Erosion explosion: a journey down Brisbane’s most eroded creek (#92)
Sheyanne Frisby
1
,
Misko Ivezich
2
- Alluvium Consulting Australia, Fortitude Valley, Queensland, Australia
- Alluvium Consulting Australia, Byron Bay, New South Wales, Australia
- Brisbane’s Oxley Creek has been heavily impacted by sand mining in the late 20th century which has triggered major channel incision. Compounded by pressure from dense and rapid urbanisation in the catchment, Oxley Creek is now one of the most actively eroding waterways in South East Queensland with 700,000 m³ of sediment lost from 13 km of stream between 2009 and 2013. The erosion is having major impacts on water quality, instream and riparian health, built assets and the social amenity values of the urban waterway.
- We undertook a series of geomorphic investigations which occurred either side of the 2022 Brisbane flooding. This allowed us to assess erosion occurring from a single event along with undertaking a historical assessment. Other investigations included a reach scale bed grade assessment, hydraulic and sediment transport potential modelling, along with an ecosystem services evaluation.
- Broad reach scale management is required when assessing complex and highly modified systems. This includes giving consideration to sediment transport continuity through the system to understand where sediments might deposit depending on their particle size. The assessment also highlighted the importance of transboundary waterway management with Oxley Creek spanning two major local government areas and an active military training base.
- By considering the broader reach scale of a system, a better understanding of the ecosystem services impacted by stream erosion can be established. This helps to identify beneficiaries of works and potential funders by quantifying the economic benefits of rehabilitation. Demonstrating the ecosystem services provided to beneficiaries can increase the feasibility of large reach scale management options resulting in better environmental and economic outcomes.
Download Full Paper