Riverbank Stabilisation

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With the assistance of NSW Department of Primary Industries Fish Habitat Action Grants, MidCoast Council has been working closely with local landholders to solve riverbank erosion problems across the Manning River estuary and to improve habitat conditions for native fish.  

2018/19 saw the construction of 1.3 km of rock fillets to protect our riverbanks at Lansdowne and on Oxley Island.

Rock fillets create mini lagoons that provide a sheltering environment for aquatic vegetation such as mangroves and saltmarsh to establish.

The immediate reduction of sedimentation performed by rock fillets also create an environment suitable for the establishment of seagrass communities.

Mangroves, saltmarsh and seagrass vegetation are of paramount importance in providing habitat structure and ecological requirements for fish stocks in our estuary.

Hand in hand with riparian revegetation, landholders have also fenced off over 2.5 km of river bank and planted 3000 native trees.

Once established the root system of these trees will help bind the bank together creating further resilience against erosion and the insects that drop off these trees into the river will become an additional tasty resource for our fish.

The Fish Habitat Action Grants are funded from the Recreational Fishing Trusts with the purpose of on ground actions to improve fish habitat for recreational fishing in NSW.

This year’s work complements the 3.5 km of stabilisation and restoration works Council has undertaken in the Manning River estuary over the past 5 years.

Ongoing bush regeneration and weed maintenance will ensure the benefits of these works are sustained well into the future.

 

 

To help combat riverbank erosion on the Manning, over the past 12 months a total of 1.65 km of riverbank at Dumaresq and Oxley Islands has been stabilised. A combination of different methods has been utilised, including rock filleting (1.12 km), stock exclusion fencing (1.65 km) and the revegetation of the riparian area with 1,816 native plants. 

This complements the 2 km of stabilisation and restoration works Council has already undertaken in the Manning River Estuary over the past three years.

Ongoing bush regeneration and maintenance will ensure the benefits of these works are sustained well into the future.  

 

Works to address on-going riverbank erosion and enhance aquatic habitat at Gereeba Island in the Wallamba River were recently completed. This project utilised biodegradable coir logs made from coconut fibre to provide direct erosion control along 300m of shoreline.

In December 2017, the logs were placed on the bed of the River, stacked three high and secured with wooden stakes and coir twine to buffer the eroding riverbank from wave action caused by boat wash. Approximately 1000 Grey Mangroves were also planted and will provide permanent bank stabilisation and increase aquatic habitat in the long term once established.

The project has proven successful in the early stages. Sediment is being captured behind the coir logs and mangroves are establishing well. With a direct reduction in erosive forces, we are also now seeing a natural recruitment of River Mangroves that had not been seen on this stretch of the riverbank prior to this work taking place.

These works, which will ultimately improve water quality, have been made possible with funds from the Recreational Fishing Trusts Habitat Action Grants and MidCoast Council's Environmental Levy.

This project complements a number of projects that have come together over the years to stabilise 7.6 km of the Wallamba Riverbank. These projects have been funded through a combination of Council's Environmental Levy, Environmental Trust grants and Recreational Fishing Trust habitat action grants.

The image below shows the installation of the coir logs as part of stabilisation works on Gereeba Island.

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