Wetland Management
Restoring a Hanging Swamp in the Blue Mountains
Author:
Trish Chadwick
Catchment Officer
Hawkesbury Nepean CMA
The project site consists of a Blue Mountains hanging swamp that spans eight private and a council-owned properties at Blackheath. Hanging swamps in this region are important because of their function in the catchment as water filters and areas that hold water longer, higher up in the catchment, allowing all downstream areas to benefit from a more gradual flow. They also provide a variety of habitat for different flora and fauna, some of which depend entirely on hanging swamps.
Currently the wetland is in poor condition with very little remaining native vegetation, ongoing stormwater erosion of the soil base, and an active headcut at the face of the swamp where it joins Centennial Glen Creek.
Project Aim
The Hawkesbury Nepean CMA’s Wetland Management Program works across the entire catchment to conserve and/or improve wetlands by providing funding and technical advice for projects.
The aim of this hanging swamp restoration project is to reduce the rate of erosion of the wetland by revegetation and weed control. Upstream works will include reinstatement of wetland function by incorporation of sterilised straw bales into the erosion gully that has incised the swamp, and revegetation with plants of local provenance.
While this is a degraded site and not the highest priority for the CMA’s Wetland Program, the potential for participation of up to eight property owners has helped get this project up and running.
The Project solution
where some of the worst problems occur due to the cumulative impacts at the downstream location. He decided to get more property owners involved after hearing about Hawkesbury Nepean CMA’s funding on the local community radio.
Property 1: The Hawkesbury Nepean CMA provided funding for soft engineering materials (such as coir logs, sterilised straw bales, stakes, etc) to place into the eroding face of the swamp to assist with slowing the loss of soil. Funding has also been provided to assist with the employment of professional bush regenerators to remove holly, honeysuckle, privet and other weeds that are invading both the swamp and the buffer vegetation zone. Further funds have been provided for plants, to assist with revegetation in the fringing vegetation, or on the banks of the swamp.
The CMA has provided $8,360 for the project while the property owner is contributing around $11,300. This property owner had carried out considerable weed control work prior to the Hawkesbury Nepean CMA’s involvement, with an estimated value of about $20,000.
Looking downstream towards the start of Centennial Glen Creek across the hanging swamp, showing the northern bank where revegetation will be undertaken.
Property 2: Blue Mountains City Council has become involved in the project as the road easement immediately upstream from Property 1 has similar weed problems. This project has been funded by the Hawkesbury Nepean CMA for $5,320 with an in-kind contribution from Council of $6,200. Weeds will be controlled on the swamp and the stormwater inflow will be treated for weeds and erosion which may be causing some sedimentation in the swamp.
Properties 3-8: The remaining properties upstream have been approached by mail to become involved in the project. Some owners have responded and further efforts will be made to involve all owners so that rehabilitation can be achieved across the whole swamp.
The upper part of the hanging swamp showing weed infestation.
