River Bank Erosion and the Influence of Environmental Flow Management
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Environmental flows aim to influence river hydrology to provide appropriate physical conditions for ecological functioning within the restrictions of flow regulation. The hydrologic characteristics of flow events, however, may also lead to unintended morphologic effects in rivers, such as increases in riverbank erosion beyond natural rates. This may negatively impact habitat for biota, riparian infrastructure, and land use. Strategic environmental flow delivery linked to monitoring and adaptive management can help mitigate risks. We monitor riverbank condition (erosion and deposition) relative to environmental flows on the Goulburn River, Victoria, Australia. We describe the process of adaptive management aimed at reducing potential impacts of flow management on bank condition. Field measurements (erosion pins) quantify the hydrogeomorphic response of banks to the delivery of planned and natural flow events. Managed flows provide opportunities for monitoring riverbank response to flows, which in turn informs planning. The results demonstrate that environmental flows have little influence on bank erosion and visual perceptions in the absence of monitoring are an unreliable guide. This monitoring project represents a mutually beneficial, science-practice partnership demonstrating that a traditional ‘know then do’ approach can be foreshortened by close collaboration between researchers and managers. To do so requires transparent, often informal lines of communication. The benefits for researchers–a more strategic and targeted approach to monitoring activities; and benefits for the practitioners–reduced time between actions and understanding response; mean that a learn by doing approach is likely to have better outcomes for researchers, stakeholders, the public, and the environment.
KeywordsEnvironmental flows Adaptive management Geomorphology Flow regulation Erosion Deposition
This project was undertaken by Streamology Pty Ltd as a sub-contractor to The University of Melbourne, and would not have been possible without the input of many individuals and organisations beyond the co-authorship list. For fieldwork and desktop/operational assistance the following have been of great assistance: Simon Casanelia, Megan Judd, Daniel Lovell, and Geoff Earl (Goulburn Broken Catchment Management Authority), Michael Sammonds (Melbourne University), Amanda Woodman and Ben Baker (Jacobs), Andrew Shields and Guy Ortlipp (GMW), and Kerry Greenwood (MDBA). We would particularly like to thank Iwona Conlan (formerly the CEWO), as well as Keith Chalmers and Courtney Johnson (VEWH), for input into setting up and managing this program and valuable comments on the manuscript. Finally, we would like to thank the editors of Environmental Management and this special issue.
This work was supported by the VEWH, the CEWO, and the GBCMA.
Conflict of Interest
The authors declare that they have no competing interests.
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