearing for urban development
  • Mowing
  • Grazing
  • Water extraction (bores, tapping natural springs and building dams)
  • Fire (both ‘wild’ and hazard reduction).

Stormwater-treatment-structure-above-Wentworth-Falls-Lake-swamp.jpg

Image: Stormwater treatment structure above Wentworth Falls Lake swamp

Why are Blue Mountains Swamps often called Hanging Swamps?

One generally expects swamps to occur in low lying flat areas with poor drainage. However, Blue Mountains swamps often ‘hang’ on steep valley sides where logic would suggest they shouldn't be able to occur. They are able to form because of the unique geology of the upper and mid Mountains.

Rainwater penetrates the soil and then starts to seep through the permeable Narrabeen sandstone layers. However when the water reaches the thin layers of impermeable claystone and ironstone interspersed among the thicker layers of Narrabeen Sandstone the vertical passage of water is impeded resulting in the water being shunted sideways.

Where the impermeable layers outcrop on the valley sides the groundwater trickles out continuously providing the constant moisture required to maintain swamp vegetation. Over millennia the peaty swamp soils develop from the decay of the swamp vegetation and start extending down the slope.

Have a look at a hanging swamp from a distance and often the distinctive line of the impermeable claystone layer can be seen at the top of the hanging swamp. The abrupt and distinctive loss of trees in the swamp vegetation layer, which are unable to survive in the constantly wet conditions below the seepage line is also characteristic.

A long, successful and ongoing history of swamp remediation

‘Save our Swamps’ (S.O.S) program
Blue Mountains City Council's Upland Swamp Rehabilitation Program was commenced in 2006 after Blue Mountains Swamps were listed as part of the federally listed Temperate Highland Peat Swamps on Sandstone endangered ecological community, with the aim of protecting and restoring Blue Mountains Swamp across the local government area (LGA).

In August 2008 Blue Mountains City Council and Lithgow City Councils formed a partnership to deliver the ‘Save our Swamps’ (S.O.S) project to restore Temperate Highland Peat Swamps on Sandstone across both LGAs supported by grant funding of $250,000 over 3 years from the Urban Sustainability program of the NSW Environmental Trust.

The ‘Save our Swamps’ project has been assisting in the management and conservation of the nationally threatened Temperate Highland Peat Swamps on Sandstone ecological community across the Blue Mountain and Lithgow LGAs. The SOS project has delivered a three part program that includes

  • education and community awareness raising
  • community and agency capacity building and;
  • an on-ground program of Temperate Highland Peat Swamps on Sandstone EEC (THPSS) swamp rehabilitation across both LGAs.

In 2009 the ‘Save our Swamps’ project received a $400,000 federal ‘Caring for Country’ grant to expand the program to incorporate Wingecarribee Shire Council and Gosford City Council. The partnership of the four councils resulted in the ‘Save our Swamps’ model being rolled out over 95% of the extent of the THPSS EEC.
 
The innovative integrated and landscape scale approach to the management of THPSS has resulted in the ‘Save our Swamps ‘project receiving four awards including:

  1. National Governments Local Government Award for Innovation in Natural Resource Management 2010
  2. United Nations World Environment Day Award for Excellence in Overall Environmental Management 2011 (Special Commendation)
  3. NSW Sustainable Cities award for Biodiversity Conservation 2010
  4. National Keep Australia Beautiful (Tidy Town award) for Biodiversity Conservation 2011

The Save our Swamps project has become an integral and ongoing part of BMCC’s Natural Areas Management Program.

In 2015 Blue Mountains City Council partnered with Central Tablelands Local Land Services to successfully apply for a 10 year $742,500 NSW Environmental Trust Save our Species Partnership grant to deliver the ‘Swamped by Threats’ project. This project will protect the swamp habitats, of two iconic and endemic threatened species, the Blue Mountains Water Skink and the Giant Dragonfly, across the Blue Mountains and the Newnes Plateau. In the Blue Mountains, $353,750 is allocated to improving the habitat condition and resilience of 16 priority swamp systems managed by BMCC, by undertaking bush regeneration, weed control and revegetation works and installing stormwater mitigation and water quality improvement treatments at stormwater outlet points discharging into these swamp systems. This long term project will run from 2016-2026.

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Image: Stormwater treatment structure above Wentworth Falls Lake swamp

Soft engineering for swamp remediation

As part of a collaborative approach to information and skill sharing the practical knowledge and lessons learnt from the Save Our Swamps project, BMCC has developed a practical set of guidelines entitled
 
Download the 'Soft engineering solutions for swamp remediation: 'how-to' guide' below
 
This publication comprehensively covers soft engineering swamp rehabilitation applications, techniques and materials. It also covers background information on swamp geomorphology, threats and impacts to Temperate Highland Peat Swamps on Sandstone swamps.

Current restoration works

Current works under the program include the installation of stormwater mitigation and water quality improvement treatments at stormwater outlet points discharging into swamp systems (including hard and soft engineering solutions), bush regeneration and weed control works and plantings at the following council managed sites:


•    Connaught Road Swamp, Blackheath 
•    Yosemite Swamp , Katoomba 
•    Marmion Road Swamp, Leura 
•    North St Swamp, Katoomba
•    Gully Swamp, Katoomba
•    McCrae’s Paddock  Swamp, Katoomba 
•    Leura Falls Swamp, Leura
•    East Leura Swamp, Leura
•    Jamison Creek Swamp, Wentworth Falls
•    Wentworth Falls Lake Swamp, Wentworth Falls
•    Franks Creek Swamp, Wentworth Falls
•    Kittyhawke Swamp, Wentworth Falls
•    Duperry and Clarendon Swamp,  Wentworth Falls
•    Red Gum Park Swamp, Bullaburra
•    Lawson Pool Swamp, Lawson
•    North Lawson Swamp, Lawson