Why did Council undertake efforts to stabilise the Nepean riverbank?

The Nepean riverbank was damaged by the flooding events of 2022. To help prevent further erosion, Camden Council undertook bank stabilisation works at four locations along the bike track at Camden.

Where were repairs completed?

The first stage of this work was undertaken on the Nepean River at the southern end of Rotary Cowpasture Reserve, Camden. This work was completed in early 2024.

The second stage of works repaired damage at three locations along the Nepean River between Belgenny Reserve and John Peat Reserve, Camden. This work was completed in September 2024.

Before - July 2023	After - July 2024

Bank stabilisation works at Rotary Cowpasture Reserve, Camden

What did the project involve?

The project included:

• Bank stabilisation and erosion control;
• Addition of large woody debris as channel roughness;
• Removal of weeds including African Olive (Olea europaea subsp. cuspidata) and African Lovegrass (Eragrostis curvulata);
• Planting riparian vegetation with local native species from the endangered ecological community of River-flat Eucalypt Forest to stabilise the bank and provide habitat; and
• Maintenance of the plants, including watering as required.
  

You can see and learn about the project on the self-guided Nepean River Waterway Walk

What is riparian vegetation?

The plants that are found along waterways are also known as riparian vegetation. This vegetation is important as it helps to stabilise the bank of the waterway, slowing the flow of stormwater, preventing erosion, and filtering out pollutants. It also provides food and habitat for both land and water-based animals including birds, fish and frogs and provides a corridor that allows connectivity of plants and animals. The shade from vegetation can help to stabilise the water temperature and reduce the likelihood of algal blooms.

What is River-flat Eucalypt Forest?

River-flat Eucalypt Forest is recognised as an endangered ecological community under state and national environmental legislation and has been in decline due to pressures of land clearing, grazing and invasive plant and animal species. While forests were found across coastal floodplains and river flats in NSW and Victoria, there is now less than 30% of the original area remaining. This vegetation community has an important function in the Nepean River biodiversity corridor by supporting local ecosystems and the surrounding landscape.

Some of the most notable species in this community are:

• Forest Red Gum (Eucalyptus tereticornis);
• Cabbage Gum (Eucalyptus amplifolia);
• Rough-barked Apple (Angophora floribunda); and
• Broad-leaved Apple (Amplifolia subvelutina).

The iconic and critically endangered Camden white gum (Eucalyptus benthamii) is also associated with this community.

Funding

Funding for this project was assisted by NSW Government through its Environmental Trust, and jointly funded by the Australian and New South Wales governments under the Disaster Recovery Funding Arrangements 2018.

Council entered into an agreement with Sydney Water to deliver a bank stabilisation project along a section of the Nepean River at Fergusons Land Cricket Facility. The project is part of a pilot project to offset nutrients released into the environment from Sydney Water’s wastewater treatment plants.

What did the area look like before?

The project site covered an area up to 200 metres along the Nepean River within the Fergusons Land Cricket Facility, located off Exeter Street, Camden.

This site was selected as it had experienced severe erosion, with some parts experiencing more than 30 metres of riverbank retreat since 2016. Measurements showed that more than 13,700 cubic metres of soil was lost between December 2021 and July 2023 due to the impacts of flood events. That’s enough material to fill almost five and a half Olympic sized swimming pools!

Site Location- the blue areas show the extent of the project work. 

What works were completed?

The on-ground component of these works were completed mid-October 2023 and involved:

• Ecologist surveys;
• Removal of almost 6 tonnes of flood debris;
• Removal of approximately 10,000 m² of woody weeds including African Olive (Olea europaea subsp. cuspidata), Honey Locust (Gleditsia triacanthos), and Broad-leaved and Small-leaved Privet (Ligustrumsp.);
• Earthworks to obtain a more stable gradient, maintain flood conveyance and reduce erosion caused by overland flow;
• Installation of two engineered log jams, two natural timber revetments, and three timber structures preventing bank toe erosion;
• Installation of rock ballast, log structures and timber pins along the bank face secured with marine grade steel cabling;
• Planting of 27,000 native plants from the endangered ecological community of Cumberland River-flat Eucalyptus Forest, including 25 critically endangered Camden white gums (Eucalyptus benthamii); and
• Installation of herbivore-proof fencing.

Timber for the project was sourced from the Transport for NSW M12 project. This provided a great opportunity to effectively reuse waste as part of a best practice riparian restoration project.

How will these works help the Nepean River?

The bank stabilisation works at Fergusons Land will provide numerous benefits to the Nepean River including:

• Reduced erosion and soil lost from the Fergusons Land bank;
• Reduced nutrients entering the Nepean River during storm and flood events;
• Replacement of woody weeds with native vegetation from the endangered ecological community of River-flat Eucalyptus Forest which provide better biodiversity value, stabilise the soil, and provide resistance during flood events;
• Protection against overland flows draining from Fergusons Land;
• Reduced flow and erosive potential of flood waters across the bank; and
• Improved fish habitat and habitat for other aquatic and terrestrial species.

This best practice riparian restoration project was led by NSW Soil Conservation Service.

Before- April 2022	After- January 2024

Funding

Sydney Water fully funded the restoration of the 200-metre section of eroded and degraded riverbank within the Fergusons Land site. Sydney Water will continue to undertake maintenance and monitoring of the project site for 10 years.

Who can I contact if I have any questions?

For more information about the project, contact Council’s Catchments Project Officer on 13 22 63 or sustainability@camden.nsw.gov.au.

Additional Resources

Site Plan for the Fergusons Land Project 

Hook, Line & Measure is a new citizen science project developed by Council that encourages the community to identify and record the species, size and distribution of fish caught and observed in the Nepean River and other local waterways in the Camden area.

This project helps the community to identify areas for recreational fishing activities and assists Council in collecting baseline data to better understand our waterways and inform the delivery of future waterway projects.

To contribute to the project or view the dashboard, visit the Hook, Line & Measure webpage.

River Snap is a citizen science project dedicated to promoting awareness and advocacy for healthy freshwater ecosystems. Using photos sent in by the community, the program monitors the Hawkesbury-Nepean River system over time at key sites along the river, including one in Camden on the Nepean River. This long-term monitoring provides information on environmental indicators, such as water quality, riparian health, bank morphology, patterns of engagement and recreational use.

To submit your photograph, click here.

To support Camden residents’ desire to fish on the Nepean River, Camden Council installed fish habitat structures and erosion control measures to promote the increase in population and passage of Australian Bass.

What did the area look like before?

The Nepean riverbank near Burrell Road, Spring Farm was heavily degraded by impacts from flooding, overland flow, and inappropriate vehicular access.

The existing bushland was of high-quality River-Flat Eucalyptus Forest. After flooding in 2021, the bank experienced mass failure and weeds began to establish.

What works were completed?

The project works were completed in August 2023 and included:

• Earthworks to obtain a more stable gradient, maintain flood conveyance and reduce erosion caused by overland flow;
• Bank stabilisation and erosion control;
• Addition of large woody debris as fish habitat;
• Removal of weeds, such as balloon vine (Cardiospermum grandiflorum);
• Planting over 2,600 native plants to stabilise the bank, provide habitat and help restore the endangered ecological community of River-flat Eucalyptus Forest.

Timber and rock for the project was sourced from the Transport for NSW M12 project. This provided a great opportunity to effectively reuse waste as part of a best practice riparian restoration project.

What are snags and why are they important?

Snags, also known as large woody debris, are trees, branches and root masses that end up in rivers from floods, bank erosion, wind, or limb shedding. This natural process provides important habitat for aquatic life, especially native fish which rely on snags for refuge during fast river flows, shelter from predators, as landmarks for navigation, to define territories, as ambush sites, and for hosting eggs during breeding.

Snags are also important for water bugs which live amongst the wood and feed on the wood or on the microbes and algae growing on it. The sensitive water bugs that rely on these habitats are essential indicators of good water quality.

These woody structures are also used by reptiles, amphibians, insects, and birds. They are also important in improving the hydraulic diversity of the river, and in providing bank toe protection and stability.

Why is vegetation important?

Vegetation is important for stabilising banks, providing habitat for land-based and aquatic animals, and providing shade to water. Did you know that over 40% of the Australian Bass diet can come from insects falling off overhanging vegetation?

Some facts about Australian Bass (Macquaria novemaculeata):

• Usually reside in freshwater rivers, lakes and streams and migrate to estuarine waters to spawn;
• Are found in south-eastern coastal rivers;
• Eat fish, crustaceans and other invertebrates and are considered general purpose carnivores;
• Can be up to 4kg in weight and 60cm in length; and
• Are very popular for recreational fishing.

Before- May 2023	After- June 2023

Community Planting 

The community assisted the rehabilitation of the site by planting 1,500 native plants local to the endangered ecological community River-flat Eucalyptus Forest. The “Plant Trees to Help Fishies” event had 55 volunteers and had three Camden SEED Network schools participate in colouring in the cardboard tree guards.

How can I help?

There are many ways you can help the success of this fish habitat project.

• Keep your vehicles out of Council’s reserves and bushland. Vehicles cause damage to natural areas by compacting the soil and preventing root migration, strip the surface off grasses and soil stabilising plants, introduce pollutants into the natural environment, and cause channelisation from wheel ruts.
• Join Council’s Bushcare program. There are groups located in Spring Farm and along the Nepean River.
• Be a responsible fisher
  
• Participate in citizen science through Hook, Line & Measure
• Plant native species in your garden
• Ask your school to be part of the Camden SEED Network to be the first to know about revegetation projects.

Funding

Funding for this project was assisted by NSW Department of Primary Industries Fisheries’ Recreational Fishing Trust’s “Habitat Action Grant Program”, which is financed from funds generated through collection of the recreation fishing licence fee in NSW.

Who can I contact if I have any questions 

For more information about the project, contact Council’s Catchments Project Officer on 13 22 63 or sustainability@camden.nsw.gov.au.

Additional resources 

Final Concept Design - Nepean River Bass habitat at Spring Farm

Project Flyer - Nepean River Bass Habitat at Spring Farm