Achieving impact

Lower Caboolture Resilience and Nutrients Offset

Lower Caboolture Resilience and Nutrients Offset

 

Offsetting nutrients, increasing resilience, improving water quality, preventing erosion, and boosting wildlife habitat.

 

Lower caboolture aerial view of boatwash and erosionResilience and nutrients offset - conquering one means conquering the other.The project is aimed to restore around 2.4 kilometres of the Caboolture riverbank with revegetation and stabilising works.

This project was funded and commissioned by Unitywater to prevent nutrients from entering the Caboolture River through bank erosion. Bank stabilisation works will improve the river's long-term resilience to flooding while providing new habitats for local fauna.

Nine sites along the river have been identified for the project, in both tidal estuaries and the upper catchment. Those sites were selected strategically to reduce streambank erosion and reduce sediment and associated nutrients from entering the waterway.

The program works include reprofiling eroded banks to create stable areas for new mangrove forests and riparian revegetation. A range of techniques has been used to protect new mangrove saplings from boatwash and allow them to mature into a robust and resilient ecosystem that will stabilise the riverbanks for decades to come. Each site uses a combination of large hardwood logs, small coir logs, or biodegradable BESE mesh to protect young mangroves and create new tidal habitats. 

 

The program focuses on:

  • Contributing to the sustainability goals of Unitywater and their commitment toward net zero nutrients.
  • Reducing the impact of additional nutrients on water quality in the Caboolture River.
  • Reduce impact on the environment and waterways, while meeting strict environmental obligations.
  • Improving habitat and environmental conditions for fish, birds, and crabs.
  • Ensure vegetation continues to hold the riverbank together while benefitting local landholders to prevent loss of land.
  • Building flood resilience for the area.

 

What we are doing

lower caboolture restoration site with stabalised banksEnsuring vegetation continues to hold the riverbank together while benefitting local landholders to prevent loss of land.

This reach-scale project aims at offsetting the nutrients discharged in the waterways and building resilience.

It involves:

  • Preserving the health of local waterways, particularly from the expected impact of future population growth.
  • Offsetting nutrient discharges from local sewage treatment plants in the Caboolture/Burpengary region.
  • Using vegetation alongside “natural engineering” solutions such as pinned logs to hold the riverbank together, preventing loss of land, maintaining the banks of the river in good condition providing benefits to local landholders and the community..

 

Measures of success

As a result of the program, nine eroded riverbank sites on the Caboolture River will be repaired by using engineering and revegetation techniques. These techniques will halt and prevent bank erosion and associated pollution of the Caboolture River and receiving waters.

Earthworks and tree planting will help prevent land loss, boost wildlife habitat, assist the community, and improve water quality. Thousands more trees will be planted to help stabilise the riverbank.

Overall, the works will build resilience for the area and preserve the health of local waterways, particularly from the expected impact of future population growth.

 

Why this project is important

Erosion affects water quality through the loss of land, loss of wildlife habitat, and increased soils and sediments in local waterways.

Unitywater is committed to operating sustainably in the community by protecting waterways and public health through strict environmental licensing agreements. 

Most nutrients that are washed out into river systems come from several main sources: treated sewage, and riverbank erosion. Treated sewage is directly connected to population growth and number. If the population grows, the sewage waste increases, hence the amount of nutrients washed out into the rivers. 

 According to population growth forecasts, the amount of nutrients that will end up in the catchments’ sewage systems will increase significantly in the next 30 years.

The population growth predictions forecast an additional need to “offset”. This offset work can contribute to corporate sustainability goals around reducing/offsetting nutrient discharge to waterways as well as environmental compliance obligations, taking measures to not cause environmental harm, and assisting the protection of Sewage Treatment Plant assets aligning with the Natural Resource Management (NRM) strategy for the river mouth shoreline.

This project will re-stabilise sections of the Caboolture River to prevent soil and nutrients from entering the water. Unitywater does this to offset the sewage treatment nutrients discharged to the river and provides a lower-cost alternative to treatment plant upgrades.

 

Project snapshot

Project name:  Caboolture River Nutrient Offset Project
Project manager:  Samille Loch-Wilkinson,  Vanessa Durand, Margie Dickson, Jordan Green & Ross Bigwood, Healthy Land & Water
Catchment:  Caboolture
Timing: 2022 – 2023
Budget: $5,163,146
Partnerships: 

This project is funded by Unitywater and run in collaboration with Alluvium, stringybark consulting, Bese, Tectonics, Converge, and Niche Environment.

Related Articles:

Lower Caboolture: nutrients offset + cutting-edge nature-based technology = resilience

 

What's next

There is huge potential to build on the successful work.

 

Project collaborators

This project is part of Unitywater's dedication to building resilience and offsetting nutrients discharged into the waterways. 

 Australian Government NLP