Short Virtual Presentation & Digital Poster 10th Australian Stream Management Conference 2021

If there’s something strange in your neighbourhood: informing management of fluvial erosion and deposition using multiple LiDAR captures (#99)

James Grove 1 , Paul Reich 2 , Shane Brooks 3
  1. School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Parkville, VIC, Australia
  2. Department of Environment, Land, Water and Planning, Melbourne
  3. Brooks Ecology & technology, Warrandyte South
  • Assessment of a rivers physical form has been based on an observation of a single point in time to infer processes, or analyses of discrete cross-sections. The assumption often made is that observed processes will continue, such as riverbank erosion. Management decisions have been based on this trajectory.  Assessments of condition have also been made without consideration of geomorphic river types, with the channel and floodplain managed separately. 
  • A 10-step process has been devised, guiding managers through questions to aid decisions on appropriate physical form objectives. The method scopes a perceived problem, using a basic river typology to consider likely river and floodplain trajectories.  To inform on these trajectories an analysis was undertaken on how multiple LiDAR DTMs of Difference (DoDs) can be used to provide data on volumes of erosion/deposition.  Regions of clustering in these data were also examined, identifying high volumetric changes that may be management concerns. 
  • A study on the King River, Victoria showed that a standard approach should be taken when using LiDAR DoDs. Data can be reported for each time period on the areas, volumes, and rates of erosion/deposition.  The total time, from first to last LiDAR capture, should also be reported.   To identify clusters the erosion and deposition data should be separated.  Rather than setting threshold volumes or rates of change as a trigger for management clustering is a more objective approach. 
  • Future river management needs to include a consideration of volumes of erosion and deposition, with the channel and floodplain combined.
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