Reef Catchments has been working with Australian Rivers Institute Geomorphologists collecting field data from areas of streambank failure along the O’Connell and Andromache Rivers as part of the Reducing Sediment Pollution in Queensland Project, which is being undertaken across three Queensland Catchments.
The aim of this research is to develop an integrated channel and catchment erosion model, tailored to Queensland conditions, which can be used to efficiently target rehabilitation actions throughout the state.
Researchers, with the assistance of Reef Catchments staff and volunteers from our regional Landcare Groups and CQUniversity, conducted Rapid Geomorphic Assessments (RGAs), Jet Testing, and Borehole Shear Tests, collecting data that will be input into the erosion model.
What’s an RGA?
A Rapid Geomorphic Assessment involves:
- Determining the relative stability index of the bank by completing a channel-stability ranking scheme assessment.
- Recording the species of vegetation present (including location, height, structural form, percentage cover and root information).
- Collecting streambank/terrace information such as bank heights, slope length and angle, the type of material present, moisture content, the compressive strength of the soil, shear strength of the bank, root density, and maximum depth of exposed roots.
These assessments are a quick geotechnical investigation which gives an idea of soil strength and the point at which shear resistance will be exceeded and streambank failure will occur.
Thanks to O’Connell River and Andromache River land managers
Reef Catchments and the Australian Rivers Institute researchers would like to extend a big ‘thank you’ to the wonderful land managers who have made the project possible by providing access to the rivers through their land, which has been very much appreciated.
The next steps
The research team have moved north to the Normanby Catchment but will be returning around the end of November to complete the project in our region.