Short Oral Presentation 11th Australian Stream Management Conference 2024

An integrated geoprocessing tool for assessing post-fire hydrogeomorphic risks in upland forested catchments (#31)

Kristen Joyse 1 , Thomas Keeble 2 , Jake Allen 3 , Petter Nyman 1 2 , Charlie Showers 4 , Gary Sheridan 2
  1. Alluvium Consulting Australia, East Melbourne, VIC, Australia
  2. School of Agriculture, Food and Ecosystem Sciences, Faculty of Science, University of Melbourne, Parkville, VIC, Australia
  3. Mosaic Insights, East Melbourne, VIC, Australia
  4. Bushfire and Forest Services, Department of Energy, Environment and Climate Action, Wodonga, VIC, Australia
  • Intense rainfall following bushfires can trigger debris flows, flash floods, and major water quality contamination events in forested upland environments. Current climate trends are producing conditions that increase the frequency and magnitude of these hazardous events. At the same time, communities are expanding into steep, upland environments, leading to increased exposure to hazards. Catchment managers require a tool to anticipate changes in the likelihood of post-fire catchment hazards to prepare for, rapidly respond to, and mitigate potential risks.
  • We have developed a scripted geoprocessing tool, based on the latest science and stakeholder engagement, to map the magnitude of post-fire hydrogeomorphic hazards along stream networks. The toolbox integrates into state forest management agencies’ existing data management systems and consists of a module for each of the following three hazards: (1) debris flow, (2) flash flood, and (3) water quality.
  • The debris flow module integrates a source area determination model, an initiation likelihood model, and a flow runout model to assign a likelihood to possible debris flows within a catchment. The flash flood module uses fire-induce soil modifications and catchment hydrological responses to determine the likelihood of a flash flood occurring within a catchment. The water quality module uses the Revised Universal Soil Loss Equation and debris flow likelihood to determine the water quality contamination potential over a burned area.
  • The tool provides catchment managers with easy access to a fast runtime model that can cover large spatial scales in order to protect the range of environmental, economic, geomorphic, and recreational values in upland catchments. Our tool provides catchment managers with a means to overlap spatial hazard information with values to evaluate the risk posed by post-fire hydrogeomorphic events.
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