Alluvium’s restoration planning work on the Fitzroy River has informed two of Australia’s largest streambank stabilisation projects resulting in an estimated 50,000 tonnes per year of fine sediment from reaching and impacting on the Great Barrier Reef.

The challenge

The Fitzroy Basin, in Central Queensland, drains into the Great Barrier Reef lagoon near Rockhampton. The floodplains of the lower Fitzroy River have undergone extensive changes since European settlement in the area. The removal of floodplain and riparian vegetation and the introduction of stock to the landscape have reduced bank stability and increased erosion. Significant erosion has occurred throughout the catchment since the 1950s resulting in excessive sediment loads being delivered to the Great Barrier Reef.

Sediment plume at the Fitzroy River Queensland

Sediment plume at the Fitzroy River mouth following the flood event associated with tropical cyclone Debbie in March 2017 (Source: ABC News)

The project

Alluvium worked with the Fitzroy Basin Association and other stakeholders, including local and state government, to develop a restoration plan to reduce sediment loss and improve riverine ecosystem health. We undertook a detailed river morphology assessment and development of a restoration plan for the lower 200 kilometres of the Fitzroy River. Our work on the project involved:

  • the classification of the geomorphology, geomorphic units and riparian condition within the river
  • multi-temporal spatial analysis of LiDAR (light detection and ranging) data and aerial imagery to determine areas generating high volumes of fine sediment
  • helping implement streambank stabilisation projects at several high priority sites identified in the restoration plan, including project scoping, detailed design, landholder engagement and agreements, environmental approvals, contractor management and construction supervision.

Ecological benefits

Since 2019, there have been several major stream bank stabilisation projects implemented at high priority erosion sites identified in the plan. Two of which include Yaamba (known as Site 7) and South Yaamba (known as Site 8).

Yaamba (Site 7)

The Yaamba stream bank stabilisation project is one of the largest ever undertaken in Australia. It has had some significant benefits for the environment:

  • Saving 30,000 tonnes per year of fine sediment from reaching the Great Barrier Reef
  • 1.2 kilometres of riverbank stabilised to reduce erosion
  • Protection of habitat for endangered species such as the White-throated Snapping Turtle and Fitzroy River Turtle
Fitzroy River site immediately following bank stabilisation works.

Fitzroy River (Site 7) immediately following bank stabilisation works.

Fitzroy River site one year after bank stabilisation works.

Fitzroy River (Site 7) one year after bank stabilisation works.

 

Before during after bank stabilisation Fitzroy River

Before (left) and after (middle and right) stabilisation works on the Fitzroy River – Alluvium undertook all stages of the project from project scoping, project design, landholder engagement and agreements, environmental approvals, contractor management and construction supervision.

South Yaamba (Site 8)

The South Yaamba site is in progress with work started by the Fitzroy Basin Association in 2021. The aim of the site works is to stop over 20,000 tonnes of sediment per year from entering the Great Barrier Reef lagoon. Site works will include:

  • Removal of 81.500 cubic metres of soil, to be reused on a landholder’s property for flood mitigation and animal safety.
  • Installation of 1,300 wooden piles to mitigate erosion
  • Over 10,000 tube stock trees planted for long-term erosion control
A near vertical eroding bank at Site 8, prior to stabilisation works.

A near vertical eroding bank at Site 8, prior to stabilisation works.

Site * Fitzroy River bank stabilisation site works installation of a rock chute.

Site 8 works on river bank during construction

Site 8 works during construction with a reprofiled bank (above) and installation of rock chute and timber pile fields (below).

 

Timber pile fields for bank stabilisation.

Funding and delivery

The stream bank stabilisation project was delivered by the Fitzroy Basin Association and Alluvium and jointly funded by the Australian and Queensland Governments under the Natural Disaster Relief and Recovery Arrangements.

The Fitzroy Water Quality Program (Site 8) is funded by a partnership between the Australian Government’s Reef Trust and the Great Barrier Reef Foundation with support from the Fitzroy Basin Association, Greening Australia, Verterra and Catchment Solutions.

Further information

For more details about Alluvium’s expertise in river health and water resource see Our Projects for more case studies.